Chemistry
for
®
CSEC
Anne
Elizabeth
Tindale
Ritchie
Dianne
Sarah
Luttig
Chapman
Jennifer
Anna
Murray
Bowman
s s er P
ytisrevinU
dr o f x O
I N C LU D E S
fo
Edition
CD
t r aP
2nd
08/08/2014
15:43
Chemistry
for
®
CSEC
Anne
2nd
Tindale
Edition
Elizabeth
Ritchie
Dianne
Sarah
Chapman
Jennifer
Anna
1
Luttig
Murray
Bowman
3
Great
Clarendon
Oxford
It
University
furthers
and
Oxford
©
Anne
The
This
in
means,
Press,
as
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Acknowledgements
Cover
photograph:
Illustrations:
Page
make-up:
Thanks
are
due
development
Photo
8.2.1,
18.3.1,
4.4.2;
18.3.2,
9.3.1,
18.3.5,
(NT)
James
Andrew
van
PA
der
Volk
Photos
Library/Andrew
Hanns-Frieder
/Maximilian
Banton
we
copyright
cases.
the
the
this
notied,
to
for
have
Ltd
made
the
501
Gateshead
for
Vision
their
contributions
PL
C
V1
10.5.2,
4.4.1b,
/JERRY
/Pascal
2.1.3b,
effort
publication
publisher
will
CD2
14.1.4;
party
materials
the
2.2.1a,
Sandy
6.1.2,
has
rectify
18.3.3,
Marshall
8.4.6,
18.1.1,
17.2.1,
/Sue
and
not
any
contact
been
errors
all
possible
or
in
omissions
websites
only.
contained
are
provided
Oxford
in
any
by
disclaims
third
party
Oxford
any
in
good
faith
responsibility
website
referenced
for
in
22.1.1,
all
at
Mike
20.4.4,
and
15.3.5,
20.5.2;
M.
20.4.5;
Photo
/Astrid
DESIGN
and
Gallery/
Science
Baker
(NT)
15.3.10,
21.1.4;
18.3.8,
20.3.4;
/LAGUNA
3.3.2,
Picture
20.5.1,
www.tropix.co.uk/V.
trace
this
17.1.3,
8.1.1a,
Goetgheluck
17.2.2,
17.3.1,
Corel
Evans
iStockphoto
Garland
8.1.5,
17.1.2,
20.4.1;
Greg
Anne
8.1.1b,
16.2.12b,
20.5.3;
opportunity.
third
in
20.5.6;
5.5.4a,
Corbis
19.1.1;
Leslie
17.1.1,
MASON
22.2.2;
(NT)
Ltd
2.5.3,
16.2.12a,
Fotolia
1.1.3,
16.1.5,
21.2.1;
to
21.2.2,
18.3.7;
Chillmaid
2.5.2,
16.1.4,
20.4.2;
(NT)
Holdings
2.2.3b,
15.1.9,
20.6.1,
Photography
11.2.4,
/Photoshot
(NT)
Bhadur/AP
every
before
information
work.
Ltd,
Murray
2.1.3c,
9.3.2b,
Ingram
2.5.1,
Shutterstock
holders
earliest
Links
and
If
Lambert
Stock
9.1.1;
Although
/Shirley
2.2.2,
1.3.2,
20.4.3,
Corel
Martyn
2.2.3a,
Michler
1.2.9,
19.2.1,
2.1.3a;
4.4.1c;
2.2.1b,
4.4.1a,
Tech-Set
Jennifer
Rogers
Lauritz/Digital
Lambert
and
9.3.2a,
5.5.4b;
(greg@gregevans.net)
15.3.8;
Bowman
1.2.10b,
9.1.2,
18.3.4,
340
and
Gateshead
book.
1.2.10a,
8.4.8,
Corel
Anna
this
Publishing
Ltd,
Alamy/Helene
1.1.2,
8.4.2,
Tech-Set
to
of
credits:
Tindale
iStockphoto
GreenGate
Shawn
Birley
3.3.3.
Contents
Introduction
A5.5
1
Str ucture
Key
Section
A1
A
Principles
States
of
of
chemistry
2
matter
Practice
The
par ticulate
nature
of
matter
Evidence
of
solids
86
exam-style
questions
Chemical
for
t he
equations
Writing
and
and
reactions
balancing
of
The
t hree
states
of
matter
Types
of
A2.1
and
exam-style
their
Elements,
questions
separation
compounds
A2.2
Solutions,
A2.3
Solubility
96
99
14
questions
The
mole
concept
101
and
mixtures
colloids
A7.1
The
mole
and
mass
A7.2
The
mole
and
gas
101
A7.3
The
mole
and
concentration
16
volumes
106
19
of
22
solutions
A2.4
A2.5
Separating
Extraction
sugar
Key
mixtures
of
sucrose
A7.4
The
mole
and
chemical
formulae
1
1
1
A7.5
The
mole
and
chemical
reactions
1
13
Key
concepts
from
cane
30
exam-style
questions
A3.1
A3.2
structure
The
The
an
A3.3
of
electronic
atoms
configuration
Acids,
bases
The
periodic
A4.1
and
radioactivity
reactions
of
acids
121
A8.2
Proper ties
and
reactions
of
bases
128
A8.3
Strengt h
A8.4
Salts
A8.5
Neutralisation
A8.6
Volumetric
table
questions
and
of
periodicity
elements
in
A4.4
Trends
46
46
Group
II
of
in
Group
VII
t he
of
A9
Period
55
3
of
t he
Structure
Formation
A5.3
Writing
ionic
A5.4
questions
bonding
A5.2
bonding
of
ionic
chemical
bonds
formulae
compounds
Formation
metallic
of
questions
154
and
reactions
reduction
156
–
an
A9.3
Oxidising
Key
156
numbers
and
159
reducing
agents
concepts
Practice
164
170
exam-style
questions
171
62
exam-style
Chemical
Oxidation
Oxidation
periodic
concepts
A5.1
exam-style
A9.2
60
and
148
152
introduction
A10
A5
145
analysis
Oxidation–reduction
A9.1
t he
table
in
Practice
132
135
reactions
concepts
Practice
periodic
table
Key
alkalis
t he
table
in
periodic
and
45
51
Trends
acids
40
table
A4.3
of
44
Arrangement
Trends
121
and
37
exam-style
periodic
A4.2
salts
Proper ties
Key
A4
and
A8.1
of
concepts
Practice
120
34
atom
Key
questions
34
str ucture
Isotopes
exam-style
33
A8
Atomic
1
19
32
Practice
A3
108
25
concepts
Practice
100
16
and
suspensions
exam-style
15
A7
Mixtures
reactions
concepts
Practice
A2
chemical
9
concepts
Practice
89
4
Key
Key
89
par ticulate
matter
A6.2
A1.3
88
chemical
equations
t heor y
80
2
A6.1
A1.2
proper ties
2
A6
A1.1
and
concepts
covalent
bonds
Electrochemistry
173
64
A10.1
The
65
A10.2
Electrical
65
A10.3
Electrolysis
69
A10.4
Quantitative
A10.5
Industrial
of
72
and
series
conduction
176
electrolysis
applications
exam-style
188
of
191
concepts
Practice
173
179
electrolysis
Key
76
electrochemical
195
questions
197
iii
Contents
A11
Rates
of
reaction
A11.1
Measuring
A11.2
Factors
Key
198
rates
of
affecting
reaction
rates
of
reaction
concepts
Practice
exam-style
questions
C18
Reactivity,
metals
202
C18.1
The
reactivity
209
C18.2
The
extraction
210
C18.3
Uses
Energetics
212
A12.1
Energy
A12.2
Calculating
Key
changes
during
energy
reactions
changes
concepts
Practice
questions
of
B
Organic
chemistry
Introduction
to
organic
B13.1
Organic
B13.2
Homologous
217
C19
chemistry
B14.1
Sources
series
–
questions
and
extraction
Metals
224
Alkanes:
C
Alkenes:
C
alkenes
in
living
systems

of
C19.2
The
impact
metals
Alcohols,
and
alkanoic
Alkanoic
Esters:
questions
acids
C
H
and
esters
OH
2n
acids:

C20.2
Chemical
proper ties
of
C
H
COOH
2n

The
C20.5
Harmful
C20.6
uses
of
Key
253
326
330
concepts
334
exam-style
questions
336
255
Water
338
C21.1
The
unique
proper ties
C21.2
The
treatment
of
water
338
260
questions
of
water
for
pur poses
342
concepts
345
271
exam-style
questions
346
Qualitative
analysis
polymers
concepts
C22.1
Identification
of
cations
questions
chemistry
of
C17.1
Physical
C17.2
Chemical
C22.2
Identification
of
anions
351
C22.3
Identification
of
gases
354
281
concepts
Reactions
of
metals
283
compounds
concepts
Practice
282
and
metals
metal
exam-style
356
questions
358
periodic
table
360
282
of
proper ties
of
exam-style
282
metals
proper ties
reactions
347
275
279
exam-style
Inorganic
347
272
The
iv
non-metals
compounds
269
polymers
Condensation
Key
of
324
263
exam-style
Characteristics
C17.3
uses
chemistr y
Practice
C17
and
non-metals
effects
t heir
Green
Key
–
preparation
318
272
Practice
C
non-metals
321
C20.4
and
C22
Section
of
1
RCOOR
Addition
Key
316
and
255
Polymers
B16.2
non-metals
gases
Practice
B16.1
of
proper ties
Laborator y
Key
B16
315
1
concepts
Practice
questions
316
Physical
domestic
Key
31
1
313
exam-style
C20.1
C20.3
239
251
n
B15.3
environment
2n
n
B15.2
living
Non-metals
246
exam-style
Alcohols:
t he
309
on
237
C21
B15.1
of
metals
concepts
Practice
B15
the
2
concepts
Practice
308
309
corrosion
Practice
242
2n
H
n
Key
and
The
226
239
H
n
302
307
questions
C19.1
of
hydrocarbons
B14.3
alloys
236
alkanes
B14.2
t heir
230
exam-style
and
and
299
226
concepts
Hydrocarbons
294
metals
exam-style
reactions
B14
of
226
compounds
Practice
metals
environment
C20
Key
of
212
Key
B13
of
metals
systems
Section
uses
concepts
Practice
223
exam-style
and
294
Key
A12
extraction
198
288
291
questions
293
Index
361
Introduction
To
the
Chemistr y
you
student
for
achieve
experienced
for
you
The
to
CSEC®
your
is
best
teachers
master
Chemistr y
Principles
t he
a
t he
who
course
examination.
have
included
It
designed
has
been
features
to
to
help
written
make
it
by
easier
is
divided
Chemistry,
into
Section
B,
t hree
sections;
Organic
Section
Chemistry,
A,
and
Section C, Inorganic Chemistry. Chapters 1–12 of t his book cover
topics
in
Section
Chapters
17–22
A,
Chapters
cover
topics
13–16
in
the
The
cover
Section
topics
in
Section
B,
and
writing
t he
of
Chemistr y
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content
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students.
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C.
teacher
Caribbean science educators to ensure t hat bot h t he requirements of
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syllabus
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key
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CSEC®
syllabus.
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help
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develops
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concepts.
in’
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concepts.
Impor tant
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and
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boxes
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contain
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relate
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text.
t hose
You
suggested
can
use
t hese
colour
to help you develop a practical approach to your teaching and also to
photographs
to
enliven
and
enrich
your
learning,
and
a
wide
assess
range
of
different
designed
your
use
to
help
learning
some
(SBA)
practical
of
you
using
t hese
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activities.
develop
your
‘hands-on’
activities
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practical
approach.
assess
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activities
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Your
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enhance
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skills
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students.
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help
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skills.
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boxes
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student’s
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and ‘Exam tip’ boxes containing valuable tips to prepare students for
t heir
examination
appear
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t he
text.
to
Each
learn
School-Based
explanator y
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Each
t he
been
unit
begins
wit h
a
list
of
learning
objectives
for
students
to
specic
clearly
see
what
t hey
are
expected
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master
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t he
unit.
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relate
objectives given in t he syllabus. Each unit t hen ends wit h a selection
fully
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specic
objectives
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t he
syllabus.
of summary questions to test your comprehension of t he material
covered
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t he
Revision
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At
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end
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each
chapter
you
will
nd
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list
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content
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questions
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chapter.
questions
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students
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at
t he
consolidate
end
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t heir
each
unit
knowledge
which
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t he
are
key
concepts
material
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for
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unit.
list
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list
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given
content
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end
of
each
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will
encounter
during
your
examination.
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rst
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CSEC®
Examination
you
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spaces
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t he
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t he
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covered
in
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and
hone
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paper for your answers. The second is an extended response question
skills.
requiring
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greater
element
of
essay
writing
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answers.
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A
marks
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t he
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par ts
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60-question
multiple-choice
test
wit h
answers
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clearly
be
found
on
t he
CD.
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will
enable
your
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material
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entire
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taken
from
all
sections
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t he
syllabus.
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you
work
t hrough
all
t he
t he Data Analysis question toget her wit h t hree practice questions for
end
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will
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chapter
questions
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School-Ba sed
you
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study.
t his
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practise.
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Assessment
section
before
t he
skills
required
in
answering
t his
question.
CD
well
as
There
is
is
also
required
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you
t hree
It
is
questions
a
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you
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embark
on
your
wit h
whic h
in
includes
for
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students
section
to
gain
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an
provides
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understanding
of
information
what
t hem
over
t heir
two-year
programme
of
is
required
study.
mark
gives
ter ms
impor t ant
two-year
also
SBA
you
from
will
develop
whic h
about
provides
to
examination.
of
t hat
course
Chemistr y
Each
activity
SBA
may
for
CSEC®
practical
may
section
be
adopts
activity
be
used
provides
used
for
t he
a
practical
begins
as
a
t he
wit h
basis
for
location
different
a
SBA.
in
types
approach
suggestion
The
t he
of
table
book
of
wherever
indicating
which
t he
possible.
how
t he
follows
t he
activities
which
assessment.
1
Section
A
States
of
matter
A1
Chemistry
is
the
study
of
the
structure
and
behaviour
of
Objectives
By
the
be
able
end
of
this
topic
you
matter.
will
Everything
has
●
give
a
●
give
the
denition
four
of
main
matter
ideas
both
beings
of
us
is
made
of
matter.
Matter
explain
theory
why
particulate
of
and
of
and
volume.
animals
are
all
Air,
water,
matter.
sand,
Matter
human
exists
in
states.
The
three
main
states
of
matter
are
solid,
matter
scientists
theory
mass
the
various
particulate
●
around
to:
nd
the
liquid
and
gas.
matter
useful
identify
●
the
three
main
states
the
relationship
of
A1.1
The
particulate
nature
of
matter
matter
explain
●
Matter
between
temperature
and
the
As
motion
of
far
bac k
idea
a
t hat
piece
half
Exam
is
important
definitions
Chemistry.
provided
boxes
of
that
key
These
for
you
you
know
terms
in
the
the
‘Key
in
how
for
par ticles.
called
example,
many
cuts
a
will
t hought
He
Democr itus
piece
you
t hat
of
have
it
asked
gold,
to
ended
t his
developed
in
make
at
question:
half
and
before
some
t hen
you
point,
‘f
t he
cut
can
t he
you
cut
cut
it
it
smallest
in
no
and
t hat
building
t hese
bloc k s
of
smallest
matter.
bits
of
Today
matter,
scientists
or
particles ,
have
added
would
to
be
bits
t he
Democr itus’
of
matter.
book.
particulate
particulate
t heor y
is
theory
theory
ver y
of
useful
of
matter
because
matter
states
it
t hat
helps
all
us
matter
to
is
explain
made
bot h
of
par ticles.
t he
physical
fact
proper ties of matter and also t he differences between t he t hree states of matter.
We
Matter
is
anything
occupies
that
has
will
Key
that
looking
at
t he
t hree
states
of
matter
in
detail
in
Unit
A1.3.
par ticulate
matter
is
t heor y
●
all
made
●
t he
●
t here
are
spaces
●
t here
are
forces
par ticles
are
of
of
in
matter
has
four
main
ideas:
par ticles
constant,
random
motion
fact
particulate
states
be
mass
space.
The
The
philosopher
of
fact’
This
!
Greek
idea and now descr ibe matter and its proper ties using t he par ticulate t heor y
are
The
and
a
Democr itus
matter,
basic
the
used
definitions
throughout
Key
matter,
again,
The
!
BC
consisted
tip
of
It
460
matter
of
fur t her?’
✔
as
particles.
all
theory
matter
is
of
between
t he
par ticles
matter
made
up
of
attraction
between
t he
par ticles.
of
particles.
matter
of

The
is
made
par ticles
par ticles
Figure
constant
1.1.1
par ticulate
The
particulate
t heor y
of
are
theory
matter
in
there
motion
of
can
are
between
spaces
par ticles
matter
be
used
to
explain
many
physical
phenomena t hat we obser ve in our ever yday lives. Examples of some of t hese
are
2
given
on
t he
next
page.
t
explains:
States
of
The
●
and
How
is
it
Why
●
e.g.
e.g.
t he
States
density
rise
in
liquid
freezer
can
smelt
t he
get
of
of
cause
forms
gas
harder
between
it
vibrate
in
in
t he
e.g.
why
matter
pebbles
change
into
a
solid,
e.g.
when
water
side
of
you
a
room,
t he
e.g.
when
chicken
is
fr ying,
kitchen.
wit h
an
increase
in
temperature,
drive.
become
crisper
when
soaked
in
water,
liquids,
e.g.
cer tain
in
insects
can
‘walk’
on
water.

Figure
1.1.2
Pebbles
sink
in
water
matter
common
in
to
increases
as
vegetables
tension
t hese
Par ticles
gases,
of
potatoes.
of
most
and
nature
ice.
Matter can exist in various forms or
t he
liquids
t hroughout
ot her
a
solids,
particulate
water.
can
it
move
at
pressure
cer tain
raw
a
a
tyres
Surface
●
in
smell
be
car
Why
●
a
can
in
bubbles
cooling
placed
Why
●
The
difference
sink
●
matter
states
t he
t heir
liquid
are
lies
solid
xed
state
t he
solid,
in
t he
state
have
energy
have
position
states. The t hree states of matter t hat are
liquid
t he
and
medium
and
and
least
t hey
amount
are
amounts
gaseous
states.
arrangement
packed
of
of
of
t hey
difference
par ticles.
energy,
closely
energy,
The
t he
t hey
toget her.
move
simply
Par ticles
about
slowly
and t hey have small spaces between t hem. Par ticles in t he gaseous state have
t he
greatest
spaces
The
energy
par ticles
in
its
t he
faster
of
hanging
a
t hey
will
can
is
g reater
t his
directly
This
substance
The
move
study
change
temperature.
substance.
t hey
energy,
You
par ticles
matter
temperature
t he
of
t hem.
of
and
changing
t he
amount
between
one
of
increases
and
detail
to
t he
physical
state
t he
kinetic
rapidly
greater
related
from
change
t he
about
in
kinetic
t hey
Unit
to
of
par ticles
large
of
anot her
because
energ y
t he
have
1.3.
temperature
state
occurs
energy
in
t he
by
increasing
t he
par ticles
possess,
t he
move.
state
by
changing
temperature
is
a
physical
change.
A
physical
change occurs when t he form of t he substance is changed wit hout changing
its
chemical
t he
same
gaseous
composition,
chemical
state,
i.e.
Summary
1
State
2
If
a
the
of
the
water
the
3
Explain
4
What
are
5
What
is
water
in
water
t he
as
a
liquid
solid,
i.e.
state
and
ice,
as
has
exactly
water
in
t he

Figure
three
vapour.
of
main
ideas
potassium
purple
particulate
evidence
example,
as
1.1.3
states
The
of
drinks
illustrate
the
matter
questions
three
crystal
water,
for
par ticles
colour
theory
of
the
particulate
manganate( VII )
spreads
of
is
theory
dropped
throughout
matter
does
this
the
of
matter.
into
water.
a
beaker
What
observation
of
features
provide
for?
why
scientists
the
the
three
nd
states
relationship
the
of
particulate
theory
of
matter
useful.
matter?
between
temperature
and
the
movement
of
particles?
3
Evidence
for
the
particulate
theory
of
matter
A1.2
Objectives
By
the
be
able
end
of
States
this
topic
you
Evidence
for
the
particulate
theory
of
of
matter
matter
will
n t he previous unit we mentioned t hat scientists nd t he par ticulate t heor y
to:
of matter ver y useful because it allows t hem to explain t he physical proper ties
explain
●
evidence
which
of
supports
the
particulate
matter.
suppor t
of
and
the
processes
same
ideas.
time
There
t hough,
are
simple
scientists
practical
have
to
provide
activities
evidence
involving
to
d iffusion
diffusion
and
describe
experiments
osmosis
which
we
can
perform
to
provide
evidence
for
t he
existence
of
and
●
t he
t heir
matter
explain
●
At
theory
movement
of
par ticles.
osmosis
which
Diffusion
demonstrate
diffusion
and
osmosis
explain
●
sugar
and
We
the
to
uses
control
preserve
of
salt
and
garden
food
have
into
pests
items.
a
all
freshener.
t he
smell
t hrough
of
had
baker y,
All
matter
air
are
Key
Diffusion
particles
t hese
to
is
in
concentration
!
cosmetic
of
seems
t he
experience
a
smells
travel
as
a
one
of
being
or
are
of
t he
air.
of
and
a
smell,
into
at
a
This
d iffusion.
motion
lower
aware
climbing
produced
t hrough
result
constant
to
of
shop
a
point
move
t hat
in
process
Diffusion
will
whet her
car
t he
of
shop
t he
occurs
from
a
it
is
walking
contains
or
smell
air
but
travelling
because
region
an
car,
par ticles
of
higher
concentration.
fact
is
the
from
movement
an
area
concentration
to
concentration
until
an
of
area
they
of
higher
of
Investigating
lower
are
the
particulate
theory
of
matter
evenly
Your
teacher
may
use
this
activity
to
assess:
distributed.
●
observation,
recording
●
analysis
interpretation.
Y
ou
will
be
potassium
and
supplied
with
and
a
manganate( VII)
reporting
straw,
a
beaker
containing
distilled
water
and
a
crystal.
Method
1
Place
the
bottom
2
Drop
the
moving
3
Very
straw
of
the
vertically
crystal
the
in
the
beaker
of
water
until
it
touches
the
beaker.
of
potassium
manganate( VII)
into
the
straw
without
straw.
carefully
remove
the
straw
trying
to
disturb
the
water
as
little
as
possible.
4
✔
Exam
tip
the
5
It
is
very
important
questions
in
distinguish
and
to
must
between
your
the
performed.
what
you
If
If
what
are
you
are
colour
immediately
begins
to
spread
throughout
the
beaker
has
and
spread
observe
conclusion
can
throughout
after
you
draw
all
a
the
few
days.
water
in
Note
the
that
beaker.
the
purple
What
a
the
spaces
b
the
movement
between
about:
the
water
particles
you
of
the
potassium
manganate( VII)
particles?
and
used
being
asked
you
purple
asked
then
is
conclude
then
the
would
experiment
would
experiment,
you
Leave
colour
to
observations
you
how
water.
answering
examinations
observations,
describe
while
when
or
conclusions.
give
see
tests
Observe
to
state
from
must
the
The
potassium
illustrated
in
manganate(VII)
Figures
1.2.1
and
cr ystal
1.2.2
are
t he
bot h
water
composed
in
of
t he
experiment
minute
particles.
give
The par ticles in t he cr ystal are packed closely toget her and t hose in t he water
what
you
can
deduce
from
the
have
observations.
A
deduction
is
ver y
minute
by
using
data
from
the
small
spaces
between
t hem.
When
t he
cr ystal
is
in
t he
water,
t he
made
cr ystal
par ticles
slowly
separate
from
each
ot her
and
diffuse
into
t he
experiment
spaces between t he water par ticles. This continues until all t he par ticles have
to
arrive
at
a
conclusion.
separated
4
from
t he
cr ystal
and
have
diffused
between
t he
water
par ticles.
States
of
matter
Evidence
for
the
particulate
theory
of
matter
straw
beaker
of
water
the
potassium
water
purple
becomes
colour
a
throughout
manganate(VII)
crystal

The
cr ystal
solution
Figure
1.2.1
Potassium
crystal
being
placed
gradually
where
diffusion
is
in
t he
t he
manganate(v II)

and
colour
an
solvent.
aqueous
Figure
solution
1.2.3
is
illustrates
water
particles
random
spaces
with
moving
crystal
small
from
between
a
while
the
throughout
i.e.
process
particles
each
diffuse
purple
the
water
a
of
other
into
the
the
separate
and
spaces
water
particles
particles
packed
manganate(VII)
After
formed,
t he
between
crystal
potassium
1.2.2
spreads
experiment.
water
at
Figure
water
d issolves
water
occurring
in
closely
together
crystal
before
dissolving
after
dissolving

Investigating
Your
teacher
diffusion
may
use
in
this
observation,
recording
●
analysis
interpretation.
Y
our
and
teacher
will
perform
and
the
1.2.3
Explanation
of
diffusion
gases
activity
●
Figure
to
assess:
reporting
following
experiment:
Method
1
Place
2
Soak
a
Seal
4
Allow
5
Use
During
them
the
time
your
t he
for
called
t he
as
off
of
the
of
the
a
at
gas
to
with
air
in
between
of
the
rubber
what
in
t he
and
1.2.4
and
glass
stands.
ammonia
solution
and
concentrated
hydrochloric
acid
and
tube.
tube
to
vapours
during
and
t he
ammonia
react
retort
stoppers.
happened
gas
ammonium
glass
chloride
Figures
The
two
concentrated
hydrogen
gas.
collide
in
end
ammonia
chlor ide
The
wool
and
illustrated
t he
length
each
explain
called
t hey
chlor ide .
in
tube
ammonia
t hrough
meet,
ammonium
1 m
cotton
glass
hydrogen
diffuse
par ticles
glass
pieces
experiment
off
par ticles
least
observations
gives
gas
at
simultaneously
ends
solution
a
tube
separate
place
3
glass
the
1.2.5,
diffuse.
and
t he
a
each
white
forms
a
any
changes.
ammonia
acid
hydrogen
towards
Observe
experiment.
hydrochloric
form
chloride
to
ot her.
solid
ring
gives
chloride
When
known
inside
t he
tube.
5
Evidence
for
the
particulate
cotton
theory
wool
in
wool
matter
soaked
hydrochloric
cotton
of
in
acid
a
chemical
involved,
(g)
equation
(g)
a
gas
The
glass
(g)
and
and
(s)
a
(s)
indicate
t he
state
of
t he
chemicals
solid:
Figure
1.2.4
chloride
gas
Ammonia
diffuse
and
cotton
each
wool
wool
other
soaked
hydrochloric
cotton
hydrogen
hydrogen
towards
in
acid
faster
This
of
soaked
●
chloride
NH
t he
forms
because
chloride
experiment
ammonium
chloride
l(s)
4
acid
t hrough
chloride
Hl(g)
ammonium
hydrochloric
tube
hydrogen


3
t he
par ticles.
air
t han
Therefore,
t he
provides
closer
t he
to
ammonia
t he
hydrogen
following
t he
cotton
par ticles
are
ammonia
chloride
wool
soaked
lighter
par ticles
t han
move
in
t he
much
par ticles.
evidence
for
t he
par ticulate
t heor y
matter:
Par ticles
are
par ticles
must
able
to
move
–
t he
ammonia
and
hydrogen
chloride
ammonia
●
There
are
between
t hem
white

matter
ammonia
NH
in
where
indicating
ammonia

of
We can represent t he reaction between t he ammonia and hydrogen chloride
as
soaked
States
Figure
1.2.5
ring
to
have
spaces
t he
air,
move
moved
between
par ticles
ammonia
between
towards
and
each
each
–
ot her
t here
hydrogen
to
must
form
have
chloride
t he
been
white
ring.
spaces
par ticles
to
allow
ot her.
forms
After
a
while
a
white
ring
Osmosis
forms
inside
the
glass
tube
Osmosis
water
region
!
Key
is
wit h
of
water
solution
is
the
from
movement
a
region
molecules,
or
a
case
of
t hrough
lot
differentially
substances
molecules
special
of
water
a
diffusion,
which
d ifferenti ally
molecules
to
a
involves
permeable
region
wit h
t he
movement
membrane
fewer
water
of
from
a
molecules.
fact
A
Osmosis
a
molecules
pure
e.g.
water,
of
with
a
to
permeable
pass
t hrough
membrane
but
not
is
a
ot hers.
membrane
You
may
also
t hat
nd
allows
t he
some
membrane
water
a
lot
being
called
membrane
dilute
a
to
a
semi-permeable
t hat
surrounds
or
selectively
biological
cells
is
permeable
membrane.
differentially
The
cell
permeable.
region
A differentially permeable membrane contains minute pores. Water molecules
with
fewer
water
molecules,
e.g.
a
are
concentrated
solution,
through
able
ot her
differentially
permeable
to
pass
t hrough
t hese
pores.
However,
t he
par ticles
of
many
a
substances,
which
may
be
dissolved
in
t he
water,
are
unable
to
pass
membrane.
t hrough.
When
concentrations,
t he
water
t he
more
two
are
separated
molecules
dilute
molecules,
solutions,
will
do
by
diffuse
solution
however,
e.g.
to
not
t he
sucrose
a
differentially
t hrough
more
move
solutions,
t he
t hey
have
permeable
pores
in
concentrated
because
which
are
t he
membrane,
membrane
solution.
unable
different
to
The
pass
from
sucrose
t hrough
t he pores in t he membrane. The volume of t he more dilute solution decreases
and
t he
volume
of
t he
more
differentially
concentrated
permeable
solution
increases.
membrane
sucrose
cannot
molecule
pass
through
the
differentially
permeable
membrane
water
molecule
diffuses
the
through
differentially
permeable
membrane
dilute
sucrose
concentrated
solution

Figure
1.2.6
Theoretical
explanation
net
of
6
osmosis
sucrose
solution
movement
water
of
molecules
States
of
matter
Evidence
Investigating
Your
teacher
may
●
manipulation
●
analysis
Y
ou
will
lled
be
with
osmosis
and
use
and
in
this
green
activity
for
the
particulate
theory
of
matter
paw-paw
to
assess:
measurement
interpretation.
supplied
distilled
with
water
a
piece
and
of
one
green
beaker
paw-paw
lled
with
(the
experiment
concentrated
may
sodium
be
done
chloride
with
potato
or
yam),
one
beaker
solution.
Method
1
Cut
2
Measure
3
Place
the
piece
and
three
containing
4
Allow
5
Remove
6
Measure
7
Explain
the
Explain
why
chloride
in
to
into
remain
from
into
the
in
the
the
the
in
solution
the
beaker
each
the
for
Feel
placed
of
equal
containing
solutions
of
which
strips
length.
strip.
chloride
beakers.
the
distilled
water
and
place
the
other
three
strips
into
the
beaker
solution.
one
hour.
strips
and
take
note
of
the
texture
of
each
strip.
strip.
in
water
distilled
water
molecules
become
move,
from
more
the
rigid
and
paw-paw
have
into
increased
the
distilled
in
length
water
or
from
the
paw-paw).
strips
(consider
or
six
each
sodium
strips
paw-paw
length
into
of
the
length
paw-paw
direction
water
length
strips
record
the
the
paw-paw
the
concentrated
strips
and
decrease
green
the
strips
why
distilled
8
of
the
the
(consider
of
record
from
the
the
placed
in
direction
sodium
concentrated
in
which
chloride
the
solution
sodium
water
into
chloride
molecules
the
solution
move,
become
from
the
oppy
and
paw-paw
softer
into
the
and
sodium
paw-paw).
distilled
water
concentrated
beaker
sodium
chloride
paw-paw

solution
Figure
1.2.7
Paw-paw
strips
in
strips
distilled
sodium
concentrated
distilled
paw-paw
increase

Figure
the
1.2.8
After
concentrated
a
chloride
water
strips
in
while
sodium
the
strips
in
water
solution
increase
decrease
in
in
t he
length
in
size
and
those
in
length
Did
experiment
illustrated
in
Figures
1.2.7
and
1.2.8,
t he
of
t he
paw-paw
cells
act
as
differentially
permeable
can
pass
t hrough
t he
cell
membranes,
eit her
into
or
out
of
t he
If
Distilled water has a higher water content (or lower sodium chloride
water.
concentration) than the paw-paw cells, therefore water moves
water
into the cells
takes
out
The
paw-paw
cells
have
a
higher
water
content
t han
t he
of
chloride
solution,
t herefore
water
moves
out
of
t he
cells
resulting
in
t he
paw-paw
strip
becoming
in
the
does
same
in
the
way
in
paw-
you
sweat
a
This
lowers
the
in
your
place
your
blood
and
lot
and
starts
cells.
you
For
lose
amount
of
osmosis
to
this
pull
water
reason
shor ter
and
important
to
drink
lots
of
it
is
water
by
on
osmosis,
it
concentrated
very
sodium
as
cells:
by osmosis, resulting in the paw-paw strip becoming longer and more rigid.
●
works
cells
paw.
●
know?
membranes.
your
Water
you
cell
Osmosis
membranes
solution
sodium
?
During
chloride
concentrated
strips
decrease
chloride
and
solution
paw-paw
size
water
a
hot
day
or
when
you
exercise.
sof ter.
7
Evidence
for
the
particulate
theory
of
matter
States
Practical
We
use
garden
t he
and
many
t han
of
snails,
to
snails
being
of
our
to
and
chloride
dissolves.
is
in
food
various
ways.
These
include
controlling
items.
herbivores,
The
ot her
by
die.
water
We
using
Figure
1.2.9
sodium
serious
of
t hese
This
garden
pests
means
evaporating
make
use
sodium
Snails
deliquescent,
When
are
skin
animals.
prevent
and
gardens

Sodium
osmosis
plants.
most
moist
dehydrate
in
of
pests
precious
skin
matter
osmosis
preser ving
garden
t hemselves
t hem
and
our
t he
of
principles
pests
Controlling
Slugs
uses
of
of
are
serious
which
chloride
lot
t hat
t hat
t hey
to
ravage
permeable
need
bodies
control
to
keep
causing
slugs
and
salt).
garden
sprinkled
which
more
t heir
facts
(table
means
is
pests
a
from
t hese
chloride
is
pests
it
absorbs
on
slugs
water
and
readily
snails,
it
absorbs some of t he moisture surrounding t heir bodies and dissolves forming
a
concentrated
solution.
This
causes
water
inside
t heir
bodies
to
move
out
and into t he solution by osmosis. f t he slugs and snails lose more water t han
t heir
bodies
Preserving
can
food
ot h
sodium
sh,
fr uits
cr ystallised
t he
●
same
tolerate,
to
and
sugar
vegetables.
fr uits,
way
die
from
dehydration.
items
chloride
and
t hey
guava
We
jelly
preser ve
are
used
are
and
all
glacé
to
preser ve
familiar
cherries.
food
wit h
ot h
items,
salt
salt
sh,
and
e.g.
meat,
salt
pork,
sugar
work
in
foods:
They withdraw water from the cells of the food items by osmosis. This
makes the water unavailable for the chemical reactions in cells which cause
decay. Without these reactions occurring, the food items do not decay.
●
They
also
decay,
wit hdraw
e.g.
growing
bacteria
and
water
and
causing
from
fungi.
t he
food
t he
This
microorganisms
prevents
items
to
(a)

8
t hese
t hat
bring
organisms
about
from
decay.
(b)
Figure
1.2.10
(a)
Salt
sh
and
(b)
crystallised
fruits
are
examples
of
preserved
food
items
States
of
matter
The
Summary
1
For
each
of
particulate
a
If
a
b
If
the
experiments
theory
the
bottles
of
2
State
of
3
Why
4
When
30
do
a
we
5.0 cm
Explain
its
of
how
control
b
to
preserve
The
You
have
and
gas.
raw
potato
was
a
a
is
the
into
a
of
the
evidence:
beaker
of
concentrated
to
each
other,
a
white
between
chip
to
case
was
have
of
osmosis
of
placed
to
diffusion.
diffusion?
in
water
increased
matter
and
to
and
left
5.5 cm.
explain
for
Use
your
this.
used:
garden
sh.
three
states
already
t hree
t hat
st ates
proper ties.
of
of
matter
matter
Objectives
matter
exists
have
in
t hree
st ates:
noticeable
solid,
differences
liquid
in
By
the
be
able
Physic al
properties
are
c haracter istics
t hat
end
of
or
measured
wit hout
c hanging
t he
c hemical
Shape,
volume,
density,
compressibility,
composition
solubility,
and
explain
of
boiling
physical
point
are
proper ties
all
of
examples
t he
t hree
of
physical
st ates
can
be
will
the
difference
the
three
states
of
a
in
terms
of
energy
and
particles,
and
melting
proper ties.
explained
of
The
forces
different
you
be
arrangement
point
topic
t heir
can
matter
subst ance.
this
to:
between
obser ved
matter
water.
and
next
feature(s)
provides
dropped
solution
special
theory
chloride
in
the
●
physical
of
bottles.
found
particulate
is
placed
differences
is
state
experiment
throughout
and
two
osmosis
long
below,
the
ammonia
the
and
length
slugs
lear nt
The
that
sodium
to
spreads
opened
between
the
a
A1.3
are
which
manganate(v II)
colour
acid
say
minutes,
described
for
potassium
similarities
knowledge
5
matter
concentrated
forms
any
of
purple
hydrochloric
cloud
states
questions
crystal
water,
three
by
of
attraction
between
t he
particles
par ticulate
t heor y
of
matter.
●
Table
and
1.3.1
t he
summarises
arrangement
t he
of
physical
par ticles
in
proper ties
t he
t hree
of
t he
t hree
states
of
matter
account
for
properties
states.
matter
in
the
of
terms
arrangement
We
can
use
t he
arrangement
of
par ticles
in
t he
t hree
states
of
matter
t he
physical
proper ties
of
t he
different
three
of
of
states
of
energy
and
particles,
and
to
forces
explain
physical
the
of
attraction
between
states:
particles
●
Solids
have
a
xed
shape
because
t heir
par ticles
are
arranged
in
a
regular
●
way
and
t hey
are
unable
to
move
out
of
t heir
xed
explain
state
●
Solids
t heir
any
have
a
xed
par ticles
closer
are
volume
packed
and
ver y
are
ver y
closely
difcult
toget her
to
the
changes
compress
and
cannot
pushed
terms
arrangement
because
be
in
●
understand
Liquids
ow
because
t heir
par ticles
are
able
to
move
past
each
energy
and
particles
melting,
evaporation,
toget her.
of
of
boiling,
condensation,
●
of
positions.
freezing
and
ot her.
sublimation
●
Liquids
can
be
compressed
slightly
because
t heir
par ticles
have
small
●
spaces
between
t hem
enabling
t hem
to
be
pushed
closer
understand
heating
●
Gases
t heir
take
t he
par ticles
attraction
shape
move
between
and
volume
freely
t hem,
and
of
t he
rapidly.
t herefore
container
They
t hey
have
spread
t hey
only
out
to
and
interpret
toget her.
are
in
weak
ll
cooling
curves.
because
forces
any
and
of
available
space.
●
Gases
are
between
easy
to
t hem,
compress
t herefore
because
t hey
can
t heir
be
par ticles
pushed
have
closer
large
spaces
toget her.
9
The
three
states
of
matter
States

T
able
1.3.1
The
properties
Property
Shape
of
the
three
states
Solid
and
volume
of
have
shape
and
a
a
fixed
Gas
Liquids
fixed
a
volume.
fixed
they
do
not
shape,
have
volume.
a
the
container
of
and
always
Gases
but
fixed
definite
shape
occupy
have
Liquids
the
is
the
part
that
the
A
take
gas
will
space
of
is
they
is,
horizontal.
of
Most
solids
have
a
high
density.
Compressibility
Solids
to
The
density
usually
are
very
difficult
compress.
density
of
Liquids
can
is
of
the
The
particles
particles
packed
together,
regular
Forces
of
between
attraction
the
The
particles
in.
volume
volume
in
a
strong
and
attraction
have
between
of
the
and
movement
are
very
of
Arrangement
in
small
kinetic
particles
fixed
not
those
Particles
particles
a
solid
have
amounts
energy.
vibrate
position.
a
gas
the
of
shape
the
entire
in.
a
low
are
easy
to
pressure
particles
and
of
the
spaces
as
attraction
strong
Particles
in
a
kinetic
The
as
large
weak
attraction
the
spaces
them.
particles
very
are
arranged
have
between
particles
between
have
forces
of
between
them.
solid.
liquid
have
Particles
energy
particles
particles
about
The
small
a
The
are
them.
of
than
their
of
it
shape
compress.
randomly
particles
more
The
in
Gases
very
arranged
forces
between
them.
Energy
have
The
of
The
is
have
the
density.
be
particles
between
forces
Gases
up
container
solids.
when
randomly
usually
is
the
it
a
volume.
take
therefore,
and
have
or
applied.
The
pattern.
particles
very
are
closely
liquids
than
compressed
slightly
Arrangement
of
lower
not
the
placed
and
surface
do
shape
container
Density
matter
matter
Liquid
Solids
of
in
a
large
solid.
energy.
move
move
slowly.
in
a
gas
amounts
The
about
of
have
kinetic
particles
freely
and
rapidly.
of
particles
Changing
Did
?
you
Matter
A
SCUBA
fact
to
divers
that
compress.
SCUBA
2250
T
o
of
use
very
of
average
tank
holds
this,
milk
think
be
of
consequently
sized
order
about
we
of
cartons
can
change
changed
state
is,
from
one
t herefore,
state
air.
a
need
changes
change
change
to
changing
milk
hold
to
a
remove
its
of
water
heat
are
t he
into
chemical
state
in
kinetic
ice
we
of
diving
milk,
tank
therefore,
holds
the
a
anot her
by
energy.
to
a
by
change
in
is
a
Figure
of
put
hanging
composition
summarised
energy
need
heating
in
or
cooling.
temperature
t he
t he
t he
par ticles.
water
state
physical
of
For
and
into
a
example,
t he
freezer,
substance
change.
The
in
i.e.
wit hout
different
1.3.1.
one
add
litre
to
caused
the
easy
compressed
understand
Most
are
An
diving
litres
carton.
make
gases
state
know?
heat
SCUBA
same
volume
evaporates/
of
air
as
2250
empty
milk
cartons!
melts
boils
LIQUID
SOLID
freezes
GAS
condenses
sublimates
sublimates

Figure
of
1.3.1
Summary
of
the
changes
remove
state
We
will
changes
10
now
in
look
state
in
in
more
Figure
detail
1.3.1.
at
heat
each
of
t he
processes
t hat
cause
t he
States
of
matter
The
three
states
of
matter
Melting
When
more
a
solid
is
heated,
vigorously.
t he
par ticles
Eventually
t he
gain
kinetic
par ticles
are
energy
able
to
and
begin
overcome
to
vibrate
t he
Key
!
strong
Melting
forces
of
attraction
between
t hem
and
t hey
move
more
freely
and
fact
point
is
the
constant
fur t her
temperature
at
which
a
solid
apar t forming a liquid, i.e. t he solid melts. The temperature remains constant
changes
into
a
liquid.
while t he solid is melting because all t he heat energy being supplied is used to
overcome
t he
temperature
forces
is
of
known
attraction
as
t he
between
melting
t he
solid
par ticles.
This
constant
point
Evaporation
When
Some
a
liquid
of
t he
is
heated,
par ticles
t he
near
par ticles
t he
gain
surface
of
kinetic
t he
energy
liquid
and
have
move
enough
faster.
Did
?
When
energy
to
overcome
t he
forces
of
attraction
between
t hem
and
are
able
t he
liquid
par ticles
and
t hat
become
leave
t he
a
vapour.
liquid
These
take
lots
par ticles
of
energy
are
wit h
said
to
t hem,
of
t he
sweat
and
the
evaporates
water
from
in
our
evaporate.
leading
to
it
takes
energy
with
it
causing
cooler.
If
we
a
our
cooling
we
sweat
skin,
The
know?
to
the
leave
you
kinetic
bodies
to
feel
put
liquid.
alcohol
even
on
faster
our
skin,
than
it
evaporates
water
because
Boiling
it
When
a
where
it
kinetic
star ts
t he
t he
is
to
energy
wit hin
while
liquid
boil.
and
liquid
liquid
overcome
heated
t he
temperature
is
At
at
boiling
of
known
temperature
t his
star ted
and
forces
is
its
point
to
move
its
because
t he
liquid
fast
surface.
attraction
as
t he
t he
eventually
heat
between
boiling
par ticles
enough
The
reaches
to
have
change
temperature
energy
t he
being
liquid
a
cer tain
gained
into
a
enough
gas
remains
supplied
point
has
a
water.
even
lower
This
differs
from
evaporation
in
oiling
place
●
occurs
at
any
oiling
place
a
specic
our
skin
when
we
than
feel
sweat.
bot h
is
par ticles.This
used
to
constant
Key
!
fact
point
two
point
temperature
ways.
temperature,
whereas
evaporation
can
is
at
into
a
the
constant
which
a
liquid
gas.
take
temperature.
takes
only
at
than
point
constant
changes
●
makes
colder
Boiling
oiling
boiling
at
place
t he
t hroughout
surface
of
t he
t he
liquid,
whereas
evaporation
takes
✔
liquid.
If
Exam
you
are
tip
asked
to
give
a
difference
Condensation
between
When
t he
temperature
of
a
gas
is
lowered,
t he
par ticles
lose
kinetic
two
things,
it
is
essential
energy
that
you
describe
the
specific
and begin to move more slowly. The forces of attraction between t he par ticles
property
become
liquid,
stronger
i.e.
t he
causing
liquid
t he
par ticles
to
move
closer
toget her
forming
a
condenses.
of
‘whereas’
describe
each,
to
link
just
using
the
the
two.
word
Do
not
one.
Freezing
When t he temperature of a liquid is lowered, t he par ticles lose kinetic energy
and begin to move more slowly. The forces of attraction between t he par ticles
become
stronger
causing
t he
par ticles
to
move
even
closer
toget her
!
Key
forming
Freezing
a
solid,
i.e.
t he
liquid
freezes.
The
temperature
at
which
t his
occurs
fact
is
point
temperature
t he
freezing
freezing
point,
e.g.
at
the
which
constant
a
liquid
point
changes
The
is
called
point
water
of
has
a
a
pure
substance
melting
point
has
and
a
t he
same
freezing
value
point
of
as
t he
into
a
solid.
melting
0 °.
Sublimation
When
t he
forces
of
attraction
between
t he
par ticles
in
a
solid
are
weak,
t he
addition of a small amount of heat can cause t he solid to change directly into
a gas, wit hout passing t hrough t he liquid state. f t he gas is t hen cooled it will
change
directly
solid
a
to
gas
or
back
a
gas
to
to
t he
a
solid.
solid
it
When
is
said
a
to
substance
changes
directly
from
a
sublime
11
The
three
states
of
matter
States
Examples
dioxide
balls
or
sublime

Figure
1.3.2
Solid
air
fresheners
of
substances
(known
as
‘dr y
camphor
balls
releasing
t heir
which
ice’),
are
undergo
sublimation
ammonium
made
of
fragrances
chloride
and
napht halene.
into
t he
are
of
iodine,
carbon
napht halene.
Solid
air
matter
Mot h
fresheners
also
air.
sublime
(a)
cotton
wool
Observing
est
sublimation
in
iodine
tube
Your
may
observation,
●
iodine
teacher
use
this
recording
activity
and
to
assess:
reporting.
crystals
iodine
vapour
Y
ou
will
cotton
be
supplied
wool
and
a
with
pair
a
of
test
tube,
a
small
iodine
crystal,
a
piece
of
tongs.
Method
1
Place
2
Hold
the
iodine
mouth
the
Bunsen
the
the
tube
of
the
test
in
crystal
test
tube
the
into
the
test
tube
and
place
the
cotton
wool
into
tube.
with
ame
tongs
of
a
at
a
Bunsen
45°
angle
burner
and
until
all
heat
the
the
bottom
iodine
of
crystal
has
burner
sublimed.
(b)
iodine
crystals
3
Observe
4
Remove
5
Observe
During
heated,
the
it
what
the
happens
tube
what
from
the
happens
experiment
sublimes
and
as
the
iodine
ame
as
the
tube
illustrated
forms
and
in
purple
is
heated.
let
is
it
cool.
cooling.
Figure
iodine
1.3.3,
vapour
as
the
which
iodine
diffuses
cr ystal
up
the
is
test
tube. The top of the tube is much cooler and when the vapour reaches the top,

Figure
1.3.3
heated
and
Iodine
(b)
sublimes
when
cooled
(a)
when
it
sublimes
back
Heating
f
t he
on
a
The
state
graph
water
and
a
solid,
forming
cooling
temperature
changes
is
to
cur ve
a
against
shown
increases.
in
shows
of
a
pure
liquid
time,
Figure
t hat
However,
temperature
12
to
a
ring
of
iodine
cr ystals
around
the
inside
of the tube.
remains
curves
solid
and
a
is
t hen
heating
measured
to
a
gas,
curve
is
at
inter vals
and
t he
as
it
is
heated
temperature
obtained.
The
is
heating
and
plotted
cur ve
for
1.3.4.
as
t he
heating
graph
constant
occurs,
has
for
a
t he
two
temperature
horizontal
period
of
time
of
t he
sections
even
substance
where
t hough
t he
heating
States
of
matter
continues.
state
is
water
These
where
melting
is
of
t he
0 °.
temperature
t he
happen
melting
point
t his
The
has
t here
and
substance
The
remains
substance
when
occurs
second
e.g.
at
for
t he
a
change
of
temperature
until
change
constant
boiled,
is
t he
all
of
t he
is
t his
where
point
is
The
remains
substance
state
boiling
water
state.
of
has
change
melted,
boiling
t he
rst
constant
occurs
substance
at
states
of
matter
of
t he
e.g.
and
three
for
t he
until
all
100 °.
140
)C°(
120
gas
and
liquid
boiling
100
point
erutarepme
T
80
60
liquid
40
20
solid
and
liquid
melting
0
20
solid
point
(ice)
40
Time

Figure
1.3.4
The
as
heating
heat
is
curve
added
for
water
f t he temperature of a gas is measured at inter vals as it is cooled and changes
state to a liquid and t hen to a solid, and t he temperature is plotted on a graph
against
shown
time,
in
a
cooling
Figure
curve
is
obtained.
The
cooling
cur ve
for
water
is
1.3.5.
140
gas
(steam)
)C°(
120
gas
and
liquid
boiling
100
point
erutarepme
T
80
liquid
60
40
20
melting
0
point
solid
20
40
Time

Like
Figure
heating
1.3.5
cur ves,
The
as
heat
cooling
cooling
is
removed
curve
cur ves
for
have
water
two
horizontal
sections.
The
rst
is
where t he state changes from gas to liquid and t he second is where it changes
from
liquid
to
solid.
Summary
1
Complete
what
is
the
of
Name
state
Gas
Solid
3
4
below.
The
rst
row
is
completed
as
an
example
of
given
to
change
Energy
state
change
Melting
added
or
removed
to
state
Added
gas
liquid
to
to
What
liquid
to
to
Liquid
2
of
to
Liquid
table
required.
Change
Solid
questions
solid
gas
are
a
Explain
b
Give
Explain
the
main
what
three
what
differences
occurs
examples
a
heating
during
of
between
and
boiling?
sublimation.
solids
curve
evaporation
which
undergo
sublimation.
shows.
13
The
three
states
of
matter
States
Key
matter
concepts
●
Matter
●
The
is
dened
proper ties
matter,
which
matter
states
made
–
t he
–
t here
are
spaces
–
t here
are
forces
par ticles
Matter
●
The
exists
are
in
difference
energy
of
t he
energy
anyt hing
matter
all
The
is
as
of
–
●
●
of
constant,
mass
states:
between
random
t he
attraction
t hree
has
explained
and
by
occupies
t he
space.
particulate
theory
of
par ticles
between
of
t hat
be
t hat:
of
in
can
t he
motion
par ticles
between
solid,
t hree
t he
liquid
states
par ticles.
and
is
due
gas
to
t he
arrangement
and
par ticles.
of
t he
par ticles
is
directly
related
to
t he
temperature
of
t he
par ticles.
●
Diffusion
t heor y
●
of
Diffusion
and
osmosis
provide
evidence
to
suppor t
t he
par ticulate
matter.
is
t he
concentration
movement
to
an
area
of
of
par ticles
lower
from
an
area
concentration
of
until
higher
t hey
are
evenly
distributed.
●
Osmosis
lot
of
wit h
is
t he
water
fewer
water
differentially
●
The
●
The
and
energy
account
of
t he
water
a
molecules,
e.g.
are
food
Matter
can
change
from
solid
Matter
can
change
from
gas
●
The
names
given
are
to
t he
melting,
of
to
from
or
a
pure
region
water,
solution,
of
processes
to
to
wit h
to
a
a
region
t hrough
pests
chloride
solids,
t hree
wit h
and
a
liquids
and
gases
states.
gas
wit h
t he
addition
wit h
t he
removal
cause
boiling,
sodium
sugar.
solid
which
evaporation,
in
t he
liquid
liquid
garden
sodium
par ticles
to
to
control
wit h
proper ties
●
anot her
solution
concentrated
used
●
to
a
items
arrangement
physical
molecules
dilute
membrane.
osmosis
preser ve
and
for
of
e.g.
permeable
principles
chloride
movement
molecules,
t he
change
of
of
from
condensation,
heat.
heat.
one
state
freezing
and
sublimation.
●
Melting
point
●
wit h
weak
When
t he
changes
against
●
When
against
14
t he
of
from
a
time,
in
attraction
of
solid
heating
from
a
temperatures
known
as
t he
melting
respectively.
at
any
gas
state
t hrough
temperature
state
specic
occurs
change
passing
forces
state
t he
liquid
temperature
time,
changes
a
at
point,
temperature
and
leads
to
t he
liquid.
is
wit hout
occur
boiling
of
t he
Sublimation
versa,
●
of
boiling
t he
Evaporation
cooling
●
and
and
to
of
a
liquid
is
is
t heir
gas,
a
t
solid
to
occurs
a
in
gas,
or
vice
compounds
molecules.
is
and
measured
t he
as
it
is
temperature
heated
is
and
plotted
obtained.
pure
liquid
to
from
state.
substance
liquid
curve
straight
between
pure
curve
to
cooling
a
t he
substance
to
solid,
is
and
obtained.
measured
t he
as
it
is
temperature
cooled
is
and
plotted
States
of
matter
Practice
i)
Practice
exam-style
State
what
t he
level
funnel
Which
is
of
made



t he
of
of
af ter
t he
expect
30
sucrose
to
have
solution
happened
in
t he
minutes.
following
provide(s)
evidence
t hat
Explain
t he
reason
for
your
(4
matter
iii)
par ticles?
Name
t he
process
occurring
in
t he
A
second
state


and

and
D

only

t he
X
as
liquid
it
t he
was
state
temperature
heated
to
t he
from
of
mark)
an
t he
gaseous
solid
state.
Her


are
plotted
in
Figure
2.
Use
t he
information
in
only
t he
C
measured
substance
t hrough
results
and
student
unknown
Diffusion
,
marks)
apparatus.
(1
b
Decomposition
B
mark)
obser vations.
Osmosis
A
t histle
(1
questions
ii)
1
would
questions
questions
to
Multiple-choice
you
exam-style
Figure
to
answer
t he
following
questions.
only
80
2
Par ticles
in
a
solid:
70
packed
B
are
capable
C
have
large
spaces
D
have
weak
forces
Liquids
A
t he
differ
closely
of
random
from
par ticles
toget her
in
of
t hem
attraction
gases
a
movement
between
in
liquid
between
t hem.
t hat:
can
move
more
freely
60
50
erutarepme
T
are
)C°(
3
A
t han
40
30
20
10
t hose
in
a
gas
0
B
t he
par ticles
in
a
gas
are
closer
toget her
t han
t hose
in
10
a
liquid
20
C
t he
par ticles
t han
D
t he
t hose
in
in
par ticles
a
a
in
liquid
possess
more
kinetic
energy
0
t hem
a
gas
t han
have
t hose
weaker
in
a
The
forces
of
conversion
of
Figure
a
gas
to
a
2
liquid
is
described
during
Graph
12
14
showing
heating
16
18
20
22
24
26
(min)
the
against
temperature
of
substance
time
as:
What
Over
state
what
is
X
in
at
68 °?
temperature
(1
range
does
X
exist
C
condensation
D
boiling.
iii)
From
take
Which
show
of
t he
following
lists
consist
of
substances
iv)
which
state?
t he
A
Aluminium
chloride,
B
Ammonium
chloride,
iodine,
C
Ammonium
chloride,
napht halene,
D
Aluminium
sulfate,
iodine,
carbon
carbon
dioxide,
it
Describe,
X
has
in
star ts
terms
what
to
melt,
completely
is
of
how
long
melted?
energy
and
happening
to
v)
monoxide.
Using
draw
iodine.
X
napht halene.
o
to
represent
a
par ticle
par ticles
as
t hey
of
n
order
to
a
investigate
student
set
t he
up
par ticulate
t he
nature
apparatus
of
shown
Extended
(2
1
below
and
lef t
it
for
30
response
glass
a
Describe
thistle
b
funnel
Water
t he
of
T WO
can
level
of
sucrose
15%
sucrose
y
for
solution
i)
35%
sucrose
differences
differentially
t hem
reference
EAH
of
steam
to
investigate
of
evidence
to
suppor t
the
a
matter.
solid,
between
of
t heir
and
to
t he
a
(4
liquid
t hese
t heir
and
t hree
par ticles,
par ticles,
t he
can
permeable
membrane
ii)
a
cr ystal
shape.
used
as
of
kinetic
a
gas.
states
forces
in
of
marks)
Explain
terms
attraction
energy.
explain
clearly
(6
t he
marks)
reason
following:
be
conver ted
to
liquid
water
by
solution
beaker
Apparatus
pieces
exist
reducing
particulate
its
of
temperature
potassium
chloride
(3
has
a
ver y
marks)
denite
(2
marks)
nature
Total
of
marks
solution
c
1
15
question
t heor y
arrangement
between
original
Figure
in
marks)
minutes.
par ticulate

X,
appear
15 °.
it
in
7
glass
as
marks)
question
matter,
Figure
of
X
substance
would
it
mark)
behaviour
(3
T WELE
at
does
substance
Total
a
t he
marks)
(1
melts.
dioxide.
carbon
(2
time
until
par ticles,
sublimation?
Structured
6
mark)
in
evaporation
liquid
5
10
melting
ii)
B
8
attraction
i)
A
6
liquid.
X
4
4
Time

between
2
gas
15
marks
matter
15
A2
Mixtures
Elements,
and
compounds
their
and
separation
mixtures
form
a
part
of
our
Objectives
By
the
be
able
end
of
this
topic
you
everyday
will
foil
●
distinguish
between
substances
and
pure
we
explain
an
When
we
wrap
our
food
in
aluminium
our
the
difference
element,
a
are
food
using
we
are
an
element.
eating
a
When
we
compound.
place
When
salt
we
on
drink
a
mixtures
cold
●
lives.
to:
soda
we
are
drinking
a
mixture.
It
may
be
useful
to
between
compound
and
a
know
how
to
separate
some
of
these
mixtures
into
their
mixture
component
●
give
examples
compounds
●
explain
a
the
of
and
mixtures
difference
homogeneous
heterogeneous
parts.
An
example
of
this
is
the
purification
elements,
and
of
drinking
water.
between
a
mixture.
A2.1
Elements,
compounds
and
mixtures
Matter can be classied into two main groups: pure substances and mixtures.
Pure
substances
●
They
●
Their
have
●
The
a
xed,
proper ties
component
physical
Mixtures
●
They
●
Their
t he
following
constant
are
xed
par ts
of
characteristics.
composition.
and
a
general
constant.
pure
substance
cannot
be
separated
by
means.
have
have
a
t he
following
variable
proper ties
individual
●
have
are
general
characteristics.
composition.
variable
since
t heir
components
retain
t heir
own,
proper ties.
The component parts of mixtures can be separated by physical means.
Pure
substances
Mixtures
can
heterogeneous
breakdown
of
can
be
be
fur t her
fur t her
mixtures .
t hese
classied
classied
The
tree
into
into
elements
and
homogeneous
diagram
in
Figure
compounds.
mixtures
2.1.1
shows
and
t he
groups.
matter
pure
mixtures
substances
elements

Pure
A
2.1.1
homogeneous
heterogeneous
mixtures
mixtures
Classication
of
matter
substances
pure
substance
following
16
Figure
compounds
xed
is
composed
of
only
one
type
of
material
proper ties:
●
a
shar ply
dened,
constant
melting
●
a
shar ply
dened,
constant
boiling
●
a
constant
density.
point
point
or
freezing
point
and
has
t he
Mixtures
and
their
separation
Elements,
compounds
and
mixtures
To determine if a substance is pure or not, its melting point or boiling point is
determined.
Any
impurities
in
a
pure
substance
will
usually
lower
its
melting
Did
?
point
and
usually
cause
raise
it
t he
to
melt
boiling
over
point
a
of
wider
a
pure
temperature
substance
range.
and
mpurities
cause
it
to
boil
over
In
a
many
ice
wider
temperature
will
chromatography
produce
only
one
(Unit
single
2.4)
spot
may
on
a
also
be
used.
f
a
chromatogram.
substance
f
it
is
not
is
pure
pure
it
is
it
more
t han
one
●
the
observation,
Y
our
boiling
points
of
pure
water
and
teacher
on
the
the
snow
the
the
(sodium
roads
dissolves
the
use
this
perform
activity
and
the
to
its
and
roads
in
chloride)
to
in
surface
the
freezing
melt
the
of
the
film
the
point
temperature
ice
starts
freezing
18 °C,
saturated
recording
will
on
lowers
about
sodium
solution
may
salt
salt
water
lower
teacher
on
ice,
spot.
and
Your
where
problem
rock
The
below
chloride
a
spread
this
Comparing
countries
pose
ice.
will
of
produce
know?
range.
winter,
Paper
you
will
to
the
melt.
point
the
sodium
of
to
ice
Salt
of
can
water
freezing
chloride
to
point
of
solution.
assess:
reporting.
following
demonstration.
Method
3
1
Place
2
Place
open
2 cm
an
Place
4
Half
a
distilled
inverted
end
3
of
facing
water
closed
in
end
a
test
tube.
capillary
tube
into
the
test
tube
with
the
downwards.
thermometer
in
the
tube.
3
ll
a
250 cm
assembly
is
5
Heat
the
ensure
of
in
beneath
the
the
oil
bubbles
indicates
bath
surface
beaker
that
beaker
is
emerges
that
the
so
of
over
even.
from
water
a
and
the
the
place
surface
Bunsen
test
of
burner,
heating
capillary
the
the
above
the
test
water
tube
in
the
test
tube
oil.
Continue
the
in
oil
that
level
gently
heating
with
tube.
tube
is
stirring
until
This
a
constantly
rapid
stream
to
stream
of
bubbles
boiling.
thermometer
6
Remove
last
7
the
bubble
Reheat
Record
the
heat
emerges
oil
the
source
bath
from
and
This
is
observe
the
the
reading
the
the
capillary
repeat
temperature
temperatures.
and
boiling
stream
tube,
cooling
after
of
record
process
each
point
of
trial
the
When
the
closed
end
stirring
rod
more.
average
test
all
three
Repeat
the
procedure
using
a
sodium
chloride
water.
solution
tube
oil
in
place
9
conclusion
sodium
can
chloride
you
draw
about
the
boiling
points
of
pure

Figure
An
element
is
t he
simplest
form
of
matter.
t
cannot
be
broken
down
simpler
by
ordinar y
chemical
or
physical
means.
We
say
means’
t hat
to
has
exclude
t he
same
nuclear
reactions.
proper ties
as
t he
The
smallest
element
is
an
the
boiling
fact
cannot
is
be
a
pure
substance
broken
down
into
‘ordinar y
par ticle
simpler
atom.
substances
by
any
in
ordinary
element
Determining
liquid
element
any
chemical
a
into
that
anyt hing
2.1.2
of
Key
!
Elements
an
solution
heat
water
solution?
point
An
or
chloride
water.
What
and
water
of
sodium
the
tube
beaker
distilled
8
capillary
temperature.
twice
and
distilled
bubbles.
chemical
or
physical
Each
means.
element
is
composed
of
only
one
kind
of
atom.
17
Elements,
compounds
and
mixtures
Mixtures
Examples
copper
of
elements
(Cu),
which
are
is
iron
(Fe),
composed
which
of
is
only
and
composed
copper
of
atoms
their
only
and
separation
iron
atoms,
oxygen
(O
),
2
which
is
composed
of
only
oxygen
atoms.
Compounds
Key
!
fact
Compounds
are
A
compound
is
a
pure
contains
types
of
element
together
or
and
properties
more
which
chemically
proportions
their
two
in
in
of
more
than
chemically,
one
t hey
are
kind
of
always
atom.
These
present
in
atoms
t he
by
mass
and
t hey
cannot
be
separated
by
physical
same
means.
A
different
are
bonded
a
compound
elements
fixed
such
have
composed
toget her
substance
propor tions
that
are
combined
way
that
can
t hat
combined,
be
t he
e.g.
represented
compound
t he
chemical
by
is
chemical
a
made
up
formula
of
of
formula ,
and
water
t he
is
H
which
ratio
in
indicates
which
t hey
t he
have
O.
2
changed.
Examples
oxygen
of
in
compounds
a
ratio
of
are
2 : 1,
water,
sodium
which
chloride
is
composed
(NaCl),
of
which
sodium and chlorine in a ratio of 1 : 1 and met hane (CH
hydrogen
is
and
composed
of
), which is composed
4
of
carbon
and
hydrogen
in
a
ratio
of
1 : 4.
The proper ties of a compound are  xed and are different from t he proper ties
of
t he
individual
hydrogen
is
a
and
elements
oxygen
are
t hat
bot h
for m
gases
at
t he
room
compound.
temperature,
For
example,
however,
water
liquid.
Mixtures
Key
!
fact
Mixtures
A
mixture
consists
substances
in
two
(elements
compounds)
together
of
more
and/or
physically
varying
or
means.
combined
are
combined,
will
be
Some
component
of
t he
investigating
of
two
t heir
physical
in
or
more
substances
components
Unit
met hods
2.4,
are
can
for
which
be
separating
ltration,
are
not
separated
chemically
by
mixtures,
evaporation,
physical
which
we
cr ystallisation,
proportions.
distillation,
Each
composed
t herefore
retains
its
fractional
distillation
and
chromatography.
n
a
mixture
t he
own
component par ts are not in a xed ratio and t hey retain t heir own, individual
independent
properties
and
has
physical
undergone
with
any
no
other
chemical
proper ties.
reaction
substance
in
the
Homogeneous
mixtures
mixture.
A
homogeneous
are
uniform
mixture
t hroughout
distinguished
from
each
is
one
t he
in
which
mixture.
ot her.
A
t he
The
solution
is
a
proper ties
and
component
composition
par ts
homogeneous
cannot
be
mixture.
Examples of homogeneous mixtures are air, salt dissolved in water and metal
alloys
such
as
brass,
Heterogeneous
a
mixture
which
can
be
t he
copper
and
zinc.
mixtures
A heterogeneous mixture
in
of
component
distinguished
is a non-uniform mixture, for example, a mixture
par ts
from
are
each
in
different
ot her,
states.
alt hough
not
The
component
always
wit h
t he
par ts
naked
(a)
eye.
Suspensions
Examples
muddy
The
can
in
Figure
distinguished
●
f
t here
is
●
f
t here
are
Figure
2.1.3
(a)
Gold
is
an
heterogeneous
mixtures
are
salt
mixtures.
and
sand,
mayonnaise,
and
only
2.1.4
by
one
show
looking
kind
of
at
how
t he
atom,
elements,
par ticles
t hen
it
is
compounds
t hat
an
make
up
and
t he
mixtures
substance.
of
an
element,
(b)
copper
sulfate
is
water
is
of
an
a
compound
example
of
a
or
more
kinds
of
atoms
element.
joined
and
(c)
it
is
a
toget her
in
t he
same
ratio,
compound.
an
●
example
two
example
t hen
18
heterogeneous
are
water.
diagrams
be
colloids
(c)
(b)

of
and
f
t here
is
a
combination
muddy
mixture.
t hen
it
is
a
mixture.
of
two
or
more
elements
and/or
compounds,
Mixtures
and
their
separation
Solutions,
suspensions
and
colloids
n Figure 2.1.4, elements are represented in diagrams D, E and H, compounds
are
represented
diagrams
atoms
A,
are
F
not
in
diagrams
and
.

is
arranged
a
B,
regularly
A
C
and
mixture
G
and
and
not
among
t he
B
a
mixtures
green
C
H
Summary
1
Copper
is
2
What
is
a
3
What
are
4
What
is
A2.2
example,
described
in
blue
D
the
E
diagrams
shown

I
the
F
atoms
Figure
of
2.1.4
as
an
element.
What
does
this
tell
us
about
are
the
differences
difference
suspensions
bot h
Elements,
compounds
and
mixtures
copper?
water
is
a
between
between
a
a
pure
substance
homogeneous
suspensions
and
colloids
solution,
form
muddy
and
par t
water
of
is
a
and
mixture
mixture?
and
a
heterogeneous
colloids
our
Objectives
ever yday
suspension
mixture?
lives.
and
milk
For
By
the
be
able
end
of
this
topic
you
will
to:
and
●
fog
different
compound?
the
sea
t he
questions
Solutions,
Solutions,
represented
because
atoms.
In
G
are
compound
explain
the
terms
solvent,
colloids.
solute
●
and
identify
solution
different
types
of
Solutions
solutions
A
solution
is
known
is
as
a
homogeneous
t he
solvent
and
mixture.
t he
minor
The
major
component
component
is
known
of
as
a
solution
t he
Some solutions may contain more t han one solute, e.g. sea water. The solute
and
a
solvent
liquid,
salt
is
can
t he
t he
be
gases,
liquid
solute
is
and
liquids
always
water
is
or
solids.
t he
solvent,
t he
solvent.
When
e.g.
in
a
a
gas
or
a
solid
mixture
of
dissolves
salt
●
solute.
in
a
●
in
2.2.1
gives
examples
of
various
between
suspension
describe
some
water,
solution,
a
T
able
2.2.1
Examples
of
different
types
Solvent
Example
Components
solid
liquid
sea
sodium
gas
liquid
soda
of
solid
solid
brass
carbon
of
chloride
the
in
in
give
dioxide
in
liquid
white
gas
gas
air
rum
a
a
examples
of
and
solutions,
colloids.
Key
fact
water
solution
is
a
homogeneous
copper
mixture
liquid
of
and
solution
water
A
zinc
the
properties
solutions.
!
water
solution,
solutions
Solute
water
a
colloid
colloid
types
of
of
a
suspension
suspensions

and
distinguishing
●
Table
distinguish
ethanol
in
water
components,
usually
oxygen,
water
vapour,
consisting
argon
and
carbon
dioxide
in
a
one
of
of
two
or
which
more
is
liquid.
nitrogen
19
Solutions,
suspensions
and
colloids
Mixtures
A
saturated
at
a
solution
par ticular
study
is
one
t hat
temperature
saturated
solutions
in
in
contains
t he
more
as
much
presence
detail
in
of
and
solute
as
can
undissolved
Unit
their
separation
be
dissolved
solute.
You
will
2.3.
Suspensions
A
suspension
cont aining
(a)
Figure
2.2.1
(a)
Soda
water
brass
are
examples
of
par ticles
mixture
whic h
can
Key
is
a
par ticles
The
be
eye.
f
in
a
lef t
are
undisturbed,
suspension
components
separated
Examples
of
which
minute,
but
by
of
eventually
a
suspension
ltration.
are
suspensions
Dust
air
dispersed
in
in
is
a
suspension
of
a
solid
visible,
in
particles
naked
heterogeneous
●
in
t he
fact
suspension
mixture
to
solutions
settle.
A
heterogeneous
and
t he
(b)
!
a
(b)
visible

is
minute
a
gas.
another

substance,
usually
a
Figure
2.2.2
Muddy
water
is
an
Powdered chalk in water is an example
●
liquid.
example
of
a
suspension
of a suspension of a solid in a liquid.
Muddy
●
water
is
anot her
example
of
a
solid
suspended
in
a
liquid.
Colloids
A
colloid
is
inter mediate
The
par ticles
undisturbed
Key
!
A
colloid
one
is
in
a
The
those
larger
the
are
than
of
particles
usually
particles
a
are
a
t hose
of
a
Examples
●
Smoke
●
Fog
also
but
solution.
you
A
1 000 000

10
in
of
air
is
and
as
nanometres

1
out
the
and
comparison
is
standing
the
for
20
be
separate
mixture
a
Transmission
a
a
microscope,
colloid
are
are
and
if
lef t
inter mediate
and
t hose
of
a
suspension.
colloid
sprays
of
in
a
solid
air
are
in
a
gas,
colloids
also
of
a
known
liquid
as
a
solid
dispersed
aerosol.
in
liquid
a
gas,
aerosols.
are
colloids
of
a
liquid
dispersed
in
a
liquid,
also
are
colloids
of
a
solid
dispersed
in
a
liquid,
also
known
t he
in
distinguishing
Table
proper ties
of
solutions,
suspensions
and
2.2.2.
T
able
2.2.2
A
comparison
of
the
properties
of
solutions,
Colloid
small
(less
than
one
nanometre
greater
than
are
visible
not
and
1000
that
to
of
a
the
solution
naked
nanometres
in
but
eye
they
(between
diameter)
heterogeneous
transparent
usually
colloids
and
suspensions
Suspension
opaque,
large
to
enough
the
1000
naked
so
eye
that
they
(greater
nanometres
in
are
visible
than
diameter)
heterogeneous
some
are
translucent
opaque
no
no
yes
no
no
yes
filtration?
components
after
a
jelly
of
given
diameter)
generally
components
by
of
t hat
suspension.
gels.
homogeneous
Appearance
Do
wit h
a
millimetre
very
mixture
separated
even
proper ties
of
emulsions.
Solution
size
the
solution
mayonnaise
as
1
Can
seen
par ticles
t hose
colloids
known
colloids
in
of
a
aerosol
Gelatine

T
ype
be
The
and
millimetres
Property
Particle
settle.
cont aining
solution
know?
6
nanometre
of
and
Milk
●
as
1
cannot
not
a
liquid.
●
Did
do
of
in
known
?
colloid
t hey
mixture
t hose
smaller
suspension,
those
of
dispersed
substance,
dispersed
than
a
between
heterogeneous
which
substance
another
in
heterogeneous
size
fact
between
mixture
a
in
has
been
while?
of
light
transmits
light
appearing
transparent
will
scatter
light
does
not
transmit
light;
it
is
opaque
Mixtures
and
their
Comparing
a
separation
the
Solutions,
properties
of
a
solution,
a
suspension
suspensions
and
colloids
and
colloid
Your
teacher
may
●
observation,
●
manipulation
Y
ou
will
be
use
this
recording
and
supplied
activity
and
to
assess:
reporting
measurement.
with
two
beakers,
a
lter
funnel
held
in
a
retort
stand,
(a)
lter
and
paper,
distilled
water,
calcium
hydroxide
powder,
copper( II)
sulfate
gelatine.
Method
1
Half
2
Place
mix
3
ll
the
a
beaker
large
with
spatula
water.
full
of
calcium
hydroxide
powder
into
the
water
and
vigorously.
Hold
the
mixture
up
to
the
light
and
look
through
it.
Is
it
transparent
or
opaque?
(b)
4
Place
the
lter
paper
in
the
lter
funnel
and
place
the
second
beaker
below

it.
5
Filter
Leave
settle
half
the
the
mixture.
other
half
of
Could
the
you
separate
mixture
for
two
the
components
hours.
Does
the
by
ltering?
Figure
(b)
2.2.3
(a)
mayonnaise
Using
is
a
your
answers
solution,
Repeat
sure
of
colloids
mixture
a
from
3,
points
suspension
or
a
4
and
5,
decide
whether
the
colloid
the
that
experiment
you
stir
each
with
colloid.
of
the
the
copper( II)
mixtures
sulfate
until
there
and
is
gelatine,
Y
ou
may
need
to
heat
the
gelatine
no
longer
particle
size
making
any
solid

Figure
of
remaining.
suspension
mixture
increasing
7
and
examples
out?
solution
6
Milk
are
2.2.4
particles
in
A
comparison
solutions,
of
the
colloids
size
and
gently.
suspensions
8
Record
your
ndings
Summary
1
2
3
How
does
the
particle
a
solution
b
a
suspension
of
a
does
b
can
c
will
be
not
Classify
a
the
not
a
table.
questions
a
Which
in
compare
transmit
separated
settle
of
with
compare
following
each
size
out
the
is
of:
that
with
true
of
a
that
of
a
suspension
of
a
colloid?
solution,
a
suspension
or
a
colloid?
light
by
ltration
after
standing?
following
as
a
solution,
a
suspension
or
a
colloid:
mayonnaise
b
chalk
c
fog
d
white
dust
in
water
vinegar.
21
Solubility
Mixtures
A2.3
Objectives
By
the
be
able
end
of
this
topic
you
dene
explain
The
the
term
solubilit y
a
in
a
of
a
 xed
solute
mass
of
is
an
indication
solvent
at
a
of
how
par ticular
muc h
of
t he
temperature.
solute
For
can
example,
solubility
we
what
separation
Solubility
dissolve
●
their
will
to:
●
and
can
 nd
t he
solubility
of
sodium
c hlor ide
in
water
by
deter mining
saturated
3
how
solution
muc h
sodium
explain
the
effect
dissolve
in
of
10 cm
water
at
temperature
on
the
reac hes
solubility
of
more
more
solute
can
be
dissolved
in
t he
a
par ticular
solvent,
saturation
point
and
we
say
t he
solution
is
t he
saturated .
from
a
solute
is
added
to
t he
solvent,
t he
solute
will
remain
in
solid
f
for m
a
and
substance
no
solubility
any
describe
When
of
solution
●
can
is
temperature.
●
c hlor ide
will
be
mixed
wit h
t he
saturated
solution.
The
solubility
of
a
solute
in
solubility
water
is
usually
measured
as
t he
mass
of
solute
t hat
will
saturate
10 0 g
of
curve
water.
perform
●
calculations
using
solubility
and
will
is
saturate
given
the
mass
100 g
of
of
solute
Key
a
solvent
at
effect
a
speci c
solubility
at
a
solute
and
in
t he
a
solvent
is
determined
by
t he
str ucture
of
t he
temperature.
of
temperature
on
solubility
For most solid solutes in water, solubility increases as temperature increases.
means
fact
saturated
which
solution
contains
can
be
as
dissolved
temperature,
undissolved
in
is
a
much
the
at
a
t hat
saturate
form
as
of
solvent,
temper ture
which
a
temperature.
will
A
has
that
This
!
combination
fact
The
Solubility
solvent
temperature.
solute
Key
and
curve.
The
!
solute
a
given
solubility
Eac h
is
a
as
will
not
saturated
since
t he
xed
less
of
temperature
mass
be
at
water.
saturated
one
t he
of
at
increases,
A
a
solution
higher
temperature
solute
can
is
dissolve
a
is
a
cr ystals
lower
mass
of
solute
saturated
temperature,
cooled,
at
greater
which
and
of
if
t he
a
at
one
solution
solute
will
temperature.
solution
You learnt earlier in t his unit t hat solubility in water is usually measured as
solute
t he mass of solute which will saturate 100 g of water. The unit for solubility
given
presence
of
is
solute.
g
n
per
100 g
water .
determining
However,
solubility
of
a
it
is
not
solute
in
practical
water
in
to
weigh
t he
100 g
laborator y,
of
water.
we
make
−3
use
of
t he
fact
t hat
pure
water
has
a
density
of
1 g cm
.
n
ot her
words,
3
1 cm
3
of
water
has
a
mass
of
1 g,
or
1 g
of
water
has
a
volume
of
1 cm
.
)retaw
3
This
70
means
t hat
100 g
of
water
has
a
volume
of
100 cm
,
and
it
is
easy
to
3
measure
g 001
60
100 cm
of
water
in
t he
laborator y.
50
When
we
plot
solubility
of
a
solute
against
temperature,
we
draw
a
graph
rep
40
known as a solubility curve . The solubility cur ve for potassium chlorate(V),
g(
30
ytilibuloS
KClO
,
is
shown
in
Figure
2.3.1.
3
20
Looking at t he solubility cur ve in Figure 2.3.1, you can see t hat t he solubility
10
of
potassium
chlorate(V)
increases
wit h
an
increase
in
temperature.
0
Solubility
0
10
20
30
40
50
60
T
emperature

Figure
2.3.1
Graph
70
80
90
information,
(°C)
showing
of
potassium
such
as
t his
can
be
used
to
obtain
various
useful
for
pieces
of
example:
the
●
solubility
cur ves
100
The
solubility
of
a
solid
at
any
temperature
wit hin
t he
range
of
t he
chlorate( V)
graph.
against
temperature
Example
✔
Exam
tip
What
Before
reading
any
graph
you
is
t he
Solubility
ensure
scale
that
of
you
each
can
axis.
interpret
the
22
two
axes
will
The
not
of
KClO
of
potassium
chlorate(V)
at
78 °C?
scales
at
78 °C

35 g
per
100 g
water
3
the
of
●
the
solubility
must
necessarily
The
temperature
at
which
cr ystals
would
just
star t
to
form
if
an
be
unsaturated
solution
point
it
containing
same.
where
is
just
saturated.
a
xed
mass
of
solute
is
cooled
to
t he
Mixtures
and
their
separation
Solubility
Example
At
what
temperature
would
cr ystals
just
begin
to
form
if
an
unsaturated
solution of potassium chlorate(V) containing 20 g of potassium chlorate(V)
dissolved
in
100 g
Temperature
at
of
water
which
is
20 g
cooled
of
from
KClO
80 °C?
saturates
100 g
of
water

55 °C.
3
∴
●
temperature
The
mass
of
at
which
solute
temperature
is
t hat
cr ystals
would
just
begin
cr ystallise
to
out
form
of
a

55 °C
saturated
solution
if
its
decreased.
Example
What
mass
solution
is
of
decreased
At
potassium
containing
64 °C,
from
25 g
of
chlorate(V)
100 g
64 °C
to
KClO
of
water
would
when
cr ystallise
t he
out
temperature
of
of
a
saturated
t he
solution
22 °C?
saturates
100 g
of
water.
3
At
22 °C,
7 g
of
KClO
saturates
100 g
of
water.
3
∴
mass of KClO
cr ystallising out of a saturated solution containing 100 g
3
of
●
The
is
water
mass

of
25 g

solute
7 g
to

be
18 g
added
to
resaturate
a
solution
if
its
temperature
increased.
Example
What mass of potassium chlorate(V) must be added to resaturate a solution
containing
increased
At
32 °C,
250 g
from
10 g
of
water
32 °C
of
to
KClO
if
t he
temperature
of
t he
saturated
solution
is
82 °C?
saturates
100 g
of
water.
3
At
82 °C,
38 g
of
KClO
saturates
100 g
of
water.
3
∴
mass
of
KClO
to
be
added
to
resaturate
a
solution
containing
100 g
3
of
and
water
mass

of
38 g

KClO
10 g
to
be

28 g
added
to
resaturate
a
solution
containing
3
28
____
250 g
of
water


250 g

70 g
100
●
The
a
minimum
given
mass
of
water
required
to
dissolve
a
xed
mass
of
solute
at
temperature.
Example
What is t he minimum mass of water required to dissolve 40 g of potassium
chlorate(V)
At
74 °C,
at
32 g
74 °C?
of
KClO
saturates
100 g
of
water.
3
100
____
∴
40 g
of
KClO
saturate

40 g
of
water

125 g
of
water.
3
32
Minimum
mass
of
water
required

125 g
23
Solubility
Mixtures
Investigating
Your
teacher
may
●
observation,
●
manipulation
Y
ou
will
be
supplied
water
the
bath),
a
a
use
this
recording
and
placed
with
effect
of
temperature
activity
and
to
on
and
their
separation
solubility
assess:
reporting
measurement.
in
groups
boiling
by
tube,
burette,
a
a
your
teacher
thermometer,
balance
and
and
a
each
beaker
potassium
group
with
will
be
water
(for
a
nitrate.
Method
Each
group
potassium
teacher
your
will
determine
nitrate,
will
tell
results
you
with
the
varying
the
the
temperature
from
mass
6 g
that
to
at
16 g,
your
which
just
group
a
specic
saturates
is
to
use.
mass
10 g
Y
ou
of
will
of
water.
then
Y
our
share
class.
1
Using
the
balance,
2
Using
the
burette,
3
Add
weigh
your
group’s
mass
of
potassium
nitrate.
3
is
equivalent
the
using
the
Carefully
all
the
nitrate
the
potassium
5
T
ake
6
Observe
the
boiling
the
7
Note
8
T
o
it
9
to
the
see
that
and
Average
outlined
of
distilled
solution
out
as
in
of
the
you
at
the
at
water
just
water
in
the
boiling
tube
(this
to
the
boiling
carefully
to
tube
and,
dissolve
as
much
the
it
which
temperature
by
stirring
it
constantly
until
bath
and
as
bottom
and
it
of
stir
cools.
the
the
solution
Look
tube
as
for
that
gently.
signs
is
of
where
it
is
forming.
the
is
temperature
board
bath,
dissolved.
water
stir
temperature
the
two
weighed
the
has
crystals
your
the
T
emperature
Mass
solution
especially
the
you
stir
nitrate
tube
note
your
on
of
possible.
temperature
ensure
again
as
solution
crystallisation,
easiest
nitrate
thermometer,
heat
10 cm
10 g).
potassium
potassium
4
to
place
your
crystals
just
accurate,
at
which
readings
teacher
reheat
the
and
(the
start
to
the
crystals
record
table
is
it
form.
solution
just
in
start
the
given
and
to
cool
form.
table
below).
(°C)
KNO
saturating
10 g
of
water
(g)
6.0
8.0
10.0
12.0
14.0
16.0
3
Solubility
of
KNO
(g
per
100 g
water)
3
10
Once
and
all
water
11
the
at
each
the
temperature.
sheet
of
1
Dene
2
What
effect
3
What
is
the
of
Record
graph
class
have
potassium
temperature,
each
a
from
mass
On
Summary
24
results
calculate
paper,
i.e.
the
these
draw
been
nitrate
solubility
solubilities
a
solubility
recorded,
that
of
in
copy
dissolved
potassium
your
curve
in
the
table
100 g
nitrate
of
at
table.
for
potassium
nitrate.
questions
solubility.
the
does
unit
temperature
used
for
have
measuring
on
the
solubility
solubility?
of
solids
in
liquids?
Mixtures
and
A2.4
Since
their
separation
Separating
mixtures
mixtures
into
form
t heir
a
Separating
mixtures
par t
of
our
component
Objectives
ever yday
par ts
is
lives,
t he
impor tant.
separation
Examples
of
t hese
include
By
the
be
able
of
drinking
water
and
t he
making
of
lter
coffee.
f
you
end
of
on
a
deser t
island
wit hout
any
drinking
water,
your
topic
you
will
identify
suitable
techniques
to
were
separate
stuck
this
to:
t he
●
purication
mixtures
knowledge
the
components
the
types
of
of
mixtures
separating
mixtures
could
help
you
to
make
pure
water
from
sea
water.
●
Mixtures
physical
are
type
means.
component
e.g.
a
met hods
of
proper ties
The
par ts
par ticle
of
is
size,
matter
met hod
t he
by
boiling
by
point,
t hat
you
component
t he
which
determined
separation
of
where
components
a
t he
mixture
physical
solubility.
will
par ts
be
t hat
can
allows
be
be
2.4.1
of
into
t hese
wit h
mixtures
to
t he
be
by
its
each
met hod.

T
able
2.4.1
simple
t he
distillation,
physical
and
separated
of
the
methods
used
to
separate
describe
the
in
method
Physical
properties
of
component
A
mixture
liquid.
of
The
a
solid
and
components
a
liquid
are
where
solid
based
does
on
not
their
dissolve
different
in
the
by
and
A
particle
ltration,
mixture
the
liquid
of
is
a
solid
lower
which
than
is
that
dissolved
in
a
liquid
of
the
solid.
The
where
methods
the
components
are
separated
only
boiling
allow
point
for
the
solid.
The
based
on
their
A
different
explain
the
liquid
of
is
collected.
a
solid
lower
The
which
than
is
that
dissolved
of
components
the
are
in
solid.
a
liquid
Both
separated
where
the
based
liquid
on
the
and
their
boiling
the
point
solid
different
terms
and
ltrate,
distillate
boiling
●
mixture
the
funnel
of
explain
the
miscible
distillation
fractional
separating
collection
points.
Simple
a
chromatography
residue
of
crystallisation,
sizes.
●
crystallisation
processes
distillation,
distillation,
and
Evaporation
funnel
parts
the
separated
fractional
separating
mixtures
simple
Filtration
crystallisation,
separating
evaporation,
Separation
mixtures
chromatography
involved
summary
a
of
ltration,
distillation,
mixtures
A
by
evaporation,
●
by
describe
separated
par ts,
summarises
toget her
t he
separated
separated
properties
Table
studying,
can
difference
and
between
immiscible
of
can
liquids.
be
boiling
points.
Fractional
distillation
A
mixture
points,
of
i.e.
two
there
completely.
The
(or
is
more)
a
miscible
difference
components
in
are
liquids
volatility.
which
have
Miscible
separated
based
different
liquids
on
are
their
boiling
ones
different
that
mix
boiling
points.
Separating
funnel
A
mixture
of
Immiscible
separated
Chromatography
A
mixture
(or
based
of
components
and
two
liquids
more)
are
on
their
dissolved
are
attraction
to
immiscible
liquids
different
liquids
do
not
which
mix.
have
The
different
components
densities.
are
densities.
substances
separated
the
which
which
based
on
will
their
travel
through
different
a
material.
solubilities
in
a
The
solvent
material.
Filtration
Filtration
does
a
not
is used to separate a mixture of a solid and a liquid where t he solid
dissolve
suspension.
in
t he
Filtration
liquid,
makes
i.e.
it
use
is
of
used
lter
to
separate
paper
to
t he
components
separate
t he
solid
filter
paper
filter
funnel
of
from
t he liquid. The lter paper works like a sieve, keeping back t he solid par ticles.
The
solid
par ticles
are
too
big
to
pass
t hrough
t he
lter
paper,
whereas
t he
the
in
liquid
par ticles
are
small
enough
to
pass
the
The
par t
residue.
t he
of
t he
The
mixture
par t
of
t he
t hat
stays
mixture
behind
t hat
solid
the
remains
filter
paper
as
t hrough.
passes
in
t he
lter
t hrough
t he
paper
lter
is
called
paper
is
residue
t he
called
suppor t
ltrate
Filtration
is
one
of
t he
steps
used
in
t he
purication
of
drinking
water.
Most
the
simple
water
purication
devices
t hat
you
might
use
in
your
homes
liquid
through:
ltration
as
t heir
solid
impurities
form
of
lter
main
from
paper
to
met hod
t he
water.
separate
of
A
purifying
coffee
t he
t he
machine
coffee
granules
water.
makes
from
They
use
t he
of
separate
a
lter
coffee.
in
filters
use
called
t he
it
the
is
filtrate
t he

Figure
2.4.1
Filtration
apparatus
25
Separating
mixtures
Mixtures
and
their
separation
Evaporation
solvent
evaporates
quickly
Evaporation is used to separate a solution of a solid dissolved in a liquid, but it
into
the
air
only allows the solid to be collected. During evaporation, the solution is boiled
allowing
boiling
the
liquid
to
vaporise
into
the
air.
The
solute
is
left
behind
in
the
solution
container.
Evaporation
is
a
fairly
rapid process
and
if
all
the
liquid
evaporates,
the solid remaining lacks any cr ystalline str ucture . The method is not suitable
if
heat
the
solid
to
be
collected
is
decomposed
by
heat.
Evaporation
is
useful
to
obtain the sodium chloride from a sodium chloride solution.
Crystallisation
solute
is
left
Like evaporation, crystallisation is used to separate a solution of a solid dissolved
behind
in

Figure
2.4.2
a
liquid,
and
it
only
allows
the
solid
to
be
collected.
Unlike
evaporation,
the
Evaporation
solution is not boiled, it is left in a container at room temperature for the liquid
to vaporise into the air. Crystallisation is a slow process and the solid remaining
has
solvent
a
distinct
water
slowly
at
of
structure.
crystallisation
is
t
required.
is
used
Water
if
of
a
hydrated
solid
crystallisation
is
containing
water
that
is
room
incorporated
temperature
this
filter
crystalline
evaporates
paper
impurities
to
in
Unit
within
8.4.
the
crystalline
Crystallisation
is
structure
useful
to
and
obtain
you
will
learn
hydrated
more
copper(II)
about
sulfate
prevent
entering
crystals (CuSO
.5H
4
O) from a copper(II) sulfate solution.
2
solution
evaporating
basin
Simple
Simple
crystals
of
the
distillation
distillation
is
also
used
to
separate
a
solution
of
a
solid
dissolved
in
a
solute
liquid. t allows both the solid and the liquid to be collected. Simple distillation is
are
left
behind
an appropriate method of separation only if the liquid has a lower boiling point

Figure
2.4.3
Crystallisation
t han
key
The
●
t he
solid,
i.e.
components
met hod
The
by
mixture
vaporisation
●
The
vapour
condenser
down
●
The
t he
poured
of
Figure
2.4.4
Apparatus
for
which
is
t he
t he
heated
up
cools
and
t he
vapour
in
before
distillation
apparatus
distillation
if
distillation
condenses
and
of
when
an
solute
t he
a
used
distillation
in
and
condenser
into
becomes
apparatus
ask
t he
is
works
until
a
is
it
solid.
Liebig
as
One
of
follows:
boils
and
t he
most
is
ask
back
collected
solution
of
evaporating
t he
in
as
and
a
t he
t he
liquid
basin
and
to
as
it
passes
liquid.
The
lef t
t he
Liebig
passes
d istillate
distillation
has
into
liquid
ask
vaporised,
to
t he
cr ystallise
gradually
solution
to
obtain
can
required.
distillation
thermometer
boiling
point
liquid
of
Liebig
condenser
distillation
water
out
flask
anti-bumping
granules
assist
smooth
boiling
receiver
cold
water
in
distillate
heat
26
be
cr ystals
simple
records
t he
condenser.
occurs.
rises
it
liquid
t he
concentration
increases

t he
of
Mixtures
The
t he
and
their
t hermometer
condenser.
t he
pure
f
liquid,
Distillation
t he
separation
solid
distilled
is
a
and
used
t hen
ver y
t he
water
is
t he
to
monitor
temperature
t he
distillate
useful
liquid
from
Separating
tap
is
met hod
af ter
water
t he
temperature
remains
of
at
t he
vapour
t he
boiling
entering
point
of
pure.
of
separation
separation.
and
constant
can
be
if
you
However,
used
to
it
need
is
obtain
to
also
pure
collect
used
water
to
bot h
make
from
✔
n
bot h
t hese
cases,
any
solution
remaining
in
t he
distillation
Exam
ask
is
very
since
it
is
not
important
to
draw
separation
Fractional
which
are
line
you
diagrams
are
of
the
required.
apparatus
Fractional
that
is
able
discarded
tip
sea
It
water.
mixtures
used
in
the
different
processes.
distillation
distillation
miscible
is
and
used
have
to
separate
different
a
mixture
boiling
points
of
two
that
or
are
more
close
liquids
together.
Miscible liquids are liquids that are able to mix. The apparatus used in fractional
distillation is similar to that used in simple distillation. However, a fractionating
column
is attached between a round-bottomed ask and the Liebig condenser.
Fractional
distillation
can
be
used
to
separate
a
solution
of
ethanol
and
water
since the boiling point of ethanol is 78 °C and that of water is 100 °C.

The
fractionating
surface
by
area.
many
liquid
the
with
top
of
of
times
fractionating
the
on
column.
the
the
has
Vaporisation
condensation
place
column
lowest
column
a
the
Vapours
boiling
of
of
The
temperature
constant
the
each
the
point
and
2.4.5
a
Fractional
fractionating
distillation
column
thermometer.
takes
surface
first
using
followed
vapour
Figure
large
at
liquid
the
as
remains
boiling
it
distils
point
of
separately
reach
enter
water
the
out
condenser
Liebig
condenser
cold
water
distillation
in
flask
receiver.
A
fresh
anti-bumping
is
used
granules
each
receiver
to
catch
distillate
heat
?
Did
The
The
met hod
by
which
t he
apparatus
for
fractional
distillation
works
is
you
process
of
know?
fractional
as
distillation
is
used
in
several
follows.
industries
come
●
The
mixture
boils
and
vapours
of
bot h
liquids
enter
and
move
up
across.
●
As
the
mixture
increasingly
lower
the
of
in
point
consists
where
vapours
richer
boiling
column
into
column
moves
more
(ethanol),
only
condenser,
the
t hey
of
the
condense
up
volatile
until
more
condenses
the
the
is
vaporise
fractionating
component,
vapour
volatile
and
and
column,
i.e.
the
reaching
component.
collected
as
the
many
the
This
top
The
vapour
of
t he
less
volatile
liquid,
i.e.
t he
one
with
t he
(water),
condenses
in
t he
fractionating
column
and
separate
the
(Unit
15.1),
have
in
the
fermentation
of
the
vapour
higher
and
in
passes
industry
to
different
fractions
kerosene
Also
the
rum
ethanol
the
mixture
separate
petroleum
and
liquid
air
into
crude
such
diesel
can
(Unit
be
oxygen
as
oil
into
gasoline,
14.1).
fractionally
and
nitrogen
boiling
returns
to
which
have
various
uses
t he
(Unit
round-bottomed
to
from
gases
point
used
the
distillate
wit h
is
becomes
distilled
●
It
might
times.
it
one
you
t he
industry
fractionating
that
20).
ask.
27
Separating
mixtures
Mixtures
●
When
almost
temperature
reaching
second
●
Once
t he
of
top
t he
to
of
container
t he
liquid,
all
begins
t he
and
liquid
Separating
is
volatile
showing
column
liquid
t hat
and
a
has
distilled
mixture
distilling
of
over.
their
over,
bot h
This
is
separation
t he
vapours
is
collected
in
a
discarded.
temperature
t hat
more
rise,
and
reaches
t hen
t he
boiling
distilled
into
a
point
t hird
of
t he
less
volatile
container.
funnel
A separating funnel is used to separate a mixture of liquids that are immiscible
and
have
different
densities.
Immiscible
liquids
are
liquids
which
are
unable
oil
liquid
to mix. A separating funnel is a container that has a tap at the bottom, allowing
interface
water
oil
one
liquid
reduce
water
to
the
are
be
drained
amount
two
of
liquids
off
before
liquids
that
lost
are
the
at
other.
the
t
is
usually
interface
immiscible
and
of
they
the
have
conical
two
in
shape
liquids.
different
Oil
to
and
densities.
f
a mixture of oil and water is placed in a separating funnel, the oil with a lower
density
The
●
met hod
The
r un
●
oats
tap
The
tap
by
is
into
of

Figure
2.4.6
separating
Separation
runs
●
The
t he
a
t he
is
tap
you
Chromatography
is
their
use
it
work.
to
forensic
For
analyse
presence
of
from
body
illegal
they
to
explosives.
crime
fluids
drugs,
scenes,
are
detect
If
the
colourless,
a
on
the
with
the
them
to
for
the
t he
liquid
wit h
again
(oil)
a
to
to
second
whic h
t hrough
a
t he
is
as
follows:
higher
density
(water)
to
interface
almost
reaches
it
and
t he
rst
second.
allow
r un
a
into
container
ver y
t he
are
small
amount
container
and
of
t he
t hen
liquid
closed.
wit h
The
discarded.
are
is
used
coloured
to
mater ial,
e.g.
or
separate
can
lter
be
a
mixture
paper.
coloured,
of
The
and
dissolved
substances
whic h
are
will
separated
on:
soluble
●
how
strongly
and,
residues
spots
that
locating
are
t hey
in
are
t he
solvent
attracted
to
used
t he
paper.
inks
and
food
colourings
are
mixtures
of
two
or
more
dyes,
which
can
at
separated
by
paper
chromatography.
by
which
from
form
agent
chromatogram.
colourless
t hey
analyse
The
met hod
paper
chromatography
works
is
as
follows:
is
A
drop
of
the
dye
mixture
is
placed
1
cm
from
the
bottom
of
a
rectangular
This
of
absorbent
paper,
e.g.
lter
paper.
The
paper
is
then
hung
in
a
spots,
containing
solvent
so
that
the
lower
edge
is
below
the
surface
of
coloured.
the
●
solvent
The
●
rates.
The
t hat
The
t he
●
dyes
paper
dyes
Once
is
t hat
t he
to
paper,
known
as
dr y.
each
a
above.
t he
paper
most
least
t he
soluble
and
and
will
be
a
in
its
t he
a
t he
solvent
in
travel
and
t he
up
mixture,
t he
paper
least
attracted
to
most
attracted
to
at
distance.
and
distance.
movement
par t
dyes
dyes
solvent
least
pattern
representing
chromatogram
t he
fur t hest
t he
completed
dissolves
different
in
t he
soluble
slowest
has
and
However,
There
one
is
fastest
t he
t he
solvent
it.
t he
t he
are
travel
allowed
t he
are
dye
up
wit h
travel
paper
the
moves
t hem
different
t he
●
and
solvent
carr ying
28
works
wit h
chromatography
beaker
making
funnel
liquid
density.
below.
chromatog raphy
piece
reacts
t he
how
●
sprayed
opened
●
be
airports,
t he
higher
scientists
example,
Many
blood
a
separating
allow
replaced
has
used
based
in
as
which
know?
travel
by
t he
to
container
density
of
substances
extensively
is
is
contents
funnel
Paper
Did
which
closed
lower
Paper
?
water
out
funnel
using
the
opened
container
water
on
of
of
up
t he
different
t he
paper,
t he
coloured
mixture.
This
paper
dyes
on
pattern
is
Mixtures
and
their
separation
Separating
mixtures
Your
may
teacher
use
Separating
using
this
mixtures
chromatography
activity
to
assess:
drop
of
dye
mixture,
●
observation,
●
manipulation
be
recording
and
Y
ou
will
two
water-based
supplied
and
datum
measurement.
with
a
markers
piece
of
e.g.
ink
reporting
of
lter
different
paper,
colours
a
beaker,
and
food
a
capillary
line
solvent
tube,
colouring.
Method
solvent
edge
1
Measure
the
length
your
depth
of
the
beaker
with
a
ruler.
The
depth
will
be
the
front
of
–
solvent
fastest
moving
of
lter
paper.
different
dye
coloured
2
Cut
the
lter
paper
into
a
rectangular
strip,
4 cm
wide
and
the
length
as
dyes
slowest
measured
in
1
point
above.
datum
line
moving
dye
3
Draw
the
a
pencil
line
at
line
1 cm
across
intervals
the
strip
with
a
2 cm
pencil
up
from
the
bottom
and
mark
dot.

Figure
2.4.7
Separation
using
paper
chromatography
4
Attach
the
5
with
6
a
a
with
drop
enough
in
the
the
its
second
place
hung
of
with
dot
the
Place
is
top
beaker
Make
to
the
strip
lower
one
of
food
water
glass
just
the
the
on
second
colouring
the
rod
on
beaker
bottom
so
above
markers
on
into
beaker,
a
edge
the
marker
of
to
the
the
rst
third
that
the
it
the
the
in
beaker.
Make
a
dot
capillary
tube
dot.
the
be
suspended
dot.
Use
pencil
will
be
of
pencil
dot.
when
strip
can
bottom
pencil
the
so
of
that
strip
of
lter
immersed
in
paper
the
?
water,
but
the
coloured
dots
will
be
above
the
Did
Using
7
Hang
the
bottom
and
strip
of
the
spread
of
lter
paper
up
the
paper
and
lter
in
the
watch
paper
beaker
the
as
so
colours
the
water
that
in
the
rises
the
water
three
up
the
wets
dots
the
Compare
colours
9
If
the
in
separate
that
plants,
known
actually
paper.
any
of
colours
Which
in
What
as
3
a
For
is
on
the
each
of
into
your
used
with
common
made
two
markers.
Did
they
contain
any
and
green
as
of
it
can
be
pigment
in
chlorophyll,
is
three
pigments,
different
orange,
yellow
green.
different
theirs
with
to
coloured
see
if
markers
different
from
coloured
you,
markers
had
yours.
questions
a
of
the
components
separation
main
separation
them
class
results
properties
deciding
2
the
your
Summary
1
from
the
common?
members
compare
results
know?
chromatography
shown
coloured
8
you
water.
the
their
of
a
mixture
are
considered
when
technique?
difference
between
using
distillation
and
evaporation
method?
following
mixtures,
component
a
a
mixture
of
salt,
b
a
mixture
of
oil,
black
sugar
explain
how
you
would
separate
parts:
pepper
and
and
water
water.
29
Extraction
of
sucrose
from
sugar
cane
A2.5
Objectives
By
the
be
able
end
of
Mixtures
this
topic
you
Extraction
of
sucrose
from
and
sugar
their
separation
cane
will
Sugar
to:
cane
was
rst
introduced
to
t he
Caribbean
by
t he
Dutch
in
about
1625
and has been a ver y impor tant par t of its economy ever since. The production
●
describe
the
extraction
of
of sucrose from t he sugar cane plant is an industrial process t hat makes use of
sucrose
from
sugar
cane
several
●
draw
a
ow
diagram
the
steps
the
separation
sugar
which
are
of
separation
involved
sucrose
in
from
The
processes
The
sugar
and
cut
The
pieces
to
The
The
cane
clarier
t he
●
The
juice
takes
mud
●
The
or
juice,
and
of
sucrose
from
sugar
cane
are
as
way
or
2.5.2
Sugar
cane
in
is
transpor ted
revolving
in
taken
t he
This
to
knives
cr ushers
produces
t he
boiler
to
is
acidic
which
and
t he
factor y,
cleaned
shredder.
water
is
juice
furnace
contains
occurs.
The
neutralises
precipitate
moves
remove
claried
or
t he
water
into
t he
juice.
juice,
under
to
syr up
Figure
as
to
t he
cane
sprayed
and
where
out,
i.e.
impurities,
juice
any
t hey
is
acids
are
t he
The
which
heated
in
t he
cane
it
is
on
t hem
bre,
burnt
enters
and
juice
conver ted
is
about
boils
evaporates
by
t he
85%
is
or
to
t he
calcium
and
into
causes
larger,
water,
pressures
successively
t he
juice
process.
35%
is
2.5.3
Andrew’s
Sugar
Factory
goes
so
to
into
t hat
juice
Barbados
t he
a
as
factor y
elds.
series
of
occurs.
t he
juice
temperatures.
concentrated
The
ltration
produces
d istillation
lower
water.
in
continuous
This
returned
lower
and
about
mud
vacuum
at
boiling
containing
where
where
successively
it
lter
impurities.
factor y
evaporators
next
rotar y
insoluble
ower

in
boilers.
which
to
caramelised
t hick
by
precipitation
t hen
are
t he
t he
added
boilers
one
har vested,
par ticles.
claried
four
from
Sugar
is
place
boilers
2.5.1
for
are
present.
bagasse
impurities
insoluble
30
separation
crushed
sugar
where
hydroxide
Figure
t he
pieces
t hen
t he
heat
stalks
small
are
dissolve
supply
●
cane
into
bagasse.

in
cane.
●
Figure
involved
follows:
●

techniques.
showing
from
but
t he
not
last
t hree
These
passes
n
t his
charred
boiler
is
a
Mixtures
and
their
separation
Extraction
●
The
t hick
place.
soon
as
‘seed’,
t he
t he
t he
are
The
added
molasses.
sugar
basket.
speed.
The
behind
damp,
tumbled
nuclei
for
it
in
of
of
molasses
are
basket
and
t he
sugar
sugar,
sugar
and
t hen
t his
The
cr ystals.
separated
t he
sugar
As
and
is
massecuite.
a
by
perforated
revolves
in
As
called
viscous
forms
cane
takes
sugar.
contains
holes
centrifuge.
wit h
of
t hick
centrifuge
t hrough
t he
grains
formation
and
from
crystallisation
massecuite
t he
sucrose
saturated
becomes
Each
in
out
dr um
t he
where
is
small
t he
syr up
cr ystals
placed
forced
outer
t he
of
molasses
is
until
exceeded,
centrifuges.
are
unrened
t hrough
sugar
(1)
in
as
is
mixture
t he
t he
cr ystalliser
remaining
massecuite
in
t he
evaporated
point
and
molasses
collected
The
The
in
into
is
ser ve
t he
cr ystals
The
remain
●
to
form,
centrifugation
are
moves
syr up
saturation
cr ystals
called
●
syr up
Here
of
at
high
basket
and
cr ystals
basket.
sugar
heated
cr ystals
are
collected
and
dried
by
being
air.
cane
shredder
(2)
crushers
bagasse
(fibre)
(3)
clarifier
(4)
cane
filter
juice
heat
water
molasses
seed
cr ystal
thick
syrup
(8)
collectors
(6)
(5)
boiler
cr ystalliser
heat
raw
sugar
(7)

Figure
2.5.4
Summary
1
Draw
a
Why
is
it
from
sugar
diagram
of
the
various
stages
in
the
extraction
of
sucrose
questions
simple
separation
2
Flow
centrifuge
of
ow
diagram
sucrose
important
to
from
use
a
of
the
sugar
steps
which
are
involved
in
the
cane.
series
of
boilers
in
the
extraction
of
sucrose
cane?
31
Extraction
of
sucrose
from
sugar
cane
Mixtures
Key
Matter
●
A
pure
can
be
Pure
●
An
par ts
substances
element
simpler
is
of
is
a
its
cannot
be
pure
by
in
of
proper ties
be
any
a
are
into
t hat
ordinar y
are
one
separated
substance
such
substances
only
classied
which
and
pure
substance
pure
element
propor tions
●
a
into
composed
can
substances
compound
types
is
composition,
component
●
classied
substance
constant
A
their
separation
concepts
●
●
and
t heir
has
and
a
xed,
t he
means.
and
or
t
constant
compounds
broken
contains
toget her
t hat
and
be
mixtures
material.
physical
cannot
t hat
of
elements
chemical
bonded
way
xed
by
and
type
down
physical
two
or
more
chemically
proper ties
in
have
into
any
means.
different
xed
changed.
A mixture consists of two or more substances combined together in varying
proportions. Each component retains its own independent properties
and has undergone no chemical reaction with any other substance in the
mixture. The components of mixtures can be separated by physical means.
●
Mixtures
can
be
heterogeneous
●
A
homogeneous
composition
cannot
●
A
classied
be
are
solution
are
mixture
is
a
A
heterogeneous
●
A
suspension
●
A
are
colloid
is
substance
dispersed
t han
●
t hose
of
100 g
●
A
●
at
The
as
wit h
mixture
a
is
each
in
which
t he
t he
sample
proper ties
and
t he
and
components
ot her.
mixture
usually
is
a
consisting
a
liquid.
a
non-uniform
heterogeneous
are
in
anot her
in
mixture
of
The
two
or
more
par ticles
in
a
solution
mixture.
in
which
substance,
mixture
anot her
smaller
in
which
substance,
t han
t hose
of
minute,
usually
a
t he
a
par ticles
usually
but
visible,
liquid.
a
of
liquid.
suspension,
but
one
The
larger
solution.
measure
at
a
of
given
solution
Possible
simple
given
t he
mass
of
solute
temperature.
also
is
a
affects
curve
solution
temperature,
temperature
The
which
will
saturate
unit
of
solubility
contains
as
much
is
a
g
is
a
t hat
in
solubility.
t he
The
presence
solubility
of
solute
as
undissolved
of
most
solids
The
met hod
separation
extraction
showing
of
by
t he
how
component
which
met hods
are
fractional
of
sucrose
cr ushing,
cr ystallisation
32
be
in
water
increases.
graph
proper ties
t he
distillation,
processes:
can
solute.
t he
solubility
of
a
solute
a
par ts
mixture
ltration,
distillation,
can
of
be
a
mixture
evaporation,
a
are
used
and
from
sugar
precipitation,
separating
centrifugation.
cane
involves
ltration,
to
separated.
cr ystallisation,
funnel
and
chromatography.
●
xed
per
temperature.
physical
determine
●
mixture
from
which
dispersed
a
a
solubility
varies
and
water
Temperature
A
a
heterogeneous
of
is
saturated
increases
●
a
solvent
dissolved
●
is
par ticles
Solubility
mass
of
dispersed
are
mixtures
small.
●
par ticles
homogeneous
t hroughout
homogeneous
one
extremely
is
uniform
distinguished
components,
into
mixtures
t he
vacuum
following
distillation,
Mixtures
and
their
separation
Practice
iv)
Practice
exam-style
At
1
Which
of
t he
temperature
and
Y
t he
v)
What
is
t he
The
following
components
vi)
What
mass
of
is
a
can
be
separated
A
mixture
contains
two
or
more
pure
Figure
2
The
Y
from
combined
shows
of
X
at
46 °C?
(1
mark)
(1
would
cr ystallise
out
of
a
mark)
saturated
100 g
62 °C
to
of
water
if
t his
24 °C?
solution
main
steps
(3
mixture
has
a
xed
component
melting
par ts
t he
in
t he
marks)
extraction
of
substances
from
sugar
cane.
toget her.
Step
D
of
containing
cooled
sucrose
A
solubility
means.
chemically
C
of
by
b
B
solubilities
correct?
mixture
is
physical
t he
same?
questions
solution
A
are
questions
questions
X
Multiple-choice
what
exam-style
of
a
1
Step
2
Step
3
Step
4
point.
mixture
are
in
a
xed
ratio.
Cutting
and
Precipitation
2
3
The
solubility
of
a
solid
in
water
A
increases
as
temperature
increases
B
increases
as
temperature
decreases
C
remains
D
decreases
The
constant
as
following
as
temperature
temperature
are
all
crushing
usually:
increases
Step
increases
colloids
6
Step
5
except:
Vacuum
A
Centrifugation
fog
distillation
B
air
C
milk
D
mayonnaise

Figure
from
4
The
process
of
fractional
distillation
depends
on
in
Flow
chart
showing
the
extraction
of
sucrose
cane
a
i)
difference
2
sugar
Complete
t he
char t
by
labelling
t he
boxes
in
3
A
melting
points
B
densities
C
solubilities
D
boiling
of
t he
components
of
t he
of
t he
components
of
t he
and
5.
(2
marks)
mixture
ii)
Describe
t he
process
taking
place
in
step
2.
mixture
(2
of
t he
components
of
t he
mixture
in
points
of
t he
components
of
t he
Why
is
it
necessar y
best
sand
is
way
to
separate
sodium
chloride
solution
boilers
B
carefully
C
ltering
simple
pouring
t he
lower
pressures
in
step
off
t he
sodium
chloride
solution
Extended
response
Chemical
(1
15
substances
marks
question
can
t he
combine
components
of
in
which
various
can
be
ways
to
separated
form
by
means.
question
1
shows
t he
solubility
cur ves
for
two
a
What
do
you
b
Solutions,
understand
by
t he
term
‘mixture’?
ionic
(2
solids,
mark)
distillation
various
Figure
4?
mixture
mixtures,
Structured
under
Total
evaporation
a
t he
and
7
6
have
by:
A
D
to
mixture
successively
The
marks)
water
iii)
5
steps
t he:
X
and
following
Y.
Use
t his
information
to
answer
marks)
t he
suspensions
and
colloids
are
examples
of
questions.
mixtures.
mixtures
90
lef t
to
Explain
in
terms
stand
and
t he
of
differences
par ticle
size,
transmission
of
between
t hese
t hree
sedimentation
light.
(6
when
marks)
)retaw
Y
80
c
You
are
given
sodium
g 001
70
The
a
mixture
chloride,
solubilities
lead
of
of
t hree
chloride
t hese
t hree
solid
and
chlorides:
silver
chlorides
chloride.
in
water
are
60
X
rep
given
in
t he
table
below.
50
g(
Compound
40
Solubility
in
cold
Solubility
ytilibuloS
water
in
hot
water
30
sodium
chloride
soluble
soluble
insoluble
soluble
insoluble
insoluble
20
lead
chloride
10
silver
chloride
0
0
10
20
30
40
50
60
70
80
i)
T
emperature
Use
t he
devise

Figure
1
Solubility
curves
for
ionic
information
substances
X
and
a
scheme
i)
Dene
t he
solubility
iii)
term
Temperature
Explain
of
‘solubility’.
has
t he
which
how
you
greatest
(2
effect
on
at
your
marks)
t he
compound?
arrived
to
ii)
Draw
a
pieces
(1
answer
to
in
separate
t he
t he
table
to
mixture
into
mark)
par ts.
labelled
of
scheme.
(5
diagram
apparatus
you
to
show
used
in
one
your
of
(2
marks)
t he
separation
(2
marks)
par t ii)
Total
above.
its
Y
component
ii)
given
(°C)
15
marks
marks)
33
A3
Atomic
For
a
long
structure
time,
people
believed
that
all
matter
Objectives
By
the
be
able
end
of
this
topic
you
will
consisted
water.
give
●
the
atomic
symbols
of
the
structure
of
Scientists
relative
charge
of
an
dene
a
proton,
a
earth,
fire,
air
and
know
that
the
smallest
identifying
is
an
atom.
Atoms
are
the
basic
and
represent
now
scale
terms
matter
matter.
into
On
a
mixtures
macroscopic
and
pure
scale
we
substances;
we
going
to
investigate
matter
on
a
microscopic
by
looking
at
the
structure
of
the
atom.
atomic
mass
atoms
of
neutron
electron
the
number
●
elements:
and
are
and
basic
now
matter
blocks
classified
the
mass
●
of
building
an
atom
give
four
elements
describe
●
the
the
particle
common
●
of
to:
number
by
A3.1
nuclear
The
structure
of
atoms
notation
Regardless
interpret
●
nuclear
determine
the
number
particles
in
an
metals
of
atom
an
have
is
the
element
the
the
one
gram
of
gold
identifying
can
and
be
one
masses
is
kilogram,
will
broken
par ticle
classied
non-metals
smallest
that
same
can
one
exhibit
gram
t he
or
same
are
into
of
an
into
smaller
element
metals
given
in
and
Units
is
par ts,
an
it
non-metals.
4.4,
17
.1
and
represented
The
and
The
in
3.1.1
by
atomic
an
atomic
symbols
of
symbol,
some
of
which
t he
represents
commonest
Tables
and
3.1.2.
properties
T
able
3.1.1
The
atomic
symbols
of
the
common
metals
element.
Element
Atomic
Aluminium
Al
symbol
Element
Atomic
Lithium
Li
Barium
Ba
Magnesium
Mg
Beryllium
Be
Manganese
Mn
Calcium
Ca
Mercury
Hg
Chromium
Cr
Nickel
Ni
Cobalt
Co
Potassium
K
Copper
Cu
Silver
Ag
Gold
Au
Sodium
Na
Iron
Fe
T in
Sn
Lead
Pb
Zinc
Zn
T
able
3.1.2
The
atomic
symbols
of
the
common
symbol
non-metals
Non-metals
is
Exam
essential
atomic
with
form
34
that
and
care,
your
letters
tip
you
symbols
elements
atom
still
of
a
For
be
gold.
proper ties
Each
of
that
making
capital
know
all
you
sure
and
the
Element
Atomic
Element
Atomic
Argon
Ar
symbol
Neon
Ne
Boron
B
Nitrogen
N
Bromine
Br
Oxygen
O
Carbon
C
Phosphorus
P
Chlorine
Cl
Silicon
Si
Fluorine
F
Sulfur
S
Helium
He
Hydrogen
H
the
common
write
that
them
you
common
Iodine
I
Krypton
Kr
correctly.
one
of
element
atom
elements
still

It
will
20.1.
Metals
✔
one
proper ties.
atom.
component
exist
chemical
be
element.

as
have
t hese
fact
can
An
if
smallest
Elements
Key
you
all
atom.
The
!
whet her
element,
of
example,
subatomic
of
notation
par ticular
to
symbol
are
of
t he
given
Atomic
We
structure
cannot
t hic kness
see
of
a
The
atoms
because
human
hair,
t hey
an
are
atom
is
incredibly
more
small.
t han
a
Compared
million
times
to
structure
of
atoms
t he
smaller.
Did
?
you
know?
7
The
average
t hat,
on
diameter
average,
However,
t here
an
are
of
an
atom
atom
is
25
par ticles
is
about
million
t hat
are
2.5

times
even
10
mm,
smaller
smaller
whic h
t han
t han
a
an
means
millimetre.
atom.
These
The
atomic
the
Latin
fundamental
par ticles
are
called
subatomic
particles
and
atoms
are
of
t hese
name
the
and
copper
Subatomic
Cu,
particles
is
are
of
of
some
derived
the
from
element.
of
the
Latin
name
For
for
iron
is
par ticles.
ferrum
Atoms
are
made
example,
up
symbols
elements
made
up
of
t hree
subatomic
par ticles:
protons,
neutrons
is
lead
Pb,
the
symbol
cuprum
is
and
and
plumbum
silver
is
for
its
and
iron
is
Fe,
symbol
its
is
symbol
argentum,
and
symbol
Ag.
electrons.
Protons
●
and
neutrons
are
found
in
t he
centre
of
an
atom
in
an
area
electrons
known
as
t he
nucleus.
Protons
and
neutrons
are
collectively
known
the
nucleons.
Electrons
●
around
Nearly
are
t he
t he
found
nucleus
(sometimes
but
all
just
volume
of
t hat
involved
are
Mass
and
Protons
are
at
in
called
movement
an
t he
of
atom.
in
mass
quite
a
a
series
t he
an
atom
distance
of
shells).
t he
levels
Most
electrons
When
charge
of
is
from
t he
known
of
t he
t he
reactions
in
nucleus,
as
atom
around
chemical
concentrated
energ y
is
in
occur,
it
nucleus.
spinning
empty
space,
constitutes
is
t he
t he
electrons
reaction.
of
subatomic
particles
the
positively
charged
par ticles
and
electrons
are
negatively
nucleus
charged.
contains
The
size
of
electron.
t he
charge
Neutrons
are
on
a
proton
electrically
is
equal
neutral
so
to
t he
have
size
no
of
t he
charge.
charge
In
an
on
atom,
an
and
an
of
atom
is
protons
is
always
electrically
t he
neutral
same
and
as
has
t he
no
number
of
electrons.
protons
neutrons
t he

number
nucleus
shells
fact
nucleus
its
orbit
as
Figure
3.1.1
The
structure
of
an
atom
Therefore,
charge.
The mass of a proton is equal to t he mass of a neutron. The mass of a proton is
24
extremely
small,
Comparing
1836
The
times
mass
heavier
proper ties
Table

t he
only
1.67

10
g.
of
proton
to
t han
of
a
a
an
The
mass
t hat
of
of
an
an
electron
electron,
a
is
even
proton
smaller.
is
about
electron.
proton,
neutron
and
electron
are
summarised
in
3.1.3.
T
able
3.1.3
Subatomic
The
properties
particle
of
a
Relative
Proton
proton,
a
neutron
charge
and
Relative
1
1
Neutron
0
1
Electron
1
an
electron
mass
1
_____
1836
Atomic
number
!
The
is
number
unique
world
t hat
to
of
a
protons
in
par ticular
have
t he
same
an
atom
element,
is
known
i.e.
t here
atomic
number.
means
t hat
For
as
are
t he
no
atomic
two
example,
number
elements
t he
atomic
in
t he
number
hydrogen
The
20
atomic
is
1,
whic h
number
of
calcium
is
ever y
20,
hydrogen
t herefore,
atom
ever y
has
calcium
1
fact
Atomic
number
protons
in
of
of
Key
and
an
the
is
the
nucleus
number
of
one
of
atom
element.
proton.
atom
has
protons.
35
The
structure
of
atoms
Atomic
In
an
atom,
protons,
Mass
!
Key
t he
since
t he
number
number
of
of
electrons
electrons
is
equal
is
to
always
t he
equal
atomic
to
t he
structure
number
of
number.
number
fact
The
number
of
protons
and
neutrons
in
an
atom
is
known
as
t he
mass
number. The mass number is not unique to a par ticular element, for example
Mass
number
is
the
total
number
polonium
of
protons
nucleus
of
and
neutrons
one
atom
of
in
an
and
astatine
bot h
have
a
mass
number
of
210.
the
element.
The number of neutrons can be calculated by subtracting t he atomic number
from
t he
mass
number
Nuclear
number,
of
i.e.
neutrons

mass
number

atomic
number
notation
We can represent an atom (or ion) of an element using the
nuclear notation:
A
X
Z
where
This
X

atomic
notation
protons,
is
symbol,
ver y
neutrons
A
useful
and

mass
number
because
electrons
The
number
of
protons
The
number
of
neutrons
is
equal
to
A
●
The
number
of
electrons
is
equal
to
t he
Examples

T
able
to
allows
us
Z
to

atomic
calculate
number.
t he
number
of
atom.
●
to
equal
it
an
●
equal
is
in
and
Z

Z
number
of
protons,
which
is
Z
are
3.1.4
given
The
Element
in
Table
number
Nuclear
of
3.1.4.
subatomic
particles
Number
of
Protons
(Z)
in
the
atoms
of
three
elements
notation
Neutrons
(A–Z)
Electrons
14
Nitrogen
N
7
7
7
AI
13
14
13
Cl
17
20
17
7
27
Aluminium
13
37
Chlorine
17
The
nuclear
elements
on
notations
page
Summary
1
Which
a
2
Dene
of
the
the
3
For
each
electrons
of
elements
in
the
the
36
B
5
is/are
be
found
responsible
b
mass
in
t he
volume
for
of
periodic
table
the:
the
atom?
following
number.
nuclear
notations,
give
the
number
neutrons.
11
a
can
terms:
number,
and
atom
atom
following
atomic
all
questions
particle(s)
mass
for
360.
40
23
b
Na
11
c
Ca
20
of
protons,
of
Atomic
structure
A3.2
The
Electrons
spin
energ y
The
electronic
around
shells.
Each
t he
configuration
nucleus
energy
shell
of
is
a
an
atom
xed
in
a
of
an
series
distance
of
from
atom
levels
and
t he
electrons
in
t he
same
shell
have
t he
t he
same
known
nucleus
amount
of
configuration
of
as
By
the
be
able
end
electrons
are
arranged
in
t he
energy
shells
in
a
specic
way.
t he
arrangement
of
electrons
in
an
atom,
known
as
t he
of
(or
str ucture),
using
anot her
scientic
this
topic
you
will
t he
We
give
the
maximum
allowed
number
in
the
of
rst
can
energy
shells
of
an
atom
electronic
work
●
conguration
atom
energy.
three
represent
an
to:
electrons
The
of
Objectives
●
atom
electronic
out
the
electronic
model.
conguration
electron
of
the
rst
20
elements
proton
represent
●
the
conguration
×
electronic
of
an
atom
in
writing
represent
●
the
conguration
energy
shells
shell
an
atom
by
a
diagram
explain
●
electronic
of
the
term
valence
electron.
neutron
nucleus
×

In
t his
Figure
scientic
around
t he
3.2.1
Model
model,
nucleus,
but
t he
as
of
the
arrangement
energy
t his
is
shells
only
a
of
are
electrons
drawn
model,
t his
is
in
as
an
atom
concentric
not
how
t hey
circles
actually
Did
?
look.
The
is
The
shell
shells
are
closest
number
2,
to
and
numbered
t he
so
according
nucleus
is
to
assigned
t heir
distance
number
1,
t he
from
next
t he
you
know?
nucleus.
fur t hest
away
on.
The
maximum
number
that
an
shell
energy
of
can
electrons
hold
is
2
Each
shell
can
hold
up
to
a
cer tain
maximum
number
of
electrons:
given
by
is
shell
3
●
shell
number
1
can
hold
a
maximum
of
2
the
can,
the
shell
number
2
can
hold
a
maximum
of
8
therefore,
shell
8
number
3
may
be
considered
to
hold
a
maximum
of
of
32
filling
electrons.
shells
maximum
hold
more
numbers
conguration
of
an
electrons,
since
atom
you
wit h
but
will
more
it
not
t han
is
not
have
20
necessar y
to
work
to
out
know
t he
t heir
electron
have
3,
in
electrons.
2
The
by
negative
an
electrostatic
around
t he
energy
t hey
energy
t han
can
electrons
only
force
nucleus
possess.
t hose
occupy
a
are
constantly
of
and
attraction .
t heir
Electrons
in
t he
distance
in
shells
specic
being
shell
t he
if
The
t hey
have
t he
closest
from
to
electrons
from
shells
fur t her
attracted
t he
t he
t he
positive
maintain
nucleus
to
t he
required
t heir
because
nucleus
nucleus.
nucleus
In
fact,
spin
of
have
t he
chemical
proper ties
of
an
element
in
an
atom
of
t hat
element,
in
depend
on
par ticular,
t he
shell
t he
outermost
energy
where
Shell
actually
n
number
hold
electrons
next
2
a
and
shell
electrons
number
However,
4.
have
(up
maximum
3,
When
in
4
to
been
electrons
number
placed
after
these
placed
any
10)
8
are
Only
are
when
something
shell
electrons
number
number
a
number
placed
electrons
shell
hold
happens.
in
remaining
placed
in
shell
3.
less
electrons
energy.
t he
arrangement
number
of
Key
fact
of
electrostatic
force
of
electrons
attraction
in
18
can
been
the
An
electrons
of
electrons.
shell
!
The
4
up
unusual
Fur t her
,
electrons
number
●
number.
2n
electrons
maximum
●
formula
is
the
force
that
exists
shell.
between
two
oppositely
charged
particles.
37
The
electronic
configuration
of
an
atom
Atomic
Shell
Key
!
by
an
electronic
atom
is
electrons
diagrams
fact
The
The
structure
the
in
configuration
arrangement
the
energy
shell
of
shells
electronic
drawing
a
conguration
shell
diagram
or
of
in
an
atom
writing
of
an
using
element
can
numbers.
In
be
represented
order
to
draw
a
of
of
diagram
of
an
atom,
t he
following
steps
must
be
followed.
the
1)
Determine
t he
number
of
protons,
neutrons
and
electrons
in
t he
atom
atom.
2)
using
t he
Draw
a
atomic
small
neutrons
3)
Work
up
out
4)
shell
circle
inside
electrons,
t he
in
2,
Represent
number
for
t his
and
t he
and
so
t he
nucleus
number
and
(Unit
write
t he
3.1).
number
of
protons
and
circle.
electronic
order,
mass
i.e.
ll
conguration
up
shell
1
rst
by
and,
lling
when
up
t hat
t he
is
shells
full,
star t
wit h
to
ll
on.
electronic
conguration
by
drawing
concentric
circles
around t he nucleus. The number of circles you should draw is determined
by t he number of shells t hat you are going to ll or par tially ll. Use crosses
or
dots
as
a
to
pair.
contains
represent
Draw
5
or
t he
more
t he
electrons.
electrons
in
Draw
t he
t he
ot her
2
electrons
shells
as
in
pairs
shell
number
when
t he
1
shell
electrons.
Examples
12
1
The
str ucture
of
a
carbon
atom,
C.
6
×
××
A
carbon
6
6p
×
atom
has:
protons
×
6n
6
neutrons
6
electrons.
(12

6)
×
12

T
able
3.2.1
Determining
the
electronic
conguration
of
a
carbon
atom
C
carbon,
6
Shell

Figure
of
a
3.2.2
carbon
Electronic
number
Maximum
number
of
electrons
Number
of
electrons
in
carbon
conguration
atom
1
2
2
2
8
4
The
t he
electronic
symbol
shell
of
conguration
t he
separated
element
by
of
a
carbon
followed
commas,
i.e.
C
by
atom
t he
can
be
number
written
of
by
electrons
writing
in
each
(2,4)
39
2
The
str ucture
of
a
potassium
atom,
K.
19
×
××
A
potassium
atom
has:
××
19
20
20n
××
××
××
××
19p
19

protons
neutrons
(39

19)
electrons.
T
able
3.2.2
Determining
the
electronic
conguration
of
a
potassium
atom
××
Shell
number
Maximum
number
of
electrons
Number
of
electrons
in
potassium
××
1
2
2
2
8
8
3
8
8
4
not
39
potassium,
K
19

Figure
of
a
3.2.3
Electronic
potassium
conguration
atom
The
38
electronic
necessary
conguration
1
of
a
potassium
atom
is
K
(2,8,8,1)
Atomic
structure
3
str ucture
The
The
of
ot her
electronic
given
in
of
t he
t he
electronic
shell
congurations
diagrams
in
Figure
3.2.4
of
atoms
and
are
of
ot her
written
×
an
atom
Table
are
3.2.3.
××
8p
×
5p
0n
elements
in
Electronic
hydrogen
H
(1)
boron
B
(2,3)
oxygen
O
sodium
Na
argon
Ar
calcium
Ca
6n
8n

(2,6)
T
able
3.2.3
(2,8,1)
(2,8,8)
(2,8,8,2)
Written
congurations
×
1
of
electronic
the
atoms
shown
in
×
Figure
11
H
configuration
××
×
1p
hydrogen,
of
atoms.
Element
Examples
configuration
boron,
B
oxygen,
O
5
1
3.2.4
16
8
×
×
××
××
××
××
20p
20n
××
××
××
××
××
××
××
××
22n
××
18p
××
××
12n
××
××
××
××
11p
××
✔
It
argon,
Na
Ar
important
that
shell
Ca
calcium,
diagrams
numbers

Figure
3.2.4
Shell
diagrams
showing
the
electronic
congurations
of
atoms
Valence
draw
of
1
to
20,
i.e.
atomic
hydrogen
in
the
periodic
to
table.
electrons
example,
The
can
atoms
elements
The electrons in t he outermost energy shell are known as
For
you
of
calcium
different
of
20
18
11
is
tip
40
40
23
sodium,
Exam
potassium
outer most
(2,8,8,1)
e le c t ro ns
are
has
t he
one
valence
on es
t h at
valence electrons .
electron.
are
involve d
in
c h emical
reactions, i.e. t he va le n ce e le ct ro n s. A dia g ram o f an a tom can b e drawn t h at
shows
only
t he
va le n c e
e le ct ro n s.
×
××
3.2.5
Diagrams
electrons
1
What
2
Represent
is
the
11p
12n
O
boron,
sodium,
oxygen,
maximum
a
number
electronic
shell
magnesium,
of
each
of
sodium
electrons
conguration
diagram
and
20n
Na
and
argon,
argon
atoms
Ar
showing
the
the
of
allowed
each
of
in
the
shell
following
35
Mg
b
elements
chlorine,
2?
atoms
20
c
Cl
neon,
17
in
number
writing:
12
For
18p
only
24
3
××
questions
the
both
of
3.2. 5.
××
oxygen,
Summary
a
Fig ure
×
B
valence
using
in
××
×
g ive n
××
8n
boron,
Figure
××
×
6n
a re
×
8p
×
5p

E xa mple s
question
2,
Ne.
10
give
the
number
of
valence
electrons.
39
Isotopes
and
radioactivity
Atomic
A3.3
Objectives
By
the
be
able
end
of
this
topic
you
Isotopes
and
structure
radioactivity
will
Isotopy
to:
The
dene
●
the
terms
isotope
atomic
number
is
unique
to
a
particular
element.
For
example,
all
atoms
and
of
magnesium
have
an
atomic
number
of
12,
i.e.
they
all
have
12
protons
and,
isotopy
therefore,
●
dene
●
explain
relative
atomic
12
electrons.
The
number
of
neutrons
in
atoms
of
the
same
element
mass
is not unique. For example, most magnesium atoms have 12 neutrons, however,
what
is
meant
by
a
some
radioactive
have
number
describe
●
13
neutrons
and
others
have
1
4
neutrons.
Atoms
the
uses
of
protons
and
electrons
but
different
numbers
of
neutrons
same
called
isotopy
isotopes.
In
ot her
words,
numbers.
Key
the
are
of
isotopes. The occurence of these different isotopes is known as
radioactive
!
with
isotope
fact
●
isotopes
Isotopes
have
t he
same
atomic
number
but
different
mass
have:
the same chemical properties and electrical properties because they have
the same number and arrangement of electrons, e.g. if the different isotopes
Isotopes
are
different
atoms
of
the
of magnesium react with oxygen, the chemical reaction would be the same
same
element
that
have
the
same
●
number
but
of
protons
different
and
numbers
slightly
different
of
of
neutrons.
neutrons,
different
Most
Key
!
are
fact
of
the
the
is
the
same
same
electrons
occurrence
element
number
but
of
that
of
have
The
isotope
abund ance
t he
proper ties
different
because
isotopes
of
of
t he
different
magnesium
have
numbers
slightly
of
of
more
unstable
an
t he
t han
ones
element
one
decay
in
a
isotope,
into
sample
but
ot her
of
t he
not
all
isotopes.
element
of
The
is
t hese
isotopes
percentage
referred
to
as
of
t he
isotope.
have
protons
different
atoms
e.g.
masses.
elements
stable.
each
Isotopy
physical
electrons
and
numbers
Examples
of
1
Carbon
neutrons.
Carbon, atomic number 6, has
three naturally occurring isotopes, one with
a mass number of 12, one with a mass number of 13 and one with a mass
number of 1
4. There are two main methods of representing these isotopes:
●
Using
nuclear
C
By
14
C
6
●
notation:
13
12
C
6
6
name:
carbon-12
or
C-12
carbon-13
or
C-13
carbon-14
or
C-14.
Carbon-12 has 6 neutrons, carbon-13 has 7 neutrons and carbon-1
4, which
is unstable, has 8 neutrons. Carbon-12 is the most abundant carbon isotope.
In fact 98.89% of all naturally occurring carbon is the carbon-12 isotope.
Did
?
you
2
know?
Hydrogen
Hydrogen
The
is
deuterium
heavier
since
it
made
of
from
normal
heavy
used
than
has
an
normal
extra
hydrogen
This
nuclear
of
is
has
three
naturally
in
known
heavy
reactors
Water
place
as
water
to
is
slow
H
thus
the
fast-moving
enabling
a
isotopes.
hydrogen
1
down
occurring
hydrogen
neutron.
deuterium
water.
in
isotope
neutrons,
sustained
2
or
protium
H
1
3
or
deuterium
1
H
or
tritium
1
chain

Figure
3.3.1
The
three
isotopes
of
hydrogen
reaction.
Hydrogen is the only element that has different names for its isotopes.
These are given in Figure 3.3.1. Protium, or normal hydrogen as it is usually
40
Atomic
structure
Isotopes
and
radioactivity
called, has a single proton in its nucleus. It is the most abundant hydrogen
isotope, making up 99.985% of all naturally occurring hydrogen.
3
Chlorine
35
Chlorine
has
two
naturally
occurring
Cl,
isotopes,
or
chlorine-35,
and
17
37
Cl,
or
chlorine-37
.
Approximately
75%
of
naturally
occurring
chlorine
17
is
t he
chlorine-35
Relative
Chemists
mass
of
smaller
system
ensure
in
To
t he
To
could
unit
t hat
a
t hese
ratio
t his
t he
units
mass
of
a
gram
t he
6
or
t he
atom.
is
t he
t hat
chlorine-37
carbon-12
of
isotope.
of
of
but
They
atoms.
t he
They
wit h,
mass
because
needed
but
of
a
t he
much
designed
t hey
each
had
atom
a
to
and
atoms.
t he
has
was
chose
number
unit
as
assigned
t he
as
a
basis
to
work
nature.
t hey
mass
new
was
one-twelf t h
chosen
in
mass,
a
t his
atom
atoms,
work
abundance
dened
carbon-12
of
to
isotope
and
carbon-12
Therefore,
mass
easier
of
clumsy.
representative
masses
stability
They
mass
ver y
t he
are
representative
A
t he
becomes
measure
are
because
neutrons.
amu.
1.00
to
actual
great
12,
25%
measure
it
numbers
numbers
as
its
be
to
small,
numbers
to
and
grams
so
us
and
mass
system
of
carbon-12
mass
a
t han
because
protons
is
gives
same
make
use
atom
t hat
carbon-12
of
atomic
an
design
from
isotope
mass
number
12,
i.e.
one-twelf t h
a
of
t he
of
mass
a
of
it
t he
12.00
carbon-12
for
has
6
mass
atomic
atom
has
Key
!
fact
amu.
Relative
atomic
mass,
A
,
is
the
r
The
mass
of
carbon-12
Relative
an
atom
atom
atomic
was
of
an
t hen
mass
is
element
assigned
given
t he
compared
a
value
symbol
to
one-twelf t h
known
as
relative
t he
mass
atomic
of
a
mass .
average
mass
element
compared
the
A
mass
of
of
an
one
atom
to
atom
of
an
one-twelfth
of
carbon-12.
r
Relative atomic mass, t herefore, compares t he mass of an atom of an element
to
one-twelf t h
value,
When
relative
t he
mass
atomic
calculating
of
mass
t he
a
carbon-12
has
no
relative
atom.
Because
it
is
a
comparative
units
atomic
mass
of
an
element,
t he
of
each
isotope
is
taken
into
account.
For
example,
fact
relative
A
abundance
Key
!
t he
radioactive
isotope
has
an
relative
unstable
nucleus
which
decays
atomic mass of chlorine, which is 35.5, is t he average mass of t he two isotopes
spontaneously
of
chlorine
gas,
and
according
approximately
25%
consists
to
75%
of
t he
t heir
of
relative
t he
abundance.
sample
chlorine-37
consists
of
In
a
t he
75
atomic
mass
of
chlorine

and
atomic
neutrons)
isotopes
not
real
a
when
whole
atom
of
mass
an
gives
atom
has.
calculating
number,
carbon
e.g.
has
a
rough
idea
However,
relative
t he
of
chlorine-35
isotope
form
by
to
emitting
a
more
stable
particles
and
radiation.
25
t he
because
atomic
relative
12.01
1
chlorine
____

(
35
)

37

)
35.5
100
number
we
mass,
atomic

(
100
Relative
of
isotope.
____
Relative
sample
are
t he
mass
of
of
nucleons
looking
relative
carbon
at
a
(protons
mixture
atomic
is
but
you
know?
of
mass
12.01
1,
Did
?
The
three
and
radiation
main
types
of
particles
is
no
nucleons.
isotopes
•
by
radioactive
are:
alpha
( )
consist
of
neutrons
Radioactivity
emitted
particles,
2
protons
and
have
which
and
a
2
charge
of
2
Some isotopes have unstable nuclei. These are known as rad ioactive isotopes .
•
beta
( )
particles,
which
These isotopes undergo radioactive decay by spontaneously ejecting par ticles
consist
and
radiation
from
t heir
nuclei.
Radioactive
isotopes
eject
t hese
become
different
more
stable
and
in
t he
process
t hey
may
produce
an
an
electron
atom
of
a
element.
•
charge
gamma
is
a
form
of
time
taken
for
half
of
t he
nuclei
in
a
sample
of
a
radioactive
isotope
( )
of
radiation,
high
radioactive
decay
is
known
as
t he
half-life
of
t he
which
energy
radiation
and
to
has
undergo
have
1
electromagnetic
The
and
par ticles
a
to
of
neither
mass
nor
a
charge.
isotope.
41
Isotopes
and
radioactivity
Uses
of
radioactive
Carbon-14
Carbon-14
up
to
d ating
living
mass.
is
of
sites.
5700
is
t he
When
It
determine
which
use
contain
in
ratio
a
of
t he
have
t he
age
of
been
fact
or
carbon-14
as
living
constantly
living
to
old,
makes
same
(animals)
a
animal
remains,
isotopes
plant
and
discovered
t hat
t he
in
places
half-life
of
such
as
radioactive
years.
present
organism
food
used
years
organisms
This
carbon-14
t he
is
60 000
archeological
All
structure
dating
about
carbon-14
Atomic
in
organism
in
body
molecules
dioxide
dies,
carbon-12
dioxide
organism’s
takes
carbon
and
carbon
it
in
in
t he
decays,
a
specic
ratio
atmosphere.
it
is
containing
replaced
carbon
in
As
by
t he
because
t he
form
(plants).
stops
taking
in
t hese
carbon
containing
molecules and t he carbon-14 is not replaced as it decays. The ratio of carbon-14
to
by
carbon-12,
expected

Figure
to
3.3.2
determine
Carbon-14
the
age
of
dating
some
is
used
fossils
of
t herefore,
comparing
t he
ratio
carbon-14
for
was
ratio
t hat
half
decreases.
of
organism
of
The
carbon-14
t he
if
age
to
it
was
expected
of
a
specimen
carbon-12
alive.
amount,
in
For
t he
can
be
example,
t hen
t he
determined
specimen
if
wit h
t he
specimen
t he
amount
would
be
5700 years old, if it was a quar ter of t he expected amount, t hen t he specimen
would
be
1
1 400
years
old.
Radiotherapy
Radiotherapy
tumours
are
sensitive
to
uses
radiation
composed
damage
of
by
to
cure
rapidly
or
control
dividing
radiation.
They
cancer.
cells
can
and
be
Cancerous
these
cells
controlled
are
or
growths
or
particularly
eliminated
by
irradiating the area containing the growth with external or internal radiation.
External
irradiation
radiation
Internal
gamma
a
tiny
from
beta
Figure
treat
3.3.3
Radiotherapy
cancerous
growths
is
used
can
involves
emitter,
protective
be
carried
radioactive
irradiation
or
cancerous

a
into
capsule
tumour.
For
or
out
cobalt-60
eit her
t he
wire
injecting
target
(a
example,
by
directing
source
area,
a
radioactive
a
t he
placing
seed)
is
beam
a
isotope,
radiation
directly
used
to
of
cancerous
radioactive
or
iodine-131
at
at
treat
t he
gamma
growt h.
usually
source
site
t hyroid
of
a
in
t he
cancer
to
and radioactive seeds containing iridium-192, palladium-103 and iodine-125
are
used
to
treat
breast
and
prostate
cancer
and
brain
tumours.
Tracers
Radioactive
isotopes
are
used
as
tracers
in
the
medical
eld
as
a
diagnostic
tool. These tracers generally have a short half-life so they do not remain in the
body
for
ver y
bloodstream
long.
and
as
A
it
small
amount
moves
around
of
the
the
tracer
body
it
is
usually
emits
injected
gamma
rays
into
the
which
can
be obser ved using special equipment. This allows the physician to obser ve the
functioning of specic organs. Examples of medical tracers are:
●
Technetium-99
studies
of
skeleton,
●
most
lungs,
Iodine-131
t hyroid
is
is
used
organs
liver,
used
to
to
in
gall
produce
t he
bladder
image
images
body,
and
and
especially
and
carr y
carr y
t he
out
brain,
functional
hear t
muscle,
kidneys.
out
functional
studies
of
t he
gland.
Another example of the use of radioactive tracers is in determining the uptake of
atmospheric carbon dioxide by plants. Plants can be grown in an environment
containing radioactive carbon dioxide, i.e. carbon dioxide that has been made
by
42
replacing
the
carbon-12
atoms
in
the
molecules
with
carbon-1
4
atoms.
Atomic
structure
Isotopes
and
radioactivity
Using a Geiger counter (a machine that detects radiation) the parts of the plant
that absorb the radioactive carbon dioxide can be identied.
Energy
generation
Radioactive isotopes are used to generate electricity in nuclear power stations.
The
isotopes
they
smaller
an
it
splits
of
of
split
ones
two
that
ssion,
Nuclear
either
into
amount
are
nuclear
nuclei.
atom
also
used
undergo
power
smaller
The
releasing
atoms
or
more
large
the
use
neutrons
and
splits,
uranium-235
releases
neutrons
amounts
nucleus
plutonium-239
and
released
ver y
when
stations
uranium-235
energy.
release
i.e.
two
can
is
or
by
a
free
neutrons
strike
This
energy
sets
when
into
two
plutonium-239.
str uck
three
then
energy.
or
of
usually
other
up
a
If
neutron,
and
atoms,
chain
a
large
which
reaction
which releases enormous amounts of energy.
Did
?
you
know?
Ba
3
One
energy
235
type
of
atom
bomb
derives
U
neutrons
Ba
Kr
its
destructive
force
from
nuclear
1
fission.
Only
two
atom
bombs
have
neutron
Ba
235
235
energy
U
been
used
during
warfare,
both
by
U
Kr
the
USA
War
Kr
II.
towards
The
first,
the
a
end
of
uranium
World
fission
Ba
235
bomb,
U
code
named
‘Little
Boy’,
energy
was
Kr
city

Figure
3.3.4
The
chain
reaction
in
splitting
a
uranium
exploded
of
The
fission
t he
chain
reaction
is
controlled,
t he
energy
produced
can
be
used
electricity.
If
t he
chain
reaction
is
not
controlled,
it
results
Heart
A
explosion
as
occurs
in
an
atom
hear t.
It
connected
in
the
Man’,
was
in
plutonium
named
detonated
Japan
three
over
days
later.
bomb.
is
to
is
a
medical
implanted
t he
hear t
device
under
muscle
t hat
t he
by
is
skin
used
just
to
regulate
below
t he
t he
collar
beating
bone
of
and
is
early
1970s,
some
Did
?
you
pacemakers
were
developed
that
were
powered
by
is
to
thought
100
that
people
pacemakers
radioactive decay, it emits energy. In the pacemaker batter y, this energy is used
by
generate
an
electric
powered
current
by
which
chemical
delivers
batteries
about
have
a
0.2
milliwatt
lifespan
of
of
about
power.
10
only
living
that
plutonium-238
use
for
Pacemakers
know?
electrodes.
batteries containing plutonium-238. As the plutonium-238 undergoes natural
to
a
code
a
It
In
Japanese
August,
pacemakers
pacemaker
t he
such
second,
bomb,
Nagasaki
nuclear
6
to
‘Fat
generate
the
on
atom
1945.
If
over
Hiroshima
was
never
several
about
today
are
powered
batteries.
really
reasons,
50
have
Their
developed
one
of
the
years.
main
ones
being
the
reluctance
of
To replace the batteries, the pacemaker has to be surgically removed and then
people
replaced.
Since
the
half-life
of
plutonium-238
is
about
87
years,
to
have
by
plutonium-238
batteries
should
be
able
to
deliver
current
for
lifetime
Summary
1
Dene
a
2
the
without
having
to
be
the
sodium,
following
in
their
body
replaced.
terms:
b
similarities
Na-23
3
Explain
why
4
Explain
what
5
How
is
plutonium
life.
questions
isotope
Give
containing
a
for
patient’s
device
pacemakers
radioactive
powered
a
and
relative
a
and
differences
atomic
the
two
mass.
isotopes
of
Na-22.
atomic
radioactive
carbon-14
relative
between
used
in
mass
has
isotope
the
no
units.
is.
dating
of
fossil
samples?
43
Isotopes
and
radioactivity
Atomic
Key
●
concepts
Atoms
are
t he
identifying
●
Atoms
basic
par ticle
consist
par ticles:
●
structure
Protons
known
of
and
an
t hree
protons,
as
building
of
of
are
nucleus.
and
found
Protons
matter.
t hat
fundamental
neutrons
neutrons
t he
blocks
element
has
An
t he
par ticles,
atom
is
proper ties
known
as
t he
of
smallest
t he
element.
subatomic
electrons
in
the
and
centre
of
neutrons
t he
are
atom
in
an
collectively
area
known
as
nucleons
●
Electrons
levels
amount
●
Protons
of
The
an
found
size
as
at
quite
energ y
a
distance
shells.
from
Electrons
in
t he
t he
nucleus
same
in
shell
a
series
have
of
t he
same
energy.
are
neutrons
●
are
known
positively
have
of
no
t he
electron.
charged,
charge
In
an
electrons
are
negatively
charged
and
charge.
on
atom,
a
proton
t he
is
equal
number
of
to
t he
protons
size
of
equals
t he
t he
charge
on
number
of
electrons.
●
The
mass
of
a
proton
is
equal
to
t he
mass
of
a
neutron.
An
electron
has
a
1
____
mass
of
t he
mass
of
a
proton
or
a
neutron.
1836
●
Protons
are
and
neutrons
responsible
●
The
number
●
The
total
mass
●
The
as
●
of
are
t he
protons
number
of
responsible
volume
in
an
protons
of
an
atom
and
for
t he
mass
of
an
atom.
Electrons
atom.
is
known
neutrons
as
in
t he
an
atomic
atom
is
number
known
as
t he
number
electrons
t he
Each
for
are
arranged
electronic
electron
in
t he
energy
shells
in
a
specic
way
known
conguration
shell
can
hold
up
to
a
cer tain
maximum
number
of
electrons.
●
Shells
●
The
closest
using
Electrons
●
The
Isotopes
number
They
is
same
nucleus
by
a
shell
outermost
proper ties
t he
are
of
have
Isotopy
t he
in
or
t he
chemical
electrons
●
in
t he
atoms
different
protons
t he
t he
ll
conguration
numbers
●
●
to
electronic
same
number
an
t he
atomic
of
are
can
known
element
be
represented
in
writing
of
t he
same
but
number
of
atoms
protons
as
valence
depend
on
t he
electrons
arrangement
of
element.
electrons
occurrence
atom
diagram.
atoms
and
rst.
an
shell
of
of
up
of
and
but
of
element
different
different
t he
same
electrons
t hat
have
numbers
but
mass
of
t he
same
neutrons.
numbers.
element
t hat
different
have
numbers
of
neutrons.
●
●
Isotopes
of
physical
proper ties.
The
an
relative
element
atomic
have
mass,
t he
A
,
is
same
a
chemical
number
t hat
proper ties
compares
but
t he
different
average
r
mass
●
of
Some
an
atom
isotopes
wit h
have
one-twelf t h
unstable
t he
nuclei.
mass
These
of
are
a
carbon-12
known
as
atom.
rad ioactive
isotopes
●
Radioactive
dating,
44
isotopes
have
radiot herapy,
many
tracers,
uses.
energy
Some
of
t hese
generation
are
and
carbon-14
pacemakers.
Atomic
structure
Practice
Structured
Practice
exam-style
1
If
t he
of
mass
atomic
in
t he
number
a
i)
of
an
of
t he
following
table
by
lling
in
t he
gaps.
atom
nucleus
question
Complete
questions
number
neutrons
questions
questions
6
Multiple-choice
exam-style
is
t he
59
and
atom
t he
is
Particle
number
32,
t hen
t he
Mass
Atomic
Number
Number
number
number
of
of
neutrons
electrons
is:
56
A
27
B
32
C
59
D
91
Fe
26
58
Fe
(7
ii)
A
sample
39
2
A
potassium
atom
is
written
as
of
56
K.
Which
of
of
t he
iron
was
found
to
contain
a
marks)
mixture
58
Fe
and
Fe
in
a
ratio
of
7
to
3.
Calculate
t he
19
following
statements
about
I
It
has
an
atomic
II
It
has
20
neutrons.
number
III
It
has
19
IV
The
A
I
B
II
C
I,
a
potassium
of
atom
are
relative
tr ue?
number
Students
were
information
protons
and
electrons
is
D
I,
IV
and
II
and
III
only
III
and
Which
of
iron.
asked
given
questions
in
t he
based
table
on
marks)
t he
below.
Atomic
Electron
number
configuration
A
25
—
2,8,2
B
17
8
—
only
IV
t he
of
Mass
only
The
3
sample
number
only
III
t he
39.
Element
and
of
(2
b
of
mass
19.
electrons.
total
atomic
following
is
t he
electronic
conguration
following
statements
were
taken
from
one
of
of
t he
student’s
exercise
books.
These
statements
19
uorine,
F?
9
are
A
INCORRECT.
In
each
case,
explain
why
t he
2,8,8,1
statement
B
2,8,1
C
2,8
D
2,7
is
incorrect
and
t hen
give
t he
correct
A
2
statement.
i)
INCORRECT
‘The
4
Isotopes
of
an
element
I
t he
same
atomic
II
t he
same
number
of
III
has
have:
number
of
but
different
electrons
but
mass
different
numbers
numbers
ii)
neutrons
t he
same
physical
proper ties
but
different
I
2
STATEMENT:
number
valence
–
Explain
–
Give
‘The
chemical
it
–
Explain
–
Give
t he
correct
element
is
because
statement
is
incorrect.
statement.
(3
conguration
has
a
why
mass
t he
of
number
statement
element
of
marks)
is
B
is
2,8,7
17
.’
incorrect.
only
B
I
C
II
and
D
I,
II
t he
correct
statement
.
(3
and
II
III
and
of
15
marks
only
III
Extended
Which
marks)
only
Total
5
it
STATEMENT:
electron
because
of
electrons.’
why
t he
INCORRECT
proper ties
A
atomic
t he
following
is
not
a
use
of
response
question
radioactive
7
a
The
following
nuclear
notations
refer
to
atoms
of
isotopes?
aluminium
A
energy
B
carbon
C
chemot herapy
D
radiot herapy
and
uorine:
generation
19
27
Al
dating
and
F
13
9
Draw
shell
diagrams
aluminium
b
A
naturally
atom
occurring
21
X
15%
i)
ii)
element
str ucture
of
atom.
X
an
(4
consists
of
marks)
85%
X.
can
you
Determine
What
is
Explain
–
deduce
a
relative
element
atomic
mass
of
X.
radioactive
occurring
isotope?
marks)
naturally
(2
marks)
(2
marks)
how:
carbon-14
and
naturally
(2
t he
uranium-235
–
about
X?
occurring
c
t he
uorine
10
What
element
ii)
show
a
22
and
10
i)
to
and
animal
is
is
used
used
to
remains.
to
generate
determine
electricity
t he
age
of
(5
Total
plant
marks)
15
marks
45
The
A4
periodic
table
and
periodicity
Elements
are
arranged
in
the
periodic
table
in
increasing
Objectives
By
the
be
able
●
end
of
this
topic
you
will
order
of
atomic
number.
The
arrangement
of
the
to:
describe
the
historical
development
of
the
elements
in
wealth
information
of
specific
rows
and
about
columns
the
provides
properties
of
a
elements
periodic
in
the
same
group
and
in
the
same
period
of
the
table
●
explain
how
arranged
in
elements
the
periodic
are
table
periodic
●
identify
metals,
explain
in
the
is
non-metals
the
periodic
difference
and
an
●
give
and
the
elements
give
the
elements
explain
in
in
in
the
same
the
the
in
same
to
a
based
periodic
group
Ever yone
the
labs
of
of
the
periodic
predict
the
chemical
properties
of
on
its
location
in
the
table.
of
elements
in
the
table
a
familiar
one
on
wit h
t he
t he
wall.
period ic
The
table
periodic
of
table
elements
is
a
as
most
chemistr y
classication
of
all
t he
elements and it is incredibly impor tant to chemists. It shows t he symbol, full
period
down
is
have
of
group
name,
t he
mass
number
elements
and
t heir
into
and
atomic
columns
and
number
rows
of
based
each
on
element
t he
and
str ucture
of
it
organises
t heir
atoms
proper ties.
period.
arranged
and
in
in
t he
periodic
order
chemically
wit h
similar
of
table
show
increasing
similar
proper ties
to
each
recur
period icity.
atomic
ot her
number,
occur
per iodically
When
all
elements
at
regular
t hroughout
t he
t hat
elements
are
inter vals,
t he
are
physically
i.e.
t hose
series.
fact
Historical
Periodicity
elements
values
of
properties
change
along
Key
ability
Arrangement
Elements
!
main
table
the
conguration
how
elements
and
the
between
conguration
similarities
electronic
●
of
periods
similarities
electronic
●
the
element
A4.1
groups
One
table
metalloids
●
table.
modern
is
with
the
recurrence
similar
development
of
the
periodic
table
of
physical
and
Early in t he 19t h centur y, scientists star ted to tr y to classify elements based on
chemical
properties
at
regular
t he similarities between t hem. Four scientists made impor tant contributions
intervals
in
the
periodic
table.
to
t he
development
Newlands,
Johann
In
Dmitri
of
t he
modern
Mendeleev
and
periodic
Henr y
table:
Johann
Döbereiner,
John
Moseley.
Döbereiner
1829,
Johann
Döbereiner
noted
that
certain
groups
of
three
elements
possessed similar chemical and physical properties, e.g. he found that lithium,
sodium
the
and
three
potassium
elements
in
were
a
all
group
soft,
were
reactive
metals.
arranged
in
He
order
also
of
observed
increasing
that
if
relative
atomic mass, then the relative atomic mass of the middle element was close to
the average of the other two elements. He called these groups

T
able
4.1.1
Elements
and
Döbereiner’s
their
relative
triads
of
atomic
elements
masses
lithium
sodium
potassium
7.0
23.0
39.0
calcium
strontium
barium
40.0
88.0
137.0
chlorine
bromine
iodine
35.5
80.0
127.0
Average
23.0
88.5
81.25
46
triads
relative
atomic
mass
The
periodic
John
In
1865,
atomic
John
periodicity
mass
had
and
ever y
arranging
t he
sodium
similar
Newlands
t hat
recurred
Arrangement
of
elements
in
the
periodic
table
was
put
for ward
discovered
discovered
eighth
t he
t hat
element.
elements
Be
Figure
Dmitri
been
in
his
at
of
time
similar
For
Octaves.
in
order
element
and
of
and
arranged
order
wit h
atomic
lit hium
of
physical
star ting
relative
bot h
He
increasing
chemical
example,
increasing
eight h
L aw
t he
and
t he
56
relative
proper ties
lit hium
mass,
he
sodium
and
found
showed
proper ties.
Li

and
Newlands
elements
t hat
table
B
4.1.1
C
N
Newlands’
O
F
octaves
of
Na
Mg
Al
Si
P
S
Cl
elements
Mendeleev
In 1869, Dmitri Mendeleev published his ‘ Periodic Classication of Elements ’
in
which
he
elements
arranged
with
elements
similar
in
chemical
increasing
and
relative
physical
atomic
properties
mass
and
together
in
placed
vertical
columns. His table was widely accepted at the time for two reasons:
●
he
lef t
been
●
he
gaps
occasionally
and
switched
families.
before
group
Using
as
his
For
1914,
of
wit h
he
suggested
to
placed
better
127
,
so
bromine,
by
elements
relative
classify
tellurium,
mass
and
was
predicted
able
t he
had
all
of
atomic
t hem
relative
t hat
to
predict
proper ties
Mendeleev
periodic
Moseley
is
not
yet
into
atomic
iodine
which
fell
mass
chemical
mass
in
128,
t he
showed
same
similar
t he
of
credited
proper ties
gallium,
wit h
being
of
t he
which
t he
missing
was
creator
not
of
t he
table.
rearranged
instead
similar
of
t heir
chemical
periodic
periodic
atomic
in
non-met als .
t he
corresponding
table
number.
t he
elements
relative
in
atomic
proper ties
all
t he
table
masses.
fell
in
t he
In
based
t his
same
on
new
t heir
order,
groups.
table
consists
A
copy
of
of
103
t he
elements
periodic
arranged
table
can
in
be
order
found
of
on
360.
Elements
r uns
order
atomic
chlorine
1875.
modern
modern
Unit
t he
elements
Mendeleev
t he
Henr y
increasing
page
relative
he
numbers
elements
The
t he
Moseley
atomic
The
t hat
proper ties.
until
version
ignored
uorine,
e.g.
discovered
In
seemed
example,
table,
elements,
Henry
it
adjacent
iodine,
chemical
rst
when
discovered
4.4.
t he
moder n
The
Looking
from
above
met als
excluding
and
per iodic
proper ties
at
t he
per iodic
aluminium
t he
hydrogen
of
(H),
are
t able
(Al)
non-met als.
t able
can
met als
in
Figure
stepping
All
met als
t he
and
be
and
divided
4.1.2,
down
elements
t he
into
non-met als
to
to
t he
solid
ast atine
t he
elements
to
met als
are
lef t
t he
line
(At)
of
and
given
in
whic h
divides
t he
r ight
line,
of
t he
47
Arrangement
of
elements
in
the
periodic
table
The
line,
including
border
t he
inter mediate
include
(Sb),
hydrogen,
line
are
known
between
boron
(B),
tellur ium
(Te)
are
as
t hose
silicon
and
non-met als.
met alloid s .
of
(Si),
met als
Some
The
and
ger manium
polonium
periodic
of
table
t he
proper ties
periodicity
elements
of
non-met als.
(Ge),
and
The
ar senic
whic h
met alloids
are
met alloids
(As),
antimony
(Po).
metals
0
non-metals
1
H
I
II
III
Li
Be
Na
Mg
IV
V
VI
He
VII
2
3
transition
4
5
B
C
N
O
F
Ne
Al
Si
P
S
Cl
Ar
metals
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
T
e
I
Xe
Cs
Ba
La
Hf
T
a
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
6
metals
Elements
on
metalloids;
metallic
Figure
4.1.2
Metals
and
non-metals
in
the
periodic
The
Did
?
The
you
periodic
most
table
textbooks
found
consists
in
of
periodic
T
o
date,
elements
have
discovered
Elements
up
californium,
exist
to
nuclear
cases
rest
few
been
table
rows
are
is
called
ver tical
Eight
t he
of
last
proper ties
including
number
have
laboratories
very
have
some
divided
into
ver tical
columns
called
groups
and
periods
columns
t hese
are
of
elements.
numbered
There
using
are
Roman
18
groups
numerals
in
t he
from
periodic
group
being
Group
0.
Elements
in
t he
same
group
I
show
to
VII,
similar
synthesised.
accelerators.
only
element
or
and
the
in
and
characteristics.
actually
atomic
naturally,
synthesised
non-metals
however,
wit h
been
are
Groups
table.
118
line
some
103
Groups
elements.
this
have
table
horizontal
know?
near
characteristics
non-metallic

or
they
In
98,
and,
because
of
t his,
some
groups
have
been
assigned
special
names:
been
●
Group
I
●
Group
II
–
alkali
●
Group
VII
●
Group
0
metals
or
–
alkaline
ear t h
metals
some
atoms
of
the
–
halogens
synthesised.
Between
–
noble
Groups
transition
gases.
II
and
elements
or
III
t here
transition
are
ten
groups
of
elements
called
t he
metals.
Periods
Did
?
you
know?
Periods are horizontal rows of elements numbered using Arabic numerals from
1
Naming
newly
discovered
to
7
.
Moving
along
a
period,
the
properties
of
the
elements
gradually
change
or
from metals on the left-hand side to non-metals on the right-hand side.
synthesised
by
the
Pure
elements
International
and
(IUPAC).
Applied
Many
are
is
controlled
Union
of
Chemistry
named
Electronic
configuration
and
the
periodic
table
after
Looking at t he electronic conguration of t he elements in t he periodic table,
famous
scientists
or
places,
immediately
e.g.
einsteinium
and
between
48
we
can
see
similar ities
between
californium.
elements
in
t he
same
period.
elements
in
t he
same
group
and
The
periodic
Figure
in
t he
4.1.3
table
and
periodicity
summarises
periodic
t he
Arrangement
electronic
conguration
of
t he
rst
20
of
elements
in
the
periodic
table
elements
table.

Figure
4.1.3
The
electronic
Groups
conguration
I
II
III
IV
V
VI
VII
of
the
rst
20
elements
0
in
H
the
periodic
table
He
1
(1)
(2)
sdoireP
Li
Be
B
C
N
O
F
(2,1)
(2,2)
(2,3)
(2,4)
(2,5)
(2,6)
(2,7)
Ne
(2,8)
Na
Mg
Al
Si
P
S
Cl
Ar
(2,8,1)
(2,8,2)
(2,8,3)
(2,8,4)
(2,8,5)
(2,8,6)
(2,8,7)
(2,8,8)
K
Ca
(2,8,8,1)
(2,8,8,2)
2
3
4
Groups
The
similarities
group
●
all
are
as
elements
t heir
●
t he
are
all
shell
electronic
in
(He)
of
conguration
(Na)
valence
(S)
has
Group
has
two
2,
any
group
i.e.
0
of
elements
t his
a
it.
have
same
same
in
as
hold,
element
t he
in
same
one
is
more
calcium
for
example,
maximum
electrons
in
hold.
electron
(Li)
for
VI
t he
eight
can
in
valence
number,
shell,
has
shell
of
electrons
Group
which
lit hium
and
group
is
(Ne)
t his
has
1
electrons
valence
electron
neon
example,
t he
of
number
(Mg)
two
and
number
maximum
For
number
t he
outermost
shell
can
t he
each
t he
all
electrons
full
in
shell
again
above
is
same
have
magnesium
t hey
valence
have
t he
t hey
(Be),
and
electrons
six
group,
t hree
have
shell,
electrons
once
directly
has
group
ber yllium
same
electrons
down
element
same
electron
t he
of
number
Moving
sodium
t he
sulfur
elements
number
t he
example,
in
number
helium
t he
for
all
example,
●
in
outermost
electrons,
(Ca)
in
follows:
has
two
shell
t han
shells
and
shells.
Periods
The
similarities
period
●
all
are
as
elements
same
electrons
t he
calcium
Moving
in
of
(Ca)
and
and
all
conguration
period
any
t he
number
is
of
elements
in
t he
same
same
period,
the
t he
number
of
each
(P)
●
the
number
of
shells,
element
For
ve
of
an
i.e.
electrons
magnesium
t hey
all
t he
have
electrons
has
electron
one
example,
valence
for
and
more
silicon
in
t he
(Mg)
t heir
and
valence
can
t he
shells
shells
t hat
it
is
in
Period
valence
has
4.
electron
four
valence
electrons.
be
same
is
of
example,
(Si)
configuration
atom
is
number
number,
remembering
electrons
occupied
and
period
contain
it.
has
number,
valence
period
t he
electronic
period
●
as
t hat
before
conguration
t he
valence
(Na),
3
shells
directly
t heir
sodium
same
electron
t he
four
have
example,
in
phosphor us
electronic
number
for
occupied
has
Determining
The
electronic
same
are
shell
element
electrons
t he
electrons,
along
t he
t he
shell,
(Al)
number
contain
t han
in
electron
aluminium
●
in
follows:
of
determined
atoms
from
t he
group
t hat:
as
the
t he
same
group
as
the
number
period
number.
49
Arrangement
of
elements
in
the
periodic
table
The
For
Exam
✔
example,
periodic
tip
electrons
Correctly
representing
electronic
the
configuration
str ucture
of
if
a
elements
is
extremely
is
used
to
reactivity
of
in
determine
of
bonding
when
it
an
an
atom
atom
forms
a
and
will
the
be
know
type
can
involved
t hat
sesaercni
increases
s
a
s
e
F
s
e
s
a
e
r
c
in
e
r
tu
a
n
cillatem
ic
ll
ta
e
m
Fr
nature
increases
cillatem-non
erutan
e
r
c
e
r
tu
erutan
sesaercni
nature
in
metallic
reactive
t he
electronic
t hat
is
in
Group
phosphor us
shells.
V
and
atom
Period
has
Therefore,
3
ve
t he
of
t he
valence
electronic
(2,8,5).
and
period
conguration
conguration
calcium
you
Unit
t he
3.2
are
be
(Fr)
is
the
most
in
learnt
arrangement
number
number
is
of
known.
an
For
element
can
example,
is
in
Group
of
II
a
calcium
and
Period
atom
4
of
is
t he
if
(2,8,8,2),
periodic
of
in
proper ties
in
t hat
of
trends
t he
summarised
down
a
a
t he
are
same
t he
be
you
you
table.
as
in
t he
t hey
way
t hat
elements
directly
group
table
chemical
electrons
such
of
periodic
electrons
valence
arranged
These
the
and
properties
atoms
have.
t here
in
a
of
t he
The
are
related
to
in
an
in
same
in
in
t he
group
electronic
t he
element
elements
trends
par ticular
elements
of
element,
or
depend
par ticular,
t he
periodic
physical
in
a
and
par ticular
congurations
period.
These
of
trends
follows.
●
Moving
●
Moving down a group, the non-metallic nature of the elements
●
Moving
along
a
period,
t he
metallic
●
Moving
group,
t he
metallic
nature
of
along
a
period,
t he
non-metallic
nature
t he
of
elements
t he
nature
increases
elements
of
t he
decreases
decreases
elements
increases
These
It
is
trends
are
impor tant
Their
Francium
a
electron
is
number
electronic
In
can
n
group
its
trends
elements
o
t he
if
General
period.
n
atom
t hat
compound.
chemical
n
occupied
phosphor us
determine
table
ic
ll
ta
e
m
-
phosphor us
periodicity
the
t he
a
t hree
t hat
determine
and
atoms
on
non-metallic
can
table
important.
determined
It
know
you
and
of
Alternatively,
of
you
table,
periodic
atoms
all
shown
to
note
have
in
Figure
t hat
full
4.1.4.
elements
outer
in
electron
Group
shells
0
are
and,
chemically
because
of
unreactive.
t his,
t hey
have
a stable electronic conguration. Atoms of all ot her elements do not have full
metal
outer
electron
shells
and
are,
t herefore,
unstable.
In
order
to
become
stable,
t hey need to attain t he electronic conguration of a noble gas, i.e. a full outer
Fluorine
reactive

Figure
4.1.4
(F)
is
the
most
non-metal
Trends
in
electron
the
shell.
They
can
do
t his
by
losing
or
gaining
valence
electrons.
periodic
The
willingness
of
an
atom
of
an
element
to
lose
or
gain
valence
electrons
is
table
a
strong
valence
shell
indication
electrons
when
t hey
of
its
and
metallic
or
non-metals
non-metallic
tend
to
gain
nature.
Metals
electrons
into
tend
t heir
to
lose
valence
react.
When atoms lose or gain valence electrons t hey form positively or negatively
Key
!
fact
charged par ticles known as
which
An
ion
is
an
electrically
atoms
or
formed
gains
when
an
atom
gain
ions. They are said to have ionised. The ease wit h
valence
how
reactive
t hey
electrons,
known
as
ease
of
ionisation ,
are.
loses
electrons.
In
●
general:
The
ease
group
wit h
and
t herefore,
along
●
The
a
a
increases
wit h
and
t herefore,
period.
will
units.
r ight
going
which
going
along
a
metal
from
atoms
to
lef t
down
lose
electrons
along
a
a
group
period.
and
increases
The
going
going
reactivity
from
right
down
of
to
a
metals,
lef t
period.
ease
group
which
going
metals,
You
50
or
charged
determines
particle
lose
be
non-metal
from
lef t
increases
studying
t he
to
atoms
r ight
going
reasons
up
for
gain
along
a
a
electrons
period.
group
t his
in
and
more
increases
The
going
detail
going
reactivity
from
in
lef t
t he
of
to
next
up
non-
right
t hree
The
periodic
table
Summary
1
Name
three
What
a
3
is
the
Group
For
scientists
For
a
it
b
is
the
in
Give
How
A4.2
Group
in
in
of
ber yllium,
Trends
made
to
Period
I
the
of
3
the
of
metallic
along
a
contributions
elements
in
c
VII
periodic
to
chemically
all
ver y
table,
the
periodic
Group
state
but
give
the
similarities
periodic
table,
give
the
similarities
and
of
an
atom
of
potassium,
given
that
4.
and
is
nature
period
S
number
of
sulfur,
given
that
its
(2,8,6).
of
elements
change
when
moving
down
a
period?
in
Group
periodic
table
II
is
calcium,
of
the
periodic
composed
strontium,
of
t he
barium
table
following
and
Objectives
elements:
radium.
By
the
be
able
metals
which
display
ver y
similar
proper ties.
end
reactive
t hey
are
and
so
are
collectively
reactive,
t hey
are
known
never
as
found
alkaline
naturally
are
always
found
in
nature
combined
wit h
ot her
The
elements
in
Group
II
are
listed
in
Figure
t heir
symbols,
atomic
numbers
and
electron
this
topic
you
will
give
the
general
properties
of
are
II
elements
earth
in
give
the
chemical
properties
of
t heir
elements
4.2.1,
of
to:
These
They
II
elements
in
compare
the
reactivity
of
Group
toget her
II
wit h
table
and
●
compounds.
periodic
table?
Group
free
the
0
●
Because
of
the
Group
metals.
II
conguration.
arrangement
Period
number
magnesium,
are
Group
conguration.
the
conguration
the
following
Group
electronic
and
group
t he
II
important
●
elements
in
table.
electronic
electronic
the
and
Group
their
Trends
II
given
their
Group
does
group
in
in
electronic
6
who
periodic
b
elements
Give
the
name
elements
differences
5
of
II
differences
4
periodicity
questions
development
2
and
elements
with
oxygen,
water
arrangements.
and
●
beryllium
dilute
predict
unknown
Be
hydrochloric
the
properties
elements
in
acid
of
Group
II
4
based
(2,2)
●
on
explain
group
why
trends
elements
in
magnesium
Group
II
show
similar
chemical
Mg
12
properties
(2,8,2)
●
calcium
explain
Group
Ca
going
20
why
II
the
reactivity
elements
down
the
of
increases
group.
(2,8,8,2)
strontium
Sr
38
(2,8,18,8,2)
barium
Ba
56
(2,8,18,18,8,2)
radium
Ra
88
(2,8,18,32,18,8,2)

Figure
4.2.1
Group
II
elements
and
their
electronic
congurations
51
Trends
in
Group
II
of
the
periodic
table
The
General
Group
II
They
are
fairly
●
They
are
shiny,
t hey
layer
!
A
cation
frmed
elements
●
as
Key
properties
react
on
t he
have
sof t
of
t he
Group
following
table
and
periodicity
elements
general
proper ties
in
common.
metals.
silver y-white
wit h
II
periodic
t he
surface
when
oxygen
of
t he
in
freshly
t he
air.
cut,
This
but
turn
reaction
dull
forms
ver y
a
quickly
dull
oxide
metal.
fact
is
a
when
positively
a
metal
charged
atom
●
They
●
Their
have
atoms
fairly
have
high
Their
atoms
lose
melting
points
and
boiling
points.
ion
two
valence
electrons.
loses
●
t heir
valence
electrons
readily
to
form
metal
cations
electrons.
2
wit h
a
Going
●
it
charge
down
becomes
Chemical
Group
II
of
t he
2,
e.g.
group,
easier
for
t he
t he
have
They
react
wit h
oxygen
●
They
react
wit h
water
●
They
react
wit h
dilute
chlorides
The
ease
(see
with
hydrochloric
as
the
Unit
reactivity
is,
of
t he
lose
Group
form
form
and
the
metal.
metal
atoms
(atomic
two
5.2).
radii)
valence
oxides
proper ties
(see
hydroxides
increase
and
electrons.
to
Unit
and
form
in
common.
8.2).
hydrogen
salts
known
gas.
as
metal
gas.
react
for
rank
Unit
elements
acid
different
we
(see
chemical
hydrogen
If
Ba
t heir
II
basic
metals
however,
the
of
to
hydrochloric
8.4)
which
acid
to
and
following
to
2
Ca
radii
of
t he
●
2
,
atoms
reactivity
elements
Mg
with
the
the
oxygen,
different
metals
water
metals
from
the
and
and
most
is
dilute
known
reactive
to
the least reactive, based on how fast or how vigorously they react, the reactivity
increases going
reactive
Comparing
Your
●
teacher
the
may
observation,
Y
ou
will
dilute
be
reactivity
use
this
recording
supplied
hydrochloric
with
acid
of
magnesium
activity
and
test
and
and
to
down the group. Ber yllium, at the top of the group, is the
radium,
and
at
the
bottom
of
the
group,
is
the
most
least
reactive.
calcium
assess:
reporting.
tubes,
strips
distilled
of
freshly
cleaned
magnesium
two
tubes.
ribbon,
pieces
of
freshly
cleaned
calcium,
water.
Method
3
1
Pour
tube
2 cm
and
of
a
dilute
piece
of
hydrochloric
calcium
to
acid
the
into
each
second
of
tube.
test
Compare
the
Add
a
strength
piece
of
of
magnesium
effervescence
ribbon
occurring
in
to
the
the
rst
two
tubes.
3
2
Pour
a
Y
ou
3
2 cm
piece
of
might
Based
on
consider
4
If
you
more
5
If
you
more
52
of
distilled
calcium
need
the
is
to
leave
or
less
barium
vigorous
or
the
to
each
of
for
dilute
dilute
two
a
while
or
hydrochloric
than
with
than
with
tubes.
the
and
Add
observe
that
a
strength
you
piece
of
them
of
magnesium
effervescence
ribbon
occurring
in
to
the
the
rst
two
tube
and
tubes.
periodically.
observed
in
steps
1
and
2,
which
metal
would
you
calcium?
acid
and
distilled
water,
would
you
expect
the
effervescence
to
be
magnesium?
hydrochloric
vigorous
test
Compare
effervescence
magnesium
vigorous
of
tube.
tubes
strength
to
less
into
second
reactive,
beryllium
vigorous
added
water
the
relative
more
added
to
acid
and
calcium?
distilled
water,
would
you
expect
the
effervescence
to
be
The
A
periodic
compar ison
wit h
oxygen,
Examples
are
of
given.
and
a
table
and
in
(aq)
of
t he
a
You
periodicity
t he
water
dilute
c hemical
indicates
an
of
magnesium,
hydroc hlor ic
equations
equations
have
Trends
reactivity
and
c hemical
Similar
bar ium.
solid
and
can
already
be
aqueous
t he
wr itten
come
equation.
for
In
across
t hese
solution,
acid
calcium
is
given
reactions
for
(g)
t he
and
equations,
i.e.
a
to
solution
II
of
the
periodic
table
4.2.1.
magnesium
wit h
indicate
(l)
Group
bar ium
Table
wit h
reactions
(s)
and
in
in
indicates
where
calcium
a
gas
a
and
liquid
water
is
t he
solvent.

T
able
4.2.1
Reactions
Reaction
Oxygen
(or
air)
of
magnesium,
calcium
Magnesium
(Mg)
Reacts
to
slowly
exposure
flame,
to
air.
producing
barium
Calcium
form
If
and
a
coating
ignited,
white,
of
magnesium
magnesium
solid
burns
magnesium
oxide
with
a
(MgO)
on
blinding
Reacts
white
oxide.
oxygen

(CaO)
magnesium
O

(g)
of
on
Very
clean
producing
magnesium
form
calcium
a
Reacts
oxide
to
form
air.
burns
a
(Ba)
very
oxide
(BaO)
to
If
air.
readily
coating
of
on
to
barium
exposure
ignited,
a
brick
red
flame,
burns
with
an
barium
apple
green
2MgO(s)
2
producing
reacts
magnesium
to
calcium
exposure
ignited,
calcium
Water
Barium
oxide
with
2Mg(s)
readily
coating
if
magnesium
(Ca)
very
hydroxide
slowly
with
)
(Mg(OH)
cold
and
Reacts
water,
hydrogen
gas
(H
2
).
cold
white,
solid
flame,
oxide.
solid
vigorously
water,
with
producing
barium
Reacts
producing
with
very
cold
white,
oxide.
vigorously
water,
2
calcium
hydroxide
producing
barium
magnesium
magnesium
water


hydrogen
(Ca(OH)
)
and
hydrogen
hydroxide
(Ba(OH)
2
)
and
2
hydroxide
gas
(H
).
hydrogen
gas
(H
2
Mg(s)
Dilute
hydrochloric
acid
Reacts
O(l)
2H

Mg(OH)
2
vigorously
to
(aq)
2
produce
magnesium
chloride
H

).
2
(g)
2
(MgCl
)
and
Reacts
very
vigorously
to
Reacts
violently
to
2
hydrogen
gas
(H
).
produce
calcium
chloride
produce
barium
chloride
2
(CaCl
)
and
hydrogen
gas
(BaCl
2
magnesium
hydrochloric
magnesium
acid
chloride


hydrogen
(H
).
(H
2
Mg(s)
From
t he
trends
in
t he
2HCl(aq)

reactivity
MgCl
(aq)
of
t he
Group
II
metals,
H

2
we
t han
vigorously
barium,
calcium,
but
and
less
t han
t he
magnesium,
reactivity
vigorous
t han
of
radium
to
strontium
react
to
even
be
can
gas
).
(g)
predict
more
more
hydrogen
2
t he
Did
?
less
and
2
reactivity of ber yllium, strontium and radium. We would expect ber yllium to
react
)
2
you
know?
vigorously
vigorous
t han
Group
II
metals
fireworks
barium.
air
or
oxygen
flames.
brick
and
red
Group
e.g.
a
a
II
bright
metals
strontium
chloride
they
red
is
used
burn
to
light
produces
a
Compounds
may
also
carbonate
colour
produces
an
in
in
coloured
used
white
calcium
colour.
crimson
often
producing
Magnesium
produce
effect
are
because
and
be
of
used,
produces
barium
apple
green
colour.

Figure
4.2.2
Compounds
of
Group
II
elements
are
often
used
as
reworks
53
Trends
in
Group
II
of
the
periodic
table
The
An
explanation
of
the
trends
in
periodic
Group
table
and
periodicity
II
Elements in Group II all have ver y similar c hemical proper ties because t heir
atoms
all
have
ionise
by
losing
ions,
i.e.
Since
t hey
Group
t he
●
t he
II
t he
t he
t he
by
atomic
The
less
radii
easier
for
full
to
t he
t herefore,
get
of
combination
attracted
of
t he
of
atoms
atoms,
t herefore,
t he
to
positive
of
t he
extra
shell
Moving
As
lled
fur t her
a
react
now
electrons
to
full.
lose,
moving
down
t hey
c harged
t he
i.e.
g roup,
electron
away
shells,
from
t he
more
shielded
from
t he
positive
nucleus
factors
nucleus
t heir
down
t he
reactive
means
going
valence
t he
t he
t he
electrons.
valence
g roup
The
electrons
and
ease
of
it
are
becomes
ionisation,
g roup.
smallest,
Group
t hat
down
ionise
II
t he
element.
least
easily.
Radium
Ber yllium
atoms,
most
being
is,
t he
reactive Group
element.
The
electronic
Figure
str ucture
of
t he
 rst
t hree
elements
in
Group
II
is
given
4.2.3.
×
×
×
××
××
××
×
Ca
××
××
××
××
××
Mg
×
××
××
×
Be
××
××

Figure
4.2.3
Summary
1
What
2
a
is
the
Does
b
3
Give
Compare
diagrams
of
the
rst
three
elements
in
Group
II
questions
reactivity
down
the
Shell
collective
the
going
54
2,
down
result:
largest, ionise t he most easily. Radium is, t herefore, t he
II
is
however,
increases.
become
t hey
positively
shells.
two
lose
electron
increases.
when
for m
nucleus
become
going
being
least
to
and
number
shells
due
metals,
proper ties,
elements
electrons
positive
increases
Ber yllium
t he
t hese
outer
same
electron
electron
t he
t heir
t he
Being
electrons
c hemical
bigger
electrons
extra
t his,
have
valence
pull
electrons.
valence
similar
occupied
t he
valence
t he
doing
reactivity
t herefore,
●
ver y
of
attractive
In
two
elements
have
number
valence
t heir
c ations.
all
all
two
the
reason
the
name
of
the
for
the
elements
elements
in
in
Group
Group
II
group?
for
reactivity
your
of
answer
beryllium
to
a
and
above.
calcium.
II?
increase
or
decrease
in
The
periodic
A4.3
Group
table
and
Trends
VII
in
t he
periodicity
in
Trends
Group
periodic
table
VII
is
of
the
composed
periodic
of
t he
table
following
in
Group
VII
of
the
periodic
table
Objectives
elements:
By
the
be
able
end
of
this
topic
you
will
to:
uorine, chlorine, bromine, iodine and astatine. These elements are all non-
●
give
the
general
properties
of
metals. They display similar proper ties and are chemically ver y reactive. They
Group
are
collectively
known
as
t he
halogens.
The
elements
in
Group
VII
are
●
in
Figure
4.3.1,
toget her
wit h
t heir
symbols,
atomic
numbers
and
VII
elements
listed
give
the
chemical
properties
of
electron
Group
VII
elements
arrangements.
●
explain
Group
uorine
why
VII
chemical
F
elements
show
in
similar
properties
9
●
(2,7)
explain
why
elements
in
the
reactivity
Group
VII
of
the
increases
chlorine
going
up
the
group
Cl
17
●
describe
displacement
(2,8,7)
reactions
bromine
Group
Br
35
●
(2,8,18,7)
of
elements
in
VII
explain
the
term
oxidising
strength
●
predict
the
properties
of
iodine
unknown
elements
in
Group
VII
I
53
based
on
group
trends.
(2,8,18,18,7)
astatine
At
85
(2,8,18,32,18,7)

Figure
General
Group
VII
4.3.1
Group
properties
elements
●
They
are
●
They
exist
have
poisonous
as
VII
of
t he
elements
Group
following
and
their
VII
electronic
congurations
elements
general
proper ties
They
are
generally
common.
elements.
non-polar,
diatomic
molecules,
e.g.
F
,
Cl
2
●
in
soluble
in
non-polar
solvents
,
Br
2
and
and
I
2
2
slightly
soluble
in
water.
●
They
have
low
●
Their
●
Their atoms readily accept an electron into their valence shells to form non-
atoms
melting
have
points
seven
and
valence
boiling
points.
!
ion
●
They
share
an
electron
1, e.g. F
readily
fact
electrons.
An
metal anions with a charge of
Key
with
, Cl
other
, Br
and I
non-metal
(see Unit 5.2).
atoms
(see
Unit
anion
is
formed
gains
a
negatively
when
a
charged
non-metal
atom
electrons.
5.4).
Group VII elements have different colours and states at room temperature, as
summarised

T
able
4.3.1
in
Table
Some
4.3.1.
physical
at
room
properties
of
temperature
the
rst
four
Element
State
fluorine
gas
pale
chlorine
gas
yellow
bromine
liquid
red-brown
elements
solid
Group
VII
Colour
yellow
green
–
temperature
iodine
in
grey-black
heated
–
the
liquid
forming
the
forming
solid
a
evaporates
an
orange
sublimes
purple
readily
at
room
vapour
readily
when
vapour
55
Trends
in
Group
VII
of
the
periodic
table
The
Chemical
Group
VII
reactivity
elements
react
of
Group
wit h
most
VII
metals
periodic
table
and
periodicity
elements
to
form
ionic
compounds
(Unit
5.2) and t hey react wit h most ot her non-metals to form covalent compounds
(Unit
5.4).
Examples
1
2
Chlorine
reacts
Sodium

2Na(s)

Chlorine
reacts
Hydrogen
H
reactivity
Fluorine,
bottom
An
at
of
t he
Cl
of
to
form
sodium
sodium
(g)
chloride.
chloride
2NaCl(s)
2
wit h
t he
top
hydrogen
gas
to
chlorine
Cl

t he
sodium
chlorine

(g)
2
The
wit h
form
hydrogen
hydrogen
(g)
chloride
gas.
chloride
2HCl(g)
2
Group
of
group,
explanation
t he
is
t he
of
VII
elements
group,
least
the
is
t he
increases
most
going
reactive
and
up
t he
group.
astatine,
at
t he
reactive.
trends
in
Group
VII
Elements in Group VII all have ver y similar chemical proper ties because t heir
atoms
all
have
seven
valence
electrons.
Being
non-metals,
when
t hey
react
t hey ionise by gaining one valence electron and t hey form negatively charged
ions,
Since
all
i.e.
all
have
t he
anions.
t he
●
reactivity
t he
radii
of
of
pull
valence
t he
inner
have
t he
elements
atoms
get
t herefore,
of
t he
of
outer
same
electron
number
proper ties.
increases.
As
smaller
t he
positive
of
a
shell
is
electrons
However,
Moving
up
now
to
gain,
moving
t he
full.
group,
i.e.
up
t he
1,
t hey
Group
VII
number
of
result:
due
to
valence
t he
decrease
electrons
in
become
number
closer
of
to
lled
t he
nucleus
become
electron
combination
t heir
decreases.
electrons
full
t his,
chemical
shells
t he
t he
The
t he
shells,
attractive
●
similar
electron
electron
doing
elements
ver y
occupied
In
less
shielded
from
t he
positive
nucleus
by
shells.
t hese
two
factors
means
t hat
t he
valence
electrons
are
more attracted to t he positive nucleus going up t he group, as are any electrons
being gained by t he atoms. It becomes easier for t he atoms to gain an electron
Key
!
fact
into t heir valence shell going up t he group. The ease of ionisation, t herefore,
Electronegativity
of
how
strongly
an
is
a
measure
atom
increases
going
up
Fluorine
atoms,
t he
group.
attracts
being
t he
smallest,
ionise
t he
most
easily.
Fluorine
is,
electrons.
t herefore,
t he
largest,
Group
F
Cl
t he
VII
most
ionise
t he
least
Group
easily.
VII
element.
Astatine
is,
Astatine
t herefore,
atoms,
t he
least
being
reactive
element.
The
tendency
The
electronegativity
Fluorine
reactive
is
for
t he
atoms
of
most
to
attract
t he
electrons
atoms,
is
t herefore,
electronegative
known
as
increases
element
and
electronegativity .
going
up
astatine
Group
is
t he
VII.
least
electronegative.
The

Figure
two
56
4.3.2
elements
Shell
in
diagrams
Group
VII
of
the
electronic
rst
Figure
4.3.2.
str ucture
of
t he
rst
two
elements
in
Group
VII
is
given
in
The
periodic
The
melting
explained
t he
t he
The
are
and
atoms,
lowest.
points
relative
t he
t hat
Astatine,
which
t he
Trends
means
t he
t he
t he
Group
t he
as
The
and
atoms,
large
melting
elements
forces
point
boiling
has
t he
astatine
and
can
Fluorine,
intermolecular
point
t he
VII
molecules.
molecules.
largest
between
t hat
t he
of
known
melting
having
forces
of
size
smallest
molecules,
means
intermolecular
t he
boiling
at
has
small
which
strongest,
periodicity
looking
t hese
weakest,
and
points
by
smallest
between
are
table
of
largest
of
VII
of
the
periodic
table
be
having
are
t he
uorine
molecules.
molecules
boiling
Group
attraction
forces ,
point
also
in
point
are
of
t he
astatine
highest.
F
F
fluorine
(F
)
2
Cl
Cl
chlorine
(Cl
)
2
Br
Br
bromine
(Br
)
2
I
I
iodine
(I
)
2

Figure
4.3.3
Displacement
A
d isplacement
t he
place
of
Comparing
the
sizes
of
the
rst
four
halogen
molecules
reactions
reaction
anot her
occurs
element
in
a
when
an
element
compound.
A
in
more
its
free
reactive
state
takes
element
will
displace a less reactive element from a compound containing t he less reactive
element.
element
However,
from
a
a
less
reactive
element
will
not
displace
a
more
reactive
compound.
For example, if chlorine gas is bubbled into a solution of potassium bromide,
t he chlorine will displace t he bromine from t he potassium bromide forming
potassium
chloride
chlorine
Cl
(g)
2
However,
will
not
if
and
are
t he
all
and
potassium bromide

2KBr(aq)
bromine
determine
solution
of
a
colour.
from
a
t he

whet her
colour
a
of
t he
e.g.
different
is
a
is
iodide
Chlorine
brown
added
potassium
colourless,
and
is
chlorine
halogen
potassium
occurs
bromine:

displace
bromine
To
and
to
potassium
and
wit h
resulting
(KI)
are
halogen
a
chloride
reaction
a
solution
is
chloride
all
it
grey-black
is
Br
(aq)
2
t he
occurred,
potassium
obser ved.
(KCl),
can
bromine
solution,
has
or
colourless.
forms,
bromine

bromine
reaction
reaction
sodium

occurs:
no
displacement
potassium
to
no
chloride
mixed
chloride
2KCl(aq)
yellow-green,
solution
potassium
If
be
halide
potassium
a
identied
and
by
its
solutions
on
(KBr)
reaction
distinctive
iodine
depending
aqueous
solution
bromide
displacement
red-brown
precipitate
The
an
halide
will
t he
range
amount
produced.
57
Trends
in
Group
VII
of
the
periodic
table
The
Investigating
Your
teacher
may
observation,
●
Y
ou
will
be
bromine,
displacement
use
this
recording
supplied
iodine,
with
activity
and
test
potassium
reactions
to
periodic
of
the
table
and
periodicity
halogens
assess:
reporting.
tubes
and
chloride,
aqueous
potassium
solutions
bromide
of
and
chlorine,
potassium
iodide.
Method
3
1
Pour
2 cm
3
of
potassium
potassium
iodide
solution
each
to
bromide
solution
tube
and
into
solution
another
shake.
into
test
a
test
tube.
tube
Carefully
Observe
any
colour
solution
into
a
and
2 cm
add
changes.
3
2
Pour
2 cm
3
of
potassium
potassium
iodide
solution
each
to
chloride
solution
tube
and
into
another
shake.
test
test
tube.
tube
and
Carefully
Observe
any
colour
solution
into
a
2 cm
add
Pour
2 cm
changes.
potassium
potassium
bromide
solution
each
4
Record
5
Using
From
●
3
of
t he
to
your
your
results
chlorine
and
in
a
the
test
Observe
elements
above
and
another
shake.
bromine
chloride
into
test
tube.
any
tube
and
Carefully
colour
2 cm
add
of
iodine
changes.
table.
place
activity
displaces
potassium
chloride
solution
tube
results,
practical
Chlorine
of
bromine
3
3
of
chlorine
we
can
from
in
see
increasing
order
of
reactivity.
t hat:
potassium
bromide
producing
bromine:

potassium bromide

2KBr(aq)
potassium
chloride
bromine

Br
(aq)
2
Cl
(aq)
2
2KCl(aq)

potassium
red-brown
bromide
chlorine
solution
●
Chlorine
displaces
iodine
from
potassium
iodide
producing
potassium
solution
chloride
and
chlorine

iodine:
potassium
iodide
potassium
chloride

iodine
I
(aq)
2
Cl
(aq)
2KI(aq)

2
2KCl(aq)

brown
●
Bromine
bromide
solution
of
bromine
displaces
and
from
potassium
iodide
producing
potassium
and
bromine
potassium
iodine
iodine:

potassium
iodide
potassium bromide

2KBr(aq)

iodine
chloride
I
(aq)
2
(aq)
Br
2

Figure
added
4.3.4
to
Chlorine
potassium
solution
bromide
2KI(aq)

brown
is
solution
●
No
displacement
reaction
occurs
between
bromine
and
potassium
chloride.
●
✔
Exam
No
From
If
a
question
displacement
reactions
occur
wit h
iodine.
tip
asks
you
to
t he
trends
in
t he
displacement
reactions
involving
chlorine,
bromine
describe
and iodine, we can predict t hat uorine, at t he top of Group VII, will displace
a
chemical
reaction,
you
must
all t he ot her halogens from compounds containing t hem. However, astatine,
provide
all
observations,
including
at
any
colour
t he
t heir
58
bottom
of
Group
changes.
compounds.
VII,
will
not
displace
any
of
t he
ot her
halogens
from
The
periodic
table
and
Displacement
Displacement
oxidising
a
substance.
moving
of
how
The
up
increases
reactions
of
can
t he
easily
oxidising
t he
g roup
moving
Trends
reactions
strengt hs
measure
periodicity
up
be
one
oxidising
explained
Group
VII
of
t he
by
t he
takes
to
t he
Oxid ising
electrons
elements
ability
ionise
Group
VII
of
the
periodic
table
strength
consider ing
elements.
substance
strengt h
because
t he
and
in
in
by
from
Group
relative
strength
VII
gaining
is
anot her
increases
an
electron
g roup.
Key
!
An
fact
oxidising
the
oxidation
agent
of
brings
another
about
reactant
Comparing t he relative oxidising strengt hs of chlorine, bromine and iodine,
by
we
see
t hat
chlorine
has
t he
strongest
oxidising
strengt h
and
iodine
has
causing
reactant
weakest.
We
say
t hat
chlorine
is
t he
strongest
oxid ising
agent
and
iodine
to
atom
lose
or
ion
electrons.
in
In
that
the
is
process,
t he
an
t he
the
oxidising
agent
gains
weakest.
electrons.
A
stronger
agent.
oxidising
This
is
why
agent
will
chlorine
accept
displaces
electrons
t he
from
bromide
a
ions
weaker
in
t he
oxidising
potassium
bromide. Each chlorine atom in a chlorine molecule accepts an electron from
a
bromide
(Cl
ion)
t hen
ion
and
pair
to
ion).
(Br
each
form
chlorine
a
As
a
bromide
bromine
result,
ion
each
forms
a
chlorine
bromine
(aq)

2
Chlorine
is
said
displacement
iodide.
Again,
You
bromide
chloride
ion
ion
from
bromine
will be a
Group
will
What
is
Group
2
a
Give
What
4
List
5
a
the
b
is
the
up
the
a
ion
atoms
bromine
2Cl
have
a
oxid ised
bot h
lot
more
in
we
t he
can
(aq)
t he
chlorine
about
molecule

(aq)
2
potassium
and
bromine
oxidation
displacement
predict
Br
t hat
bromide.
oxidised
reactions
reactions
uorine,
at
in
In
t he
t he
Unit
involving
t he
top
of
ot her
potassium
9.
chlorine,
Group
VII,
weaker
oxidising
agent
t han
iodine.
questions
in
the
electronic
reactivity
the
conguration
of
the
elements
in
by
elements
would
Give
a
for
the
in
you
potassium
of
the
elements
in
Group
VII
increase
or
decrease
group?
reason
meant
What
to
chloride
oxidising agent t han chlorine and astatine, at t he bottom of
similar
Does
3
a
bromine
VII?
going
b
(aq)
trends
be
Summary
1
to
iodine,
stronger
VII,
2Br
learn
t he
and
Two

reactions,
will
forms
molecule:

molecule
Cl
atom
atom.
term
Group
for
answer
VII
if
in
above.
strength’?
order
an
a
to
‘oxidising
observe
iodide
reason
your
of
increasing
aqueous
solution
oxidising
of
strength.
chlorine
is
added
solution?
your
answer
to
a
above.
59
Trends
in
Period
3
of
the
periodic
table
The
A4.4
Objectives
By
the
be
able
end
of
this
topic
you
Trends
give
Period
the
properties
of
3
how
the
properties
elements
change
Period
explain
the
t he
why
the
to
along
Period
Did
Silicon
is
abundant
oxygen,
the
second
the
It
in
on
up
is
which
which
are
from
silicon
1961.
a
Earth
of
led
found
The
following
elements:
sulfur,
chemical
proper ties
of
t hese
chlorine
elements
4.4.1
Moving
from
lef t
to
right,
t he
metallic
change
nature
decreases
and
t he
non-metallic
nature
increases.
The
in
metals,
t hose
or
to
t he
right
are
non-metals
and
silicon,
in
properties
of
metals
and
non-metals
have
t he
following
solid
at
room
physical
They
are
●
They
have
high
melting
●
They
have
high
densities.
●
They
are
good
●
They
are
shiny
●
They
are
malleable,
proper ties
temperature,
points
and
except
boiling
in
common.
mercur y,
which
is
a
liquid.
points.
Trends
conductors
in
of
heat
and
electricity.
appearance.
i.e.
t hey
i.e.
can
be
t hey
can
drawn
be
out
hammered
into
into
different
shapes,
and
wires.
its
●
They
are
sonorous,
chip
t hey
make
a
ringing
sound
when
hit.
have
t he
following
physical
proper ties
in
common.
●
its
They
are
bromine
usually
is
a
gases
at
room
temperature,
however,
some
are
solid
and
liquid.
debut
forms
●
They
have
low
melting
points
and
●
They
have
low
densities.
●
They
are
●
In
t he
solid
state
t hey
are
dull
●
In
t he
solid
state
t hey
are
brittle.
●
In
t he
solid
state
t hey
make
boiling
points.
the
computer
not
in
i.e.
silicon
electronic
made
would
number
its
invention
exist
Period
poor
conductors
of
heat
and
electricity.
today.
summar y
of
t he
trends
of
a
t he
in
appearance.
dull
sound
elements
in
when
hit.
Period
3
is
given
in
Table
4.4.1.
3
Na
Mg
Al
Si
P
S
Cl
Ar
I
II
III
IV
V
VI
VII
0
11
12
13
14
15
16
17
18
(2,8,1)
(2,8,2)
(2,8,3)
(2,8,4)
(2,8,5)
(2,8,6)
(2,8,7)
(2,8,8)
loses
loses
loses
shares
configuration
Loses/gains/shares
1e
2e
3e
4e
gains
3e
gains
2e
gains
1e
none
electrons
at
25 °C
Electrical
conductivity
solid
solid
solid
conductor
conductor
conductor
solid
semi-
solid
solid
insulator
insulator
gas
insulator
gas
insulator
conductor
60
Metal/non-metal
metal
Ease
increasing
of
ionisation
t he
metalloid.
●
computer
without
Electronic
State
of
elements
after
calculators
modern
and
number
Atomic
and
period.
semi-metal
Physical
A
Group
t he
the
to
of
first
silicon
devices
T
able
of
phosphor us,
semiconductor,
has
chips
of
technology

silicon,
most
28%
pocket
The
foundation
such
composed
from
moving
manufacture
computers.
using
is
3.
element
crust.
devices
to
physical
t he
are
a
Non-metals
chips
table
aluminium,
know?
making
property
in
periodic
properties
change
non-metal
you
is
ductile,
use
The
along
lef t
Metals
a
table
3
elements
metal
Earth’
s
t he
elements
middle,
?
periodic
moving
to
along
of
the
of
t he
●
of
periodicity
non-metals
describe
the
in
magnesium,
argon.
moving
●
3
and
metals
and
and
Period
table
will
to:
sodium,
●
in
periodic
metal
ease
of
ionisation
metal
metalloid
non-metal
increasing
non-metal
ease
of
ionisation
non-metal
non-metal
The
periodic
table
and
periodicity
Trends
(a)

(b)
Figure
An
As
4.4.1
you
Metals
along
learnt
to
t he
As
t he
positive
3.
ease
and
one
electrons
has
more
of
its
of
the
periodic
table
around
or
to
elements
t heir
volcano
vent
and
(c)
chlorine
gas
3
atoms
tend
a
lose
or
gain
valence
non-metallic
gain
electrons.
decreases
non-metallic
nature.
Moving
because
nature
t heir
increases
increases.
valence
moving
electron
sulfur
metallic
t he
and
(b)
which
t heir
3
(c)
Period
non-metals
nature
However,
in
wit h
of
decreases
3
sparklers,
trends
t he
gain
Period
has
t he
radii
to
in
Period
electrons
from
and
one
lef t
in
t he
to
more
same
right
electron
along
proton
t han
t he
t he
shell,
period,
element
result:
number
electrons
4.1,
metallic
ability
a
the
electrons
t he
in
burning
indication
electrons
number
causing
●
3,
element
it.
Unit
lose
lose
element
before
of
strong
to
t heir
shell
each
in
a
Period
because
Each
is
tend
ability
●
Magnesium
explanation
electrons
i.e.
(a)
in
of
to
of
positive
attraction
get
t he
protons
between
in
t he
t he
nuclei
positive
of
t he
atoms
nucleus
and
gets
t he
greater,
valence
stronger
atoms
protons
in
get
t he
smaller
nucleus,
due
to
pulling
t he
increasing
t he
outer
number
electrons
of
closer
to
t he
nucleus.
The
combination
more
attracted
harder
gain
for
t he
Since
t he
is
t he
Aluminium
Figures
reactive.
ionisation
t he
protons
i.e.
17
.
Argon
has
a
is
is
a
t heir
atoms
its
t he
ionise
stable
is
of
t hree
t he
by
ionises
full,
and
electronic
t he
is
found
i.e.
it
two
and
easily
gaining
is
t he
is
least
t he
to
t he
contains
t he
t he
and
and
t he
has
its
and
t he
is
i.e.
t he
13
most
reactive.
t he
atoms
two
least
of
period.
nucleus.
ease
chlorine
t hree
and
is
easily
t he
in
to
ot her
3.
nucleus,
t herefore,
sulfur
of
Period
ionisation
its
least
t hem
In
and
more
reactive.
of
increases
has
15
protons,
Chlorine
reactive.
right
eight
conguration,
is
smallest
easily
most
most
electrons,
largest
t he
t he
in
are
becomes
for
along
protons
protons
and
phosphor us,
of
It
period.
along
ease
1
1
easier
t he
decreases
has
more
ionises
least
Chlorine
t he
electrons
period.
and
along
increases
electrons,
atoms
valence
t he
electrons
aluminium
has
t he
along
moving
elements
Sodium
non-metals
easily
t he
t hat
going
valence
and
Phosphor us
means
shell
losing
and
ionises
non-metal
shell
t he
4.4.3).
nucleus.
most
by
smallest
and
period.
in
of
factors
nucleus
valence
ionise
largest
t he
4.4.2
of
t he
electron
lose
magnesium
Phosphor us
ionises
to
t heir
Aluminium
Non-metal
along
atoms
sodium,
Sodium
(see
into
two
positive
electronegativity
metal
metals
t hese
t he
atoms
electrons
words,
of
to
it
of
chlorine.
electrons.
does
not
However,
Because
ionise
and
it
of
is
its
valence
t his,
argon
chemically
unreactive.
61
Trends
in
Period
3
of
the
periodic
table
The
Silicon
of
sodium
Na
12p
found
reacts
usually
ionise.
magnesium
M

Group
IV
and
non-metallic
by
electronic
13p
in
and
usually
The
11p
is
metallic
sharing
str ucture
a
electrons
of
14p
is
metalloid
proper ties.
t he
wit h
elements
15p
It
because
has
ot her
in
periodic
four
table
it
has
3
a
valence
non-metal
Period
and
is
combination
electrons
atoms.
given
periodicity
in
It
Figure
16p
17p
18p
silicon
phosphorus
sulfur
chlorine
argon
Al
Si
P
S
Cl
Ar
4.4.2
Electronic
conguration
of
the
elements
in
Period
not
4.4.2.
aluminium
Figure
and
does
3
0.20
)mn(
0.18
suidar
0.16
0.14
cimotA
0.12
0.10
0.08
Na
Mg
Al
Si
P
S
Cl
Ar
Element

Figure
Summary
1
Chlorine
of
2
the
4
5
62
Trends
in
the
atomic
and
magnesium
table.
One
are
is
both
a
Which
one
is
the
metal?
b
Which
one
is
the
non-metal?
does
3
a
Which
Give
a
Which
b
Give
Which
the
metallic
change
b
is
the
is
the
of
the
from
more
more
in
for
for
Period
3
THREE
elements
in
Period
and
the
which
one
is
a
3
reasons
THREE
are
found
or
answer
for
your
reasons
non-metallic
for
or
answer
has
the
a
nature
of
above.
chlorine?
to
a
above.
greatest
Period
3
answer.
your
magnesium?
to
in
non-metal.
right?
sulfur
your
and
Give
sodium
your
reactive,
reason
element
to
reactive,
reason
Give
nature
left
elements
metal
a
How
radii
questions
periodic
Period
3
4.4.3
metallic
nature?
answer.
elements
in
The
periodic
Key
table
Scientists
●
Dmitri
●
t he
star ted
Period icity
The
The
elements
All
periodic
All
●
The
in
This
two
●
Group
dilute
●
The
of
●
II
down
The
The
of
t he
The
of
the
periodic
table
in
t he
being
early
t he
19t h
creator
centur y.
of
t he
rst
version
elements
inter vals
periodic
wit h
in
t he
table
similar
physical
periodic
are
and
table.
arranged
in
order
of
same
II
ver tical
group
is
t he
period
is
of
columns
called
groups
and
periods
t he
have
of
an
in
have
same
same
have
all
t he
as
t he
as
same
t he
element
similar
number
group
are
valence
of
occupied
electron
number.
determined
t he
of
number.
number
period
par ticular,
ver y
same
t he
number
proper ties
of
by
t he
valence
because
electrons.
t hey
all
have
have
of
similar
reactions
wit h
oxygen,
water
and
acid.
Group
to
t he
lose
II
of
elements,
t heir
Group
II
valence
elements
t heir
atoms
being
metals,
depends
on
t he
ability
electrons.
increases
to
lose
going
t heir
down
valence
t he
group
electrons
increases
group.
Group
reactivity
VII
have
ver y
similar
proper ties
because
t hey
all
have
electrons.
of
Group
atoms
of
VII
to
Group
ability
of
elements,
gain
VII
t heir
an
being
electron
elements
atoms
to
non-metals,
into
t heir
increases
gain
an
depends
valence
going
up
electron
on
t he
shell.
t he
group
increases
going
up
group.
elements
reactive
in
Group
element
containing
●
of
t heir
t he
modern
electrons,
ability
reactivity
because
●
3
electrons.
valence
ability
●
in
wit h
of
regular
proper ties
atoms
Elements
seven
t he
Group
reactivity
going
●
Period
1869.
consists
elements
t he
at
called
t he
of
reactivity
because
●
in
number.
hydrochloric
t heir
The
in
valence
credited
in
number
in
chemical
Elements
t he
number
arrangement
●
Trends
elements
recurrence
table
This
elements
shells.
in
rows
elements
electrons.
●
t he
atomic
horizontal
●
is
is
table
proper ties
increasing
●
classifying
Mendeleev
period ic
chemical
●
periodicity
concepts
●
of
and
t he
Displacement
will
less
reactions
strength
a
of
how
undergo
reactive
oxid ising
measure
VII
displace
of
of
t he
easily
a
a
less
d isplacement
reactive
reactions .
element
from
a
A
more
compound
element.
Group
VII
elements,
substance
elements
where
takes
depend
oxidising
electrons
on
t he
relative
strengt h
from
is
anot her
substance.
●
The
oxidising
strengt h
of
Group
VII
elements
increases
going
up
t he
group.
●
Going
along
elements
●
Going
along
elements
●
The
to
Period
decreases
Period
increases
3
from
lef t
because
3
from
because
electronegativity
of
to
t heir
lef t
to
t heir
right,
ability
right,
ability
elements
in
t he
to
t he
to
metallic
lose
nature
electrons
non-metallic
gain
Period
3
electrons
increases
of
t he
decreases.
nature
of
t he
increases.
going
from
lef t
right.
63
Practice
exam-style
Practice
questions
The
exam-style
periodic
table
and
periodicity
questions
N
Multiple-choice
questions
Na
1
Elements
in
t he
modern
periodic
table
are
arranged
Mg
Si
Cl
in
Ca
order
of
Br
A
chemical
B
atomic
C
mass
reactivity
The
periodic
table
showing
the
position
of
some
elements
number
a
i)
Name
two
elements
which
occur
in
t he
same
number
period.
D
relative
atomic
State
t he
An
element
of
atomic
number
20
is
expected
to
in
Group
II
of
t he
periodic
t he
reason
same
for
placing
t hese
two
period.
(1
a
transition
i)
Name
two
elements
which
occur
in
t he
same
in
IV
a
A
I
Period
4
of
t he
periodic
State
t he
reason
for
placing
t hese
two
mark)
elements
same
group.
(1
mark)
metal
c
and
III
Element
I,
II
and
IV
I,
D
III
III
and
IV
3
valence
IV
element
X
electrons
in
its
and
correct
4
electron
position
in
above.
(1
Give
t he
electronic
conguration
of
a
calcium
atom.
only
(1
e
Which
element
shows
ver y
similar
chemical
Bot h
magnesium
and
calcium
react
acid.
barium?
i)
A
Which
element
would
you
expect
to
react
B
(1
mark)
aluminium
ii)
C
sulfur
D
magnesium
f
X
is
an
element
periodic
I
II
react
table.
ver y
ionise
III
react
A
I
only
B
I
and
C
II
D
I,
below
X
calcium
would
be
vigorously
more
slowly
readily
wit h
in
Group
expected
wit h
t han
cold
II
of
t he
ii)
to:
Explain
What
g
and
II
of
potassium
Explain
i)
Explain
reason
for
to
above.
(2
obser ve
added
to
an
if
an
aqueous
bromide?
your
t he
(1
obser vation
to
right
elements
for
t he
along
fact
Period
decreases
and
t hat,
3,
when
t he
t he
mark)
in
(2
reason
marks)
aqueous
above.
lef t
t he
t he
is
i)
marks)
moving
metallic
nature
non-metallic
increases.
(3
marks)
only
III
and
which
expect
solution
Total
only
15
marks
III
Extended
In
you
to e
chlorine
nature
II
would
answer
of
from
acid
your
solution
f
water
calcium
hydrochloric
i)
of
5
more
sodium
vigorously?
4
mark)
wit h
proper ties
hydrochloric
to
t he
mark)
only
d
and
has
Place
only
gure
C
X
only
shells.
3
in
table
t he
B
(1
element
ii)
III
in
mark)
table
group.
II
mark)
elements
be:
b
I
(1
mass
ii)
2
Kr
increasing:
group
of
t he
periodic
table
are
t he
response
question
halogens
8
a
Outline
t he
contributions
of
Döbereiner
and
found?
Mendeleev
A
Group
to
t he
development
of
t he
periodic
(4
B
Group
II
C
Group
VII
b
The
reactivity
table
D
Group
0
Which
of
t he
following
is
t he
most
of
increases
statement
and
6
by
calcium
elements
going
reference
wit h
in
down
to
Group
t he
t he
oxygen,
II
group.
of
reactions
water
and
t he
of
hydrochloric
(6
silicon
C
sulfur
D
phosphor us
Element
X
potassium
reaction
i)
Place
X,
Structured
position
gure
in
to
iodide
t he
be
to
displace
solution,
potassium
following
found
chlorine,
but
iodine
was
chloride
elements
going
iodine,
of
cer tain
elements
in
t he
periodic
Explain,
in
terms
marks)
down
from
found
to
have
no
solution.
in
order
Group
as
VII:
uorine.
t hey
element
was
to
displace
able
t he
gure
answer
t he
below.
Use
following
t he
information
questions.
of
oxidising
(2
iodine
strengt h,
marks)
from
t he
why
X
potassium
table
iodide
given
found
question
ii)
The
was
wit h
would
64
t his
magnesium
chlorine
B
is
periodic
electronegative?
c
7
marks)
Suppor t
acid.
A
table.
I
in
solution.
(3
marks)
t he
Total
15
marks
A5
Most
substances
Structure
occur
as
compounds
in
and
bonding
n a t u re .
Objectives
Compounds
chemically
a re
with
formed
each
when
o t h e r.
atoms
The
combine
compounds
By
the
be
able
formed
a re
m o re
stable
than
the
f re e
of
elements
why
chemical
w e re .
The
noble
gases
a re
an
exception
to
do
occur
in
n a t u re
as
atoms.
The
state
e l e c t ro n i c
of
the
noble
gases
is
the
their
will
atoms
form
bonds
how
atoms
form
chemical
name
the
three
types
of
re a s o n
chemical
behind
you
bonds
●
configuration
topic
this;
●
they
this
to:
explain
●
a re
end
which
s t a b i l i t y.
describe
●
chemical
work
●
of
out
binary
bonding
three
types
of
formulae
the
empirical
compounds
formulae
from
their
names.
A5.1
Chemical
Introduction
When
atoms
to
bond
bonding
chemical
wit h
eac h
bonding
ot her,
only
t he
o u t e r m o st
electrons,
k n ow n
a s va l e n c e e l e c t r o n s , a r e u s u a l ly i nvo lve d i n t h e p r o c e s s . A t o m s c o m b i n e
He
wit h
eac h
3.2).
The
shell
is
is
t his
noble
t heir
are
t he
st a b l e
g i ve s
ga s
st a b l e
a to m s
t hem
a
electron
configuration
electronic
because
st a b l e
configuration.
o u t e r m o st
electronic
m o st
t heir
electronic
A to m s ,
shell
of
configuration
t he
o u t e r m o st
or
electron
configuration.
t h e r e fo r e ,
valence
f i r st
( Un i t
t hree
bond
shell.
noble
This
wit h
eac h
Fi g u r e
5 .1.1
××
Ne
××
fill
att ain
ga s e s
and
t he
t he
to
××
to
s h ow s
noble
full
called
ot h e r
ot h e r
ga s e s .
××
A to m s
ga i n
n e a r e st
st a b i l i t y
noble
ga s
to
if
t h ey
t hem
in
att ain
t he
t he
noble
per iodic
ga s
t able,
configuration
i.e.
t he
element
of
t he
t hat
is
××
c l o s e st
is
by
neon
and
n e a r e st
Fo r
noble
e xa mp l e ,
ga s
to
t he
n e a r e st
c hlor ine
is
noble
argon.
ga s
This
is
to
sodium
××
i l l u st r a t e d
××
××
××
××
××
×
Ar
××
5 .1. 2 .
××
Fi g u r e
t he
n u m b e r.
××
in
a to m i c
××
××
××
××
●
gain
●
share
one
one
or
or
more
more
valence
gas
valence
electrons
××
××
××
××
structure
of
sodium
and
chlorine
to

Figure
of
5.1.1
helium,
The
neon
electronic
and
structures
argon
their
argon
conguration
This
valence
Ar
××
donate
noble
××
●
a
change.
electronic
and
××
achieve
chemical
the
neon
××
gases,
××
Comparing
noble
××
can
a
××
5.1.2
nearest
during
Cl
××
Figure
Atoms
×
Ne
××

××
××
××
××
Na
can
occur
electrons
electrons
wit h
in
to
from
anot her
by
bonding
three
ways.
anot her
anot her
wit h
They
ot her
atoms
can:
atom
atom
atom.
65
Chemical
bonding
Structure
During
!
Key
are
A
chemical
attraction
results
their
bond
is
between
from
the
chemical
involved.
fact
a
force
atoms
of
These
caused
toget her.
by
bonding,
bonds
t he
There
chemical
are
forces
redistribution
are
three
main
bonds
of
of
t heir
types
are
formed
attraction
of
between
between
electrons,
chemical
and
and
t he
t hey
bonding
t he
atoms
join
atoms
which
t he
atoms
bonding:
that
redistribution
●
ionic
bond ing ,
●
covalent
●
metallic
which
occurs
when
a
metal
bonds
wit h
a
non-metal
of
bond ing ,
which
occurs
when
two
or
more
non-metals
bond
electrons.
onic
and
bond ing ,
covalent
which
occurs
bonding
wit hin
bot h
metals.
result
in
t he
formation
of
chemical
compounds.
Chemical
Just
by
as
elements
ionic
or
Chemical
are
in
compound.
●
are
The
can
be
covalent
a
There
are
are
be
impor tant
as
well
various
formula ,
atoms
compound.
by
can
atomic
because
as
t he
types
symbols,
represented
of
by
t hey
ratio
tell
us
between
chemical
compounds
chemical
which
t he
formulae.
formed
formulae .
elements
elements
The
in
t hree
t he
main
below.
molecular
of
compounds
represented
compound
given
number
of
bonding
formulae
found
types
formulae
For
of
which
each
uses
element
example,
t he
subscripts
present
molecular
in
to
one
formula
give
t he
actual
molecule
of
water
of
is
a
H
O,
which
2
means
atom.
one
molecule
Ot her
of
molecular
water
contains
formulae
2
hydrogen
include
CO
for
atoms
carbon
and
1
oxygen
dioxide
and
2
C
H
6
●
O
12
The
for
structural
molecule
bonds.
atom
The
of
For
OCO
●
glucose.
6
and
t he
between
compound
empirical
which
compound
example,
which
t he
shows
carbon
empirical
ratio
formula ,
t he
t hat
formula
diagrammatic
between
formula
t here
are
for
two
representation
t he
atoms
carbon
bonds
to
dioxide
between
of
one
represent
is
each
oxygen
atom.
which
elements
consists
a
lines
str uctural
us
formula ,
t he
is
using
of
for
in
gives
t he
multiples
of
magnesium
t he
simplest
compound
t hese
smallest
chloride
is
whole
using
number
subscripts.
units.
MgCl
,
For
which
The
example,
tells
us
t he
t hat
2
magnesium
and
chlorine
are
present
in
a
ratio
of
1
to
2.
Example
The
t hree
types
●
Molecular
●
Str uctural
of
chemical
formula:
C
formula:
et hane
are:.
6
formula:
H
Empirical
for
H
2
●
formulae
H
H
C
C
H
H
H
CH
3
!
Key
fact
Writing
Valence
number
(valency)
is
A
maximum
number
of
bonds
can
form
when
it
binary
bonds
t he
compound
empirical
number
atoms.
atom
66
of
binary
compounds
is
composed
formulae
of
of
two
binar y
different
elements
compounds
using
only.
t he
We
can
concept
of
with
valence
other
formulae
an
write
atom
empirical
the
can
form.
or
valency,
which
is
t he
maximum
number
of
bonds
an
Structure
and
bonding
Chemical
bonding
The number of valence electrons an atom has determines its valence number.
This
is
because
of
chemical
in
forming
electrons
it
is
t he
bonds.
bonds,
an
valence
Since
t he
atom
electrons
atoms
valence
has
to
lose,
number
lose,
gain
which
gain
or
can
or
par ticipate
share
be
share
t heir
t hought
during
in
t he
formation
valence
of
as
t he
bonding.
electrons
number
The
of
valence
number of an element is related to its position in t he periodic table as shown
in

Table
T
able
Group
5.1.1
Valence
number
Valence
n
5.1.1.
number
ot her
numbers
I
II
transition
1
2
variable,
metals
often
2
III
IV
V
VI
VII
0
3
4
3
2
1
0
words:
●
valence
number
of
elements
in
Groups

●
valence
number
of
elements
in
Groups
V
Since
same
bot h
types
number
element
in
of
t he
of
atom
valence
forming
a
electrons,
compound
must
be
to
V
to
V
compound
t he
sum

of
t he

8
must
t he
group

t he
lose,
number
group
gain
valence
or
number.
share
numbers
of
t he
each
equal.
Example
The
chemical
formula
of
aluminium
oxide
is
Al
O
2
●
●
●
Number
Valence
Sum
i.e.
To
of
t he
write
of
atoms
number
t he
of
of
t he
each
each
valence
sum
t he
of
element
element:

3.
(Group
),
O

2
(Group
V).
2

3


3

2

numbers
a
2,
O
3

of


O
formula
3
Al
Al
numbers: Al
valence
chemical
present:
of
t he
binar y
6,
6,
two
elements
compound,
is
follow
equal.
t he
steps
given
below.
1)
Determine
2)
Write
down
symbol
3)
Write
Write
5)
Write
Points
t he
to
●
There
●
f
1
●
t he
as
a
Some
The
by
a
e.g.
of
t he
symbol
valence
t he
numbers
symbol
of
t he
of
rst
t he
two
elements
element.
f
a
present.
metal
is
present,
write
its
rst.
t he
symbol
4)
t he
of
valence
t he
number
rst
symbol
of
valence
t he
of
t he
second
element
as
a
subscript
af ter
t he
element.
t he
second
number
second
of
element
t he
rst
directly
af ter
element
as
a
t he
subscript.
subscript
af ter
t he
element.
note
must
be
valence
no
number
subscript
of
t he
spaces
(see
transition
number
Roman
numeral
copper(II)
one,
example
valence
example
is
between
write
t hese
placed
indicates
t hat
symbols
only
t he
and
subscripts.
symbol
wit hout
t he
number
2).
metals
of
t he
have
is
in
more
t han
indicated
brackets
copper
has
in
af ter
a
one
t he
valence
name
t he
of
name
valence
number.
t he
of
compound
t he
number
of
metal,
2
(see
3).
67
Chemical
bonding
Structure
●
The
●
To
valence
write
t he
simplest
number
of
empirical
form,
t hen
hydrogen
formula,
cancel
to
if
its
and
t he
t he
transition
ratio
simplest
of
t he
form
element,
subscripts
(see
and
is
example
bonding
silver,
not
in
is
1.
its
4).
Examples
1
Magnesium
●
nitride
Determine
t he
●
Write
down
●
Write
t he
t he
valence
t he
symbol
valence
symbol
of
numbers
t he
of
number
rst
t he
of
of
rst
t he
element:
t he
two
elements
element:
second
present:
Mg

2
(Group
),
N

3
(Group
V).
Mg
element
as
a
subscript
af ter
Mg
3
●
Write
t he
symbol
of
t he
second
element:
Mg
N
3
●
Write
t he
symbol
valence
of
t he
number
second
of
t he
element:
rst
Mg
The
empirical
formula
of
element
as
a
subscript
Potassium
●
●
t he
magnesium
2
nitride
is
Mg
N
3
2
af ter
N
3
2
sulde
Valence
numbers
Empirical
of
formula
t he
of
elements:
potassium
K

1
(Group
),
S

2
(Group
V).
sulde
is
K
S
2
3
ron( )
●
●
bromide
Valence
numbers
Empirical
of
formula
t he
of
elements:
iron ()
Fe

3
(given
Br

1
(Group
bromide
is
FeBr
in
t he
name),
V).
.
3
4
Carbon
●
●
dioxide
Valence
numbers
Empirical
of
formula
t he
of
elements:
carbon
C

4
(Group
V),
O

2
(Group
V).
dioxide
is
CO
.
2
simplest
Summary
1
Explain
why
2
Explain
how
3
Name
4
Using
the
a
O
2
is
cancelled
to
4
questions
atoms
form
types
periodic
binary
sodium
form
atoms
three
your
following
(C
ratio.)
of
compounds.
compounds.
chemical
table
to
help
bonding.
you,
write
the
formula
of
each
of
the
compounds:
oxide
b
copper(II)
c
tetrachloromethane,
bromide
a
compound
formed
between
carbon
and
chlorine
68
d
aluminium
e
ammonia,
sulde
a
compound
formed
between
nitrogen
and
hydrogen.
its
Structure
and
A5.2
bonding
Formation
Formation
of
ionic
bonds
atoms.
Compounds
formed
by
ionic
ionic
bonds
Objectives
onic bonding involves t he transfer of valence electrons from metal atoms to
non-metal
of
bonding
are
known
as
By
the
be
able
end
of
this
topic
you
will
to:
ionic
●
explain
the
principles
of
ionic
compounds
bonding
The
principles
of
ionic
bonding
are
explained
as
follows.
●
●
Metals
are
valence
noble
●
found
to
electrons.
gas
t he
f
lef t
t hey
of
lose
t he
periodic
t heir
table
valence
and
most
electrons
have
t hey
can
1,
2
or
attain
3
Non-metals
are
found
to
t he
right
of
t he
periodic
table
and
most
how
cations
and
form
a
conguration.
explain
metal
atoms
non-metal
form
atoms
anions
●
name
●
describe
ionic
compounds
the
formation
of
ionic
have
bonds
5,
6
or
7
valence
electrons.
f
t hey
gain
electrons
into
t heir
valence
shell
●
t hey
can
attain
a
noble
gas
represent
shell
●
When
an
atom
loses
or
gains
electrons
it
forms
an
ion.
The
ions
now
charged
par ticles
because
t hey
no
longer
contain
t he
of
electrons
as
t he
number
of
deduce
When
t han
●
a
metal
atom
electrons.
When
a
The
non-metal
electrons
t han
loses
ion
electrons,
has
atom
protons.
a
gains
The
t he
positive
ion
has
formed
charge
electrons,
ion
a
ionic
the
empirical
formulae
compounds
protons.
●
●
using
same
of
number
bonding
diagrams
formed
●
are
ionic
conguration.
and
t he
ion
negative
is
has
more
called
formed
charge
a
describe
sodium
the
structure
chloride
of
a
crystal.
cation
has
and
protons
is
more
called
an
anion
Examples
1
Lithium
When
now
is
in
Group
bonding
has
one
wit h
more

of
a
t he
periodic
non-metal,
proton
t han
table
lit hium
electron.
and
has
loses
its
one
valence
valence
Therefore
it
electron.
electron
carries
a
and
single

positive
charge,
,
and
is
represented
as
Li
.
t
is
known
as
t he
lit hium

ion
or
Li
ion.

3p
3p
4n
4n

lithium
atom
lithium
an
electron
ion

Li
(2,1)
Li
(2)


2
Nitrogen
electrons.
and
now
is
Figure
in
Group
When
has
5.2.1
V
Formation
of
bonding
t hree
more
t he
of
a
lithium
periodic
wit h
a
table
metal,
electrons
t han
ion,
Li
and
nitrogen
protons.
has
ve
gains
valence
t hree
Therefore
it
electrons
carries
a
3
triple
negative
charge,
3 ,
and
is
represented
as
N
.
t
is
known
as
t he
3
nitride
ion
or
N
ion.
3
7p
7p

three
electrons
7n
nitrogen
7n
atom
nitride
ion
3
N
(2,5)
N
(2,8)
3

Figure
5.2.2
Formation
of
a
nitride
ion,
N
69
Formation
of
ionic
bonds
Structure
When
Key
!
naming
electrons,
fact
t he
t he
negative
name
changes
anions
from
formed
t hat
of
when
t he
and
non-metal
atom.
The
name
bonding
atoms
of
t he
gain
anion
2
always
Ionic
bonds
created
by
are
the
chemical
bonds
and
of
attraction
between
charged
negatively
‘ide’.
For
ion
example,
(Br
t he
chloride
ion
(Cl
),
t he
oxide
ion
(O
)
).
t he
cations
charged
anions
compounds
formed
by
ionic
bonding,
t here
are
strong
electrostatic
the
forces
positively
in
bromide
electrostatic
n
forces
ends
t he
of
attraction
between
t he
positive
cations
and
negative
anions.
and
in
These
ionic
forces
of
attraction
are
known
as
ionic
bonds
and
t hey
hold
t he
ions
toget her. The strengt h of t he ionic bonds accounts for t he proper ties of ionic
compounds.
compounds
(Unit
Examples
to
The
formation
and
potassium
cross
5.5).
show
of
the
sodium
nitride
by
formation
chloride,
ionic
of
magnesium
bonding
is
ionic
compounds
uoride,
shown
next
aluminium
by
means
of
oxide
dot
and
diagrams.
Sodium
Sodium
chloride
is
a
metal
wit h
one
valence
electron.
t
loses
t his
electron
to
form
a

positive
is
a
sodium
non-metal
negative
sodium
atom
to
atom
in
seven
ion
t hat
accept
a
single
valence
which
loses
t his
has
has
one
electron.
positive
electrons.
a
single
electron
The
t
charge,
gains
negative
t here
empirical
will
one
need
formula
.
Chlorine
to
i.e.
be
Cl
to
.
one
sodium
form
For
a
each
chlorine
chloride
is,
shows
how
to
use
shell
diagrams
to
represent
t he
ionic
bonding
chloride.
–
+
××
××
××
××
Cl
××
××
××
××
Na
Na
××
sodium
of
Na
electron
charge,
×
1
i.e.
NaCl
5.2.3
sodium
which
wit h
chloride
t herefore,
Figure
ion
Cl
××
atom
1
chlorine
atom
1
sodium
ion
1
chloride
ion
+
(Na)
Did
?
you
term
(Na
)
(Cl
)
know?

The
(Cl)
‘lattice’
refers
Figure
5.2.3
Ionic
bonding
in
sodium
chloride
to
t is important to note that NaCl is not a separate, individual entity. NaCl simply
a
regular,
three-dimensional

represents
arrangement
of
the
ratio
of
Na
ions
to
Cl
ions
in
sodium
chloride,
i.e.
it
is
the
particles.
empirical formula. t can also be called the
Sodium
c hlor ide
formula unit of sodium chloride.
t hat
we
spr inkle
on
our
food
is
composed of tiny cr yst als t hat are cubic in shape. Eac h
−
=
−
Cl

of
t hese
cr yst als
is
made
up
of
millions
of
Na
ions

and
−
+
millions
of
Cl
ions
in
a
ratio
of
one
Na
ion
to
−
one
Cl
way;
ion.
t hey
These
occur
ions
are
ar ranged
alter nately
in
in
rows
a
ver y
and
regular
columns.
+
+
=

Na
Eac h
+
−
Na
ion
is
bonded
+
to
six
Cl
ions
and
eac h
Cl

ion
is
bonded
to
six
Na
ions
by
strong
ionic
bonds.
−
This
t hree-dimensional,
for ms
strong
ionic
charged
ordered
ar rangement
lattice.
+
−
oppositely
ions

70
cr yst al
bonds
−
between
a
Figure
5.2.4
Crystal
lattice
of
sodium
chloride
of
ions
Structure
and
Magnesium
Magnesium
bonding
Formation
of
ionic
bonds
fluoride
is
a
metal
wit h
two
valence
electrons.
t
loses
t hese
electrons
to
2
form a positive magnesium ion which has a double positive charge, i.e. Mg
Fluorine
to
form
For
is
a
each
negative
atoms
one
uoride
non-metal
is,
to
wit h
uoride
magnesium
uorine
accepts
a
atom
accept
electron.
t herefore,
seven
ion
t hat
t hese
The
valence
which
loses
two
has
two
electrons.
a
single
electrons
electrons
empirical
formula
gains
negative
t here
since
or
t
each
formula
will
one
charge,
i.e.
need
be
uorine
unit
of
.
electron
to
atom
F
.
two
only
magnesium
MgF
2
–
F
F
×
2+
×
××
××
×
××
××
××
××
Mg
Mg
–
××
××
F
F
×
1
magnesium
2
fluorine
1
magnesium
2
fluoride
2+
atom,

Mg
Figure
atoms,
5.2.5
Aluminium
Ionic
F
ion,
bonding
in
magnesium
Mg
ions,
F
uoride
oxide
Aluminium
is
a
metal
wit h
three
valence
electrons.
t
loses
t hese
electrons
to
3
form
a
positive
Oxygen
is
a
aluminium
non-metal
ion
wit h
which
six
has
valence
a
triple
positive
electrons.
t
charge,
gains
two
i.e.
Al
.
electrons
to
2
form a negative oxide ion which has a double negative charge, i.e. O
each
has
to
total
six
aluminium
gain
of
six
two
The
Al
O
2
To
as
simplify
in
Figure
has
electrons,
electrons
electrons.
t herefore,
atom
and
to
lose
two
t hree
empirical
t hree
electrons
aluminium
oxygen
formula
or
atoms
atoms
will
will
formula
and
be
unit
each
be
needed
needed
of
. Since
oxygen
to
to
gain
aluminium
atom
lose
a
t hese
oxide
is,
.
3
t he
diagrams,
sometimes
only
t he
valence
electrons
are
shown,
5.2.6.
2–
×
O
O
×
3+
×
Al
Al
2–
×
×
O
O
3+
×
×
Al
Al
2–
×
×
O
O
×
2
aluminium
3
oxygen
2
aluminium
ions,
3
oxide
3+
atoms,

Figure
Al
5.2.6
atoms,
Ionic
O
bonding
Al
in
aluminium
ions,
2–
O
oxide
71
Writing
chemical
formulae
of
ionic
compounds
Structure
Potassium
Potassium
and
bonding
nitride
has
one
valence
electron.
t
loses
t his
electron
to
form
a
positive

potassium ion wit h a single positive charge, i.e. K
electrons.
t
gains
t hree
electrons
to
form
a
. Nitrogen has
negative
nitride
ve
ion
valence
which
has
3
a
triple
t hree
of
negative
electrons
potassium
charge,
to
one
nitride
i.e.
N
.
nitrogen
is,
Three
atom.
t herefore,
K
potassium
The
atoms
empirical
are
formula
needed
or
to
formula
lose
unit
N
3
+
K
K
3
+
×
K
N
×
×
+
K
3
K
potassium
1
nitrogen
3
potassium
ions,
1
nitride
+
atoms,

K
atom,
Figure
5.2.7
Summary
1
Explain
2
Use
a
happens
diagrams
sodium
bonding
in
potassium
ion,
3
K
N
nitride
questions
what
shell
Ionic
N
and
to
during
ionic
represent
oxygen
to
form
bonding.
the
ionic
sodium
bonding
oxide,
Na
between:
O
2
b
magnesium
and
nitrogen
to
form
magnesium
nitride,
Mg
N
3
3
4
the
be
able
●
end
this
topic
you
●
ionic
Give
the
name
b
Give
the
formula
Describe
the
of
compound
the
unit
structure
Writing
will
the
the
names
common
and
formulae
cations
and
with
2
uorine.
compound.
of
of
the
the
compound.
crystal
chemical
lattice
of
sodium
formulae
of
chloride.
ionic
compounds
work
out
onic
compounds
formula
of
an
compound.
anions
●
an
to:
give
of
of
forms
a
A5.3
Objectives
By
Calcium
the
formula
ionic
compound
write
the
name
compound
from
of
from
of
an
the
an
the
name
ionic
●
ionic
are
ionic
There
represented
compound
are
using
is
impor tant
also
empirical
known
points
to
as
note
formulae .
t he
The
formula
when
writing
empirical
unit
of
t he
formulae
of
compounds.
Metals
generally
generally
gain
lose
electrons
electrons
forming
forming
positive
negative
cations.
Non-metals
anions.
formula.
●
The magnitude of the charge on an ion is the same as the valence number.
Therefore, when writing formulae of ionic compounds, the magnitude of
the charge on the ion can be used in place of the valence number.
●
Not
all
atoms
were
72
ions
are
bonded
formed
from
toget her.
previously
known
one
These
as
atom.
ions
radicals).
are
Many
ions
known
as
are
made
from
polyatomic
several
ions
(t hese
Structure
●
When
writing
t he
Writing
formula
charges
types
atom
or
group
number
of
electrons.
The

bonding
positive
same
in
and
of
names
Tables
T
able
and
5.3.1
5.3.1
Monovalent
must
formulae
and
of
equal
of
of
an
t he
atoms
t he
ionic
sum
compound,
of
t he
bonded
ions
t hat
toget her
you
are
of
must
required
lose
to
of
ionic
compounds
t he
since
or
bot h
gain
know
t he
are
given
cations
cations
Divalent
cations
Trivalent

magnesium
Li
sodium
Na
potassium
K
calcium
Ca
barium
Ba
iron(II)
Fe
copper(II)
Cu
Ag
zinc
Zn
tin(II)
Sn
lead(II)
Pb
aluminium
Al
2

silver
3
2

Cu
Fe
2

copper( )
3
iron(III)
Mg

lithium
cations
2
H
2

2

ammonium
sum
charges,
formulae
5.3.2.
Common
hydrogen
t he
negative
chemical
2
NH
4
2

T
able
5.3.2
Monovalent
Common
anions
anions
Divalent
anions
Trivalent
anions
2
fluoride
oxide
F
3
O
nitride
N
phosphate
PO
2
chloride
sulfide
Cl
3
S
4
2
bromide
Br
carbonate
CO
iodide
I
sulfite
SO
hydride
H
sulfate
3
2
(sulfate(IV))
3
2
(sulfate(VI))
SO
4
2
hydroxide
OH
nitrite
NO
dichromate(VI)
Cr
O
2
(nitrate(III))
7
✔
Exam
tip
2
Success
nitrate
(nitrate(V))
in
chemistry
depends
on
NO
3
being
manganate(VII)
MnO
hydrogensulfate
HSO
able
to
write
the
names
and
4
formulae
4
hydrogencarbonate
the
important
HCO
3
this
ethanoate
CH
of
compounds.
formulae
of
step
ions
is
towards
Knowing
a
very
achieving
success.
COO
3
n order to write t he chemical formula of an ionic compound from t he name,
follow
1)
t he
steps
and
below.
5.3.2.
2)
Rewrite
3)
Write
t he
t he
formula
outside
Write
formula
of
magnitude
of
required,
4)
given
Write down t he formulae of t he two ions t hat are involved from Tables 5.3.1
t he
place
t he
t he
cation.
t he
bracket
formula
t he
of
cation,
t he
f
it
is
a
polyatomic
(see
of
on
t he
polyatomic
cation
example
t he
omitting
charge
anion
in
its
charge.
anion
as
cation
brackets
a
subscript
and
and
more
write
af ter
t han
t he
t he
one
is
subscript
4).
directly
af ter
t he
subscript,
omitting
its
charge.
5)
Write
t he
formula
required,
outside
magnitude
of
t he
place
t he
of
anion.
t he
bracket
t he
f
it
charge
is
a
polyatomic
(see
on
t he
polyatomic
anion
example
in
cation
as
anion
brackets
a
subscript
and
and
more
write
af ter
t han
t he
t he
one
is
subscript
5).
73
Writing
chemical
formulae
of
ionic
compounds
Structure
Points
●
f
to
t he
f
t he
bonding
note
magnitude
subscript
●
and
(see
ratio
simplest
of
of
t he
charge
examples
t he
form
2
and
subscripts
(see
example
is
one,
do
not
write
t he
number
1
as
a
3).
is
not
in
its
simplest
form,
t hen
cancel
to
its
6).
Examples
1
Aluminium
sulde
3
●
Write
down
t he
ions
●
Write
down
t he
formula
●
Write
t he
t he
involved:
magnitude
formula
of
t he
of
of
t he
t he
cation:
Al
2
,
S
cation
charge
wit hout
on
t he
its
anion
charge:
as
a
Al
subscript
af ter
Al
2
●
Write
t he
formula
of
t he
●
Write
t he
magnitude
anion
wit hout
its
charge:
Al
S
2
t he
formula
of
t he
of
t he
anion:
charge
Al
formula
unit
of
t he
cation
aluminium
Calcium
a
subscript
af ter
3
sulde
is
Al
S
2
2
as
S
2
The
on
3
iodide
2
●
ons
involved:
●
Magnitude
●
Formula
Ca
,

2
of
unit
t he
of
charges:
calcium
Ca

iodide
is
2,


1
CaI
2
3
Sodium
phosphate

●
ons
involved:
Na
3
,
PO
4

●
Magnitude
of
t he
charges:
Na
3

1,
PO

3
4
●
Formula
unit
of
sodium
phosphate
is
Na
PO
3
4
Ammonium
sulfate

●
ons
involved:
NH
2
,
SO
4
4

●
Magnitude
of
t he
charges:
NH
2

1,
SO
4
●
Formula
4
unit
of
ammonium

2
4
sulfate
is
(NH
)
4
SO
2
4

(The
polyatomic
ammonium
ion,
NH
,
is
placed
in
brackets
wit h
4
subscript
5
outside.)
Copper(II)
nitrate
2
●
ons
involved:
Cu
,
NO
3
2
●
Magnitude
●
Formula
of
t he
charges:
Cu

2,
NO

1
3
unit
of
copper ()
nitrate
is
Cu(NO
)
3
(The
polyatomic
nitrate
ion,
NO
,
is
placed
in
2
brackets
3
subscript
6
outside.)
Magnesium
carbonate
2
●
ons
involved:
Mg
2
,
CO
3
2
●
Magnitude
of
t he
charges:
Mg
2

2,
CO

2
3
●
Formula
unit
of
magnesium
carbonate
is
MgCO
3
(Mg
(CO
2
74
)
3
is
2
cancelled
to
its
simplest
ratio.)
wit h
t he
t he
Structure
and
Naming
The
name
bonding
ionic
of
an
Writing
chemical
formulae
of
ionic
compounds
compounds
ionic
compound
is
built
from
t he
cation
and
anion
names.
Examples
1
Al(OH)
is
composed
of
t he
aluminium
cation
and
hydroxide
anion.
ts
3
name
2
K
O
is
is
aluminium
composed
of
hydroxide.
t he
potassium
cation
and
t he
oxide
anion.
ts
name
2
is
3
potassium
Ca
(PO
3
f
t he
is
is
by
composed
of
t he
calcium
cation
and
phosphate
anion.
ts
2
calcium
cation
charge
its
)
4
name
oxide.
is
phosphate.
t hat
looking
of
at
a
t he
transition
subscript
metal,
af ter
t he
determine
anion
and
t he
use
magnitude
t his
to
of
its
determine
name.
Examples
1
FeCl
2
●
The
subscript
af ter
●
The
magnitude
●
The
cation
●
The
name
of
t he
t he
chloride
charge
ion
on
is
t he
2.
iron
ion
must
be
2.
be
3.
2
2
Fe(NO
must
of
t he
be
t he
iron (II)
compound
is
ion,
Fe
iron (II)
chloride.
)
3
3
●
The
subscript
●
The
magnitude
af ter
of
t he
t he
nitrate
charge
ion
on
is
t he
3.
iron
ion
must
3
●
The
cation
●
The
name
Summary
1
2
Write
the
must
of
be
t he
iron (III)
compound
is
ion,
Fe
iron (III)
nitrate.
questions
chemical
a
iron(III)
b
calcium
c
sodium
d
ammonium
e
silver
f
zinc
g
potassium
h
copper(II)
Write
t he
formula
of
each
of
the
following
ionic
compounds:
sulde
hydroxide
sulfate
phosphate
oxide
nitrate
names
a
Mg
b
AgCl
c
ZnI
d
Al(HCO
e
FeBr
(PO
3
manganate( VII)
carbonate
for
each
of
the
following
compounds:
)
4
2
2
)
3
3
3
f
FeSO
g
Cu
4
O
2
h
Pb(NO
)
3
2
75
Formation
of
covalent
and
metallic
bonds
A5.4
Objectives
By
the
be
able
end
of
topic
you
the
formation
of
Covalent
metal
covalent
shell
covalent
and
metallic
bonding
bonds
bonding
bonding
bonding
atoms.
covalent
involves
t he
Compounds
sharing
formed
of
by
valence
covalent
electrons
bonding
between
are
non-
known
as
compounds
diagrams
Non-metals
write
●
of
and
will
bonds
represent
using
Formation
Covalent
covalent
●
this
to:
describe
●
Structure
formulae
of
are
found
to
t he
right
of
t he
periodic
table
and
have
4,
6
or
shell
5,
to
covalent
7
valence
electrons.
They
need
to
gain
electrons
into
t heir
valence
compounds
attain
describe
●
metallic
the
formation
a
noble
gas
conguration.
of
bonds
Since all t he atoms involved in covalent bonding need to gain electrons, t hey
relate
●
the
properties
of
metals
achieve t his by approaching each ot her so t hat t heir outermost electron shells
to
the
bonding
in
metals.
overlap.
are
Any
t hen
valence
shared,
in
electrons
pairs,
pair of electrons forms a
are
Key
!
known
orbiting
electron
covalent
bond
is
a
a
pair
formed
of
covalent bond
bond ing
pair.
Each
not
two
in
pairs
in
overlapping
t he
original
atoms.
Each
atoms
shared
and t he electrons in a covalent bond
bonding
shell
by
the
electrons
around
and
is
each
stable.
nucleus.
Two
Each
pair
atoms
atom
spends
may
now
share
has
one,
a
time
wit h
two
completed
bot h
or
t hree
outer
pairs
of
chemical
electrons
bond
a
were
t he
fact
atoms,
A
as
t hat
between
sharing
between
between
t hem.
of
two
Two
or
more
non-metal
atoms
can
bond
toget her
by
sharing
electron
atoms.
pairs.
When
molecules.
The
electrostatic
!
Key
bonding
fact
molecule
more
atoms
bonded
is
a
group
which
together
are
of
two
or
may
behave
chemical
as
a
reaction.
atoms
of
pairs
bond
t hey
wit hin
form
a
attraction
of
molecule
between
electrons.
toget her
by
separate,
Atoms
covalent
are
t he
of
individual
held
toget her
nuclei
t he
entities
same
of
t he
by
known
t he
atoms
element
or
of
as
strong
and
t he
different
bonding.
covalently
strongly
single
t his,
or
enough
Examples
to
do
forces
pair
elements
A
t hey
unit
in
to
show
the
formation
of
covalent
a
substances
The
by
formation
means
Chlorine
of
of
dot
a
variety
and
cross
of
substances
by
covalent
bonding
is
shown
next
diagrams.
gas
Chlor ine
is
a
non-metal
wit h
se ven
valence
electrons.
t
needs
one
more
electron to ll its valence electron shell and attain a noble gas conguration.
Dur ing t he for mation of a chlor ine molecule, two chlor ine atoms come close
enough
pair
of
for
t heir
outer
electrons
for ming
chlor ine
a
is
electron
between
single
shells
t hem.
covalent
The
bond
to
overlap.
shared
between
pair
t he
The
two
orbit
two
atoms
around
atoms.
The
share
bot h
for mula
Cl
2
××
××
××
××
××
××
Cl
Cl
××
××
××
××
2
chlorine
atoms,
Cl
1
××
×
××
××
××
××
××
Cl
chlorine
Cl
molecule,
Cl
2

76
Figure
5.4.1
Covalent
bonding
in
chlorine
one
atoms
for
Structure
and
bonding
Formation
of
covalent
and
metallic
bonds
Water
Water
is
a
its
t
is
a
compound
non-metal
valence
needs
atoms
water
more
needed
hydrogen
for
electron
two
are
wit h
atom
is
H
formed
one
shell.
to
provide
shares
one
hydrogen
electron.
Oxygen
electrons
to
from
valence
is
ll
t he
a
its
and
valence
wit h
one
wit h
atoms.
more
six
electron
electrons
pair
oxygen
needs
non-metal
two
electron
t
valence
shell.
required
t he
oxygen
Hydrogen
electron
Two
by
to
hydrogen
oxygen.
atom.
ll
electrons.
The
Each
formula
O
2
H
O
H
O
H
H
2
hydrogen
1
oxygen
1
water
molecule,
H
O
2
atoms,

H
atom,
Figure
5.4.2
O
Covalent
bonding
in
water
Methane
Met hane is a compound formed from carbon and hydrogen. Carbon is a non-
metal
wit h
electron
Four
Each
formula
valence
electrons.
Hydrogen
hydrogen
carbon.
The
four
shell.
atoms
are
hydrogen
for
needs
needed
atom
met hane
is
t
one
needs
four
electron
to
shares
to
provide
one
electrons
ll
t he
its
four
electron
pair
to
valence
ll
electrons
wit h
its
valence
electron
t he
shell.
required
carbon
by
atom.
CH
4
Oxygen
gas
Oxygen
needs
formation
for
t heir
two
an
outer
electrons
oxygen
of
electron
between
is
electrons
oxygen
shells
t hem,
to
ll
molecule,
to
its
two
valence
overlap.
forming
a
electron
oxygen
The
double
atoms
two
atoms
covalent
shell.
come
During
close
share
bond .
two
The
t he
enough
pairs
formula
of
for
O
2
H
×
×
××
××
×
C
H
×
H
O
O
×
×
×
H
1
methane
molecule,
CH
1
oxygen
molecule,
O
4

Carbon
Figure
needs
valence
electron
electrons
t he
carbon
Covalent
bonding
in
methane
and
oxygen
dioxide
Carbon
wit h
5.4.3
2
four
required
carbon
dioxide
is
electrons
shells.
by
and
oxygen
oxygen
carbon.
atom,
CO
Two
Each
forming
a
needs
atoms
oxygen
double
are
two
electrons
needed
atom
to
shares
covalent
two
bond.
to
provide
ll
t he
electron
The
t heir
four
pairs
formula
for
.
2
77
Formation
of
covalent
and
metallic
bonds
Structure
and
bonding
Nitrogen
Nitrogen
is
electrons
to
molecule,
a
non-metal
ll
two
its
wit h
valence
nitrogen
ve
electron
atoms
valence
shell.
come
electrons.
During
close
t he
t
needs
formation
enough
for
t heir
t hree
of
a
more
nitrogen
outer
electron
shells to overlap. The two atoms share t hree pairs of electrons between t hem,
forming
a
triple
covalent
bond .
The
formula
for
nitrogen
is
N
2
××
××
×
×
××
×
×
O
×
×
×
1
carbon
dioxide
molecule,
CO
1
nitrogen
molecule,
N
2
The
Figure
drawing
simplied
shell
of
by
5.4.4
dot
Covalent
and
showing
diagram
are
bonding
cross
only
shown
in
in
carbon
diagrams
t he
to
valence
Figure
dioxide
represent
electrons.
and
nitrogen
covalent
bonding
Examples
of
t his
can
be
type
of
5.4.5.
O
C
N
O

2
N
O
H
Exam
✔
1
It
is
very
important
that
you
are
draw
dot
and
cross
water
molecule
show
the
bond
compounds.
T
o
first
the
decide
ionic
is
or
if
from
a
this,
you
compound
covalent.
formed
formation
do
If
the
metal
carbon
dioxide
molecule
1
nitrogen
molecule
Figure
5.4.5
Covalent
bonding
in
water,
carbon
dioxide
and
nitrogen
showing
diagrams
valence
to
1
able

to
H
tip
only
in
must
is
Str uctural
covalent
compound
and
electrons
formulae
bond
str uctural
is
may
also
shown
formulae
of
be
by
a
used
line
molecules
are
to
represent
between
given
in
t he
molecules
two
Figure
in
atoms.
which
each
Examples
of
5.4.6.
a
H
non-metal
formed
it
will
from
be
ionic,
non-metals
if
it
is
only
it
Cl
will
be
metal
covalent.
usually
Remember
has
1,
2
or
3
that
Cl
H
O
H
C
has
4,
5,
and
6
or
a
7
non-metal
valence
electrons.
chlorine
Valence
Number
bonds
1
1
of
1
1
chlorine
1
1
formulae
of
chlorine,
water,
carbon
methane,
dioxide
oxygen,
nitrogen
carbon
dioxide
nitrogen
Unit
5.1
bonds
you
with
learnt
other
that
the
atoms
is
number
known
of
as
bonds
its
that
valence
an
atom
can
number.
form
This
is
when
shown
clearly by these dot and cross diagrams. Hydrogen has a valence number of one
and
the
diagrams
number
bromine
Structural
oxygen
covalent
it
fluorine
5.4.6
methane
formed
n
hydrogen
N
H
water
Figure
and
number
N
usually

Element
O
valence
H
electrons
H
a
of
two
show
and
it
the
forming
diagrams
one
covalent
show
it
bond.
forming
Oxygen
two
has
covalent
a
valence
bonds.
The
1
1
valence numbers and number of covalent bonds formed by the common non-
iodine
1
1
oxygen
2
2
sulfur
2
2
nitrogen
3
3
carbon
4
4
metals when bonding to form covalent compounds are given in Table 5.4.1.
Polar
and
Molecules
t he

T
able
5.4.1
number
of
Valence
covalent
number
bonds
and
formed
atoms
atom
78
atoms
may
in
be
t he
attracts
polar
or
molecule.
electrons.
covalent
non-polar
as
molecules
a
result
Electronegativity
Oxygen,
nitrogen,
is
a
of
t he
electronegative
t han
atoms
of
uorine
ot her
electronegativity
measure
and
by
strongly
non-metal
non-polar
elements.
of
how
strongly
chlorine
are
of
an
more
Structure
●
n
a
and
polar
electrons
of
the
bonding
molecule,
in
the
the
bond
molecule
negative
Formation
has
charge.
atoms
with
a
slightly
Water
(H
at
each
different
positive
O),
side
of
charge
ammonia
(C
H
2
OH)
and
covalent
The
and
(NH
2
ethanol
a
strengths.
),
result
one
bond
is
side
hydrogen
attract
that
has
one
a
of
covalent
(C
5
H
6
O
12
)
metallic
bonds
the
side
slightly
chloride
(HCl),
3
glucose
and
δ
molecules
are
all
polar.
6
O
●
n
non
a
attract
have
polar
molecule,
electrons
any
wit h
charged
t he
equal
sides.
atoms
at
strengt hs
Oxygen
(O
each
such
),
side
t hat
nitrogen
t he
(N
2
carbon
dioxide
(CO
)
and
met hane
The
formula
each
of
element
formula.
of
of
n
elements
a
covalent
one
some
are
molecule
),
same,
) and met hane (CH
3
(Cl
(CH
)
not
H
H
δ
),
δ
2
molecules
are
all
non-polar.

Figure
5.4.7
A
polar
water
molecule
compound
of
gives
t he
compounds
e.g.
water
t he
exact
compound,
t he
(H
O),
molecular
carbon
number
i.e.
it
is
formula
dioxide
of
t he
atoms
and
(CO
of
molecular
),
t he
Prefix
Number
mono
1
di
2
of
atoms
ratio
ammonia
2
). n t hese compounds t he molecular and empirical
4
formulae
are
molecular
t he
same.
formula
of
n
ot her
glucose
is
compounds
C
H
6
The
does
chlorine
2
(NH
bond
compounds
molecule
covalent
t he
covalent
4
covalent
in
a
2
2
Formulae
of
name
formula.
placed
of
This
a
is
before
prexes
are
covalent
done
t he
given
in
12
compound
by
name
O
using
of
Table
t he
t he
but
t hey
its
are
not
empirical
t he
same,
formula
is
e.g.
t he
CH
6
O.
tri
3
tetr
4
2
can
sometimes
prexes
element
to
di,
tri,
indicate
tetr,
which
and
t hey
are
its
so
pent
5
hex
6
molecular
on.
These
referring.
are
These

5.4.2.
T
able
in
5.4.2
naming
Prexes
covalent
sometimes
used
compounds
Examples
●
CO
●
SO
●
SO
is
t he
formula
for
carbon
monoxide.
is
t he
formula
for
sulfur
dioxide.
is
t he
formula
for
sulfur
trioxide.
2
3
●
CCl
is
t he
formula
for
carbon
tetrachloride,
more
correctly
known
as
4
tetrachloromet hane.
●
N
O
2
t
is
a
you
is
t he
formula
for
dinitrogen
tetroxide.
4
good
come
names,
idea
to
across
e.g.
learn
t hem,
ammonia
t he
molecular
especially
(NH
)
and
formulae
since
some
met hane
(CH
3
of
covalent
cannot
be
compounds
derived
from
as
t heir
).
4
positive
Metallic
ions
bonding
–
–
–
–
+
Metals
type
of
have
ver y
bonding
distinct
t hat
chemical
occurs
and
between
physical
t he
metal
proper ties
atoms.
as
The
a
result
type
of
of
+
t he
bonding
–
+
between
metal
atoms
in
a
metal
is
known
as
metallic
bond ing
–
The atoms in a metal are packed ver y closely together to form a
–
–
–
–
metal lattice.
+
Because of this tight packing, the outer electron shells overlap and the valence
electrons
become
par ticular
atom.
delocalised,
These
i.e.
delocalised
they
are
electrons,
no
also
longer
associated
known
as
mobile
with
any
‘delocalised’
a
belong
‘sea’
to
of
the
electrons
lattice
as
a
which
whole.
move
around
Positive
within
metal
the
cations
metal
are
electrons
electrons,

form
+
lattice
formed
Figure
5.4.8
The
structure
of
metals
and
from
the
metal atoms when the electrons become delocalised. The metal lattice is held
!
together by the strong electrostatic force of attraction, known as the
Key
bond, which exists between the positive cations and the moving, delocalised,
The
negative
bond
electrons.
Figure
5.4.8
illustrates
the
bonding
in
metals.
metallic
force
t
is
impor tant
to
note
t hat
metals
are
still
made
up
of
atoms
and
not
created
of
t he
valence
even
electrons
t hough
t hey
have
are
no
not
been
longer
lost.
They
attached
to
a
are
still
t here
par ticular
by
is
the
attraction
in
cations
the
chemical
electrostatic
between
and
the
the
moving,
t he
delocalised
str ucture
bond
ions
positive
because
fact
metallic
negative
electrons.
atom.
79
Structure
and
properties
of
solids
Structure
The
way
in
which
understand
explained
Metals
●
high
forces
of
amounts
Metals
●
t he
of
metal
t he
atoms
are
proper ties
of
bonded
metals
in
metal
given
in
lattices
Unit
bonding
helps
4.4.
us
These
to
are
below.
have
strong
Large
some
and
have
melting
points
attraction
of
high
heat
and
between
energy
densities
are
boiling
t he
required
because
points
cations
t he
to
and
because
separate
atoms
are
of
t he
delocalised
t he
packed
electrons.
atoms.
ver y
closely
toget her.
Metals
●
are
electrons
which
These
are
Metals
●
t he
an
good
moving
carried
are
Use
a
shell
t he
electricity
moving
current
act
of
as
to
be
heat
heat
because
electrons
carried
because
carriers,
t he
act
delocalised
as
t hrough
of
t he
charge
t he
carriers,
metal.
delocalised
which
allows
electrons.
heat
and
can
roll
metallic
diagrams
ductile
all
of
over
because
t he
same
each
t he
size.
ot her
atoms
f
into
in
force
new
a
is
metal
are
applied
positions
to
all
of
t he
wit hout
bond.
to
represent
covalent
H
bonding
b
phosphorus
d
carbon
in
the
following:
triuoride,
PF
2
hydrogen
be
questions
hydrogen,
c
to
metal.
t herefore,
atoms
t he
of
The
conductors
malleable
Summary
1
move.
electrons
type,
t he
breaking
to
electric
t hrough
same
metal,
conductors
free
allows
Metals
●
good
are
3
bromide,
HBr
disulde,
CS
2
2
Draw
the
chlorine
shell
and
3
Explain
the
4
Explain
why
diagram
give
the
terms
of
the
formula
covalent
of
‘delocalised
metals
are
the
bonding
carbon
and
compound.
electron’
electrical
between
and
‘metallic
bond’.
conductors.
Objectives
By
the
be
able
end
of
this
topic
you
will
A5.5
●
describe
the
examples
●
relate
the
chloride
●
Structure
and
properties
of
solids
to:
of
its
the
examples
of
and
give
crystals
properties
to
describe
structure
ionic
of
structure
proper ties
atoms,
sodium
structure
simple
The
individual
chemical
and
give
molecular
of
molecules
an
or
par ticles.
bond
element
ions,
This
between
or
compound,
depend
means
t he
on
t hat
par ticles.
t he
t he
n
whet her
forces
of
proper ties
addition,
it
is
composed
attraction
depend
t he
between
on
t he
proper ties
of
t he
type
depend
of
on
t he arrangement of t he par ticles, for example, if t he par ticles are packed ver y
tightly
toget her,
t he
element
or
compound
will
have
a
high
density.
crystals
When
●
distinguish
between
ionic
t he
simple
molecular
describe
the
way
structure
and
of
giant
describe
the
diamond
●
relate
of
of
and
and
the
crystals
because
pattern
●
ionic
●
simple
●
giant
●
met allic
graphite
identify
are
bonded
four
different
wit hin
t he
str uctures
solid.
They
based
are
on
known
t heir
par ticles
t hroughout
t he
are
arranged
str ucture.
The
in
four
a
t hree-dimensional,
types
of
solid
are:
cr yst als
molecular
cr yst als
term
molecular
cr yst als
cr yst als.
to
allotropy.
We
have
We
will
unit.
80
can
uses
structures
explain
we
par ticles
graphite
properties
diamond
their
●
the
structure
and
solids,
t he
molecular
crystals
●
which
give
ordered
examples
in
crystals
as
●
considering
and
already
be
studied
studying
t he
t he
str ucture
str ucture
and
and
proper ties
proper ties
of
of
t he
metals
ot her
in
Unit
t hree
in
5.4.
t his
Structure
Ionic
Ionic
is
in
represented
by
sodium
n
are
solids
composed
a
Unit
ionic
as
a
result
lattice
in
repeating,
of
called
formulae
have
an
of
which
ionic
t he
bonding.
cations
t hree-dimensional
attraction
empirical
bonding
and
properties
of
solids
or
ionic
formula
ionic
cr ystal
and
An
ionic
anions
are
arrangement
bonds.
units.
onic
All
str ucture,
by
cr ystals
compounds
for
example,
chloride.
structure
form
formed
an
forces
by
ionic
of
regular,
electrostatic
formed
The
Structure
crystals
toget her
strong
are
bonding
crystals
cr ystal
held
and
5.2
you
sodium
and
studied
chloride.
properties
t he
ionic
You
may
of
bonding
sodium
between
remember
t hat
t he
chloride
sodium
and
sodium
chloride
chlorine
to
cr ystal

lattice
is
composed
chloride
ions
or
of
Cl
millions
ions
held
of
sodium
toget her
ions
by
or
strong
Na
ions
ionic
and
bonds.
millions
Also
t hat
of
t he

ions
are
in
formula
a
ratio
unit
for
of
1
Na
sodium
ion
to
1
chloride
Cl
is
ion
and
t hat
t he
empirical
formula
or
NaCl.

ionic

Figure
5.5.1
Crystal
lattice
of

Na

Cl
ion
ion
bonds
sodium
chloride
a)
The
i.e.
proper ties
t he
of
sodium
arrangement
chloride
and
can
bonding
of
be
its
explained
par ticles,
by
as
its
Solid
sodium
chloride
str ucture,
summarised
in
–
Table

T
able
5.5.1
Properties
of
Property
Explanation
High
The
melting
point
–
about
801 °C
high
the
to
weaken
and
The
to
sodium
melting
sodium
solid
Hard
+
–
+
5.5.1.
ions
point
and
these
is
due
to
chloride
forces
+
–
+
–
–
+
–
+
chloride
and
the
ions.
very
A
strong
large
separate
the
electrostatic
amount
ions
of
from
heat
each
forces
energy
other,
between
is
needed
allowing
the
melt.
sodium
and
chloride
ions
are
closely
packed
and
held
together
by
strong
+
brittle
electrostatic
crystal
forces
lattice,
the
making
ion
the
solid
hard.
layers
move
slightly
charges
come
to
When
with
pressure
respect
to
is
applied
each
to
other
the
–
–
and
+
ions
with
between
the
the
same
like
charges
and
the
lie
next
lattice
to
each
breaks
other.
apart,
i.e.
Repulsion
it
is
occurs
brittle.
+
Soluble
in
When
sodium
chloride
is
added
to
water
the
ions
can
separate
resulting
+
in
–
–
–
water
sodium
water
chloride
molecules
being
soluble
attract
the
in
water.
negative
The
partial
chloride
ions
positive
and
the
ends
of
partial
the
polar
negative
+
ends
attract
the
positive
sodium
ions.
This
pulls
the
ions
out
of
the
–
lattice
+
and
the
crystal
molecules
water
a
and
dissolves.
new
The
forces
of
ions
become
attraction
surrounded
now
exist
by
between
the
water
the
ions
and
the
molecules.
Conducts
For
electricity
particles
substance
when
are
which
b)
to
are
conduct
able
to
an
electric
move.
In
current
molten
it
must
(melted)
contain
sodium
Sodium
chloride
dissolved
charged
chloride,
the
ions
–
+
i.e.
molten,
NaCl(l),
or
no
longer
sodium
held
chloride
together
to
by
conduct
ionic
bonds
electricity
in
and
the
they
liquid
are
state.
able
to
When
move
allowing
sodium
water
+
Na
Cl
dissolved
in
water,
chloride
an
dissolves
aqueous
in
solution
water,
of
the
sodium
ions
move
chloride
to
freely
throughout
conduct
an
the
electric
water,
allowing
molecule
current.

i.e.
Figure
5.5.2
What
happens
when
NaCl(aq)
sodium
chloride
dissolves
in
water
81
Structure
and
properties
of
solids
Structure
Simple
Simple
molecular
molecular
and
bonding
crystals
crystals
are
solids
composed
of
small
molecules.
Each
molecule is composed of only a few atoms bonded toget her by strong covalent
bonds. These molecules are t hen arranged in a regular, t hree-dimensional way
to
create
weak
a
These
of
molecular
attraction
intermolecular
formulae
are
Examples
●
simple
forces
ice,
of
used
to
simple
composed
lattice .
between
forces
hold
represent
water
t he
simple
molecular
of
The
t hem
small
as
wit hin
t he
lattice
intermolecular
molecules
molecular
cr ystals
molecules,
molecules
known
toget her.
have
forces .
Molecular
cr ystals.
include:
molecular
formula
H
O
2
●
iodine,
●
dr y
composed
●
glucose,
of
iodine
molecules,
molecular
formula

2
ice,
composed
of
carbon
dioxide
molecules,
molecular
formula
CO
2
composed
of
glucose
molecules,
molecular
formula
C
H
6
Distinguishing
between
ionic
and
simple
O
12
6
molecular
solids
onic
t he
and
simple
different
summarised

T
able
way
in
5.5.2
Property
molecular
in
which
Table
solids
t heir
have
ver y
par ticles
different
are
proper ties
bonded.
These
Comparison
Ionic
of
the
properties
of
ionic
and
solids
simple
Simple
NaCl,
KBr
molecular
molecular
Examples:
I
,
CO
2
of
chemical
bond
Ionic
bonds
These
are
are
very
found
between
ions.
strong.
Covalent
atoms
are
of
very
the
point
Have
the
a
high
strong
ions.
A
melting
ionic
large
needed
to
separate
allowing
amount
weaken
the
the
point
bonds
ions
of
heat
these
from
solid
to
because
between
of
the
energy
bonds
each
Have
of
is
and
other,
a
the
low
between
much
melt.
the
simple
when
Due
and
in
to
being
polar
are
Do
not
strong
the
ionic
move.
water
because
together
they
are
free
but
are
do
held
and
conduct
the
by
to
ions
ionic
move,
current
or
to
not
are
by
free
electricity
dissolved
no
bonds
which
be
solid
together
are
in
in
longer
and
allows
carried.
the
not
is
from
solid
the
because
forces
Not
needed
and
to
separate
other,
melt.
solids
e.g.
forces
weak.
each
to
the
bonds
between
point
forces
rule
e.g.
Some
sublime
iodine
‘like
and
in
in
dissolves
substances
solvents,
like’.
polar
e.g.
in
dissolve
iodine
tetrachloromethane.
conduct
move.
dissolves
dissolve
glucose
because
charged
to
are
energy
non-polar
state
found
Non-polar
dissolves
Do
Intermolecular
substances
water.
These
dioxide.
solvents,
solvents.
when
Polar
between
molecules.
heated,
Follow
soluble
solvents,
organic
(melted)
held
positive
water,
electricity
bonds
They
of
are
tetrachloromethane,
ions
molten
electric
e.g.
other
when
an
82
and
most
non-polar
conduct
because
to
in
kerosene,
gasolene
Conductivity
ions,
solvents,
insoluble
e.g.
composed
negative
occur
molecular
carbon
O
intermolecular
these
the
H
melting
molecules
allowing
Solubility
are
the
heat
weaken
solids
2
These
weak
solids
molecules.
strong.
attraction
,
2
bonds
in
molecules.
Melting
of
are
5.5.2.
Examples:
T
ype
because
differences
electricity
they
particles
do
not
which
in
any
have
are
free
any
Structure
and
bonding
Investigating
ionic
Your
and
teacher
may
observation,
●
manipulation
will
(simple
be
in
solubility
use
and
supplied
this
conductivity
properties
of
solids
of
solids
activity
and
electrical
and
to
assess:
reporting
measurement.
with
sodium
solids),
solvent)
Figure
and
molecular
recording
molecular
(non-polar
shown
the
simple
●
Y
ou
Structure
and
chloride
distilled
the
water
apparatus
(ionic
(polar
used
to
solid),
glucose
solvent),
test
and
iodine
tetrachloromethane
electrical
conductivity
5.5.3.
Method
1
Investigate
following
the
the
solubility
of
instructions
sodium
chloride,
iodine
and
glucose
by
below.
3
●
Place
5 cm
●
Add
small
of
a
glucose
Shake
●
Repeat
●
in
the
of
water
into
sodium
second
tube
thoroughly
each
chloride
and
and
a
of
to
three
the
crystal
observe
of
if
test
rst
tubes.
tube,
iodine
each
to
a
small
the
spatula
third
switch
tube.
substance
A
not.
experiment
using
tetrachloromethane
instead
of
water.
Investigate
shown
distilled
tubes
or
the
distilled
2
to
the
dissolves
of
spatula
the
electrical
Figure
5.5.3
conductivity
and
by
of
following
solutions
the
using
instructions
the
apparatus
beaker
below.
carbon
electrodes
Make
●
three
solutions
by
adding
three
small
spatulas
of
sodium
solution
3
chloride
to
25 cm
of
distilled
water,
three
small
spatulas
of
glucose
3
to
to
of
distilled
water
and
one
crystal
of
iodine
to
25 cm
Place
the
switch.
not
the
and
3
Draw
up
4
What
can
a
an
test
table
you
three
into
ammeter
current,
conduct
them,
in
electrodes
If
electric
if
it
electric
the
to
the
sodium
record
not
a
two
all
beakers.
chloride
reading,
register
current.
other
conclude
separate
registers
does
a
Remove
solutions
your
the
the
for
the
solution
and
solution
reading,
Figure
then
conducts
the
electrodes
electrical
close
solution
and
the
type
of
solid
(ionic
●
the
type
of
solid
and
strong
a
covalent
gi ant
or
its
t hroughout
t he
bonds
does
conductivity.
simple
molecular)
and
its
solubility
?
conductivity?
in
a
composed
regular,
such
of
non-metal
t hree-dimensional
The
covalent
t hat
a
giant
bonds
bonded
arrangement
exist
molecular
atoms
between
cr ystal
is
to
t he
also
by
Did
macromolecule,
i.e.
formula
is
of
giant
●
diamond,
●
graphite,
is
form
atoms
known
as
it
is
a
molecule
composed
of
millions
of
atoms.
used
to
represent
giant
molecular
in
type
of
and
sand.
occurs
molecular
composed
of
cr ystals
carbon
silicon
composed
dioxide,
empirical
of
carbon
atoms,
composed
of
silicon
and
as
formula
empirical
oxygen
a
quartz.
Earth’
s
of
crust.
almost
the
main
all
Quartz
It
every
is
a
rock
component
of
this
crystalline
forms
large
These
ornamental
precious
C
formula
silica
form
that
is
known
almost
and
atoms,
are
beautiful
very
stones
gemstones.
is
purple
popular
and
For
semi-
example,
quartz,
citrine
is
C
orange
and
rose
quartz
is
a
empirical
pink
formula
known
abundant
The
yellow
●
also
most
cr ystals.
include:
atoms,
the
is
amethyst
also
the
Almost
in
crystals.
Examples
know?
dioxide,
silica,
pure
empirical
you
component
as
a
solution
results.
electrical
are
lattice .
lattice
a
crystals
crystals
molecular
measure
of
clean
mineral
molecular
to
an
as
Gi ant
Apparatus
conductivity
the
Silicon
molecular
5.5.3
electrical
about:
●
Giant
tested
of

tetrachloromethane
●
be
3
25 cm
to
rose-red
variety.
SiO
2
83
Structure
and
properties
of
solids
Structure
Structure
Diamond
to
four
is
The
in

carbon
consists
t hroughout
t he
bonds,
t he
of
5.5.3
Explanation
about
word
‘diamond’
ancient
which
Greek
means
diamond
diamond
is
another
known
the
as
cut
using
make
is
covalent
be
has
by
from
hard
of
each
Diamond
not
conduct
bonds
heat
other,
is
the
is
covalent
useful
industry
as
the
carbon
needed
allowing
hardest
of
in
the
between
energy
strength
The
valence
Carbon
the
solid
naturally
bonds
diamond
to
diamond,
is
hard,
the
a
you
to
strengt h
melting
str ucture,
as
of
point.
summarised
occurring
often
are
these
very
strong.
forces
and
A
very
separate
large
the
atoms
melt.
between
is
atoms
solid.
the
used
The
carbon
electrons
does
not
have
of
the
any
carbon
‘free’
atoms
in
hardness
atoms.
cutting
electrons
are
to
all
and
shared
conduct
is
This
due
to
the
property
is
high
very
drilling.
an
between
electric
the
atoms.
current.
a
cutting,
to
create
used
to
(b)
Figure
5.5.4
(a)
A
cut
diamond
and
(b)
ago
at
in
the
an
we
see
(if
depths
below
molten
mantle
where
temperature
Powerful
brought
Earth’
s
diamond
today
not
of
bonds
billions)
about
the
Earth’
s
rock
are
the
of
the
atom
pressure
both
magma
the
uncut
know?
carbon
Earth’
s
then
t he
of
anot her
corner
gems
millions
kilometres
high.
of
high
cr ystal
one
polished
powder
diamonds
surface
and
ver y
to
covalently
A
technique
After
then
sparkling
formed
years
150
Because
a
its
weaken
covalent
of
bonded
it.
from

were
bonded
jewellery.
Did
Most
bonds.
and
explained
(a)
?
atoms
is
around
‘adámas’,
so
using
diamond
beautiful,
comes
word
bruiting.
diamond
carbon
hard
atom
tetrahedron
‘unbreakable’.
Because
of
covalent
amount
electricity
the
Each
a
know?
Does
The
t hese
strong
can
in
diamond
The
melting
Extremely
you
of
Very
–
of
diamond
atoms.
arranged
extremely
diamond
Properties
3550 °C
Did
by
is
Property
high
carbon
millions
cr ystal
of
bonding
5.5.3.
T
able
point
?
of
of
atoms
diamond
proper ties
Table
properties
composed
ot her
diamond
and
and
extremely
eruptions
diamonds
to
the
surface.

Structure
Graphite
is
and
also
Figure
5.5.5
properties
composed
of
Structure
of
carbon
of
diamond
graphite
atoms.
Each
atom
is
bonded
covalently
to three other carbon atoms, forming hexagonal rings of atoms which link up to
form at sheets or layers of carbon atoms. The four th electron of each atom is
not bonded to another atom and becomes delocalised. These layers of carbon
atoms
then
atoms
in
weak
forces
str ucture,
84
lie
the
as
on
top
layers
of
of
are
each
ver y
attraction.
summarised
other.
strong,
The
in
The
covalent
however,
proper ties
Table
5.5.4.
of
the
bonds
layers
graphite
between
are
can
held
be
the
carbon
together
explained
by
by
its
Structure
and
bonding
Structure

Property
Explanation
Very
The
high
point
–
melting
about
3600 °C
from
in
Soft
covalent
amount
and
each
weak
over
Good
of
conductor
The
electricity
other,
the
fourth
Because
molten
act
of
These
this,
the
between
as
a
of
the
carbon
needed
the
in
a
to
solid
metals,
resulting
electron
crystal.
is
allowing
for
other
can
between
energy
forces
each
graphite
bonds
heat
containers
The
lubricating
of
to
e.g.
melt.
are
these
very
strong.
forces
Because
of
and
this,
A
very
separate
graphite
5.5.4
the
can
of
carbon
crystal
atoms
which
allow
feels
the
slippery.
layers
to
Because
slide
of
this,
lubricant.
each
moving
graphite
carbon
atom
electrons
is
used
as
can
is
delocalised
carry
allowing
electricity
electrodes
during
it
through
to
the
move
within
crystal.
electrolysis.
Did
Constructing
fit

together
models
of
sodium
chloride,
diamond
Figure
use
this
activity
to
and
Structure
Exam
of
graphite
tip
is
important
that
you
can
draw
measurement.
and
supplied
with
similar
5.5.6
assess:
It
(or
of
and
✔
may
manipulation
be
form
layers
graphite
will
stable
graphite
layers
plasticine
more
diamond.
forces
between
Y
ou
a
atom
weak
●
is
than
know?
bond
carbon
teacher
you
layer
covalent
Your
graphite
used
carbon
how
of
solids
atoms
be
Graphite
graphite
Properties
of
large
?
one
properties
crucibles.
layers
‘soft’
atoms
weaken
T
able
and
toothpicks
round,
soft
and
material
small,
to
use
different
as
coloured
atoms
or
pieces
of
describe
sodium
chloride,
graphite
ions).
their
the
and
that
properties
structure
diamond
you
and
can
uses
of
and
relate
to
their
Method
structures.
Using
show
the
diagrams
their
●
sodium
●
diamond
●
graphite.
Use
the
Unit
5.5
to
help
you,
make
models
of
the
following
to
chloride
plasticine
represent
in
structure:
the
to
bonds
represent
between
atoms
or
ions
and
the
toothpicks
to
them.
85
Structure
and
properties
of
solids
Structure
and
bonding
Allotropy
Key
!
fact
Diamond
t hey
Allotropes
are
different
are
t heir
forms
same
of
the
same
physical
and
bot h
graphite
made
are
out
of
known
t he
as
same
allotropes
element,
of
carbon.
carbon,
This
is
but,
in
t he
occurence
of
t hese
because
solid
state,
structural
element
in
carbon
atoms
are
bonded
differently.
The
different
the
allotropes
state.
is
known
as
allotropy
Because diamond and graphite are bot h composed of carbon atoms, t hey have
t he
Key
!
same
fact
different
Allotropy
is
the
existence
structural
forms
t hey
proper ties.
have
physical
different
However,
cr ystal
t heir
atoms
str uctures
are
which
bonded
result
in
differently,
t hem
having
proper ties.
of
Several
different
chemical
t herefore,
of
ot her
elements
exhibit
allotropy.
These
include
sulfur
and
the
phosphor us, when in the solid state, and oxygen, when in the gaseous state.
same
element
in
the
same
physical
state.
Summary
1
Did
?
you
diamond
dream
the
of
its
to
bonding
that
the
and
force
consuming
and
long
crystal
structure
does
each
of
the
following
have?
is
b
Iodine
c
Ice
d
Graphite
e
Calcium
bromide
held
extremely
carbonate
temperatures
carbon
to
have
2
Why
3
Compare
4
Why
are
5
Why
can
can
sodium
chloride
dissolve
in
water?
change
meant
extremely
the
melting
points
of
an
ionic
solid
and
a
simple
molecular
solid.
time-
diamonds
extremely
hard?
energy-intensive.
Consequently
it
achieved
any
with
of
Potassium
graphite
the
structure
process
a
throughout
However,
pressures
required
been
scientists
world.
high
inexpensive
has
type
know?
a
Converting
to
What
questions
has
not
real
yet
been
graphite
conduct
an
electric
current?
success.
Key
●
concepts
Atoms
bond
wit h
conguration,
●
Atoms
can
electronic
●
There
are
each
i.e.
lose,
t hat
gain
ot her
of
or
to
t he
share
attain
nearest
a
more
noble
valence
stable
gas
in
electrons
to
electronic
t he
periodic
attain
a
table.
stable
conguration.
t hree
main
types
of
chemical
bonding:
ionic,
covalent
and
metallic.
●
A
chemical
t he
●
Chemical
can
●
be
There
are
V
alence
form
Ionic
t hree
Metal
form
86
force
t heir
by
main
formulae
number
ot her
of
types
atoms
of
a
result
chemical
t he
positive
called
atoms
t hat
results
from
is
of
ionic
or
covalent
bonding
formulae:
molecular
formulae,
formulae.
t he
number
number
composed
forming
ions
between
formulae.
Valence
involves
form
negative
as
empirical
valency
atoms.
atoms,
attraction
formed
and
or
of
electrons.
chemical
compounds
bond ing
non-metal
●
a
compounds
wit h
formulae
●
is
of
represented
str uctural
●
bond
redistribution
of
transfer
two
of
of
can
bonds
be
used
different
electrons
an
to
atom
write
can
empirical
elements.
from
metal
atoms
to
ions.
ions
called
anions
cations
and
non-metal
atoms
Structure
●
n
ionic
t he
●
A
●
onic
ions
lattice
metal
Atoms
forces
n
to
or
The
strong
electrons
Four
●
The
●
in
a
t he
an
t he
attraction
ionic
empirical
ions
made
shar ing
solids
between
bonds,
hold
of
of
formula
par ticles.
or
formula
present.
from
shared
in
held
t he
a
several
atoms
bonded
ions .
electrons
pair
of
are
between
electrons
bonded
chemical
toget her
nuclei
of
become
which
non-
for ms
a
by
t he
toget her
strongly
reaction.
t he
strong
atoms
and
electrostatic
t he
bonding
delocalised
remain.
These
and
are
able
delocalised
to
move
electrons
are
electrons.
force
positive
of
attraction
cations
forms
between
t he
t he
metallic
delocalised
bond
which
holds
toget her.
of
metals
of
are
due
str uctures
wit hin
t he
different
par ticles
result
t he
and
from
molecular
crystals
solid
t he
bonding
identied
str uctures
arrangement
bonding.
and
anions
are
wit hin
based
t he
on
composed
way
to
forces
depend
of
They
are
t he
are
held
arrangement
t hree-dimensional
intermolecular
t he
be
metal
t he
way
lattice.
t he
solids.
ionic
cations
to
can
t he
t hree-dimensional
Weak
which
electrons
cations
solid
which
regular,
lattice.
of
as
arrangement
polyatomic
A
unit
are
between
bonded
t heir
atoms
molecule
lattice
repeating,
Simple
as
t he
single
electrostatic
are
in
of
a
mobile
crystals
lattice
●
as
proper ties
Ionic
of
are
known
regular
using
ratio
molecules.
valence
different
between
are
forces
known
of
electrons.
proper ties
par ticles
t he
involves
as
metal
and
metal
The
represented
group
a
t he
known
●
anions,
properties
lattice.
compounds
for m
a
of
t he
also
●
is
pairs
metals,
t he
cr ystal
give
ions
attraction
between
●
are
behave
wit hin
of
electrostatic
t hree-dimensional
ionic
to
a
strong
negative
and
bond
molecule
pair
a
bond ing
atoms
enough
●
in
t he
and
in
which
These
covalent
●
of
ions
Covalent
A
is
compounds
toget her.
●
cations
toget her
bot h
Many
Structure
compounds,
cr ystal
unit,
●
bonding
positive
t hese
●
and
by
of
strong
a
between
in
ionic
a
bonding
of
an
ionic
regular,
bonds.
molecules
simple
t he
t he
composed
toget her
small
create
on
par ticles.
arranged
molecular
molecules
hold
t hem
toget her.
●
onic
and
●
Simple
polar
●
cr ystals
t hey
molecular
solvents
Gi ant
bonds
in
molecular
high
melting
electricity
cr ystals
and
molecular
covalent
giant
have
conduct
t hey
have
do
crystals
a
lattice,
Diamond
and
graphite
are
●
Diamond
and
graphite
are
●
carbon,
Diamond
is
ver y
are
also
●
element,
not
regular,
but
t heir
hard,
has
points,
when
low
or
melting
conduct
dissolve
points,
electricity
composed
of
known
as
a
of
allotropes.
atoms
high
are
in
dissolved
polar
in
most
in
solvents
water.
dissolve
any
non-metal
t hree-dimensional
examples
a
most
molten
in
non-
state.
atoms
arrangement
bonded
to
form
by
a
macromolecule.
giant
They
are
bonded
melting
molecular
cr ystals.
composed
of
t he
same
differently.
point
and
does
not
conduct
electricity.
●
Graphite
conduct
is
‘sof t’
and
lubricating,
has
a
high
melting
point
and
does
electricity.
87
Practice
exam-style
questions
Structure
7
Practice
exam-style
Multiple-choice
1
Which
of
calcium
t he
Ca
(PO
B
Ca(PO
2
A
isotopes
B
isomers
C
allotropes
following
is
t he
correct
formula
for
D
allomers
carbon
of
of
carbon
carbon
Structured
3
question
2
The
table
gives
t he
mass
number
and
atomic
number
of
4
Ca
(PO
3
X
of
)
four
The
are:
carbon
questions
8
2
of
PO
3
D
graphite
questions
)
4
4
Ca
and
bonding
phosphate?
A
C
Diamond
and
Y
elements.
)
4
2
formula
and
different
of
would
t he
compound
formed
between
Element
Mass
fluorine
19
number
Atomic
9
neon
20
10
aluminium
27
13
phosphorus
31
15
number
atoms
be:
a
i)
Which
element
would
not
be
capable
of
forming
compounds?
ii)
b
A
XY
B
X
Give
Two
an
ionic
Name
(1
reason
elements
form
i)
a
in
for
t he
your
table
answer.
are
(2
capable
of
mark)
marks)
bonding
to
compound.
t hese
elements.
(1
mark)
Y
3
ii)
C
Give
t he
formula
of
t his
compound.
(1
mark)
XY
3
iii)
D
X
By
means
onic
bonding
A
two
B
a
occurs
c
between:
and
a
i)
non-metal
C
a
D
two
metalloid
and
a
and
cross
diagram,
show
a
in
covalent
Name
Give
formed.
table
are
(3
capable
of
atom
wit h
atomic
an
atomic
number
of
15
and
an
atom
number
A
form
a
B
form
an
elements.
formula
of
t his
compound.
Draw
a
dot
and
cross
diagram
to
show
C
form
a
D
not
covalent
ionic
of
9
bonding
in
mark)
t his
Describe
t he
compound.
(2
marks)
i)
bonding
in
aluminium.
(2
marks)
would:
Why
is
aluminium
able
to
conduct
an
electric
compound
metallic
bond
wit h
aqueous
solution
A
water
B
electrons
can
Total
only
conduct
electricity
when
9
conduct
become
free
a
electricity
when
t hey
free
when
t hey
t he
lattice
are
are
response
Wit h
in
i)
aqueous
ii)
become
in
aqueous
b
marks
free
when
t hey
are
in
question
of
a
sodium
diagram
in
EACH
case,
describe
chloride
reference
each
sodium
to
of
t he
of:
graphite.
Wit h
i)
aid
str ucture
explain
solution
become
15
in
solution
protons
mark)
ot her
because:
molecules
ions
(1
lattice
each
Extended
D
mark)
(1
compound
compounds
t he
(1
t he
current?
C
to
wit h
ii)
onic
marks)
bonding
compound.
t hese
t he
is
t he
non-metals
d
5
how
non-metal
iii)
an
compound
elements
form
metals
metal
Two
ii)
An
dot
3
t his
4
a
Y
7
3
of
t he
t he
str ucture
and
type
of
(3
marks)
(3
marks)
bonding,
following:
chloride
is
able
to
conduct
electricity
aqueous
when
molten
(2
marks)
solution
ii)
6
Which
of
t he
molecular
following
is/are
t he
proper ties
of
a
simple
They
are
usually

They
conduct
iii)
soluble
electricity
in
in
water.
any
state.
is
able
to
conduct
electricity
in
state
compound?

graphite
(2
bot h
sodium
melting
c
Some
t he
types
chloride
and
graphite
have
points.
of
sand
high
(3
consist
of
silica,
SiO
.
solid
marks)
marks)
Silica
is
2

They
have
A


low
melting
points.
relatively
state
and
and

C

and
has
a
does
high
not
conduct
melting
electricity
point.
in
Describe
any
t he
only
bonding
B
hard,

which
you
would
expect
to
nd
in
silica.
only
(2
and

Total
D
88

only
mark)
only
15
marks
Chemical
equations
and
A6
reactions
Chemical
equations
represent
chemical
use
symbols
and
formulae
to
Objectives
standards
for
change.
writing
There
chemical
are
universal
equations
which
make
By
the
be
able
●
possible
for
chemists
all
over
the
world
to
interpret
end
of
this
the
understand
the
conventions
equations
written
by
others.
The
theory
behind
is
very
important
in
the
chemical
you
will
different
used
when
writing
chemical
chemical
reactions
topic
to:
it
industry.
It
●
write
equations
balanced
chemical
equations
reduces
the
risk
of
and
increase
accidents,
can
improve
productivity
●
can
the
yield
of
chemicals.
soluble
●
A6.1
A
Writing
chemical
using
formed
The
equation
symbols
reactants,
and
and
are
t he
and
any
all
on
t he
reactions,
i.e.
are
representation
The
lef t
chemical
chemicals
side
t he
of
t he
by
a
an
are
or
a
compound
insoluble
balanced
in
ionic
is
water
equations.
equations
chemical
are
equation
products,
separated
of
t hat
write
whether
reaction
reacting,
and
shown
t he
on
t he
i.e.
t he
chemicals
right
side.
arrow:
products
Understanding
that
shor t hand
products
reactants
Chemists
a
formulae.
shown
during
reactants
is
balancing
predict
use
person
the
chemical
same
reading
a
equations
conventions
chemical
when
equation
writing
will
chemical
understand
equations
exactly
so
what
it
means. The conventions used when writing chemical equations are as follows:
●
The
symbol
side
of
on
●
An
t he
A
plus
●
A
state
and
●
( )
on
is
t he
and
products.

solid
is
The
liquid

gas
(aq)

aqueous
conditions
a
above
specic
about
to
of
each
symbol
separate
or
reactant
formula
t he
state
is
of
reactants
catalyst.
wit hout
A
are
a
a
used
1
1.2.
t he
solution
for
is
a
up
t he
as
placed
each
on
t he
product
lef t
is
placed
from
t he
products.
and
t he
symbol
where
t he
or
state
water
reaction
to
temperature,
t he
each
right
product.
it
means
formula
of
t he
The
‘and’.
of
each
reactants
follows:
chemical
in
on
physical
are
specic
For
and
af ter
used
required
e.g.
catalyst
being
Unit
brackets
i.e.
reactant
wit h’
indicates
symbols
arrow,
each
‘reacts
in
This
which
in
separate
solution,
t he
catalysts
to
means
written

reaction
used
used
(l)
or
is
lef t
(g)
written
t he
‘produces’.
product.
(s)
Any
a
)
symbol
reactant
formula
and
side.
means
sign
sign
chemical
(
arrow
plus
or
equation
right
arrow
The
●
t he
a
is
occur
solvent.
can
specic
substance
reaction.
t he
You
which
will
be
pressure
speeds
learn
up
more
example,
898 °C
CaCO
(s)
CaO(s)

CO
3
This
shows
decompose
(g)
2
t hat
into
calcium
calcium
carbonate
oxide
and
requires
carbon
heating
to
898 °C
for
it
to
dioxide.
89
Writing
and
balancing
chemical
equations
Chemical
●
f
t he
reaction
NH
is
reversible,
Cl(s)
NH
4
●
will
The
equation
balance
When
learn
on
more
must
each
t he
AgNO
an
about

arrow
(
)
in

t he
t he
t hat
arrow
sections
equation,
following
(aq)
of
so
each
reactions
t he
is
t he
t hat
par t
in
number
same.
For
example,
6.2.
atoms
will
or
ions
learn
of
how
each
to
follow.
represents
a
word
or
a
statement.
example:
KCl(aq)
AgCl(s)

KNO
(aq)
3
equation
chloride
used.
Unit
of
You
3
The
is
reactions
HCl(g)
reversible
balance
side
equations
reading
Consider
double
and
3
You
element
a
(g)
equations
reads
solution
as
to
follows:
‘silver
produce
solid
nitrate
silver
solution
chloride
reacts
and
wit h
potassium
potassium
nitrate
solution’.
Balancing
You
should
chemical
have
noticed
equations
t hat
in
t he
t hree
chemical
equations
above,
t he
atoms are not changed during t he reactions. The way in which t he atoms are
bonded to each ot her changes, but t here is t he same number of atoms of each
element
created
When
on
nor
bot h
writing
atoms
of
sides
destroyed
each
a
of
in
each
chemical
element
equation.
chemical
equation,
on
t he
n
ot her
reactions,
right
you
side
t hey
must
of
words,
are
ensure
t he
atoms
only
t hat
equation
are
neit her
rearranged.
is
t he
t he
number
same
as
of
t he
number on t he lef t side. A chemical equation t hat conforms to t his is known
as
a
balanced
You
learnt
about
understand
2H
●
2H
●
H
chemical
how
represents
represents
equation .
writing
to
chemical
balance
two
one
formulae
chemical
atoms
of
hydrogen,
molecule
of
in
equations,
not
hydrogen,
Unit
5.
consider
bonded
To
t he
help
you
to
following:
toget her
consisting
of
two
atoms
of
2
hydrogen
●
2H
bonded
represents
toget her
two
molecules
of
hydrogen
and,
in
total,
four
atoms
of
2
hydrogen
H
2
●
3CO
represents
t hree
molecules
of
carbon
dioxide.
n
total,
t he
number
2
of
●
atoms
Ca(NO
of
)
3
each
element
represents
one
is
3C
and
formula
6O
unit
atoms
of
calcium
nitrate,
which
consists
2
2
of
one
Ca
ion
and
two
NO
ions;
t herefore,
t he
number
of
atoms
of
3
2H
2
each
●
element
2Ca(NO
)
3

Figure
6.1.1
Different
atoms
and
1Ca,
2N
represents
and
two
6O.
formula
units
of
calcium
nitrate.
n
total,
t he
2
representations
number
of
is
of
atoms
of
each
element
is
2Ca,
4N
and
12O.
molecules
The number in front of each formula in t he list above is called t he
A
coefcient
equations.
to
H
as
(g)
is
not
t he
hydrogen
written.
reaction
chloride
Coefcients
between
gas.
We
are
used
hydrogen
can
gas
summarise
coefcient.
when
and
t his
balancing
chlorine
reaction
gas
using
follows:

Cl
2
Studying
one
Consider
produce
formulae
of
(g)
HCl(g)
2
t his
equation
we
can
see
t hat
t here
are
two
atoms
of
hydrogen
on
t he lef t side, but only one atom on t he right side. Also, t here are two atoms of
chlorine
on
t he
lef t
side,
but
only
one
atom
on
t he
right
side.
The
equation
is, t herefore, not balanced. f a coefcient, 2, is placed in front of t he formula
90
Chemical
for
of
equations
hydrogen
chlorine
H
(g)
chloride,
on

t he
Cl
2
The
t
is
ver y
t he
How
below
●
is
gives
two
atoms
of
hydrogen
and
two
and
balancing
chemical
equations
atoms
2HCl(g)
elements
write
writing
Write
now
balanced.
t he
of
t heir
t hat
when
number
t he
of
always
balancing
balancing
atoms
coefcient
in
remain
balanced
of
front
t he
of
a
t he
elements
formula.
formulae
can
The
only
be
subscripts
same.
chemical
chemical
equations
t he
equations
equations,
t he
guidelines
outlined
followed.
correct
of
note
The
must
and
be
t he
– Seven
to
changing
should
note
now
Writing
side:
(g)
changed.
by
to
When
t his
right
impor tant
be
changed
af ter
reactions
2
equation
cannot
and
chemical
formula
for
each
reactant
and
product,
taking
following:
t he
free
common
st ate.
These
elements
are
H
,
involving
any
of
t hese
exist
N
2
,
O
2
,
as
F
2
elements,
,
diatomic
Cl
2
wr ite
,
Br
2
t he
molecules
and

2
.
n
when
in
reactions
2
for mula
for
t he
diatomic
molecule.
–
n
reactions
atomic
wr ite
involving
symbol
of
t he
ot her
elements
element,
e.g.
if
in
a
t heir
free
reaction
st ate,
wr ite
involves
t he
magnesium,
Mg.
●
Separate
t he
●
Separate
each
●
Write
●
Star t
t he
reactants
and
reactant
state
and
symbol
balancing
t he
products
each
af ter
in
an
product
each
elements
by
by
reactant
t he
arrow.
a
plus
and
product
sign.
product.
immediately
af ter
t he
arrow
rst.
●
Any
polyatomic
ion
which
appears
unchanged
from
one
side
to
t he
2
ot her
can
be
balanced
as
a
unit,
e.g.
if
SO
appears
at
bot h
sides,
✔
4
consider
it
as
a
single
unit
(see
Example
It
●
f
any
compounds
contain
hydrogen
Exam
or
oxygen,
balance
is
essential
from
last
and
balance
oxygen
last
(see
Examples
2
and
f
any
elements
balance,
e.g.
occur
Fe,
Ca,
in
Cl
,
t heir
●
Use
of
coefcients
each
in
element
t he
state,
leave
t hese
until
t he
ver y
last
to
of
the
each
lef t
and
formula
right
to
sides.
balance
The
t he
number
formulae
must
of
not
atoms
reactions
Always
same
2
front
on
free
O
2
you
chemical
can
write
equations
for
3).
all
●
that
hydrogen
balanced
second
tip
4).
of
check
type
each
you
that
and
arrow,
and
the
correct
you
on
that
encounter.
have
number
element
the
will
of
both
you
the
atom
sides
have
of
given
be
state
symbol
for
each
changed.
reactant
●
Check
t hat
t he
coefcients
are
in
t he
lowest
possible
and
product.
ratio.
Examples
1
Write
a
balanced
chemical
equation
for
the
reaction
in
which
magnesium
burns in oxygen to form magnesium oxide as the only product.
Write
t heir
each
t he
chemical
state
element
Mg(s)
formulae
symbols.

on
O
Af ter
each
(g)
of
t he
doing
side
of
reactants
t his,
t he
and
determine
products
t he
toget her
number
of
wit h
atoms
of
arrow:
MgO(s)
2
Reactants
Products
Mg

1
Mg

1
O

2
O

1
91
Writing
and
balancing
chemical
equations
Chemical
O
does
not
balance.
Mg(s)

O
Balance
by
placing
a
2
in
equations
front
of
t he
and
reactions
MgO
2MgO(s)
(g)
2
Reactants
Now
Products
Mg

1
Mg

2
O

2
O

2
Mg
does
2Mg(s)
not

O
balance.
Balance
by
placing
a
2
in
front
of
t he
Mg
2MgO(s)
(g)
2
Reactants
The
2
gas
a
(C
2
Mg

2
O

2
O

2
Write
t heir
is
now
balanced
H
3
on

equation
Write
Products
Mg
)
and
balanced.
chemical
oxygen
to
equation
form
t he
each
C
chemical
symbols
side
H
3
of
(g)
t he

O
8
formulae
and
of
t he
determine
reaction
and
between
propane
steam.
of
leaving
(g)
CO
2
(g)

H
2
3
C

1

8
H

2
O

2
O

2
elements
oxygen
t he
products
atoms
of
toget her
each
O(g)
CO
balance.
in
.
its
free
Balance
Balance
state
t he
t he
until
H
by

1

3
carbon
last.
and
Balance
placing
a
4
in
hydrogen
t he
C
front
by
of
H
3
(g)

O
8
t he
H
still
(g)
3CO
2
(g)

4H
2
O(g)
2
C

3
C


8
H

8
O

2
O

6
not
3
Products
H
does
a
O
2
Reactants
O
rst,
placing
2
C
wit h
element
2

of
of
Products
C
t he
and
number
H
t he
front
reactants
t he
arrow:
Reactants
in
t he
dioxide
8
state
None
for
carbon
balance.
Balance
by
3

placing
4
a

5
10
in
front
of
t he
O
2
C
H
3
(g)

5O
8
(g)
3CO
2
3
4H
2
C

3
C

3

8
H

8
O

10
O

6
t he
is
now
)
3
(aq)

4

10
balanced.
following
Ca(HCO
O(g)
Products
H
equation
Balance

2
Reactants
The
(g)
equation:

HCl(aq)
2
CaCl
(aq)

CO
2
(g)

H
2
O(l)
2
Determine the number of atoms of each element on each side of the arrow:
Ca(HCO
)
3
(aq)

HCl(aq)
2
CaCl
(aq)
92
Ca

1
H

2
C

O
Cl

CO
2

1
H

2
2
C

1

6
O

2

1
Cl

2
1


3

1
H
O(l)
2
Products
Ca

(g)
2
Reactants

3
Chemical
Star t
equations
by
arrow.
front
and
balancing
Ca
of
t he
balances,
t he
reactions
Writing
elements
but
Cl
does
in
t he
not
product
balance.
immediately
Balance
)
3
(aq)

2HCl(aq)
CaCl
2
(aq)
of
Ca

1
H

2
C

O
Cl
t he
t he

CO
2
Ca

1
H

2
2
C

1

6
O

2

2
Cl

2

carbon
CO
Ca(HCO
.
)
3
2

and
4
hydrogen
Balance
t he
H
next.
by
Balance
placing
a
2
t he
in
C

by
front
(aq)

2HCl(aq)
CaCl
2
(g)

1
H

2
C

O
Cl
t he
of
(aq)



)
3
t his
3
H
a
2
in
O
1

4
2
C

2

6
O

4

2
Cl

2
2
now
(aq)

(g)

4
2H
O(l)
2

2

6
balanced.
equation
NaOH(aq)
Al(OH)
3
(s)

NaNO
3
t he

2

reaction,
O(l)
placing
t he
2CO
H
is
H
Products
Ca

following
Al(NO
n
in
2
1
2
Ca
equation
Balance
2
2
Reactants
4
equations
Products
2
The
chemical
t he
a
2
Reactants
front
af ter
placing
balancing
HCl
Ca(HCO
Balance
by
and
NO
and
t he
OH
ions
are
(aq)
3
polyatomic
ions
which
3
remain
treated
unchanged
as
element
single
at
each
Al(NO
)
3
from
units
side
(aq)

one
when
of
t he
side
to
t he
ot her.
determining
t he
They
number
of
t herefore,
atoms
NaOH(aq)
Al(OH)
3
(s)

NaNO
3
Al
NO

1

3
of
(aq)
3
Products
Al
NO
3

1

1
3
Na

1
Na

1
OH

1
OH

3
Start with the product immediately after the arrow.
Balance by placing a
3 in front of the
OH
does not balance.
NaOH. Move on to the next product.
does not balance. Balance by placing a
3
in front of the
NaNO
3
3
Al(NO
)
3
(aq)

3NaOH(aq)
Al(OH)
3
Al
NO
State

3NaNO

1

3
Al
NO

1

3
3
Na

3
Na

3
OH

3
OH

3
is
now
symbols
(aq)
3
Products
3
equation
(s)
3
Reactants
The
each
arrow.
Reactants
NO
are,
of
balanced.
ionic
compounds
n Unit 5.5 you learnt t hat most ionic compounds are soluble in water. Some
ionic
compounds
involving
ionic
compound
is
are,
however,
compounds,
soluble
or
it
insoluble
is
ver y
insoluble
in
in
water.
impor tant
water.
f
it
to
is
When
know
writing
equations
whet her
insoluble,
t hen
t he
it
ionic
would
93
Writing
and
balancing
chemical
equations
Chemical
always
t he
t he

be
state
solubility
T
able
6.1.1
Solubility
All
and
t he
of
state
(aq).
ionic
Solubility
symbol
Table
(s).
6.1.1
compounds
of
ionic
e.g.
f
it
gives
in
is
soluble
t he
it
would
solubility
and
reactions
usually
r ules
for
be
given
determining
water.
compounds
rule
compounds
soluble,
All
given
symbol
equations
in
water
Exceptions
of
Group
I
compounds
metals
of
are
lithium,
None.
sodium
potassium.
ammonium
compounds
Most
nitrates
and
Most
chlorides,
are
ethanoates
soluble.
are
None.
soluble.
Silver
ethanoate
(CH
COOAg)
is
only
slightly
soluble.
3
bromides
and
iodides
are
Those
soluble
(PbCl
of
)
lead
and
and
silver
lead(II)
are
insoluble.
bromide
(PbBr
2
sulfates
are
soluble.
Those
in
of
(CaSO
)
hot
All
Exam
hydrogencarbonates
are
soluble.
chloride
moderately
water.
lead
and
and
barium
silver
sulfate
are
insoluble.
(Ag
4
✔
are
2
soluble
Most
)
Lead(II)
SO
2
)
are
Calcium
slightly
sulfate
soluble.
4
None.
tip
Most
carbonates
and
phosphates
are
Those
of
Group
I
metals
and
ammonium
are
soluble.
Those
of
Group
I
metals
and
ammonium
are
soluble.
insoluble
It
is
essential
that
you
learn
the
Most
solubility
rules
so
that
you
metal
hydroxides
are
insoluble.
can
Barium
hydroxide
(Ba(OH)
)
is
moderately
soluble,
2
give
the
correct
state
symbols
calcium
hydroxide
(Ca(OH)
)
is
slightly
soluble
and
2
when
This
writing
is
chemical
particularly
magnesium
equations.
important
ionic
metal
oxides
t hey
●
two
●
an
●
an
be
6.1.2
a
Example
of
a
and,
star ted.
t he
The
ionic
equations
two
●
in
insoluble.
Those
with
reaction
formed
are
equations.
onic
Figure
)
is
very
slightly
ions
ions
ion
in
only
result,
known
may
form
be
element
Group
to
I
metals,
form
the
calcium
equivalent
and
barium,
react
hydroxides.
t he
end
atoms
up
in
a
or
ions
which
different
state
actually
from
take
t he
one
par t
in
in
a
which
example,
solution
may
in
a
may
as
a
to
covalent
conver ted
its
join
free
form
an
insoluble
compound
wit hin
precipitate
to
state
compound
an
atom,
may
be
i.e.
composed
it
may
conver ted
to
be
an
of
molecules
discharged
ion,
i.e.
it
may
ionised.
following
Write
2)
Rewrite
t he
steps
should
balanced
t he
individual
precipitate
a
For
of
water
equations
show
as
solution,
1)
be
followed
chemical
equation,
but
when
equation
show
any
for
ions
writing
t he
t hat
ionic
equations.
reaction.
are
present
in
solution
in
solution
as
ions.
solution
3)
Delete
bot h
not
4)
any
sides
take
Rewrite
5)
t
Cancel
is
ions
of
par t
t he
change,
i.e.
t he
acid
which
t he
in
remain
equation.
t he
ionic
t hose
to
equation
which
note
(HNO
(aq))
unchanged,
These
are
i.e.
called
which
are
spectator
ions
and
t hey
to
t hat
and
showing
actually
t he
only
take
lowest
when
acids,
sulfuric
t he
par t
in
possible
acid
such
(H
3
as
SO
2
atoms
t he
or
ions
which
reaction.
ratio
if
necessar y.
hydrochloric
(aq)),
are
in
acid
(HCl(aq)),
aqueous
solution
4

t hey
ionise
to
form
on
do
reaction.
coefcients
impor tant
nitric
94
soluble.
when
Writing

(Mg(OH)
2
Most
writing
hydroxide
hydrogen
ions,
or
H
ions,
and
negative
anions.
Chemical
equations
and
reactions
Writing
and
balancing
chemical
equations
Examples
1
Write
t he
chloride
1)
ionic
Write
t he
Pb(NO
)
3
2)
equation
solution
Rewrite
to
balanced
(aq)

for
t he
produce
chemical
between
lead
lead
chloride
nitrate
and
2NaCl(aq)
PbCl
(s)

2NaNO
2
t he
equation
solution
sodium

2NO
showing
(aq)

sodium
solution.
ions
(aq)
3
present
in
solution
as
individual

(aq)
and
nitrate
equation:
2
2
Pb
reaction
insoluble
2Na
ions:

(aq)

2Cl
(aq)
PbCl
3
(s)

2Na
(aq)

2NO
2
(aq)
3

3)
Delete
t he
Na
(aq)
and
NO
(aq)
ions
since
t hey
remain
unchanged:
3
2
Pb

(aq)




2Cl
(aq)
PbCl
(s)


2
2
4)
Rewrite
t he
ionic
equation:
Pb
(aq)

2Cl
(aq)
PbCl
(s)
2
2
Write
t he
SO
(H
2
1)
ionic
(aq))
to
equation
produce
for
t he
2KOH(aq)

H
SO
2
between
sulfate
(aq)
K
4
2K
SO
2

2)
reaction
potassium
and
potassium
hydroxide
and
sulfuric
acid
water.
4
(aq)

2OH
(aq)

2H
2H
O(l)
2

(aq)

4
2
(aq)


SO
(aq)
2K
2
(aq)

SO
4



2OH
(aq)

2H
2
(aq)
(aq)

2H
4

O(l)
2
2



2H
O(l)
2

4)
2OH
(aq)

2H
(aq)
2H
O(l)
2

5)
OH
(aq)

H
(aq)
H
O(l)
2
3
Write
t he
(HCl(aq))
ionic
to
equation
produce
for
t he
Key
!
reaction
magnesium
between
chloride
and
magnesium
hydrogen
and
hydrochloric
acid
It
is
give
1)
Mg(s)

2HCl(aq)
MgCl
(aq)

H
2
2)
Mg(s)

2H
2
(aq)

2Cl
(aq)
Mg
the
that
you
correct
(g)
2

extremely
important
gas.
fact
(aq)

2Cl
(aq)

H
state
symbols
when
writing
ionic
(g)
2
equations

3)
Mg(s)

2H
and
2
(aq)

(aq)


H
that
(g)
the
equations
2
balance

4)
Mg(s)

2H
2
(aq)
Mg
(aq)

H
(g)
2
Summary
1
Write
questions
balanced
a
Aluminium
b
N
(g)

H
2
CH
d
The
(g)
(g)

f
2
State
reaction
the
b
KOH(aq)
CO
2
Ba(NO
H
O(g)
2
aluminium
between
Na
3

hydrogen
and
water
to
and
dioxide
oxygen
are
)
hydroxide
and
equations
HCl(aq)
(NH
4
and
then
)
4
write
NaCl(aq)

or
(NH
)
(aq)

SO
2
Na
(aq)
4
SO
2
K
SO
2
(aq)
4
(aq)

(s)
in
equation
H
water:
for
each
reaction:
O(l)
2
(g)

3
4
(HCl(aq))
4
NH
4
BaSO
acid
steam.
insoluble
ionic
(g)

hydrochloric
PO
3
the
CO
and
water.
2

2
potassium
produce
soluble
KMnO
3
and
to
3
3
produce
hydrogencarbonate
carbon
compounds
CO
2
following
(aq)
chloride,
following
4
c

potassium
between
)
3
Na
(g)
2
the
Fe(NO
a
oxide
(g)
CO
between
aluminium
reaction
Balance
reactions:
gas.
whether
AgI
3
NH
(g)
produce
The
following
aluminium
2
reaction
hydrogen
The
the
3
O
4
to
for
oxygen
2
c
e
equations


NaNO
H
O(l)
2
(aq)
3
95
Types
of
chemical
reactions
Chemical
A6.2
Objectives
By
the
be
able
end
of
this
topic
you
identify
Chemical
the
seven
main
t ake
of
chemical
give
write
the
of
reactions
reactions
place
in
for m
our
an
integ ral
bodies,
suc h
as
par t
of
our
respiration
lives,
whic h
from
reactions
c hanges
energy,
to
complex
reactions,
whic h
produce
glucose
phar maceutical
reactions
examples
types
●
chemical
reactions
types
into
●
of
and
will
to:
t hat
●
Types
equations
of
the
chemical
balanced
different
products.
There
descr ibed
below.
are
se ven
main
types
of
c hemical
reactions
whic h
are
main
reactions
equations
types
of
for
chemical
Synthesis
reactions
reactions.
Synthesis reactions
chemically
A
to
synt hesis
form
reaction
A
Examples
of
are reactions in which two or more substances combine
a
single
is


O
generally
B
synt hesis
2Mg(s)
product.
symbolised
by:
AB
reactions
are
as
follows:
(g)
2MgO(s)
(g)
2FeCl
2
2FeCl
(s)

Cl
2
Decomposition
Did
?
you
down
islands
being
coral
largely
When
of
in
the
islands,
calcium
the
started
of
sugar
are
composed
carbonate.
industry
Barbados,
and
carbonate
roasted
calcium
in
oxide.
a
first
coral
was
lime
The
into
compound
or
if
an
state
or
juice
then
used
during
the
to
is
at
one
from
current
dissolved
time
decomposition
kilns
to
produce
calcium
was
island
a
A
in
A
clarify
the
cane,
major
(Unit
in
if
t he
compound
is
passed
aqueous
reaction
B
is
A
a
single
reactant
reaction
will
is
broken
occur
is
t hrough
solution
heated
t he
(t hermal
if
t he
compound
decomposition)
when
in
t he
liquid
(electrolysis).
generally
symbolised
by:

B
of
decomposition
reactions
are
as
follows:
cane
of
heat
(s)
CaO(s)
3
which

CO
(g)
2
heat
industry
)
(s)
2PbO(s)
2

4NO
(g)

O
2
(g)
2
2.5).
Single
A
single
displacement
d isplacement
in
its
of
(displaces)
will
free
●
state
always
reactions
A
metal
This
and
a
be
may
t he
type
of
of
Mg(s)
reaction
a
element
less
divided
displace
single
t his

involves
The
in
reactive
into
from
t he
type
CuSO
of
(aq)
single

2HCl(aq)
from
a
free
A
between
state
more
an
takes
reactive
compound.
element
t he
place
element
Displacement
from
a
compound
or
it
may
acid.
reaction
AX

can
generally
MgSO
(aq)
reaction

Cu(s)
4
ZnCl
(aq)
2
be
symbolised
B
displacement
4
Zn(s)
its
compound.
metal
an
BX
reaction
in
types.
displacement

t he
element
element
two
anot her
hydrogen
A
Examples
reactions
compound.
anot her
displace
can
displace
96
which
decomposition
oxide
3
the
reactions
island,
2Pb(NO
within
are
products.
quarried
extraction
sugar
more
unstable,
CaCO
sucrose
reactions
or
electric
Examples
was
two
Caribbean,
A
calcium
reactions
know?
Decomposition
Many
(s)
3
2

H
(g)
2
are
as
follows:
by:
Chemical
equations
Writing
t hese
and
as
reactions
ionic
Types

Cu

2H
reactions
2
(aq)
Mg

Zn(s)
chemical
equations:
2
Mg(s)
of
(aq)

Cu(s)
2
(aq)
Zn
(aq)

H
(g)
2
n
t he
above
appears
●
A
examples,
above
non-metal
This
type
of
may
single
X
An
example
Cl
(g)
of

magnesium
hydrogen
in
displace
t he
anot her
displacement

AY
t his
of
single
2KBr(aq)
more
reactive
series
non-metal
reaction
AX
type
is
reactivity

can
t his
Ionic
Ionic
be
displacement
2KCl(aq)

Br
(g)
as

an
ionic
a
and
zinc
compound.
generally
symbolised
by:
reaction
is
as
follows:
(aq)
2Br
equation:
(aq)
2Cl
(aq)

Br
2
n
from
copper
18.1).
2
t his
Cl
t han
Unit
Y
2
Writing
(see
(aq)
2
example,
chlorine
precipitation
precipitation
is
more
reactive
t han
bromine.
reactions
reactions
are
sometimes
referred
to
as
double
d isplacement reactions . They usually involve two compounds which are in
solution,
An
ionic
AX
where
t he
compounds
precipitation

BY
reaction
AY

exchange
is
ions.
generally
symbolised
by:
BX
To have a successful ionic precipitation reaction, one or bot h of t he products
must
be
because
incapable
t hey
form
of
one
undergoing
product
t he
which
reverse
is
reaction.
insoluble,
known
This
as
a
is
generally
A
Examples
of
ionic
precipitation
reactions
are
as
Key
!
precipitate
that
follows:
forms
result
AgNO
(aq)

KBr(aq)
AgBr(s)

KNO
3
BaCl
of
a
in
is
a
an
insoluble
solution,
chemical
solid
often
as
a
reaction.
(aq)
3
(aq)

Na
2
Writing
fact
precipitate
SO
2
t hese
as
(aq)
BaSO
4
ionic
(s)

2NaCl(aq)
4
equations:

Ag
(aq)

Br
2
Ba
AgBr(s)
(aq)
2
(aq)

SO
BaSO
(aq)
Neutralisation
Neutralisation
acid.
The
salt
acid
are
a
and
An
example
reactions
reactions
is
(s)
4
4
are
neutralised
reactions
by
t he
between
base
(or
a
alkali)
base
and
(or
t he
an
alkali)
products
and
an
formed
water.
of
a
NaOH(aq)
neutralisation

reaction
HCl(aq)
is:
NaCl(aq)

H
O(l)
2
Writing
t his
as
an
ionic
equation:

OH
(aq)

H
(aq)
H
O(l)
2
Redox
Redox
in
reactions
reactions,
which
reactions
or
oxidation–reduction
one
reactant
will
be
is
covered
reduced
in
more
and
t he
detail
in
reactions,
ot her
Unit
are
chemical
reactant
is
reactions
oxid ised.
Redox
9.
97
Types
of
chemical
reactions
Chemical
Reversible
Reversible
can
be
one
f
and
reactions
reactions
reactions
reversed
reactants
equations
occur
easily,
again.
Most
i.e.
when
t he
t he
direction
products
reactions
are
not
can
react
reversible;
of
to
a
chemical
produce
t hey
can
t he
only
change
original
proceed
in
direction.
a
reaction
is
reversible,
a
double
arrow
(
)
is
used.
n
a
reversible
reaction, we refer to t he for ward reaction as proceeding from lef t to right and
t he
A
reverse
reversible
A
For

ring
of
backward
reaction
B
NH
is
C
example,
ammonia
white
or
for ms
near
symbolised
ammonium
hydrogen
Cl(s)
proceeding
from
right
to
lef t.
by:
D
chloride
NH
4
ammonium
as
generally

when
and
reaction
(g)

chloride
is
heated,
it
decomposes
into
gases:
HCl(g)
3
chloride
the
top
f
t he
ammonia
temperature)
NH
(g)
and
t hey

hydrogen
react
to
chloride
form
HCl(g)
gases
ammonium
NH
3
are
cooled
(or
mixed
at
room
chloride:
Cl(s)
4
ammonium
The
chloride
reaction
is,
t herefore,
reversible
and
t he
equation
can
be
written
as
follows:
NH
Cl(s)
NH
4
n
Figure
6.2.1,
hydrogen
is
Bunsen
much
cooler
many
t he
and
can
6.2.1
chloride

HCl(g)
t he
ammonium
gases,
and
which
when
t he
chloride
diffuse
gases
up
reach
is
heated
t he
test
here,
it
forms
tube.
t hey
The
react
ammonia
top
and
Heating
ammonium
chloride
reversible
same
time
products.
enter
backward
reached
or
f
1
dynamic
t he
t he
are
a
inside
t he
occurs
stage
equal.
is
of
reaction
reaction
reaction
t hen
reactions
Balance
t hat
t he
leave,
around
reactions,
such
Summary
form
t he
a
and
tube
can
always
in
a
ring
of
directions
at
tube.
proceed
contains
sealed
reached
The
t he
system
where
reaction
t he
does
in
a
where
rates
not
bot h
mixture
of
stop
the
Mg(NO
)
3
b
Fe(s)

following
equations,
single
then
displacement,
(s)
MgO(s)

classify
ionic
NO
2
the
reactions
precipitation
Cl
c
Zn(s)
d
NaOH(aq)
(g)
or
(g)
FeCl
HCl(aq)

(aq)
3
O
(g)
(s)
3
H
ZnCl
SO
2
AgNO
substances
for ward
said
to
and
have

(aq)
(aq)

4
MgBr
(aq)
(g)
SO
2
2
H
2
Na
(aq)
4
AgBr(s)

H
O(l)
2

Mg(NO
)
3
(aq).
2
as
synthesis,
neutralisation
2
2
e

2
2

is
reactants
questions
reactions:
a
no
t he
and
of
equilibrium
decomposition,
98
of
bur ner
n
Figure
as
chloride
ammonium

(g)
3
Chemical
Key
●
equations
Chemical
The
t he
●
●
n
●
state
a
(l)
of
are
shown
each
for
representations
at
element
are
are
t he
Ionic
lef t
of
an
ionic
equations
and,
t hey
Writing
chemical
reactions
of
chemical
reactions
using
equation
and
t he
products
on
any
determine
Spectator
t herefore,
and
bot h
r ules
in
t here
sides
placed
in
which
given
for
must
of
t he
front
Formulae
water.
is
(aq)
can
These
be
be
t he
formula
using
(s)
solution.
same
formulae.
never
used
are
its
number
of
equation.
of
must
af ter
aqueous
to
useful
be
They
determine
in
are
used
changed.
t he
solubility
determining
state
compounds.
show
as
a
only
result,
t he
end
atoms
up
in
a
or
ions
which
different
actually
situation
take
from
t he
par t
one
in
in
star ted.
ionic
showing
product
gas
equation
on
numbers
solubility
reaction
and
for
equations.
compounds
of
(g)
chemical
each
There
ionic
reactant
liquid,
balancing
which
●
are
when
a
of
formulae.
balanced
symbols
●
of
solid,
Coefcients
of
●
equations
and
reactants
atoms
●
Types
right.
The
for
reactions
concepts
symbols
●
and
equations
ions
which
ions
t hat
ions
are
remain
involves
are
do
t he
writing
present
not
ions
in
change
which
unchanged.
do
These
t he
full
solution
in
any
not
are
as
rst,
but
ions
to
way.
take
lef t
equation
individual
par t
out
of
in
a
t he
reaction
nal
and,
ionic
equation.
●
There
are
seven
main
decomposition,
redox
●
A
and
●
A
A
its
An
ionic
A
of
A
a
is
to
redox
a
is
any
synt hesis,
precipitation,
neutralisation,
in
which
two
or
more
reactants
reaction
where
a
single
reactant
is
products.
reaction
compound
is
any
where
reaction
to
insoluble
reaction
t he
between
element
an
element
displaces
anot her
usually
produce
solid
a
t hat
involves
two
compounds
in
precipitate.
forms
in
a
solution,
of ten
as
a
reaction.
reaction
salt
reaction
reaction
more
reacting
an
a
reactions:
ionic
compound.
chemical
form
chemical
product.
or
precipitation
neutralisation
alkali)
●
t he
any
reaction
two
and
solution
precipitate
result
●
state
from
aqueous
A
into
is
single
d isplacement
free
element
●
a
of
displacement,
reactions.
reaction
form
down
single
in
●
to
decomposition
broken
●
reversible
synthesis
combine
types
single
and
occurs
occurs
when
an
acid
reacts
wit h
a
base
(or
water.
when
one
reactant
is
reduced
and
t he
ot her
is
oxidised.
●
A
reversible
can
be
reaction
reversed
reactants
easily,
occurs
i.e.
t he
when
t he
products
direction
can
react
of
to
a
chemical
produce
change
t he
original
again.
99
Practice
exam-style
questions
Chemical
Equations
Practice
exam-style
questions
Write
Which
of
t he
following
a
sulfuric
reaction
correctly
acid
to
between
represents
produce
sodium
The
NaOH(aq)

H
SO
sodium
sulfate
2
B
2NaOH(aq) 
C
2NaOH(aq)
(aq)
and
NaSO
4
H
(aq)
Na
4
water?
(aq)

b
H
reaction
The
SO
2
SO
(s)

2H
4
Na
each
of
t he
aluminium
chloride
as
and
t he
chlorine
only
to
product.
(H
SO
2
between
(aq)),
aluminium
which
oxide
produces
and
sulfuric
aluminium
sulfate
4
2
2
(aq)
4
between
aluminium
reaction
O(l)
SO
2
and
water.
The
reaction
and
hydrochloric
O(l)
2
c
H
for
and
4
SO
2

equation
t he
hydroxide
acid
A
chemical
reactions.
produce
chemical
reactions
write
balanced
following
a
1
and
questions
6
Multiple-choice
to
equations
between
potassium
carbonate
solution
(aq)
4

2H
acid
(HCl(aq))
to
produce
O(l)
2
potassium
D
Na(OH)
(aq)

H
2
SO
2
(aq)
NaSO
4
chloride,
carbon
dioxide
and
water.
(aq)
4
d
The
reaction
between
et hane
(C
H
2

2H
(g))
and
oxygen
to
6
O(l)
2
make
2
Which
of
t he
following
compounds
is
soluble
in
copper(II)
B
magnesium
C
zinc
sulfate
The
reaction
nitrate
and
aqueous
potassium
The
reaction
and
ammonium
sulfate
solutions
to
make
of
lead(II)
lead(II)
sulfate
nitrate.
between
potassium
Aqueous
sulfate
solutions
react
of
which
of
t he
following
hydroxide
to
form
solution
potassium
to
form
a
precipitate
when
A
sodium
chloride
B
zinc
C
potassium
D
lead
sulfate
and
and
copper(II)
magnesium
ammonia
The
reaction
and
nitrate
(HCl(aq)),
and
ammonium
which
h
The
reaction
between
hydroxide
following
and
hydrochloric
calcium
sodium
and
chloride
and
and
water
to
produce
hydrogen.
The
reaction
between
magnesium
carbonate
hydrogencarbonate
t he
makes
nitrate
i
nitrate
water.
calcium
hydrogen.
chloride
sodium
and
between
mixed?
sodium
hydroxide
gas
compounds
acid
Consider
solution
phosphate
g
4
steam.
hydroxide
calcium
would
between
potassium
and
sulfate,
3
and
carbonate
f
D
dioxide
water?
e
A
carbon
solution
and
nitric
acid
reaction:
(HNO
(aq)),
which
produces
magnesium
nitrate,
3
Mg(HCO
)
3
(aq)

2HCl(aq)
MgCl
2
(aq)
carbon
2

2CO
(g)

2H
2
The
best
ionic
equation
for
t his
reaction
dioxide
and
water.
O(l)
2
j
is:
The
reaction
and
sulfuric
between
acid
(H
2
A
Mg

(aq)

2HCO
(aq) 
2H
and
2
(aq)
Mg
sodium
SO
2
(aq))
hydroxide
to
make
solution
sodium
sulfate
4
water.
(aq)
3

2CO
(g)

2H
2
O(l)
2
7
Write
balanced
f,
and
ionic
equations
for

B
2HCO
(aq)

2H
(aq)
2CO
3
(g)

2H
2
O(l)
2

C
HCO
(aq)

2H
(aq)
CO
3
(g)

H
2
O(l)
2

D
HCO
(aq)

H
(aq)
CO
3
5
What
to
type

H
of
reaction
would
you
O(l)
2
consider
t he
following
be?
2Al(s)

3H
SO
2
100
(g)
2
(aq)
Al
4
A
a
neutralisation
B
a
single
C
a
double
D
a
synt hesis
(SO
2
reaction
displacement
reaction
displacement
reaction
reaction
)
4
(aq)
3

3H
(g)
2
g,
i
j
in
question
6
above.
t he
reactions
in c,
e,
A7
Chemistry
often
The
involves
mole
determining
the
concept
amount
of
a
Objectives
substance
required
how
ammonia
much
to
produce
and
nitric
a
product.
acid
are
For
example,
required
By
the
be
able
1 kg
of
the
fertiliser
ammonium
nitrate?
to
of
an
devise
atom
is
another
so
small
method
that
of
chemists
measuring
have
the
the
this
method
uses
the
had
and
amount
relative
calculate
●
of
dene
molar
The
mole
and
atomic,
will
relative
atomic
molecular
formula
relative
mass
mass
molecular
and
masses
the
terms
mole
and
mass
●
give
●
perform
Avogadro’s
constant
mass
moles,
Relative
you
mole.
●
A7.1
topic
terms
relative
formula
substances;
this
The
mass,
mass
of
to:
dene
●
produce
end
to
molecular
and
formula
calculations
masses
and
involving
number
of
masses
particles.
Yo u
lear nt
in
Unit
scientists
use
known
relative
t he
A
as
mass
of
a
an
carbon-12
amu,
1.0 0
3. 3
m uc h
atomic
ato m
atom
t herefore,
t ha t
be cause
s malle r
m a ss .
wit h
wa s
unit
t he
ma ss
t han
They
a
on e -t welf t h
t he
a
atoms
to
designed
on e -t we lf t h
assign e d
of
g ram
t he
mass
mass
of
of
a
a
is
ex t remely
compare
s y st e m
ma ss
of
12.0 0
a
wh ic h
s mal l,
mas s es ,
c ompares
carbo n - 12
a tomic
carb o n - 12
t h eir
mass
a tom
has
a tom.
un i ts
a
or
ma s s
of
amu.
Relative
atomic
element
to
compara tive
mass
is
mass,
t herefore,
one-twe lf t h
valu e ,
given
t he
t he
re la tive
s y mb ol
compares
ma ss
of
a to mic
a
t he
mass
carbo n - 12
mass
has
no
of
an
a tom.
units.
atom
B ec au se
Relative
of
it
an
is
a
a to mic
A
r
n t he denition of relative atomic mass given in t he Key fact box, we use t he
word
‘average’
because
relative
atomic
mass
takes
into
account
t he
Key
!
fact
relative
Relative
atomic
mass,
A
,
is
the
r
abundance
nearest
same
each
whole
example,
When
of
t he
number,
relative
calculating
logic
isotope.
by
can
The
be
atomic
t he
found
mass
masses
comparing
relative
of
t heir
of
in
atomic
t he
periodic
calcium
covalent
masses
to
mass
is
and
t he
40
an
table
and
ionic
of
of
element,
on
page
uorine
compounds
carbon-12
to
360.
is
we
t he
For
19.
average
mass
element
compared
the
use
elements
composed
of
and
compounds
formed
by
of
an
one
atom
to
atom
of
an
one-twelfth
of
carbon-12.
t he
atom.
Key
!
Molecular
mass
of
covalent
bonding
fact
are
Relative
molecular
mass,
M
,
is
r
molecules.
We
use
t he
term
relative
molecular
mass
to
the
compare
t he
mass
of
a
molecule
of
a
molecular
element
or
compound
t he
mass
of
a
carbon-12
atom.
Relative
molecular
mass
is
symbol
Compounds
of
formed
by
ionic
bonding
use t he term relative formula mass
ionic
an
element
compound
wit h
are
represented
by
formula
units.
an
molecule
or
compound
one-twelfth
determine
t he
one-twelf t h
relative
toget her
t he
relative
t he
molecular
atomic
the
mass
Since
values,
have
mass
of
a
carbon-12
Key
!
atom.
mass
or
relative
formula
mass,
masses
of
all
t he
elements
present
in
relative
no
molecular
and
formula
masses
are
fact
formula
mass
is
the
we
mass
of
one
formula
unit
t he
a
compound
compared
to
one-
comparative
twelfth
t hey
carbon-12.
We
of
compound.
of
to compare t he mass of a formula unit of
average
add
to
atom
Relative
To
one
M
r
an
of
given
compared
t he
mass
wit h
of
one-twelf t h
average
the
mass
of
an
atom
of
units.
carbon-12.
101
The
mole
and
mass
The
mole
concept
Examples
1
Calculate
t he
relative
molecular
mass
of
nitrogen,
N
2.
N
consists
of
2
atoms
of
N.
2
∴
relative
molecular
mass
of
N

(2

14)

28
2
2
Calculate
t he
relative
molecular
mass
of
glucose,
C
H
6
C
H
6
O
12
∴
consists
6
atoms
of
H,
12
atoms
of
H
and
6
6.
atoms
of
O.
6
relative
C
H
6
3
of
O
12
molecular
O
12

(6

mass
12)

of
(12

1)

(6

16)

180
6
Calculate
t he
relative
formula
mass
of
magnesium
carbonate,
MgCO
3.
MgCO
consists
of
1
atom
of
Mg,
1
atom
of
C
and
3
atoms
of
O.
3
∴
relative
formula
MgCO

(1

mass
24)

of
(1

12)

(3

16)

84.
3
The
mole
We use different terms to represent a xed amount of somet hing, e.g. a dozen
apples
same
can
be
mole
large
!
mole
is
of
to
12
apples
used
in
describe
atoms
or
a
and
a
pair
anyt hing,
mole
is,
and
chemistr y.
of
of
The
e.g.
a
molecules.
t herefore,
used
gloves
represents
mole
represents
mole
of
apples,
However,
mainly
as
a
a
a
a
two
mole
mole
gloves.
xed
The
number.
of
represents
measurement
t
gloves,
of
a
a
ver y
atomic
par ticles.
fact
Like
A
used
is
number
sized
Key
represents
concept
the
amount
of
relative
atomic
mass,
t he
mole
has
been
dened
using
t he
carbon-12
a
isotope because of its high abundance and stability. t was found t hat 12.00 g
substance
that
number
particles
contains
the
same
23
of
of
as
there
carbon-12
contains
6.0

10
atoms
of
carbon-12.
One
mole
represents
are
23
t he
atoms
in
12.00 g
of
number
of
atoms
in
12.00 g
of
carbon-12,
i.e.
6.0

10
.
This
number
is
carbon-12.
known
as
A
vogadro’s
constant ,
or
N
A
23
n
ot her
words,
par ticles
Looking
of
at
t he
t he
‘amount’
●
‘par ticles’
n
t he
if
is
t he
denition
refer
t he
can
same
mole
amount
of
a
substance
t hat
contains
6.0

10
substance.
can
substance
●
a
to
a
t he
to
t hat
mole
mass
substance
refer
way
of
is
a
atoms,
it
was
in
of
a
t he
Key
fact
substance
box:
or
t he
volume
of
a
gas
molecules,
found
formula
t hat
units
12.00 g
of
or
ions.
carbon-12
contains
23
6.0

10
carbon-12
atoms,
it
was
found
t hat:
23
●
40 g
of
calcium
(Ca)
contains
6.0

10
Ca
atoms
23
●
28 g
●
180 g
of
nitrogen
(N
)
contains
6.0

10
N
2
molecules
2
23
of
glucose
(C
H
6
O
12
)
contains
6.0

10
C
6
H
6
O
12
molecules
6
23
●
84 g
of
magnesium
carbonate
(MgCO
)
contains
6.0

10
MgCO
3
formula
f
we
look
numerical
is
t he
NB
102
mass
When
3
units.
at
t he
value
of
masses
as
one
t he
mole
writing
t he
given
relative
of
above
mass
par ticles
mole
as
a
of
we
of
t he
unit,
it
see
t he
t hat
each
element
or
mass
has
compound
t he
and
substance.
is
usually
abbreviated
to
mol
same
each
The
mole
Molar
The
concept
The
of
one
mole
of
a
substance
is
known
as
its
a
compound
molar
mass,
or
!
M
Key
Molar
molar
mass
of
an
element
or
is
given
t he
unit
mass
mole
or
g mol
mass,
grams,
.
For
example,
because
12.00 g
of
carbon
fact
M,
is
the
mass,
in
grams
1
per
and
mass
mass
The
mole
of
one
mole
of
a
substance.
contains
23
6.0  10
carbon atoms, or 1 mol of carbon atoms, t he molar mass of carbon
1
is
12 g mol
The
molar
t hough
apples
are
mass
t hey
will
bot h
a
different,
of
are
be
as
Calculating
Looking
at
t he
different
dozen.
just
different
all
t he
This
t he
elements
mass
from
is
molar
of
t he
an
and
one
compounds
mole,
mass
because
mass
ndings
of
t he
of
a
is
as
will
t he
g rapes
of
atoms
t he
different
from
be
different
mass
dozen
mass
apple
just
of
even
of
t he
one
t hough
each
mass
even
dozen
t hey
element
of
a
is
g rape.
mass
above,
it
can
be
seen
t hat:
23
●
because
40 g
of
calcium
contains
6.0

10
Ca
atoms,
or
1 mol
of
1
Ca
atoms,
t he
molar
mass
of
calcium
is
40 g mol
23
●
because
28 g
of
nitrogen
contains
6.0

10
N
molecules,
or
1 mol
of
2
1
N
molecules,
t he
molar
mass
of
nitrogen
is
28 g mol
2
23
●
because
180 g
of
O
of
glucose
contains
6.0

10
C
H
6
O
12
molecules,
or
1 mol
6
1
C
H
6
12
molecules,
t he
molar
mass
of
glucose
is
180 g mol
6
23
●
because
84 g
of
magnesium
carbonate
contains
6.0

10
MgCO
3
formula
units,
or
1 mol
of
MgCO
formula
units,
t he
molar
mass
of
3
1
magnesium
carbonate
is
84 g mol
Therefore, t he molar mass of an element or compound is t he relative atomic,
molecular
More
or
formula
mass
amount
expressed
in
grams
per
mole.
examples
1
M(H
O)

(2

1)

)

64
)

(3

40)
)

(2

14)
16

18 g mol
2
1
M(CuSO

32

(4

16)

160 g mol
4
1
M(Ca
(PO
3
)
4

(2

31)

(8

16)

310 g mol
2
1
M((NH
)
4
Moles
Molar
mass
t he
an
mass
(8

1)

12

(3

16)

96 g mol
mass
gives
us
element
or

3
and
mass
of
CO
2
number
t he
or
of
relationship
compound.
moles
of
an
between
We
can
element
t he
use
or
number
t he
molar
of
moles
mass
to
and
t he
calculate
compound.
Examples
1
Calculate
t he
number
of
moles
in
10 g
of
calcium
carbonate,
CaCO
3
First
calculate
t he
molar
mass
of
CaCO
3
1
M(CaCO
)

40

12

(3

16)

100 g mol
3
i.e.
mass
of
1 mol
CaCO

100 g
3
10
____
∴
number
of
moles
in
10 g

mol

0.1 mol
100
103
The
mole
and
mass
The
2
Calculate
t he
mass
of
0.2 mol
of
sulfuric
acid,
H
calculate
t he
molar
mass
of
H
SO
2
performing
1
SO
2
chemistry,
involving
the
including
mole,
it
)

(2

1)

32
you
show
each

(4
is
essential
step
of
i.e.
mass
of
1 mol
H
SO
down
a
set
by
You
of
making
must
not
numbers
a
what
you
are
98 g mol

98 g
mass
of
0.2 mol
of
H
SO

0.2

98 g

19.6 g
4
clear
just
put
without
Moles
stating

4
2
clearly
statement.
16)
your
∴
working

4
those
2
that
4
calculations
M(H
in
4
tip
First
When
concept
SO
2
Exam
✔
mole
and
number
of
particles
calculating.
23
The
number
can
calculate
t hat
t he
●
t he
type
of
f
a
in
number
par ticle
substance
f
a
are
one
of
in
of
f
is
an
mole
is
par ticles
a
always
in
substance
element,
individual
substance
compound,
●
par ticles
t he
any
6.0

10
number
depends
on
.
of
t he
Using
t his
moles.
type
of
fact
is
e.g.
a
e.g.
bonding
and
t he
noble
gases,
t hen
t he
atoms
molecular
water,
metals
element,
t hen
t he
e.g.
par ticles
oxygen,
are
or
a
molecules
covalent
made
up
atoms
a
substance
par ticles
are
is
an
ionic
formula
compound,
units
made
up
e.g.
of
sodium
chloride,
t hen
t he
ions.
Examples
1
Calculate
t he
number
of
atoms

10
in
0.5
mole
of
copper,
Cu.
23
1 mol
Cu
contains
6.0
atoms.
23
∴
2
0.5 mol
Calculate
Cu
t he
contains
number
0.5
of

6.0
moles
of

10
23
atoms
carbon

3.0
dioxide,

CO
,
10
atoms
t hat
contain
2
23
2.0

10
carbon
dioxide
molecules.
23
1 mol
CO
contains
6.0

10
molecules.
2
23
2.0
number
of
moles
in
2.0


10
__________
23
∴
10
molecules

mol
23
6.0

We
can
extend
number
●
of
1 mol
our
moles
of
calculations
or
water,
par ticles
H
O,
of
moles
inside
consists
of:
a
and
1 mol
of
2
H
●
atoms
2 mol
and
of
1 mol
potassium
H
O
For
to
or
at
t he
molecules,
or
2 mol
of
2
of
O
atoms
carbonate,
K
CO
2
units,
look
example:
consists
of:
2 mol
4 mol
of
K
of
K
3
CO
2
3
2

formula
10
0.33 mol
par ticles
compound.

ions
and
2 mol
of
CO
ions.
3
Exam
✔
tip
Example
It
is
essential
correct
in
your
unit
that
you
after
place
each
calculations,
the
value
given
especially
Calculate
t he
number
of
hydrogen
atoms
in
1.5 mol
of
met hane,
CH
4
your
1 mol
CH
contains
4 mol
H
atoms.
4
final
answers.
have
no
units
The
are
only
values
relative
that
atomic,
∴
1.5 mol
CH
contains
1.5

4 mol
H
atoms

6
mol
H
atoms
4
molecular
and
formula
masses.
23
1 mol
Your
answer
wrong
the
104
unit
value
is
or
for
incorrect
no
unit,
relative
if
it
has
unless
mass.
it
H
atoms
contains
6.0

10
atoms.
the
is
23
∴
6 mol
H
atoms
contains
6

6.0

10
24
atoms

3.6

10
we
Remember
substance.
par ticles
●
of
atoms
in
The
mole
concept
Moles,
We
can
mass
now
number
The
of
and
combine
number
our
of
mole
and
mass
particles
calculation
of
moles
and
mass,
and
moles
and
par ticles.
Examples
1
Calculate
t he
number
of
molecules
in
1.8 g
of
water,
H
O.
2
1
M(H
O)

(2

1)

16

18 g mol
2
i.e.
mass
of
1 mol
H
O

18 g
2
1.8
___
∴
number
of
moles
in
1.8 g

mol

0.1 mol
18
23
1 mol
H
O
contains
6.0

10
molecules
2
23
∴
0.1 mol
H
O
contains
0.1

6.0

10
molecules
2
22

6.0

10
molecules
23
2
Calculate
t he
mass
of
1.5

10
molecules
of
hydrogen
chloride,
HCl.
23
1 mol
HCl
contains
6.0

10
molecules
23
1.5
number of moles in 1.5


10
__________
23
∴
10
molecules

mol

0.25 mol
23
6.0

10
1
M(HCl)
i.e.
∴

mass
1
of
mass

35.5
1 mol
of

36.5 g mol
HCl
0.25 mol

36.5 g
HCl

0.25

36.5 g

9.13 g
3
3
Calculate
oxide,
t he
Al
number
of
aluminium
ions,
Al
,
in
40.8 g
of
aluminium
O
2
3
1
M(Al
O
2
i.e.
)

(2

27)

(3

16)

102 g mol
3
mass
of
1 mol
Al
O

2
3
moles
in
102 g
40.8
_____
∴
number
of
40.8 g

mol

0.4 mol
102
3
1 mol
Al
O
2
contains
2 mol
Al
ions.
3
3
∴
0.4 mol
Al
O
2
contains
0.4

2 mol
Al
ions
3
3

0.8 mol
3
1 mol
Al
Al
ions
23
ions
contains
6.0

10
ions
3
∴
0.8 mol
Al
23
ions
contains
0.8

6.0

10
ions
23

Summary
1
Calculate
a
mass
of
Calculate
a
20 g
of
10
ions
of:
sodium
sulfate,
Na
the
number
of
moles
b
SO
2
2

questions
the
0.25 mol
4.8
b
Calculate
the
number
4
Calculate
the
mass
of
of
glucose,
C
H
6
O
12
6
in:
neon
3
1.2 mol
4
molecules
in
63.0 g
of
1.5 mol
magnesium
of
hydrogen
carbonate.
chloride,
HCl.
23
Ca
(PO
3
of
2.5

10
formula
units
of
calcium
phosphate,
)
4
2.
5
Calculate
the
number
of
molecules
6
Calculate
the
number
of
chloride
in
34 g
of
ammonia,
NH
3
ions
in
6.8 g
of
zinc
chloride,
ZnCl
2
105
The
mole
and
gas
volumes
The
A7.2
Objectives
By
the
be
able
end
of
this
topic
you
The
state
gas
volumes
Gases have ver y small masses because of t heir low densities, so chemists have
Avogadro’s
●
dene
●
perform
molar
relationship
occupied
by
t he
between
t he
number
of
moles
of
a
gas
and
t he
gas.
volume
calculations
and
t he
law
volume
moles
and
concept
will
to:
investigated
●
mole
mole
volumes
involving
of
gases.
n 181
1, Amedeo Avo ga dro notice d t h at a ll gase s un d er t h e same c on d iti on s
of
temperature
t he
same
and
number
pre ssure,
of
an d
mo le cules.
o cc u pying
He
propose d
t he
same
volume,
A
vogad ro’s
con t ain
law
3
As
!
Key
at
fact
an
a
example,
using
temperature
of
Avogadro’s
25 °C
and
law,
we
pressure
can
of
say
t hat
101.3 kPa
100 cm
has
t he
of
same
oxygen
gas
number
of
3
molecules
Avogadro’s
law
states
that
as
of
100 cm
nitrogen
gas
at
25 °C
and
101.3 kPa.
equal
23
volumes
same
and
of
all
gases,
conditions
pressure,
number
of
of
under
the
temperature
contain
the
same
f
t he
number
1 mol
must
of
all
of
molecules
gases
occupy
t he
under
same
in
t he
each
gas
same
is
6.0

conditions
10
,
of
i.e.
1 mol,
it
temperature
follows
and
t hat
pressure
volume.
molecules.
Molar
The
volume
volume
of
one
mole
of
a
gas
is
known
as
its
molar
volume,
or
V
m
!
Key
fact
Molar
volume
is,
t herefore,
t he
volume
of
a
gas
which
contains
23
Molar
volume,
V
is
the
volume
6.0

10
molecules
of
t he
gas.
m
occupied
by
1 mol
of
a
gas.
Since
temperature
volume
of
●
will
and
depend
pressure
on
bot h
of
bot h
t hese.
affect
t he
Chemists
volume
mostly
of
a
work
gas,
wit h
molar
two
sets
conditions.
Stand ard
temperature
and
pressure ,
or
stp,
which
equates
to
a
o
temperature
of
0
C
(273 K)
and
a
pressure
of
101.3 kPa
3
Molar
●
Room
volume
at
stp
temperature
temperature
of
is
22.4 dm
and
25 °C
and
a
22 400 cm
or
rtp,
which
pressure
of
Molar
t he
volume
volume
volume
number
of
of
at
r tp
gives
a
gas.
moles
of
us
is
t he
We
a
24.0 dm
can
t he
to
(1
a
atmosphere).
3
or
24 000 cm
relationship
use
equates
101.3 kPa
3
Molar
atmosphere).
3
or
pressure ,
(298 K)
(1
between
molar
volume
t he
to
number
calculate
of
moles
t he
and
volume
or
gas.
Examples
1
Calculate
t he
volume
occupied
by
0.25 mol
nitrogen,
N
,
at
stp.
2
3
Volume
of
1 mol
of
N
at
stp

22.4 dm
2
3
∴
volume
of
0.25 mol
of
N
at
stp

0.25

22.4 dm
3

5.6 dm
2
3
2
Calculate
t he
number
of
moles
in
2.4 dm
of
oxygen
gas,
O
,
at
r tp.
2
3
Volume
of
1 mol
of
O
at
r tp

24.0 dm
2
2.4
_____
3
∴
number
of
moles
in
2.4 dm
of
O
at
r tp

mol

0.1 mol
2
24.0
We
can
moles,
106
now
mass,
combine
volume
our
and
calculations
number
of
wit h
par ticles.
t hose
in
Unit
7
.1
to
involve
The
mole
concept
The
mole
and
gas
volumes
Examples
1
Calculate
t he
volume
occupied
by
6.4 g
of
oxygen,
O
at
stp.
2
Calculate
t he
molar
mass
of
O
gas.
2
1
M(O
)

2

16

32 g mol
2
i.e.
mass
of
1 mol
of
O

32 g
2
6.4
____
∴
number
of
moles
in
6.4 g

mol

0.2 mol
32
3
volume
of
1 mol
O
at
stp

22.4 dm
2
3
∴
volume
of
0.2 mol
O
gas
at
stp

0.2

22.4 dm
3

4.48 dm
2
3
2
Calculate
t he
mass
of
600 cm
of
carbon
dioxide,
CO
,
at
r tp.
2
3
Volume
of
1 mol
CO
at
r tp

24 000 cm
2
600
_______
3
∴
number
of
moles
in
600 cm

mol
24 000

0.025 mol
1
M(CO
)

12

(2

16)

44 g mol
2
i.e.
mass
of
1 mol
CO

44 g
2
∴
mass
of
0.025 mol
CO

0.025

1.1 g

44 g
2
3
3
Calculate
t he
number
of
molecules
in
6.72 dm
of
ammonia,
NH
,
at
stp.
3
3
Volume
of
1 mol
NH
at
stp

22.4 dm
3
6.72
_____
3
∴
number
of
moles
in
6.72 dm

mol
22.4

0.3 mol
23
1 mol
NH
contains
6.0

10
molecules
3
23
∴
0.3 mol
NH
contains
0.3

6.0

10
molecules
3
23

1.8

10
molecules
22
4
Calculate
chloride
t he
gas,
volume
HCl
at
occupied
by
4.5

10
molecules
of
hydrogen
r tp.
23
1 mol
HCl
contains
6.0

10
molecules.
22
4.5
number
of
moles
in
4.5


10
__________
22
∴
10
molecules

mol
23
6.0


10
0.075 mol
3
volume
of
1 mol
HCl
at
r tp

24 dm
3
∴
volume
of
0.075 mol
HCl
at
r tp

0.075

24.0 dm
3

Summary
1
Calculate
questions
the
ammonia,
1.8 dm
mass,
volume
and
number
of
molecules
in
2.5 mol
of
NH
3
3
2
Calculate
the
number
3
Calculate
the
volume
of
of
atoms
16 g
of
in
4.8 dm
sulfur
of
neon
dioxide,
gas
SO
,
at
at
rtp.
stp.
2
3
4
Determine
the
mass
of
840 cm
of
oxygen
gas,
O
,
at
rtp.
2
107
The
mole
and
concentration
of
solutions
A7.3
Objectives
By
the
be
able
end
of
The
this
topic
you
The
You
explain
what
is
meant
of
a
have
already
explain
the
terms
a
solution
solutions
come
and
across
saturated.
ways
of
describing
However,
we
can
solutions
express
such
t he
as
dilute,
concentration
in
more
solutions.
precise
The
ways,
which
concentration
allow
of
a
us
to
perfume
solution
is
a
calculations
measure
of
t he
mass
quantity
concentration
of
solution
involving
●
concentration
by
of
concentration
and
concept
will
to:
concentrated
●
mole
mole
and
of
a
solute
dissolved
in
molar
a
xed
volume
3
of
solution
usually
used
is
1 dm
of
t he
solution.
The
volume
3
,
i.e.
1000 cm
concentration
dene
●
the
term
Concentration
standard
of
a
solution
can
be
expressed
in
two
ways.
3
solution
perform
●
●
calculations
involving
Mass
of
concentration ,
solution.
The
unit
which
for
gives
mass
t he
mass
of
concentration
solute
is
dissolved
grams
of
solute
in
1 dm
per
cubic
3
concentrations
of
solutions.
decimetre
●
Molar
of
solution
or
concentration ,
g dm
which
gives
t he
number
of
moles
of
solute
3
dissolved
in
1 dm
of
solution.
The
unit
for
molar
concentration
is
moles
3
of
solute
per
cubic
decimetre
of
solution
or
mol dm
t is ver y impor tant to note t hat concentration is expressed as t he quantity of
3
solute
in
1 dm
3
of
solution
and
not
in
1 dm
of
solvent.
Example
A
solution
of
sodium
hydroxide
contains
10.0 g
of
sodium
hydroxide
3
Did
?
you
dissolved
know?
in
1 dm
of
3
g dm
Molar
concentration
may
solution.
Express
t he
concentration
of
t he
solution
in
3
and
mol dm
also
3
The
be
called
molarity
molarity.
is
M.
A
The
unit
solution
solution
contains
10.0 g
of
NaOH
in
1 dm
for
with
3
a
Therefore,
mass
concentration

10.0 g dm
3
concentration
be
or
described
‘1 M
of
1 mol dm
as
a
‘1
may
molar
To
solution’
determine
hydroxide
solution’.
t he
molar
concentration,
nd
t he
number
of
moles
of
sodium
present:
1
M(NaOH)
i.e.
Key
!
mass
of
1

23
mole

16

1

40 g mol
NaOH

40 g
fact
10
___
∴
number
of
moles
in
10.0 g
NaOH

mol
40
A
standard
solution
is
one
whose

concentration
is
known
0.25 mol
accurately.
3
Therefore,
A
molar
standard
concentration

0.25 mol dm
solution
A solution whose concentration is known accurately is referred to as a standard
solution. A standard solution is made in a volumetric ask as shown in Figure
meniscus
of
the
solution
3
7
.3.1.
These
asks
come
in
various
sizes,
e.g.
100
cm
,
3
250
cm
3
,
500
cm
and
3
etched
line
1 dm
indicating
.
A
known
mass
of
solute
is
added
to
the
ask
and
distilled
water
is
then
3
volume,
e.g.
250 cm
added until the solution reaches the mark on the neck of the ask.
3
To
make
mass
volumetric
a
fixed
flask
volume
of
a
standard
solute
solution
required
must
which
be
does
not
calculated
have
a
volume
of
1 dm
,
rst.
contains
of
solution
Example
when
the
the
meniscus
etched
3
e.g.
is
on
line,
Determine
t he
mass
of
potassium
carbonate
which
must
be
dissolved
in
250 cm
3
distilled
water
to
make
250 cm
of
potassium
carbonate
solution
wit h
3
concentration
of
3

108
Figure
7.3.1
A
volumetric
ask
1000 cm
0.2 mol dm
3
(1 dm
)
of
t he
required
solution
contains
0.2 mol
K
CO
2
3
a
t he
The
mole
concept
The
mole
and
concentration
of
solutions
0.2
_____
3
∴
1 cm
of
t he
required
solution
contains
mol
K
CO
2
3
1000
3
and
250 cm
of
t he
required
solution
contains
0.2
_____

250 mol
K
CO
2

0.05 mol
K
3
CO
2
3
1000
Therefore
0.05 mol
K
CO
2
is
required
to
make
t he
solution.
3
1
M(K
CO
2
i.e.
)

(2

39)

mass
of
1 mol
K
CO
2
∴
12

mass

16)

138 g mol
of

Therefore
0.05 mol
t he
mass
138 g
3
K
CO
2
of

Making
Your
a
K
CO
may
manipulation
use
and

138 g

6.9 g
required
is
6.9 g
3
standard
teacher
0.05
3
2
●
(3
3
solution
this
activity
to
assess:
measurement.
3
Y
ou
are
going
Y
ou
will
be
to
make
250 cm
3
of
sodium
carbonate
solution
with
a
concentration
of
0.1 mol dm
3
supplied
with
sodium
carbonate,
distilled
water,
a
balance,
a
sheet
of
weighing
paper,
a
100 cm
beaker,
3
a
glass
rod
and
a
250 cm
volumetric
ask.
Method
1
Calculate
the
above
to
2
Weigh
a
3
Weigh
the
4
Carefully
5
Add
6
Transfer
7
Rinse
8
of
mass
of
sodium
the
distilled
the
sodium
weighing
transfer
the
of
water
solution
glass
rod
to
the
with
three
Add
distilled
water
to
Place
the
bottom
stopper
on
stir
required
to
make
the
solution.
(Use
the
calculation
given
in
the
example
the
the
the
with
over
transfer
the
beaker,
the
in
your
calculation
making
glass
rod
sure
until
all
it
is
the
on
all
the
sheet
of
weighing
paper.
transferred.
sodium
carbonate
has
dissolved
completely
.
ask.
water
line
meniscus
ask.
determined
to
solution
and
below
the
balance.
you
volumetric
times
just
of
a
carbonate
distilled
water
on
carbonate
and
distilled
the
paper
sodium
with
until
carbonate
you.)
sheet
some
drop
9
mass
help
is
Holding
in
the
on
the
the
beaker
these
and
washings
volumetric
the
transfer
to
the
ask.
the
ask
Add
washings
each
the
nal
to
the
ask.
Wash
the
beaker
time.
quantity
of
distilled
water
drop
by
line.
stopper
in
place,
invert
the
ask
three
times
to
mix
the
solution.
Calculations
We can extend our calculations involving solutions as shown in t he examples
below.
Examples
1
Calculate
t he
molar
concentration
of
a
solution
of
hydrochloric
acid,
3
HCl,
which
has
a
mass
concentration
of
9.125 g dm
1
M(HCl)
i.e.

mass
1
of

35.5
1 mol

36.5 g mol
HCl

36.5 g
9.125
______
∴
number
of
moles
HCl
in
9.125 g

mol

0.25 mol
36.5
109
The
mole
and
concentration
of
solutions
The
mole
concept
3
i.e.
number
of
moles
HCl
in
1 dm

0.25 mol
3
Therefore,
2
Calculate
which
molar
t he
concentration
molar
contains
6 g

0.25 mol dm
concentration
of
sodium
of
a
solution
hydroxide
of
sodium
dissolved
in
hydroxide
distilled
water
to
3
make
200 cm
Calculate
of
t he
solution.
molar
mass
of
sodium
hydroxide,
NaOH.
1
M(NaOH)
i.e.
mass

of
40 g mol
1 mol
of
NaOH

40 g
6
___
∴
number
of
moles
in
6 g
NaOH

mol

0.15 mol
40
3
200 cm
of
solution
contains
0.15 mol
NaOH
0.15
____
3
∴
1 cm
of
solution
contains
mol
NaOH
200
0.15
3
and
1000 cm
____
3
(1 dm
)
of
solution
contains

1000 mol
NaOH
200

0.75 mol
NaOH
3
Therefore
t he
molar
concentration

0.75 mol dm
3
3
Determine how many moles of sodium sulfate are present in 250 cm
of a
3
sodium sulfate solution which has a molar concentration of 0.2 mol dm
3
1 dm
of
solution
contains
0.2 mol
Na
SO
2
,
4
3
i.e.
1000 cm
of
solution
contains
0.2 mol
Na
SO
2
_____
3
∴
4
0.2
1 cm
of
solution
contains
mol
Na
SO
2
4
1000
0.2
_____
3
and
250 cm
of
solution
contains

250 mol
SO
Na
2
4
1000

0.05 mol
Na
SO
2
Therefore,
4
You
wish
number
to
make
of
a
moles
sodium
of
sodium
chloride
sulfate
solution
present
wit h
a
4

0.05 mol
molar
3
concentration
chloride.
of
What
Calculate
t he
0.25 mol dm
is
t he
molar
,
maximum
mass
of
but
you
volume
sodium
only
of
have
1
1.7 g
solution
chloride,
you
of
sodium
can
make?
NaCl.
1
M(NaCl)
i.e.
mass

of
23

35.5
1 mol


58.5 g
mol
58.5 g.
1
1.7
_____
∴
number
of
moles
in
1
1.7 g

mol
58.5

0.2 mol
3
Required
solution
has
a
molar
concentration
of
0.25 mol dm
,
3
i.e.
0.25 mol
NaCl
is
contained
in
1 dm
of
solution
3
or
0.25 mol
NaCl
is
contained
in
1000 cm
of
solution.
1000
_____
∴
1 mol
NaCl
is
contained
in
3
cm
of
solution
0.25
1000
_____
and
0.2 mol
NaCl
is
contained
in
3

0.2 cm
of
solution
0.25
3

800 cm
of
solution
3
Therefore, the maximum volume of solution which can be made is
110
800 cm
The
mole
concept
The
Summary
1
Dene
2
Calculate
the
mole
and
chemical
formulae
questions
terms
the
‘molar
mass
concentration’
concentration
and
and
‘standard
molar
solution’.
concentration
if
2.8 g
of
potassium
hydroxide
is
dissolved
in
3
distilled
water
to
make
up
500 cm
of
solution.
3
3
What
mass
of
calcium
chloride,
CaCl
,
needs
to
be
weighed
to
make
a
solution
of
volume
200 cm
and
2
3
concentration
0.1 mol dm
?
3
4
How
many
moles
of
sodium
carbonate
are
present
in
400 cm
of
sodium
carbonate
solution,
which
has
a
3
concentration
A7.4
The
Empirical
n
terms
of
of
0.25 mol dm
mole
and
and
?
chemical
molecular
moles,
a
chemical
formulae
Objectives
formulae
formula
shows
how
many
moles
of
By
the
be
able
each
●
element
combine
to
form
one
mole
of
t he
compound.
For
example,
H
O
n
Unit
2 mol
5.1
you
of
hydrogen
learnt
t hat
atoms
combined
chemical
formulae
wit h
can
1 mol
be
of
oxygen
written
in
atoms.
We
The
●
will
be
considering
empirical
ratio
between
formula ,
t he
atoms
two
of
which
or
t hese
gives
ions
in
ways
t hree
t he
t he
main
here.
explain
the
whole
number
terms
The
molecular
atoms
onic
t he
of
each
element
compounds
ratio
of
Covalent
t he
formula ,
are
ions
which
present
always
wit hin
compounds
are
gives
in
one
mole
represented
t he
actual
●
by
of
number
t he
of
moles
will
empirical
determine
formula
and
the
empirical
formulae
of
and
a
compound
mole
compound.
t he
you
composition
determine
the
composition
●
topic
molecular
molecular
simplest
this
percentage
●
ways.
of
to:
formula,
2
represents
end
percentage
of
a
compound.
of
compound.
empir ical
formulae ,
which
give
compound.
represented
by
molecular
for mulae .
The
empir ical
and molecular for mulae of covalent compounds may be t he same, e.g. water
(H
O),
ammonia
(NH
2
)
and
met hane
be
a
simple
molecular
whole
for mula
of
we
we
know
can
use
molecular
and
its
To
we
butene
is
multiple
C
H
work
t he
of
a
molar
of
out
t he
t he
or
of
its
t he
t he
molecular
empir ical
empir ical
for mula
for mula,
for mula
is
e.g.
2
empirical
t he
t he
CH
8
elements,
compound
mass
and
of
is
by
mass,
formula
different
of
from
compound,
we
in
a
t he
t he
can
compound,
compound.
empirical
use
t his
to
t hen
f
t he
formula
work
out
formula.
determine
t hese
to
formula
know
of
propor tions
t his
molecular
moles
of
t he
),
4
number
4
f
(CH
3
may
t he
each
empirical
element
formula,
present
and
we
t hen
need
to
calculate
determine
t he
t he
number
simplest
mole
of
ratio
elements.
Examples
1
A
sample
of
potassium,
empirical
mass
a
solid
4.34 g
formula
(g)
is
of
decomposed
chromium
of
t he
and
and
found
5.34 g
of
to
contain
oxygen.
6.52 g
What
is
of
t he
compound?
K
Cr
6.52
4.34
O
5.34
39
52
16
1
molar
mass
(g mol
)
6.52
4.34
____
number
of
moles
simplest
mole
ratio
2
5.34
____

39
0.167
____

52
1
0.083

0.333
16
4
111
The
mole
and
chemical
formulae
The
The
empirical
formula
is
K
of
2
To
each
On
determine
element
analysis,
6.7%
a
by
t he
t he
sample
hydrogen
and
4
simplest
smallest
of
concept
CrO
2
Note:
mole
mole
glucose
53.3%
ratio,
number,
was
oxygen.
found
The
divide
i.e.
t he
number
of
moles
0.083.
to
contain
molar
mass
40.0%
of
t he
carbon,
compound
is
1
180 g mol
f
t he
each
.
mass
Determine
of
t he
element
mass
t he
sample
can
be
(g)
is
molecular
assumed
expresses
in
formula
to
be
of
100 g,
glucose.
t hen
t he
percentage
of
grams.
C
H
40
6.7
O
53.3
12
1
16
1
molar
mass
(g mol
)
40
6.7
___
number
of
moles
simplest
The
mole
ratio
empirical
53.3
___

____
3.3

12
6.7

1
1
2
formula
of
glucose
is
3.3
16
1
CH
O
2
To
determine
t he
molecular
formula,
calculate
t he
molar
mass
of
CH
O:
2
1
M(CH
O)

12

(2

1)

16

30 g mol
2
1
M(glucose)

180 g mol
180
____
Ratio
between
M(glucose)
and
M(CH
O)


6
2
30
∴
t he
The
molecular
molecular
formula
formula
of
is
6

t he
glucose
is
empirical
C
H
6
Percentage
The
by
of
composition
each
composition
of
.
6
composition
percentage
mass,
O
12
formula.
element
water
in
shows
of
the
what
a
compound
compound.
percentage
indicates
For
of
the
the
example,
mass
of
a
the
percentage,
percentage
water
molecule
is made up of hydrogen and what percentage is made up of oxygen.
f
we
mass,
1 mol
1 mol
know
of
of
of
t he
each
t he
t he
formula
element
of
a
compound,
present
compound
and
can
t he
be
t he
percentage
calculated
mass
which
by
each
composition,
calculating
element
t he
mass
contributes
by
of
to
compound.
Examples
1
Calculate
t he
percentage
composition
of
hydrogen
1
M(H
O)

(2

1)

16

18 g mol
2
i.e.
mass
of
1 mol
H
O

18 g
2
Mass
of
hydrogen
in
1 mol
H
O

2

1
2
2
___
∴
percentage
hydrogen


100%
18

Mass
of
oxygen
in
1 mol
H
11.11%
O

16 g
2
16
___
∴
percentage
oxygen


100%
18

112
88.89%

2 g
and
oxygen
in
water.
The
2
mole
concept
Calculate
t he
phosphate,
The
percentage,
(NH
)
4
by
mass,
of
nitrogen
in
mole
and
chemical
reactions
ammonium
PO
3
4
1
M((NH
)
4
i.e.
PO
3
mass
)

(3

14)
of
1 mol
(NH
)
4
Mass
of

(12

1)

31

(4

16)

149
g mol
4
nitrogen
in
PO
3

149 g
4
1 mol
(NH
)
4
PO
3

3

14 g

42 g
4
42
____
∴
percentage
nitrogen


100%
149

Summary
1
On
analysis
Determine
2
A
liquid
28.19%
questions
a
compound
the
used
empirical
in
rocket
was
found
formula
fuel
is
of
to
contain
the
found
to
11.64 g
of
sodium,
16.20 g
of
sulfur
and
12.15 g
of
oxygen.
compound.
consist
of
3.04 g
of
nitrogen
and
6.94 g
of
oxygen.
The
molar
mass
of
the
1
compound
3
Calculate
is
92 g
the
mol
.
Determine
percentage
the
composition
molecular
of
formula
hydrogen,
sulfur
of
the
and
compound.
oxygen
in
sulfuric
acid,
H
SO
2
4
Determine
the
percentage,
by
mass,
of
carbon
in
aluminium
carbonate,
Al
(CO
2
A7.5
The
n
The
Law
Un i t
mole
of
6 .1
yo u
lear nt
reactions,
c hemical
e qu a t i o n
of
This
Key
is
t he
t hat
t h ey
t he
e qu a t i o n
summed
fact
chemical
Conservation
c hemical
side
and
up
a to m s
are
o n ly
number
m u st
in
t he
of
be
are
of
neit her
a to m s
same
of
as
created
and
eac h
t he
d e st r oye d
when
element
number
C o n s e r vat i o n
nor
t hat
of
)
3
3
Objectives
Matter
rear ranged,
of
t he
L aw
reactions
4
on
on
t he
M at te r
in
wr iting
t he
lef t
g i ve n
By
the
be
able
●
r ight
●
t he
●
b ox .
this
topic
you
will
the
Law
of
Conservation
Matter
apply
the
mole
balanced
side.
in
of
to:
state
of
a
end
concept
chemical
using
masses
apply
the
to
equations
mole
concept
to
mole
concept
to
ionic
equations
Since
all
t he
atoms
t hat
were
present
at
t he
beginning
of
t he
reaction
are
●
apply
the
present at t he end of t he reaction, it follows t hat t he total mass of t he products
balanced
must
We
be
can
water.
t he
same
prove
The
as
t his
t he
using
balanced
total
t he
mass
of
reaction
equation
for
t he
original
between
t he
and
oxygen
to
make
●
using
volumes
of
apply
the
concept
balanced
is:
using
2H
(g)

O
2
This
(g)
2H
2
molecules
on
a
reactant
chemical
to
equations
concentration
of
solutions.
O(g)
of
H

1
molecule
of
O
bigger
and
scale,
product.
2
molecules
of
H
2
t he
The
coefcients
equation,
O
2
show
t he
t herefore,
number
of
moles
of
each
means:
!
2 mol
of
H

1 mol
of
O
2
2 mol
of
2
H
we
now
take
t his
a
step
Key
O
fur t her
and
use
our
mole/mass
relationship,
Law
Matter
neither
means:
during
2(2

1) g
of
H

1(2

16) g
of
2
4 g
of
H
2
O
2[(2

1)

16)] g
of
2

32 g
fact
2
The
it
gases
2
2
f
mole
means:
2
Or,
equations
reactants.
hydrogen
reaction
chemical
of
O
H
Conservation
be
a
that
created
chemical
matter
nor
of
can
destroyed
reaction.
O
2
36 g
2
of
states
of
H
O
2
113
The
mole
and
chemical
reactions
The
We
can
total
We
clearly
mass
can
of
see
t he
use
t hat
t he
original
balanced
mass
of
reactants,
chemical
t he
water
hydrogen
equations
produced
and
to
is
oxygen,
determine
mole
t he
i.e.
t he
concept
same
as
t he
36 g.
quantities
of
unknown reactants and products in a reaction. f t he quantity of one reactant
or
product
ot her
is
known,
reactants
Mass
and
and
it
is
possible
to
calculate
t he
quantities
of
any
of
t he
products.
chemical
reactions
When answering questions involving masses of reactants and products, you will
always be given the mass of one reactant or product and be asked to determine
the
mass
of
another
reactant
or
product.
To
do
this
we
use
our
mole/mass
relationship and the mole ratio from the balanced equation for the reaction.
The
1)
steps
Calculate
its
given
one
2)
involved
Use
t he
t he
Use
1),
of
4)
t he
and
t he
Use
Note:
write
f
you
number
number
and
you
t he
its
have
and
have
been
moles
not
given
is
t he
in
t he
in
2),
of
t he
to
t he
equation
t he
mass
or
reactant
using
is
t he
you
are
product
t he
or
ratio
products.
The
calculating.
found
number
product
of
in
step
moles
found
in
mass
equation
before
product
product
mole
and/or
calculate
its
or
or
question.
reactant
unknown
follows:
reactant
whose
to
as
reactant
determine
determine
given
are
reactants
known
step
t he
one
product.
chemical
known
known
to
or
mass,
been
t he
unknown
found
reactant
of
of
problems
The
equation
t he
moles
of
mass.
product
ratio
molar
balanced
moles
molar
or
of
mole
of
mass–mass
chemical
known
unknown
3),
its
reactant
t he
t he
step
mass
t he
unknown
3)
and
balanced
between
solving
number
mass
whose
in
for
you
t he
begin
reaction,
your
you
must
calculation.
Examples
1
Calculate
t he
magnesium
mass
in
The
balanced
The
mass
2Mg(s)
of
excess
magnesium
equation

O
oxide
formed
by
burning
12 g
of
oxygen.
for
t he
(g)
reaction
is:
2MgO(s)
2
of
t he
magnesium
1)
Find
t he
reactant,
oxide,
is
number
Calculate
t he
to
of
magnesium
be
moles
molar
is
known.
The
mass
of
t he
product,
determined.
mass
of
of
Mg
using
its
mass
and
molar
mass:
Mg.
1
M(Mg)
i.e.

mass
24 g mol
1 mol
of
Mg

24 g
in
12 g
12
___
∴
number
of
moles
of
Mg

mol

0.5 mol
24
2)
Use
t he
balanced
between
2 mol
∴
3)
Mg
1 mol
Use
to
t he
and
form
Mg
Mg
chemical
2 mol
t he
equation
to
determine
t he
mole
ratio
MgO:
forms
number
calculate
0.5 mol
114
Mg
of
MgO.
1 mol
moles
number
forms
MgO
of
of
0.5 mol
Mg
from
moles
MgO
of
1),
and
MgO
t he
mole
produced:
ratio
from
2),
The
mole
4)
concept
Use
t he
The
number
determine
t he
of
moles
mass
of
of
MgO
MgO
from
3),
and
its
molar
mass,
mole
and
chemical
reactions
to
produced.
1
M(MgO)

24
i.e.
of
1 mol
∴
2
mass
mass
Determine
of
sodium
of
CO
2
The

of
0.5 mol
t he
mass
40 g mol
MgO
of
of

MgO
40 g

sodium
when
t he
0.5

40 g
carbonate
sodium

20 g
required
carbonate
to
equation
(s)

for
t he
reaction
mass
of
wit h
23.4 g
excess
2HCl(aq)
is:
2NaCl(aq)

CO
3
reactant,
produce
reacts
acid.
balanced
Na
16
chloride,
hydrochloric
The

(g)

H
2
t he
product,
sodium
sodium
carbonate,
is
chloride,
to
be
is
known.
O(l)
2
The
mass
of
t he
determined.
1
1)
M(NaCl)
i.e.

mass
23
of

35.5
1 mol

NaCl
58.5 g mol

58.5 g
23.4
_____
∴
number
of
moles
in
23.4 g

mol

0.4 mol
58.5
2)
1 mol
Na
CO
2
forms
2 mol
NaCl.
3
1
__
3)

0.4 mol
Na
CO
2
forms
0.4 mol
NaCl

0.2 mol
Na
3
CO
2
3
2
1
4)
M(Na
CO
2
i.e.
)

(2

23)

mass
of
1 mol
Na
CO
2
∴
3
mass
Determine
of
0.2 mol
t he
magnesium
The
12

(3

MgCO

decrease
carbonate
balanced
equation

0.2
in
is
(s)
t he
106 g mol
106 g

106 g
mass
heated
for
t he

t hat
21.2 g
would
until
its
reaction
MgO(s)

CO
occur
mass
when
remains
21.0 g
of
constant.
is:
(g)
2
decrease
nd

3
3
The
16)
3
in
mass
decrease
in
is
due
mass,
to
t he
t he
loss
mass
of
of
carbon
carbon
dioxide,
dioxide
t herefore,
produced
to
must
be
mass
of
determined.
The
t he
mass
of
t he
product,
reactant,
carbon
magnesium
dioxide,
is
to
be
carbonate,
is
known.
The
determined.
1
1)
M(MgCO
)

24

12

(3

16)

84 g mol
3
i.e.
mass
of
1 mol
MgCO

84 g
3
21.0
_____
∴
number
of
moles
in
21.0 g

mol

0.25
mol
84
2)
1 mol
MgCO
forms
1 mol
CO
3
3)
0.25 mol
2
MgCO
forms
0.25 mol
CO
3
2
1
4)
M(CO
)

12

(2

16)

44 g mol
2
i.e.
mass
of
1 mol
CO

44 g
2
∴
mass
of
0.25 mol
CO

0.25

44 g

11.0 g
2
Therefore,
We
four
can
also
t he
decrease
apply
t he
in
mass
mole
is
11.0 g
concept
to
ionic
equations
using
t he
same
steps.
115
The
mole
and
chemical
reactions
The
mole
concept
Example
Calculate
t he
mass
of
lead(II)
hydroxide
t hat
could
be
produced
when
a
solution containing 3.4 g of hydroxide ions reacts wit h a solution containing
excess
The
lead
ionic
ions.
equation
for
t he
reaction
is:
2
Pb
(aq)

2OH
(aq)
Pb(OH)
(s)
2
The
of
mass
t he
of
t he
product,
hydroxide
lead(II)
ions
present
hydroxide,
is
to
in
be
t he
solution
is
known.
The
mass
determined.
1
1)
M(OH
i.e.
)

mass
16
of

1
1 mol

17 g mol
OH
ions

17 g
3.4
____
∴
number
of
moles
in
3.4 g

mol

0.2 mol
17
2)
2 mol
OH
ions
form
1 mol
Pb(OH)
2
3)
0.2 mol
OH
4)
M(Pb(OH)
ions
form
0.1 mol
Pb(OH)
2
1
)

207

(2

16)

(2

1)

241 g mol

241 g
2
i.e.
mass
of
1 mol
Pb(OH)

241 g
2
∴
mass
of
0.1 mol
Pb(OH)

0.1

24.1 g
2
Gas
Exam
✔
volumes
used
must
pay
very
careful
the
conditions
under
to
determine
stp
or
the
involving
rtp,
to
correct
gases
ensure
value
unknown
and
volume
t he
of
mole
a
reactant
ratio
from
or
t he
product
using
balanced
t he
equation
t he
reaction.
occur,
that
for
t he
relationship
which
for
reactions
use
reactions
attention
mole/volume
i.e.
chemical
A balanced chemical equation for a reaction which involves gases can also be
You
to
and
tip
you
When
answering
questions
involving
volumes
of
gases,
use
t he
same
four
molar
steps
as
are
used
in
solving
mass–mass
problems.
volume.
Example
Nitrogen reacts wit h hydrogen to produce ammonia. Calculate t he minimum
3
volume of hydrogen t hat would be required to react completely wit h 6.0 dm
of
nitrogen
The
at
balanced
N
(g)

r tp.
equation
3H
2
The
t he
(g)
reaction
2NH
2
volume
reactant,
for
of
is:
(g)
3
t he
hydrogen,
reactant,
is
to
be
nitrogen,
is
known.
The
volume
of
t he
ot her
determined.
3
1)
Volume
of
1 mol
N
at
r tp

24 dm
2
6.0
____
3
∴
number
of
moles
in
6.0 dm

mol

0.25 mol
24
2)
1 mol
N
reacts
wit h
3 mol
H
2
3)
0.25 mol
2
N
reacts
wit h
3

0.25 mol
H
2

0.75 mol
H
2
2
3
4)
Volume
of
1 mol
H
at
r tp

24.0 dm
2
3
∴
volume
of
0.75 mol
H
at
r tp

0.75

24.0 dm
3

18.0 dm
2
Problems can also be solved involving bot h mass and volume using t he same
four
116
steps.
The
mole
concept
The
mole
and
chemical
reactions
Example
Calculate t he volume of sulfur trioxide gas formed at r tp when 9.6 g of oxygen
reacts
The
wit h
excess
balanced
2SO
(g)
sulfur
equation

O
2
dioxide.
for
t he
(g)
reaction
2SO
2
is:
(g)
3
The mass of t he reactant, oxygen, is known. The volume of t he product, sulfur
dioxide,
is
to
be
determined.
1
1)
M(O
)

32 g mol
2
i.e.
mass
of
1 mol
O

32 g
2
9.6
____
∴
number
of
moles
in
9.6 g

mol

0.3 mol
32
2)
1 mol
O
forms
2 mol
SO
2
3)
0.3 mol
3
O
forms
2

0.3 mol
SO
2

0.6 mol
SO
3
3
3
4)
Volume
of
1 mol
SO
at
r tp

24.0 dm
3
3
∴
volume
of
0.6 mol
SO
at
r tp

0.6

24.0 dm
3

14.4 dm
3
Molar
concentration
and
chemical
reactions
A balanced chemical equation for a reaction which involves a solution whose
volume
t he
and
mass
same
of
four
molar
t he
steps
concentration
ot her
as
reactant,
for
solving
or
are
t he
mass
known
mass
and
or
can
also
volume
volume
be
of
used
a
to
determine
product,
using
t he
problems.
Examples
3
1
To
prepare
t he
salt,
sodium
sulfate,
a
student
adds
50 cm
of
sodium
3
hydroxide
sulfuric
The
solution
acid.
wit h
Calculate
balanced
equation
2NaOH(aq)

H
a
t he
for
SO
2
The
are
volume
known.
and
The
3
1)
1000 cm
mass
t he
(aq)
sulfate
SO
2
t he
product,
t hat
to
excess
would
form.
of
(aq)

2H
4
t he
reactant,
sodium
O(l)
2
sulfate,
sodium
is
to
be
hydroxide,
determined.
3
(1 dm
1 cm
2.0 mol dm
is:
Na
concentration
of
of
sodium
reaction
)
NaOH(aq)
contains
2 mol
NaOH
2
_____
3
∴
of
4
molar
mass
concentration
NaOH(aq)
contains
mol
NaOH
1000
2
_____
3
and 50 cm
NaOH(aq) contains

50 mol NaOH

0.1 mol NaOH
1000
2)
2 mol
NaOH
forms
1 mol
Na
SO
2
4
1
__
3)
0.1 mol
NaOH
forms

0.1 mol
Na
SO
2

0.05 mol
4
Na
SO
2
4
2
1
4)
M(Na
SO
2
i.e.
mass
of
)

(2

23)
1 mol
Na
SO
2
∴
mass
of

32

(4

16)

142 g mol
4
0.05 mol

142 g
4
Na
SO
2

0.05

142 g

7.1 g
4
117
The
mole
and
chemical
reactions
The
2
What
volume
when
20 cm
reacts
wit h
of
carbon
dioxide,
measured
at
stp,
would
be
mole
concept
produced
3
The
(CO
2
)
is
(s)
acid
aluminium
equation
3
volume
acid,
hydrochloric
excess
balanced
Al
The
3
of

for
wit h
a
concentration
t he
reaction
6HCl(aq)
is:
2AlCl
(aq)

3CO
3
and
molar
The
concentration
volume
1.5 mol dm
carbonate?
3
known.
of
of
t he
of
t he
product,
(g)

3H
2
reactant,
carbon
O(l)
2
hydrochloric
dioxide
is
to
be
determined.
3
1)
1000 cm
HCl(aq)
contains
HCl.
1.5
_____
3
∴
1.5 mol
1 cm
contains
mol
HCl
1000
1.5
_____
3
and
20 cm
contains

20 mol
HCl

0.03 mol
HCl
1000
2)
6 mol
HCl
form
3 mol
CO
2
∴
2 mol
HCl
form
1 mol
CO
2
1
__
3)
0.03 mol
HCl
forms

0.03 mol
CO

0.015 mol
CO
2
2
2
3
4)
Volume
of
1 mol
CO
at
stp

22.4 dm
2
3
∴
volume
of
0.015 mol
CO
at
stp

0.015

0.336 dm

22.4 dm
2
3
Summary
1
Ethene
(C
H
2
according
C
H
2
If
2
2.8 g
)
burns
(g)
the
oxygen

following
3O
4
of
in
to
form
(g)
2CO
2
ethene
(g)
burn
in
excess
of
moles
in
b
calculate
the
number
of
moles
of
c
calculate
the
mass
d
calculate
the
volume
carbonate
calcium
Carbon
gas.
and
steam
of
carbonate
monoxide
the
carbon
of
is
gas
the
O(g)
2
2.8 g
of
ethene
dioxide
formed
formed
dioxide
into
mass
of
carbon
dioxide
carbon
decomposes
Calculate
Calculate
2H
oxygen,
number
heated.

2
the
of
dioxide
equation:
calculate
Calcium
carbon
4
to
a
when
3
questions
formed
calcium
carbon
at
oxide
dioxide
stp.
and
carbon
released
dioxide
when
300 g
heated.
reacts
volume
with
and
oxygen
mass
of
gas
to
carbon
form
carbon
monoxide
gas
dioxide
required
to
3
produce
4
4 dm
Potassium
of
carbon
carbonate
dioxide
reacts
with
gas
at
nitric
rtp.
acid
(HNO
)
to
produce
potassium
3
nitrate,
carbon
dioxide
and
water.
Calculate
the
mass
of
potassium
3
chloride
formed
when
40 cm
of
potassium
carbonate
solution
3
concentration
118
of
0.5 mol dm
reacts
with
excess
nitric
acid.
with
a
The
mole
Key
●
concept
mole
and
chemical
reactions
concepts
Relative
masses
of
The
a
atomic
of
carbon-12
●
Relative
●
A
mole
mass,
atoms,
is
t he
as
and
mass
and
formula
formula
units
mass
wit h
compare
one-twelf t h
t he
t he
mass
atom.
atomic
par ticles
molecular
molecules
mass,
molecular
amount
t here
are
of
a
mass
substance
atoms
in
and
t hat
12.00 g
of
formula
contains
mass
t he
have
same
no
units.
number
of
carbon-12.
23
●
The
number
A
vogadro’s
of
par ticles
number
or
in
a
mole
is
6.0

10
,
which
is
also
known
as
N
A
●
Molar
●
The
mass
molar
is
t he
mass
molecular
mass
mass,
of
an
or
in
grams,
element
formula
or
mass
of
one
mole
compound
amount
of
is
a
t he
substance.
relative
expressed
in
atomic
grams
per
mass,
mole.
1
Molar
●
mass
is
A
vogadro’s
conditions
given
law
of
t he
states
unit
t hat
temperature
g mol
equal
and
volumes
pressure,
of
all
gases,
contain
t he
under
same
t he
same
number
of
molecules.
●
Molar
molar
volume
volume
temperature
is
is
t he
t he
and
volume
same
occupied
for
all
gases
by
one
under
mole
t he
of
same
a
gas.
The
conditions
of
pressure.
3
●
Molar
volume
at
standard
temperature
and
pressure
(stp)
is
22.4 dm
3
●
Molar
●
The
volume
at
room
concentration
dissolved
in
a
xed
of
temperature
a
solution
volume
of
and
is
t he
a
pressure
measure
(r tp)
of
t he
is
24 dm
quantity
of
a
solute
solution.
3
●
Mass
concentration
gives
t he
mass
of
solute
dissolved
in
1 dm
of
3
solution.
●
Molar
Mass
concentration
concentration
gives
is
t he
given
t he
number
of
unit
g dm
moles
of
solute
dissolved
3
●
●
of
solution.
A
stand ard
A
standard
The
The
●
f
solution
t he
t he
of
atoms
t hen
formula
molar
of
a
mass
its
or
one
a
using
t he
a
t he
volumetric
gives
present
formula
by
is
unit
mol dm
known
accurately.
ask.
t he
gives
in
simplest
be
from
known,
t he
one
mass,
can
different
is
t he
mole
ratio
compound.
compound
compound
given
concentration
a
elements,
is
is
compound
in
of
empirical
t he
whose
element
compound
of
of
ions
each
of
concentration
made
formula
of
propor tions
known,
is
is
formula
atoms
molecular
moles
Molar
solution
empirical
between
●
in
3
1 dm
in
actual
mole
a
of
its
f
empirical
molecular
of
compound.
compound
determined.
t he
number
t he
are
t he
molecular
formula
formula
and
can
t he
be
determined.
●
The
by
●
percentage
mass,
The
L aw
created
●
The
of
element
in
a
product
ot her
and
is
a
chemical
t he
known,
states
chemical
can
it
and
indicates
t he
percentage,
t hat
matter
can
neit her
be
reaction.
equation
give
t he
mole
ratios
products.
products
reactants
compound
compound.
Matter
a
equations
reactants
or
of
balanced
and
of
t he
during
reactants
chemical
t he
in
Conservation
t he
unknown
reactant
composition
destroyed
coefcients
Balanced
any
each
of
nor
between
●
of
is
be
in
used
a
to
determine
reaction.
possible
to
f
t he
quantities
quantity
calculate
t he
of
of
one
quantities
of
products.
119
Practice
exam-style
questions
The
b
Practice
exam-style
Calcium
hydrogencarbonate
Ca(HCO
)
3
questions
(s)

The
2HNO
mass
of
0.25 mol
of
potassium
carbonate
t he
following
nitric
an
(aq)
Ca(NO
)
3
investigation
in
t he
(aq)

2CO
2
(g)

B
34.5 g
C
38.5 g
O(l)
2
a
student
is:
i)
8.1 g
of
calcium
hydrogencarbonate
to
excess
acid.
Determine
t he
number
hydrogencarbonate
D
of
used
moles
by
t he
of
calcium
student.
552.0 g
(2
A
2H
2
laborator y,
24.75 g
nitric
2
acid
equation:
3
added
A
to
2
During
1
wit h
concept
questions
according
Multiple-choice
reacts
mole
mass
of
32 g
of
ii)
oxygen:
Determine
23
A
contains
6.0

B
contains
2 mol
C
contains
6.0
D
contains
t he
oxygen
10
of
dioxide
atoms
iii)
oxygen
35.5 g
of
10
molecules
same
number
of
of
at
oxygen
molecules
of
oxygen
c
as
of
moles
of
marks)
carbon
(2
t he
volume
of
carbon
dioxide
r tp.
marks)
made
(1
Magnesium
produce
chlorine
number
made.
Determine
23

t he
reacts
wit h
magnesium
hydrochloric
chloride
and
acid
mark)
to
hydrogen.
n
3
anot her
investigation,
a
student
reacted
20 cm
3
3
What
is
t he
A
0.88 g
B
224 g
C
448 g
D
880 g
mass
of
448 cm
of
carbon
dioxide
at
stp?
of
hydrochloric
acid
wit h
a
concentration
of
3
1.5 mol dm
i)
Write
a
wit h
excess
balanced
magnesium.
chemical
equation
for
t he
reaction.
ii)
(2
Calculate
acid
t he
number
of
moles
of
marks)
hydrochloric
used.
(1
mark)
3
4
You
are
required
to
make
250 cm
of
a
solution
of
iii)
sodium
hydroxide
which
has
a
concentration
Determine
t he
number
of
moles
of
magnesium
of
chloride
produced.
(2
marks)
3
0.1 mol dm
.
What
mass
of
sodium
hydroxide
would
iv)
you
need
to
weigh
Calculate
t he
mass
of
magnesium
chloride
out?
produced.
A
(2
d
B
1.0 g
C
4.0 g
On
analysis
24.45 g
of
empirical
D
a
compound
iron
and
formula
was
10.55 g
of
t he
found
of
to
oxygen.
contain
Determine
compound.
A
t he
(2
marks)
15
marks
25.0 g
Total
5
marks)
0.1 g
compound
W
combined
of
W
is
of
t he
40
was
found
wit h
and
t he
7 g
of
to
consist
Z.
relative
f
t he
of
30 g
relative
atomic
mass
of
element
atomic
of
Z
is
mass
14,
Extended
8
following
is
t he
correct
empirical
formula
response
question
which
for
a
i)
What
do
you
understand
by
t he
term
‘standard
t he
solution’?
(1
mark)
compound?
3
ii)
A
WZ
B
W
You
wish
to
carbonate
prepare
solution
250 cm
of
of
potassium
concentration
Z
2
3
0.8 mol dm
C
W
t he
laborator y.
Determine
3
mass
W
of
potassium
carbonate
required.
Z
3
2
(3
6
Hydrogen
reacts
wit h
oxygen
according
to
t he
iii)
following
Name
make
equation:
2H
(g)

O
2
(g)
2H
2
b
O(g)
A
volume
oxygen
of
reacts
steam
wit h
could
excess
8.96 dm
12.8 dm
C
17
.92 dm
D
25.6 dm
apparatus
solution
wishes
be
produced
at
stp
if
lead(II)
to
you
would
in.
make
a
marks)
use
(1
sample
of
t he
to
mark)
chloride,
in
t he
laborator y.
insoluble
Determine
12.8 g
mass
reacting
B
of
of
lead(II)
chloride
which
could
be
made
by
hydrogen?
3
A
piece
your
student
t he
of
t he
2
salt,
What
t he
Z
2
D
in
wit h
3
a
a
solution
solution
containing
containing
excess
23.4 g
of
lead()
sodium
nitrate
chloride.
(6
3
marks)
3
c
Ammonium
extensively
wit h
Structured
question
in
t he
This
question
is
concerned
wit h
t he
mole
and
by
By
in
and
ammonium
gardeners
nitrogen
growt h.
nitrogen
7
nitrate
t hey
as
each
of
t he
fer tilisers
need
calculating
sulfate
to
t he
make
to
supply
protein
percentage,
fer tilisers,
are
by
determine
used
plants
for
use
mass,
of
which
its
would
be
t he
better
value
for
money
if
t hey
bot h
cost
application.
t he
a
Give
a
denition
for
t he
term
‘mole’.
(1
same
per
kilogram.
marks)
15
marks
mark)
Total
120
(4
A8
The
concept
of
Acids,
acids,
bases
and
salts
bases
has
been
and
salts
around
Objectives
for
As
a
very
our
long
time;
knowledge
as
of
early
as
the
chemistry
has
17th
century.
developed,
By
the
be
able
●
classification
of
a
compound
as
an
acid,
a
end
base
or
a
salt
explain
when
has
been
refined.
Acids,
bases
and
salts
are
used
in
of
our
lives.
Properties
was
have
not
always
and
until
somet hing
substance
a
in
few
known
hundred
common,
t hat
reacts
reactions
t hat
a
vinegar
years
t hey
wit h
of
acids
●
ago
bot h
base
and
t hat
contain
to
form
a
it
lemon
was
acids.
salt
juice
taste
discovered
An
and
acid
sour,
t hat
can
be
but
t hese
it
in
t heir
anhydrous
an
give
you
ionisation
acid
have
dened
as
a
form,
i.e.
not
dissolved
●
water.
in
the
in
in
acids
describe
the
acids
will
of
acids
water
terms
of
are
composed
with
properties
reactive
carbonates,
and
describe
which
the
can
dene
of
reactions
hydrogencarbonates
acids
water,
general
aqueous
metals,
●
Acids
the
dissolved
dene
of
People
topic
protons
●
A8.1
this
all
●
aspects
of
to:
the
be
acid
ways
in
bases
classied
anhydride
and
give
of
examples
of
acid
anhydrides
covalent molecules and t hey may be solid, liquid or gas at room temperature.
●
Solids
include
citric
acid,
tar taric
acid
and
ascorbic
acid
(vitamin
C).
give
examples
of
acids
in
living
Liquids
systems.
include
sulfuric
acid
and
nitric
acid.
Gases
include
hydrogen
chloride
All acids have hydrogen in t heir formulae, e.g. nitric acid, HNO
gas.
and sulfuric
3
acid,
H
SO
2
.
Table
8.1.1
gives
t he
names
and
formulae
of
some
common
4
acids.

T
able
8.1.1
Some
Name
acid
HCl
acid
H
SO
2
nitric
acids
Formula
hydrochloric
sulfuric
common
acid
4
HNO
3
phosphoric
acid
H
PO
3
methanoic
ethanoic
acid
4
HCOOH
acid
CH
COOH
3
(a)

Figure
(b)
8.1.1
(a)
Some
common
laboratory
acids,
(b)
some
common
household
acids
121
Properties
and
reactions
of
acids
Acids,
Ionisation
When
an
of
acid
is
acids
added
in
to
bases
and
salts
water
water,
t he
acid
molecules
ionise,
i.e.
t hey
for m

ions.
Acids
always
ionise
to
for m
hyd rogen
ions ,
or
H
ions,
and
negative

anions.
The
H
ions
t hen
become
att ac hed
to
t he
polar
water
molecules

for ming
hyd ronium
ions
or
H
O
ions
(sometimes
called
hydroxonium
3
ions).
Using
an
t he
ionisation
of
hydrogen
chloride
gas
to
form
hydrochloric
acid
as
example:

HCl(g)
water

H
(aq)

H

(aq)
H

O(l)
H
2
(aq)
O
(aq)
3
hydronium
t he
Cl

overall
reaction
can
be
summarised
ion
as:

HCl(g)

H
O(l)
H
2
For
simplicity,
it
O
(aq)

Cl
(aq)
3
is
usual
to
represent
t he
reaction
as
follows:
in
water

HCl(aq)
Ot her
examples
t hat
H
show
t he
(aq)

Cl
ionisation
(aq)
of
acids
are:

HNO
(aq)
H
(aq)

NO
3
(aq)
3

H
SO
2
(aq)
2H
2
(aq)

SO
4
(aq)
4

H
PO
3
(aq)
3H
3
(aq)

PO
4
(aq)
4

CH
COOH(aq)
CH
3
COO
(aq)

H
(aq)
3
1
A hydrogen atom,
H, has one proton in its nucleus and one electron spinning
1
around
single
!
Key
proton
electron,
acid
is
nucleus
in
since
it
t he
is
rst
energy
formed
by
a
shell.
A
hydrogen
hydrogen
atom
ion
losing
is,
its
t herefore,
one
a
valence
fact
an
An
t he
a
proton
acid
leaving
to
only
donate
its
t he
nucleus
hydrogen
containing
ions,
or
t he
protons,
one
to
proton.
anot her
The
ability
reactant
can
of
be
donor.
used
to
When
dene
an
dissolves
an
an
acid
in
aqueous
acid
as
reacts,
water,
can
solution
being
t he
be
of
a
proton
hydrogen
given
to
donor.
ions,
t he
hydroc hlor ic
ot her
acid
or
protons,
react ant.
reacts
for med
For
wit h
when
example,
sodium
it
when
hydroxide,

t he
hydroc hlor ic
acid
gives
its
H
ions,
or
protons,
to
t he
OH
ions
of
t he
sodium hydroxide, for ming water. This can be summar ised by t he following
ionic
equation:

OH
(aq)

H
(aq)
H
O(l)
2
General
properties
of
aqueous
acids

The
presence
of
H
ions
in
aqueous
solution
gives
acids
t heir
proper ties. Aqueous solutions of acids are described as being
have
122
t he
following
●
t hey
have
a
●
t hey
change
●
t hey
have
a
sour
common
taste
blue
pH
proper ties:
litmus
value
of
to
red
less
t han
7
characteristic
acid ic
and t hey
Acids,
bases
and
salts
Properties
●
t hey
are
corrosive
●
t hey
are
electrolytes,
Chemical
Since
all
in
a
an
The
ions
salt.
acid
A
is
t he
is,
of
except
nitric
Reactive
of
(see
metals
aluminium,
This
can
reactive
When
as
produce
t
is
heat,
acid
dioxide
is
i.e.
impor tant
nitric
be
to
(NO
),
are
and
wit h
an
current.
aqueous
n
metal
all
ions
formed
detail
solution,
of
or
t hese
acids
t he
have
reactions,
ammonium
when
ammonium
t he
ions
hydrogen
to
ion
ion.
below.
reactive
above
metals
to
hydrogen
potassium,
by
t he
acid
sodium,
following
salt
wit h
and
reactions
it
acids,
t he
are
t hat
metals
not
in
t hose
i.e.
react
wit h
or
acids
in
produce
t he
a
salt
reactivity
calcium,
and
series
magnesium,
lead.
evolved,
and
ion
react
remember
reacts
in
compound
summarised
t he
by
of
acids
reactants.
replaced
a
electric
reactions
metals
18.1),

an
when
ot her
discussed
acid,
iron
ions
metal
metals
metals
gas
a
are
metal
reactive
hydrogen
by
conduct
aqueous
t herefore,
Unit
zinc,
reaction
are
reactive
hydrogen.
of
cer tain
acid
acids
with
t hey
hydrogen
wit h
replaced
react
Acids,
in
salt
reactions
Acids
form
reactions
hydrogen
form
reactions
acids
common
i.e.
and

effervescence
described
acid
produces
word
equation:
hydrogen
reactions
nitric
general
as
become
being
does
not
oxides
of
(bubbling)
hotter
is
seen
because
t hey
exothermic
react
in
t his
nitrogen,
way.
e.g.
When
nitrogen
hydrogen.
2
Example
Magnesium
reacts
wit h
sulfuric
acid
to
produce
magnesium
sulfate
and
hydrogen:
Mg(s)

H
SO
2
The
ionic
(aq)
MgSO
4
equation
for
t his
reaction

Mg(s)

2H
(aq)

H
4
(g)
2
is:
2
(aq)
Mg
(aq)

H
(g)
2
Acids
react
with
metal
carbonates
and
hydrogencarbonates
Acids react wit h metal carbonates and metal hydrogencarbonates to produce
a
salt,
carbon
dioxide
and
water.
These reactions can be summarised by the following general word equations:
carbon
metal
carbonate

acid
salt


water

water
d ioxide
metal
carbon

acid
salt
hydrogencarbonate
When
metal
effervescence
carbonates
is
seen
as

d ioxide
and
carbon
hydrogencarbonates
dioxide
gas
is
react
wit h
acids,
evolved.
123
Properties
and
reactions
of
acids
Acids,
bases
and
salts
Examples
1
Potassium
nitrate,
K
CO
2
The
carbonate
carbon
reacts
dioxide
(aq)

2HNO
3
ionic
wit h
and
nitric
(aq)
2KNO
for
2
t his
(aq)

2H
reaction
(aq)
CO
(g)

H
O(l)
2
is:
CO
hydrogencarbonate
chloride,
)
3
ionic

2
(g)

H
2
Ca(HCO
The
potassium

(aq)
calcium
produce
3
3
Calcium
to
3
equation
CO
2
acid
water:
carbon
(aq)

reacts
dioxide
wit h
and
O(l)
2
hydrochloric
acid
2HCl(aq)
CaCl
2
(aq)

2CO
2
equation
for
t his
reaction
to
produce
water:
(g)

2H
2
O(l)
2
is:

HCO
(aq)

H
(aq)
CO
3
Acids
Did
?
you
know?
Acids
react
react
with
Any
reactive
metals,
that
react
salts
the
and
with
appear
salt
insoluble
acids
to
to
O(l)
2
bases
to
reactions.
produce
t
is
a
salt
impor tant
and
to
water.
note
t hat
These
are
base
a
a
is
known
metal
a
metal
hydroxide.
soluble
because
These
reactions
can
be
summarised
by
t he
following
general
word
equations:
dissolves.
metal
metal
When
bases
oxide
hydroxide
react
exothermic
wit h


acid
salt
acid
acids,
t he

salt
reactions
water

water
become
warmer
because
t hey
reactions.
Examples
1
Copper(II)
and
oxide
reacts
wit h
sulfuric
acid
to
produce
copper(II)
sulfate
water:
CuO(s)

H
SO
2
onic
(aq)
CuSO
4
(aq)

H
4
O(l)
2
equation:

CuO(s)

2H
2
(aq)
Cu
(aq)

H
O(l)
2
✔
Exam
tip
extremely
important
n
t his
and
It
is
that
a
reaction,
blue
t he
solution
black
copper(II)
forms.
This
is
oxide
because
appears
soluble
to
dissolve
copper(II)
slowly
sulfate
is
you
2
can
write
balanced
equations
acids.
good
word
so
T
o
for
help
idea
to
the
you
products
for
to
do
memorise
given
know
each
produced
chemical
reactions
you
equations
that
the
the
in
it
is
a
general
this
of
the
must
also
common
learn
the
t he
solution
contains
blue
2
Sodium
hydroxide
chloride
and
ions.
reacts
wit h
hydrochloric
acid
to
produce
water:
NaOH(aq)

HCl(aq)
NaCl(aq)
formulae

H
O(l)
2
reaction.
equation:
of
acids.

OH
(aq)

H
(aq)
H
O(l)
2
124
Cu
section
general
type
and
of
this,
onic
You
as
oxide
bases
form
dissolve
produced
H
insoluble
or
carbonates

bases
wit h
neutralisation
(g)
2
sodium
are
Acids,
bases
and
salts
Investigating
Your
teacher
Properties
reactions
may
use
this
of
observation,
recording
●
analysis
interpretation.
Y
ou
will
be
copper(II)
acid,
and
supplied
with
carbonate,
nitric
acid,
and
lime
water,
of
acids
to
assess:
reporting
magnesium
calcium
reactions
acids
activity
●
and
ribbon,
hydroxide,
test
tubes
zinc,
copper( II)
and
a
sodium
oxide,
wooden
hydrogencarbonate,
hydrochloric
acid,
sulfuric
splint.
Method
1
Reactions
between
an
acid
and
metals:
2
a
Place
2 cm
of
magnesium
if
b
it
of
a
2
Repeat
Reaction
Observe
splint
gas.
pop
the
acid
the
in
a
test
tube
reaction.
Feel
and
the
add
a
piece
bottom
of
of
the
tube
to
see
hotter.
burning
hydrogen
squeaky
c
ribbon.
becomes
Place
hydrochloric
If
and
at
the
ame
experiment
between
an
the
mouth
hydrogen
is
will
using
acid
and
be
a
a
of
being
the
test
tube
produced,
to
the
test
for
splint
the
will
presence
make
a
extinguished.
small
piece
of
zinc.
hydrogencarbonate:
delivery
tube
3
a
Place
2 cm
of
sulfuric
acid
in
a
test
cork/bung
tube
and
add
a
spatula
hydrogencarbonate.
of
test
tube
sodium
Observe
the
reaction.
b
Cork
the
running
test
tube
through
with
the
a
delivery
cork
into
a
tube
test
tube
dilute
sulfuric
of
colourless
Figure
8.1.2,
lime
to
water,
test
for
as
the
shown
acid
in
presence
lime
sodium
of
carbon
dioxide.
If
carbon
dioxide
(calcium
hydrogencarbonate
is
water
hydroxid
solution)
being
produced,
a
white
precipitate
will

form
in
the
lime
Figure
sulfuric
3
Reaction
between
8.1.2
Reaction
between
water.
an
acid
and
a
acid
and
sodium
hydrogencarbonate
carbonate:
3
a
Place
and
4
2 cm
add
b
T
est
c
Observe
for
Reactions
a
of
sulfuric
spatula
the
of
presence
any
colour
between
an
acid
in
a
copper( II)
of
test
carbon
changes
acid
and
tube
carbonate.
dioxide
Observe
as
occurring
in
step
during
the
the
reaction.
2
reaction.
bases:
3
a
Place
2 cm
hydroxide.
tube
b
to
Repeat
the
5
Record
for
Write
7
Explain
a
if
it
all
your
any
time
any
in
tube
felt
colour
a
the
spatula
tube
and
add
the
a
spatula
reaction.
Feel
of
calcium
the
bottom
of
the
of
copper( II)
periodically
oxide
until
no
instead
further
of
calcium
changes
changes.
for
each
equation
changes
steps
tube
observe
reaction,
including
the
results
of
the
tests
dioxide.
chemical
in
test
and
using
shake
carbon
a
hotter.
observations
and
colour
you
the
experiment
balanced
changes
acid
becomes
This
Observe
hydrogen
6
nitric
Shake
see
hydroxide.
occur.
of
you
1a
for
each
observed
and
in
reaction.
steps
3c
and
4b,
and
any
heat
4a
125
Properties
and
reactions
of
acids
Acids,
During
and
f
t he
experiment,
carbon
dioxide
hydrogen
is
you
learnt
how
to
test
for
t he
bases
presence
of
and
salts
hydrogen
gases.
produced
in
a
reaction,
it
causes
a
burning
splint
to
make
a
squeaky pop and to be extinguished. The ‘pop’ is t he sound of a small explosion
as
t he
hydrogen
2H
(g)

O
2
f
carbon
(g)
2H
is
lime
calcium
produced
water.
hydroxide,
and
(aq)

Acids
can
be
Inorganic
●
of
compounds
geological
do
not
origin.
contain
exceptions
Organic
of
and
●
carbon
compounds
biological
and
contain
animals.
carbon
to
form
steam:
a
reaction,
is
because
carbon
and
dioxide
water.
it
forms
t he
reacts
The
a
lime
white
water
wit h
calcium
precipitate
is
t his
a
when
solution
forming
carbonate
of
white,
forms
t he
(g)
CaCO
of
and
(s)

H
3
O(l)
2
acids
in
organic
a
variety
of
ways.
acids
and
be
classied
as
acid
inorganic
contains
a
acids
or
organic
non-met allic
acids.
element
origin,
They
e.g.
as
well
as
Most
organic
acids
it
are
hydrogen.
Examples
of
inorganic
or
polyatomic
acids
are
given
in
8.1.2.
is
t he
acids
contain
hydrogen
at
t he
t he
carboxyl
end
of
t he
group,
i.e.
carboxyl
COOH.
group
n
t hese
which
forms
t he

ion
when
t he
acid
dissolves
in
water.
Examples
of
organic
acids
are
from
given
plants
t he
CO
classied
inorganic
Table
the
H
mainly
can
An
g roup
carbonates,
hydrogencarbonates
dioxide.
air
are
Most
carbon,
being
t he
know?
Acids
Inorganic
in
2
Classification
?
in
O(g)
This
carbonate
2
you
oxygen
precipitate:
Ca(OH)
Did
wit h
2
d ioxide
into
insoluble
white
explosively
2
bubbled
calcium
reacts
in
Table
8.1.3.
always
most
contain

T
able
8.1.2
Common
inorganic
acids

T
able
8.1.3
Common
organic
acids
hydrogen.
Acid
hydrochloric
nitric
acid
acid
Formula
Acid
HCl
methanoic
HNO
ethanoic
3
sulfuric
acid
H
phosphoric
acid
H
acid
lactic
4
acid
H
acid
H
dibasic
COOH
CH
CH(OH)COOH
acid
C
H
6
citric
acid
C
O
8
H
6
6
O
8
7
3
CO
2
Monobasic,
CH
SO
2
carbonic
acid
acid
ascorbic
4
HNO
2
sulfurous
HCOOH
3
PO
3
nitrous
acid
3
SO
2
Formula
3
and
tribasic
acids

Acids
!
Key
fact
per
can
also
molecule
be
classied
when
according
dissolved
in
to
water,
t he
number
known
as
of
t heir
H
ions
t hey
produce
basicity.


Basicity
is
produced
when
it
the
per
number
molecule
dissolves
in
of
of
H
●
A
monobasic
acid
produces
one
H
ion
per
molecule
when
it
dissolves
ions
in
acid
water.
Hydrochloric
acid
(HCl),
nitric
acid
(HNO
)
and
et hanoic
acid
3
(CH
water.
COOH)
are
examples
of
monobasic
acids.
3

●
A
d ibasic
water.
acid
Sulfuric
produces
acid
(H
two
SO
2
)
H
is
ions
an
per
molecule
example
of
a
when
dibasic
it
dissolves
in
acid.
4

●
A
tribasic
water.
acid
produces
Phosphoric
acid
t hree
(H
PO
3
126
H
)
4
is
ions
an
per
molecule
example
of
a
when
tribasic
it
dissolves
acid.
in
Acids,
bases
Dilute
Acids
A
●
and
can
and
salts
Properties
concentrated
also
d ilute
be
acid
one
reactions
of
acids
acids
classied
is
and
based
t hat
on
t he
contains
a
quantity
lot
of
of
water,
water
e.g.
Did
?
present.
hydrochloric
you
know?
acid,
A
concentrated
acid
is
always
3
which
has
a
concentration
A concentrated acid
●
of
0.1 mol dm
,
is
dilute.
diluted
to
is one that contains very little water, e.g. hydrochloric
3
on
reaction
i.e.
Strong
and
weak
the
can
when
t he
also
be
A
●
strong
acid
A
●
weak
e.g.
We
and
is
classied
be
is
fully
sulfuric
acid
is
carbonic
will
dissolved
acid
based
on
t he
degree
of
ionisation
t hat
a
is
slowly
When
lot
to
of
an
acid
water
,
heat
the
energy
,
exothermic.
spattering
ionised
slowly
when
dissolved
in
water,
e.g.
only
at
can
This
be
of
hydrochloric
to
water
If
the
can
the
acid
water
,
is
the
absorb
added
larger
the
heat
volume
energy
produced.
par tially
and
and
occurs
water.
acid.
acid
looking
in
ionised
et hanoic
strong
and
when
dissolved
in
water,
acid.
weak
acids
in
more
detail
in
Unit
8.3.
Key
!
Acid
acid
added
off
reaction
cause
dangerous.
acid
water
.
being
gives
the
acids
can
Acids
adding
distilled
ionises
, is concentrated.
acid, which has a concentration of 12 mol dm
the
by
fact
anhydrides
An
Cer tain
compounds
react
wit h
water
to
form
an
acid.
These
are
known
acid
which
as
anhydride
reacts
with
is
a
compound
water
to
form
an
acid.
acid
anhydrides
Acid anhydride literally means ‘an acid wit hout water’. Many acid anhydrides
are
acidic
oxides
of
non-metals.
Carbon
dioxide
(CO
),
sulfur
dioxide
2
(SO
),
sulfur
trioxide
(SO
2
)
and
nitrogen
dioxide
(NO
3
)
are
examples
of
acid
Did
?
2
you
know?
anhydrides:
Nitrogen
CO
(g)
2

H
O(l)
H
2
CO
2
in
carbonic
the
(g)
2

H

H
O(l)
H
2
SO
2
(g)
3
O(l)
H
2
SO
2
acid
When
in
(aq)
the
H
O(l)
HNO
2
it
(aq)

HNO
2
it
rain
can
buildings
acid
nitric
water
living
to
with
come
some
Table

of
across
t hese
variety
in
of
our
8.1.4
Acid
acid
vitamin
H
O
8
acids
ever yday
Acids
in
living
C
In
many
fruits,
foods,
West
)
sweet
Methanoic
In
acid
ant
(HCOOH)
Important
e.g.
Indian
citrus
A
shortage
Lactic
acid
O
of
calcium
dissolve
them
to
It
acidic
make
as
it
can
for
soluble
also
certain
make
organisms.
These
are
We
also
to
aquatic
survive.
use
summarised
in
peppers,
to
vitamin
note
C
to
heat,
in
e.g.
the
diet
during
can
lead
cooking,
to
scurvy.
vitamin
the
leafy
C
is
destroyed
by
being
oxidised.
tomatoes,
)
hydrogencarbonate
is
sometimes
added
to
fruits
and
vegetables
to
improve
their
appearance
and
vegetables
venom
of
bee
and
texture.
This
neutralises
Causes
itching,
any
redness,
vitamin
swelling
C
and
present,
pain
reducing
around
the
the
vitamin
C
content.
sting.
stings
Produced
during
in
muscle
strenuous
cells
If
can
be
treated
by
hydrogencarbonate.
too
much
lactic
acid
applying
These
builds
a
paste
both
up
it
of
sodium
neutralise
prevents
the
hydrogencarbonate
or
calamine
lotion
which
contains
acid.
muscles
from
contracting
and
the
person
collapses.
activity
3
Ethanoic
(CH
living
points
of
exposure
zinc
6
made
slowly
cherries,
Stings
H
in
activities.
Sodium
3
This
statues
6
green
(C
cause
systems
On
6
vapour
rain.
systems
organic
Occurrence
Ascorbic
(C
the
8.1.4.
T
able
or
a
acids
then
nitrate.
too
organisms
We
water
acid
in
vehicles.
acid
calcium
in
with
forms
present
motor
(aq)
reacts
acids
also
of
3
nitrous
of
is
reacts
air
carbonate
Examples
it
fumes
acid
and
2

naturally
lightning
4
sulfuric
(g)
and
exhaust
acid
2NO
made
when
acid
(aq)
3
sulfurous
SO
is
atmosphere
occurs
SO
dioxide
(aq)
3
acid
COOH)
In
vinegar
Vinegar
is
enzymes
used
that
to
preserve
cause
decay
food
and
items.
inhibits
Being
the
acidic,
growth
of
it
has
a
low
bacteria
pH,
and
which
denatures
(destroys)
the
fungi.
3
127
Properties

T
able
and
8.1.4
bases
Acids,
Occurrence
Citric
acid
H
6
of
O
8
In
citrus
fruits,
Important
e.g.
limes
Lime
)
(Fe
7
juice
O
2
)
in
points
is
used
the
rust
to
to
O
2
stains
rust
making
(s)

3
6H
stains
a
from
soluble
clothes.
Summary
Write
and
the
Give
three
4
Give
the
5
terms
Write
balanced
reaction
b
the
reaction
c
the
reaction
7
Why
does
is
and
‘acid
show
how
other
that
are
than
the
be
able
chemical
zinc
work
for
aluminium
to
preserve
hydrogencarbonate
a
an
2Fe
the
stain
acids
ionise
of
with
the
the
iron(
III)
oxide
clothes:
(aq)

3H
O(l)
removed
when
placed
in
water:
sulfuric
acid,
hydrochloric
acid
topic
you
base
in
terms
of
are
typical
of
aqueous
acids.
with:
following:
and
hydrochloric
sulfuric
some
used
of
as
a
acid
and
nitric
acid
acid.
the
A8.2
this
which
react
hydrogencarbonate
foods
we
treatment
eat?
for
ant
Properties
stings?
and
reactions
of
bases
will
base
and
dene
acids
the
and
A
dene
reacts
out
carbonates.
magnesium
between
vinegar
of
●
juice
acid
reactions,
when
hydroxide
to:
●
lime
washed
3
(aq)
from
following
their
equations
between
between
sodium
end
the
b
Objectives
By
the
be
anhydride’.
formed
oxides
the
How
which
properties,
a
6
‘acid’
products
metal
in
can
acid.
3
a
acid
which
questions
equations
nitric
The
compound
2
oxide
(rust)
2
salts
note
remove

Fe
Dene
and
3
iron(III)
1
bases
(continued)
Acid
(C
reactions
can
be
water.
dened
Bases
are
as
a
substance
normally
metal
which
oxides
reacts
and
wit h
metal
an
acid
to
form
hydroxides.
a
salt
However,
protons
ammonia
is
also
classied
as
a
base.
Examples
of
bases
include
magnesium
alkali
oxide
(MgO),
copper(II)
oxide
(CuO),
magnesium
hydroxide
(Mg(OH)
)
and
2
give
●
the
general
properties
of
copper(II)
hydroxide
(Cu(OH)
).
2
●
aqueous
alkalis
describe
the
with
acids
●
dene
●
classify
an
reactions
and
of
bases
ammonium
amphoteric
oxides
into
salts
substance
acidic,
You
learnt
protons
t he
acid
and
Unit
t he
and
8.1
base,
t his
fact
t hat
when
forming
can
be
a
base
water.
used
to
reacts
The
wit h
base
dene
a
has
base
an
acid,
accepted
as
a
t he
t he
proton
acid
donates
protons
from
acceptor.
basic,
Using
amphoteric
in
to
t he
same
example
as
in
Unit
8.1,
when
hydrochloric
acid
reacts
wit h
neutral.

sodium
ions,
by
or
t he
hydroxide,
protons,
following
t he
from
ionic
OH
t he
ions
of
t he
hydrochloric
sodium
acid
hydroxide
forming
water,
accept
as
t he
H
summarised
equation:

Key
!
A
base
is
OH
fact
a
Key
proton
acceptor.
in
alkali
water
(aq)
H
O(l)
bases
known
as
or
ions.
OH
are
soluble
alkalis.
When
in
water,
t hey
ot hers
dissolve
in
are
insoluble.
water,
t hey
a
base
form
a
which
dissolves
solution
common
hydroxide
(Ca(OH)
),
alkalis
(NaOH),
which
is
include
which
are
potassium
fully
moderately
soluble
soluble.
hydroxide
in
For
water,
OH
ions.

NaOH(s)
128
bases
hydroxide

water
Na
(aq)

OH
(aq)
(KOH)
and
example:
2
containing
Soluble
form
are
ions,
fact
is
to
H
Alkalis
The
An

2
Some
!
(aq)
and
calcium
sodium
hydroxide
Acids,
bases
and
salts
Properties
and
reactions
of
bases
When ammonia gas is added to water it reacts wit h water to form ammonium
hydroxide
(NH
OH),
which
is
also
an
alkali:
4

NH
(g)

H
3
O(l)
NH
2
Potassium
oxide
(aq)

OH
O),
sodium
oxide
(Na
2
react
wit h
water
(aq)
4
(K
to
O)
and
calcium
oxide
(CaO)
also
2
form
t he
equivalent
hydroxide.
For
example:

Na
O(s)

H
2
Like
on
●
acids,
t he
A
alkalis
degree
strong
A
weak
e.g.
of
2Na
can
be
classied
ionisation
alkali
hydroxide
●
O(l)
(aq)

2OH
(aq)
2
and
alkali
is
fully
sodium
is
only
t hat
into
strong
occurs
ionised
when
when
alkalis
t he
and
alkali
dissolved
in
is
weak
alkalis
dissolved
water,
e.g.
in
based
water.
potassium
hydroxide.
par tially
ionised
when
dissolved
in
water,
ammonia.

We
will
be
looking
at
strong
and
weak
alkalis
in
more
detail
in
Unit
Figure
8.2.1
These
products
contain
8.3.
bases
General
properties
of
aqueous
alkalis
The presence of OH
ions in aqueous solution gives alkalis t heir characteristic
proper ties.
solutions
t hey
have
Aqueous
t he
following
●
t hey
have
●
t hey
change
a
●
t hey
have
●
t hey
are
corrosive
●
t hey
are
electrolytes,
●
t hey
feel
a
bitter
red
pH
Chemical
alkalis
are
described
as
being
alkaline
and
proper ties:
taste
litmus
value
soapy
of
common
to
of
i.e.
when
blue
more
t hey
t han
7
conduct
an
electric
current
touched.
reactions
of
bases
Since bases contain oxide or hydroxide ions, bases have common reactions with
certain other reactants. The reactions of bases are discussed in detail below.
Bases
Bases
react
react
These
with
wit h
acids
reactions,
following

Remember
to
which
general
base
acids
word
produce
you
looked
salt
when
salt
at
and
in
water.
Unit
8.1,
can
be
summarised
by
t he
equation:
acid
t hat
a
bases

water
react
wit h
acids,
t he
reactions
become
warmer
because t hey are exot hermic reactions. Also, any insoluble bases which react
to
produce
soluble
salts,
appear
to
dissolve.
Examples
1
Magnesium
chloride
oxide
and
MgO(s)
reacts
wit h
hydrochloric
acid

2HCl(aq)
MgCl
(aq)

H
2
onic
to
produce
magnesium
water:
O(l)
2
equation:

MgO(s)

2H
2
(aq)
Mg
(aq)

H
O(l)
2
2
Potassium
sulfate
hydroxide
and
2KOH(aq)

H
SO
2
onic
reacts
wit h
sulfuric
acid
to
produce
potassium
water:
(aq)
K
4
SO
2
(aq)
4

2H
O(l)
2
equation:

OH
(aq)

H
(aq)
H
O(l)
2
129
Properties
and
reactions
of
bases
Acids,
Bases
Bases
react
react
base
n
order
wit h

to
with
ammonium
ammonium
ammonium
react,
t he
and
salts
salts
salts
to
produce
salt
reactants
bases
salt
need
to
be
a
salt,

ammonia
ammoni a

and
water:
water
heated.
Examples
1
Copper(II)
chloride,
oxide
reacts
ammonia
CuO(s)

wit h
and
2NH
ammonium
Cl(s)
CuCl
4
2
Calcium
sulfate,
hydroxide
ammonia
Ca(OH)
(s)
reacts
ammonium
(NH
Your
●
teacher
will
paper,
be
a
may
wit h
SO
2

2NH
(g)

H
3
ammonium
sulfate
(s)
CaSO
4
reaction
use
this
recording
supplied
dry
produce
copper(II)
O(l)
2
to
produce
calcium
(s)

2NH
4
between
(g)

2H
3
calcium
O(l)
2
hydroxide
and
chloride
observation,
Y
ou
)
4
the
to
water:
2
Investigating
(s)
2
and

chloride
water:
test
with
tube
activity
and
assess:
reporting.
calcium
and
to
hydroxide,
ammonium
chloride,
red
litmus
tongs.
Method
1
Place
2
Add
mix
Did
?
you
litmus
it
paper
reacts
form
gas
causes
to
with
turn
the
ammonium
moist
(g)

H
3
blue
water
because
present
hydroxide
O(l)
heat
paper
ammonia
4
Look
5
Write
OH(aq)
4
6
Explain
hydroxide
amphoteric
substance
substance
which
both
and
can
with
react
strong
is
the
and
test
tube.
shake
the
tube
to
mixture
If
the
and
while
mouth
ammonia
gas
of
is
heating
the
tube
hold
to
produced
test
the
a
piece
for
the
litmus
of
moist
presence
paper
will
red
of
turn
blue.
at
the
sides
of
the
test
tube
to
see
if
any
water
droplets
form.
a
balance
the
chemical
formation
of
oxides
equation
the
water
and
for
the
reaction.
droplets.
hydroxides
metal
wit h
oxides
acids
and
and
also
hydroxides
behave
as
can
acids
behave
as
because
bases
t hey
because
can
react
t hey
wit h
can
strong
a
with
alkalis.
These
substances
are
referred
to
as
being
amphoteric
alkalis.
The
and
●
following
general
hydroxides
The
word
equations
summarise
●
The
amphoteric
amphoteric
strong alkali
The

amphoteric
how
amphoteric
oxides
react.
substance
reacting
as
amphoteric oxide or hydroxide
130
in
chloride
fact
Some
acids
calcium
ammonium
is
react
An
the
across
gas.
Amphoteric
!
of
of
to
which
NH
2
Key
spatulas
spatulas
solids.
Carefully
litmus
red
alkaline:
NH
the
small
small
know?
3
Ammonia
two
two
substance
reacting
as
a
base:

an
acid
salt
and
hydroxides
are
water
acid:
amphoteric oxide or hydroxide
oxides

listed
in
Table
salt
8.2.1.

water
Acids,

bases
T
able
and
8.2.1
Amphoteric
aluminium
salts
Properties
Amphoteric
oxides
oxide
oxide
oxide
reactions
of
bases
hydroxides
Formula
Amphoteric
Al
aluminium
O
2
zinc
and
and
hydroxide
Formula
hydroxide
Al(OH)
3
3
ZnO
zinc
hydroxide
PbO
lead(II)
Zn(OH)
2
lead(II)
oxide
hydroxide
Pb(OH)
2
Examples
1
Aluminium
aluminium
hydroxide
chloride
Al(OH)
(s)

reacts
and
wit h
hydrochloric
3HCl(aq)
AlCl
3
2
Aluminium
to
produce
acid
to
(aq)

3H
3
hydroxide
sodium
NaOH(aq)
reacts
wit h
aluminate
Al(OH)

produce
water:
t he
and
O(l)
2
strong
alkali,
sodium
hydroxide,
water:
(s)
NaAlO
3
(aq)
2H

2
O(l)
2
sodium
aluminate
3
Zinc
oxide
reacts
wit h
hydrochloric
acid
to
produce
zinc
chloride
and
water:
ZnO(s)

2HCl(aq)
ZnCl
(aq)

H
2
4
Zinc
oxide
sodium
reacts
zincate
2NaOH(aq)
wit h
and
t he
strong
O(l)
2
sodium
hydroxide,
to
produce
water:
ZnO(s)

alkali,
Na
ZnO
2
(aq)
H

2
O(l)
2
sodium
zincate
Classification
So
far
in
t his
Anot her
unit
type
t herefore,
be
of
oxides
Acid ic
oxides
a
salt
you
are
and
oxides
have
oxide
classied
Acidic
form
of
as
for
of
across
exists,
acidic,
oxides
water,
come
also
acidic,
known
basic,
cer tain
as
basic
a
and
neutral
amphoteric
non-metals
and
amphoteric
oxide.
oxides.
Oxides
can,
neutral.
which
react
wit h
alkalis
to
Key
!
example,
Acidic
2NaOH(aq)

CO
(g)
Na
2
CO
2
(aq)

H
3
O(l)
oxides
SO
(g)
also

H
3
react
wit h
water
O(l)
H
2
to
SO
2
form
an
acid,
for
(SO
)
and
nitrogen
Basic
oxides
for
dioxide
(NO
), sulfur dioxide (SO
),
2
).
2
are
oxides
of
metals
which

2HNO
(aq)
react
Cu(NO
3
wit h
acids
to
form
a
salt
and
!
)
3
(aq)

H
2
O(l)
2
few
basic
alkalis,
K
for
O(s)
oxides
which
react
oxides
also
react
wit h
water
to
form
a
hydroxide,
i.e.
t hey
and
are
with
oxides
acids
to
of
metals
form
a
water.
are

H
O(l)
2KOH(aq)
2
Examples
)
fact
example,
2
O
Key
Basic
salt
2
alkalis
water.
example,
CuO(s)
(Fe
and
certain
oxides
water,
A
salt
of
with
(aq)
3
Basic
a
oxides
react
example,
2
trioxide
form
are
which
4
Examples of acidic oxides include carbon dioxide (CO
sulfur
oxides
non-metals
2
to
Acidic
fact
of
and
basic
oxides
copper(II)
include
oxide
magnesium
oxide
(MgO),
iron(III)
oxide
(CuO).
3
131
Strength
of
acids
and
alkalis
Acids,
Basic
oxides
which
are
alkalis
include
potassium
oxide
(K
bases
O),
and
sodium
salts
oxide
2
(Na
O)
and
calcium
oxide
(CaO).
2
Amphoteric
!
Key
fact
Amphoteric
acids
Amphoteric
of
oxides
certain
oxides
metals
are
which
the
and
oxides
strong
are
alkalis
t he
to
oxides
form
a
of
salt
cer tain
and
acids
and
strong
alkalis
a
salt
and
which
react
wit h
bot h
example,
with
PbO(s)

2HNO
(aq)
Pb(NO
)
3
(aq)

H
2
O(l)
2
to
2NaOH(aq)
form
for
oxides
react
3
both
metals
water,

PbO(s)
Na
PbO
2
(aq)

2
H
O(l)
2
water.
sodium
plumbate
The
t hree
and
lead(II)
amphoteric
oxides
are
aluminium
oxide
(Al
O
3
Neutral
!
Key
),
zinc
oxide
(ZnO)
3
(PbO).
oxides
fact
Neutral
acids
Neutral
oxide
oxides
are
oxides
or
oxides
are
alkalis.
oxides
These
of
cer tain
include
non-metals
carbon
monoxide
which
(CO),
do
not
nitrogen
react
wit h
monoxide
of
(NO)
and
dinitrogen
monoxide
(N
O).
2
certain
react
non-metals
with
acids
which
or
do
not
alkalis.
Summary
1
Dene
2
Give
the
three
aqueous
3
Write
questions
terms
‘base’,
properties,
‘alkali’
other
and
than
‘amphoteric
their
substance’.
reactions,
which
are
typical
of
alkalis.
balanced
chemical
equations
for
a
the
reaction
between
magnesium
b
the
reaction
between
calcium
c
the
reaction
between
sodium
the
following:
hydroxide
oxide
and
hydroxide
and
nitric
ammonium
and
zinc
acid
nitrate
hydroxide.
Objectives
4
By
the
be
able
end
of
this
topic
you
Calcium
calcium
●
explain
a
●
the
strong
give
difference
acid
and
examples
of
a
is
a
basic
oxide.
Explain,
using
a
chemical
equation,
why
basic.
strong
acid
and
Strength
of
acids
and
alkalis
acids
explain
the
difference
between
Aqueous
a
is
oxide
between
weak
A8.3
weak
●
oxide
will
to:
strong
alkali
and
a
solutions
of
both
acids
and
alkalis
can
be
classied
as
strong
or
weak
weak
based on the degree of ionisation which occurs when they are dissolved in water.
alkali
You
●
give
examples
of
strong
must
not
confuse
this
with
concentration.
The
concentration
of
an
acid
or
and
alkali is based on the quantity of water present in the solution (see Unit 8.1).
weak
●
alkalis
explain
the
relationship
Strong
between
the
pH
acidity,
alkalinity
and
weak
acids
and
scale
When
an
acid
dissolves
in
water,
its
molecules
ionise
to
form
hydrogen
ions,

●
give
the
acids,
values
weak
alkalis
●
pH
and
explain
acids,
weak
how
to
for
strong
or
of
a
Strong
give
the
and
negative
anions.
determine
acids
the
strong
acid
is
fully
ionised
when
it
dissolves
in
water.
This
means
colours
of
t he
in
acidic
acid
molecules
ionise
and
t here
is
a
high
concentration
of
H
ions
certain
t he
indicators
t hat
and
solution.
Hydrochloric
acid
is
an
example
of
a
strong
acid:
alkaline

HCl(aq)
H
(aq)

Cl
(aq)
solutions.
Ot her
strong
acids
include
nitric
acid
(HNO
)
3
132
all

solution
of
●
ions,
strong
alkalis
A
pH
H
and
sulfuric
acid
(H
SO
2
).
4
in
Acids,
bases
Weak
A
and
salts
Strength
of
acids
and
alkalis
acids
weak
acid
is
only
partially
ionised
when
it
dissolves
in
water.
This
means
that the solution contains a mixture of acid molecules which have not ionised
and ions produced from the molecules which have ionised. The solution has a

low concentration of H
ions. Ethanoic acid is an example of a weak acid:

CH
COOH(aq)
CH
3
COO
(aq)
et hanoate
At
any
i.e.
t he

H
(aq)
3
one
time,
solution
only
about
contains
1%
1%
of
ion
et hanoic
et hanoate
ions
acid
(CH
molecules
COO
)
and
are
ionised,
hydrogen
ions
3

(H
)
and
99%
et hanoic
acid
molecules
(CH
COOH).
3
Most
organic
(HNO
),
acids
sulfurous
are
acid
weak.
(H
2
Strong
When
and
an
Strong
weak
alkali
hydroxide
A
SO
2
ions,
is
and
inorganic
carbonic
include
CO
nitrous
acid
).
3
OH
to
water,
it
ionises
to
form
positive
cations
and
ions.
alkalis
strong
a
(H
2
alkali
is
fully
ionised
when
contains a high concentration of OH
of
acids
acid
alkalis
added
or
Weak
)
3
strong
it
dissolves
in
water.
The
solution
ions. Sodium hydroxide is an example
alkali:

NaOH(aq)
Potassium
Weak
Na
hydroxide
(aq)
(KOH)
is

OH
(aq)
anot her
example
of
a
strong
alkali.
alkalis
A weak alkali is only par tially ionised when it dissolves in water. The solution
contains a low concentration of OH
ions. Ammonia is an example of a weak
alkali:

NH
(g)

H
3
Measuring
The
The
strengt h
pH
scale
solutions
greater
pH
of
The
is
pH
stronger
●
A
a
t he
strong
)
aqueous
pH
7
less
are
as
also
A
weak

OH
t han
7
a
neutral
t he
us
pH,
acids
or
wit h
are
considered
tells
lower
of
acid
scale
(aq)
alkali
t he
and
is
numbers
be
strong
ranging
to
alkaline.
Distilled
t he
stronger
be
An
acid,
using
from
acidic
0
or
is
pH
14.
scale.
Aqueous
t hose
wit h
a
solution
wit h
a
neutral.
alkaline
and
t he
to
and
aqueous
water
acidic
t he
alkalis
measured
considered
to
solution.
how
t he
solution
higher
t he
is.
pH,
n
t he
alkali.
acid
and
has
a
pH
sulfuric
close
acid
to
(H
3
●
(aq)
strength
number
dened
t he
(HNO
an
a
t han
scale
general,
NH
4
the
of
is
wit h
pH
7
O(l)
2
1,
SO
2
acid
has
a
pH
of
e.g.
hydrochloric
acid
(HCl),
nitric
acid
).
4
about
4
or
5,
e.g.
et hanoic
acid
(CH
COOH).
3
●
A
neutral
●
A
weak
substance
has
a
pH
of
7
,
e.g.
distilled
water
(H
O).
2
alkali
has
a
pH
of
about
9
or
10,
e.g.
aqueous
ammonia
(NH
OH).
4
●
A
strong
and
alkali
potassium
has
a
pH
close
hydroxide
to
14,
e.g.
sodium
hydroxide
(NaOH)
(KOH).
133
Strength
of
acids
universal
pH
and
alkalis
Acids,
indicator
There
are
two
main
met hods
t hat
solution.
One
are
used
in
bases
t he
and
salts
laborator y
to
paper
measure
ot her
0
is
t he
a
pH
pH
of
a
is
universal
indicator
and
t he
meter.
very
acidic
hydrochloric
1
Universal
●
acid
indicates
2
lemon
ind icator
t he
pH
of
is
a
a
chemical
solution
by
substance
colour,
i.e.
which
its
colour
juice
acidic
orange
changes
depending
on
t he
pH
of
t he
solution.
Universal
juice
indicator
3
can
be
in
paper
form
or
solution
form.
When
vinegar
using
t he
paper,
a
small
piece
of
paper
is
dipped
into
t he
4
solution
and
its
colour
is
compared
wit h
a
pH
colour
char t.
slightly
black
5
coffee
Figure
acidic
8.3.1
different
shows
pH
t he
colour
of
universal
indicator
paper
at
values.
rainwater
6
A
●
pure
pH
meter
is
an
electronic
instr ument.
t
consists
of
a
neutral
water
7
measuring
sea
probe
connected
to
an
electronic
meter,
which
water
8
baking
milk
soda
of
displays
t he
met hod
for
pH
reading.
A
pH
meter
is
a
more
accurate
slightly
magnesia
determining
t he
pH
of
a
solution
t han
universal
alkaline
9
soap
indicator
paper.
10
11
Other
12
washing
soda
acid–alkali
indicators
alkaline
There
are
acidic
solution
ot her
ind icators
which
change
to
one
colour
in
an
13
oven
impor tant
Figure
8.3.1
hydroxide
The
pH
you
is
may
met hyl
you
in
an
alkaline
solution.
t
to
note
t hat
t hese
solution,
t hey
only
indicators
do
not
measure
t he
is
pH
a
indicate
if
it
is
acidic
or
alkaline.
scale
Litmus
Did
colour
alkaline
of

anot her
very
cleaner
14
sodium
and
an
example
come
orange,
across
of
in
t his
t he
type
of
indicator.
laborator y
phenolpht halein
and
include
Ot her
indicators
met hyl
bromot hymol
orange,
blue.
These
which
screened
are
used
in
know?
neutralisation experiments to indicate t he neutralisation point (see Unit 8.5).
?
The
compounds
which
and
are
red
the
and
be
in
fruit
in
They
colour
of
skins.
extracted
anthocyanins
acidic
purple-blue
conditions.
for
called

T
able
parts,
Anthocyanins
cabbage,
and
acid–alkali
naturally
is
made
certain
e.g.
from
the
used
indicator.
occurring
by
of
8.3.1
Indicators
t heir
colours
in
acidic
and
used
in
the
alkaline
solutions
laboratory
Indicator
Colour
can
litmus
red
blue
as
a
of
in
acidic
solution
Colour
red
yellow
red
green
phenolphthalein
colourless
pink
bromothymol
yellow
blue
in
alkaline
solution
crude
Litmus
is
indicator
dyes
orange
red
screened
methyl
orange
a
which
from
blue
lichens.
Investigating
Your
teacher
observation,
●
manipulation
will
be
universal
orange
the
may
●
Y
ou
134
and
8.3.1.
these
leaves
extracting
species
indicators
Table
flowers
methyl
plant
in
responsible
many
easily
common
given
conditions
alkaline
are
are
use
this
recording
and
supplied
indicator
and
acidity
and
alkalinity
activity
and
to
of
various
solutions
assess:
reporting
measurement.
with
paper,
samples
pH
phenolphthalein.
of
colour
solutions
chart,
red
to
be
and
tested,
blue
test
litmus
tubes,
paper,
methyl
Acids,
bases
and
salts
Salts
Method
1
Y
ou
the
are
going
colour
and
of
to
measure
each
the
indicator
phenolphthalein
when
pH
in
of
each
the
each
of
the
solution.
solution
you
solutions
Only
are
use
and
methyl
testing
is
investigate
orange
colourless.
3
a
Place
b
Dip
2 cm
a
tube
of
piece
and
chart
to
Dip
piece
d
Place
the
If
of
second
there
each
two
is
of
meter
3
Record
4
Classify
weak
a
tube.
your
alkali
Summary
What
2
Name
3
Describe
of
4
is
the
Give
the
values
a
of
in
neutral
a
paper
of
the
four
test
solution
colour
litmus
with
in
the
tubes.
the
pH
rst
colour
paper
into
the
solution
in
colours.
orange
use
each
into
the
blue
other
that
each
solution.
of
their
the
after
results
the
in
the
you
and
two
phenolphthalein,
tubes.
meter
rinse
to
the
Observe
their
determine
measuring
the
colours.
pH
probe
of
of
the
reading.
table.
as
a
strong
acid,
a
weak
acid,
a
strong
alkali,
a
substance.
questions
strong
the
pH
colours
each
between
acids
scale,
alkaline
for
of
methyl
Ensure
water
tested
Compare
piece
available,
difference
three
acidic,
the
substance
or
pH
a
each
solutions.
each
1
the
be
indicator
Observe
meter
to
colour.
and
of
into
distilled
all
red
drops
pH
the
in
its
determine
respectively,
2
solution
universal
observe
c
a
of
the
and
of
of
and
methyl
strong
three
giving
the
neutral
the
a
acid
weak
range
and
a
weak
acid?
acids.
of
the
scale
and
the
pH
values
solutions.
orange
and
phenolphthalein
and
the
pH
following:
a
aqueous
ethanoic
c
aqueous
ammonia
acid
b
sodium
d
aqueous
hydroxide
solution
hydrochloric
acid.
Objectives
A8.4
You
Salts
have
molecule
one
already
when
hydrogen
learnt
t hey
ion
t hat
all
dissolve
per
in
molecule
acids
form
water,
and
e.g.
sulfuric
at
least
one
hydrogen
hydrochloric
acid
(H
SO
2
)
acid
ion
(HCl)
forms
two.
By
the
be
able
end
t hey
are
ions
can
known
hydrogen
ions
as
are
be
replaced
by
ot her
positive
replaceable
hydrogen
replaced
metal
by
or
ions .
ions
a
salt
is
●
dene
●
distinguish
acids
the
acids
ions
react
from
and
t he
and
be
of
classied
or
an
acid
a
normal
salt
●
explain
●
distinguish
water
of
crystallisation
t he
between
a
hydrated
ot her
and
decide
an
on
method
all
salt
between
and
anhydrous
only
of
the
most
salt
appropriate
preparing
a
salt
salts
●
can
term
formed.
Classification
whet her
will
These
react
●
Salts
you
per
salt
reactant,
topic
4
when
When
ammonium
this
forms
salt
hydrogen
of
to:
into
some
two
of
groups,
t he
normal
hydrogen
ions
salts
are
and
acid
replaced:
salts,
based
on
describe
of
●
preparing
describe
everyday
●
the
state
the
different
methods
salts
uses
of
salts
in
life
some
of
the
dangers
of
salts.
135
Salts
Acids,
Normal
!
by
fact
and
salts
salts
Normal salts are formed when
Key
bases
metal
or
ammonium
ions.
all of the hydrogen ions in an acid are replaced
For
example,
when
sodium
hydroxide
(NaOH)

reacts with sulfuric acid (H
SO
2
), if all of the H
ions in the acid are replaced by
4

A
salt
is
a
compound
formed
when
Na
ions, the normal salt, sodium sulfate (Na
SO
2
some
or
all
of
the
hydrogen
ions
2NaOH(aq)

H
SO
2
an
acid
are
ammonium
replaced
ions.
by
metal
), is formed:
4
in
(aq)
Na
4
SO
2
(aq)

2H
4
O(l)
2
or
All
acids
can
Acid
salts
Acid
salts
replaced
form
are
by
normal
formed
metal
or
salts.
when
the
hydrogen
ammonium
ions.
For
ions
in
an
example,
acid
when
are
only
sodium
partially
hydroxide

reacts
with
sulfuric
acid,
if
only
one
of
the
H
ions
in
the
acid
is
replaced
by
a

Na
ion, the acid salt, sodium hydrogensulfate (NaHSO
), is formed:
4
NaOH(aq)

H
SO
2
Only
The
dibasic
type
of
quantity
of
2 mol
was
of
and
salt
produced.
1 mol
The
of
tr ibasic
formed
each
sodium
acids
by
However,
acid,
can
For
acid
and
acid
1 mol
only
salt
phosphoric
of
in
two
different
hydroxide,
it
can
acid
form

H
1 mol
was
salts.
acid
t he
For
salts.
acids
t he
of
depends
two
on
reactions
acid
sodium
reacted,
t he
relative
above,
a
hydroxide
when
normal
reacted
salt
wit h
produced.
(H
PO
),
can
produce
one
normal
salt
4
example,
normal
O(l)
2
sulfuric
3
and
(aq)
tribasic
example,
and
when
an
form
dibasic
reactant.
acid,
NaHSO
4
hydroxide
sulfuric
tribasic
(aq)
4
salt,
in
t he
sodium
reaction
phosphate
wit h
(Na
sodium
PO
3
),
when
4

all
t hree
H
ions
are
replaced.
t
can
also
form
t he
two
acid
salts,
sodium

hydrogenphosphate
(Na
HPO
2
)
when
two
H
ions
are
replaced
and
sodium
4

dihydrogenphosphate
(NaH
PO
2
3NaOH(aq)
2NaOH(aq)
NaOH(aq)
Again,
you
which
salt
Table

8.4.1
T
able
can
is
H

H

H
see
PO
3
shows
8.4.1
acid
acid
one
(aq)
PO
3
Na
(aq)
PO
t hat
Na
(aq)
t he
Salts
salts
formed
HCl
HNO
acid
acid
PO
2
relative
(aq)
4
NaH
quantity
by
formed
common
Salt(s)
by
t he
(aq)
4
of
t he
common
replaced:

3H

2H

H
two
O(l)
2
O(l)
2
O(l)
2
reactants
determines
CH
H
2
acids.
acids
formed
Anion
T
ype
present
salt
chlorides
Cl
normal
salt
NaCl
nitrates
NO
of
Example
normal
salt
NaNO
3
3
COOH
ethanoates
3
sulfuric
(aq)
HPO
4
t he
is
4
2
3
ethanoic
ion
PO
3
4
3
H
4
4
Formula
hydrochloric
when
produced.
Acid
nitric

)
COO
normal
salt
2
normal
salt
CH
CH
sulfates
4
SO
4
hydrogensulfates
COONa
3
3
SO
Na
SO
2
acid
HSO
salt
4
NaHSO
4
carbonic
acid
H
CO
2
carbonates
3
4
2
normal
CO
salt
3
hydrogencarbonates
Na
CO
2
acid
HCO
salt
3
NaHCO
3
phosphoric
acid
H
3
PO
phosphates
4
3
3
normal
PO
salt
4
hydrogenphosphates
acid
salt
4
dihydrogenphosphates
H
2
136
Na
PO
3
2
HPO
Na
4
HPO
2
PO
4
acid
salt
4
NaH
2
PO
4
Acids,
bases
Water
Some
ions
of
salts
in
a
cr yst al
water
of
cr ystallisation
CuSO
Salts
contain
t heir
following
●
salts
crystallisation
containing
of
and
 xed
number
lattice,
cr yst allisation
can
be
given
in
water
as
are
t he
molecules
water
refer red
for mula
of
to
of
between
cr ystallisation .
as
hyd rated
t he
salts .
salt
as
shown
The
formula
t he
Salts
Water
in
t he
examples.
.5H
4
O
represents
hydrated
copper(II)
sulfate.
shows
2
2
t hat
of
known
for
ever y
mole
of
Cu
2
and
SO
ions
wit hin
t he
cr ystal
lattice,
4
t here
are
CoCl
●
ve
.6H
2
.7H
4
FeSO
●
and
.7H
of
O
represents
O
represents
cr ystallisation
sometimes
becomes
copper(II)
heated
molecules.
hydrated
cobalt(II)
chloride.
hydrated
magnesium
sulfate.
hydrated
iron(II)
sulfate.
2
cr ystallisation
it
water
2
4
Water
of
represents
2
MgSO
●
moles
O
t he
is
removed
powder y
sulfate
t hey
is
essential
colour,
and
by
its
cr ystals
become
of
to
colour
t he
may
bright
and
develop
cr ystals
heating,
are
white
t he
solid
also
blue
t he
cr ystalline
containing
loses
its
change.
and
have
it.
str ucture,
t his
cr ystalline
For
a
f
example,
regular
water
of
str ucture,
hydrated
shape.
When
powder y:
heat
CuSO
.5H
4
O(s)
CuSO
2
(s)
5H

4
O(g)
2
white
blue
cr ystals
powder
Salts
wit hout
water
Preparation
We
use
later
be
in
salts
t his
in
When
of
all
unit.
produced,
cr ystallisation
are
known
as
anhydrous
salts
salts
aspects
There
some
deciding
of
of
on
of
are
which
a
our
many
we
lives.
Some
different
will
preparation
be
of
t hese
met hods
discussing
met hod,
it
in
is
uses
by
will
which
t his
be
discussed
t hese
salts
can
section.
impor tant
to
know
t he
solubilit y of t he salt t hat is to be produced and t he solubilit y of t he compounds
whic h may be used to prepare t he salt. Met hods of prepar ing insoluble salts
differ
You
from
can
t hose
nd
a
table
Preparation
Insoluble
t he
of
salts
cations
t he
of
salt.
used
insoluble
can
This
is
prepare
summarising
of
t he
to
be
salt
prepared
being
known
as
soluble
t he
salts.
solubility
r ules
in
Unit
6.1.
salts
by
reacting
prepared
ionic
and
two
t he
solutions,
ot her
precipitation .
n
one
containing
an
ionic
containing
t he
anions
precipitation
reaction, t he two soluble salts in solution react to form an insoluble salt, i.e. a
precipitate,
wit h
and
sodium
nitrate
soluble
salt.
solution
For
to
example,
form
barium
insoluble
nitrate
barium
solution
sulfate
and
reacts
sodium
solution:
)
Ba(NO
3
onic
a
sulfate
(aq)

Na
2
SO
2
(aq)
BaSO
4
(s)
4

2NaNO
(aq)
3
equation:
2
Ba
2
(aq)

SO
(aq)
4
BaSO
(s)
4
137
Salts
Acids,
bases
and
salts
Method
The
1)
following
Choose
salt
two
and
Dissolve
3)
Mix
4)
Filter
5)
Wash
When
t he
best
t he
t hat
one
t he
form
collect
for
preparing
containing
water
to
wit h
used
to
anions
make
t he
t he
distilled
t he
cations
salts.
required
to
make
t he
required.
solutions.
insoluble
salt
precipitate
water
insoluble
as
while
as
a
t he
it
is
precipitate.
residue
still
in
t he
lter
funnel
dr y.
t he
all
to
two
salts
nitrates
c hoose
above
to
are
would
use
in
your
soluble,
be
a
preparation,
as
nitrate
and
a
preparation
are
to
all
supply
sodium
it
sodium
t he
salt
is
impor tant
salts.
cations,
to
supply
to
Therefore,
i.e.
t he
bar ium
anions,
sulfate.
prepare
Your
adding
to
t he
in
and
residue
it
salts
in
salts
mixture
sodium
T
o
two
salts,
is
containing
solutions
c hoosing
nitrate
e.g.
t he
leave
remember
t he
ot her
two
t he
met hod
soluble
t he
2)
and
general
an
teacher
may
●
observation,
●
manipulation
Y
ou
will
two
beakers,
be
insoluble
use
and
supplied
a
this
recording
lter
salt
by
activity
and
ionic
to
precipitation
assess:
reporting
measurement.
with
solutions
funnel
and
of
lter
barium
nitrate
and
sodium
sulfate,
paper.
barium
Method
nitrate
solution
sodium
to
3
sulfate
1
Place
10 cm
of
sodium
sulfate
solution
into
a
small
beaker.
solution
3
2
Add
3
Using
4
Wash
10 cm
allow

Figure
8.4.1
insoluble
Preparation
salt,
barium
of
the
the
it
Record
6
Write
all
your
both
reaction
sulfate
are
a
●
direct
●
t he
●
t he
a
Salts
by
sulfate
138
precipitate
solution
lter
distilled
and
paper,
water
swirl
lter
while
the
it
is
to
mix.
mixture.
still
in
the
lter
funnel
and
observations
as
you
chemical
prepare
equation
the
and
sample
an
ionic
of
the
salt.
equation
of
barium
of
the
insoluble
soluble
main
met hods
salt
that
you
have
for
the
prepared.
salts
for
preparing
soluble
salts:
combination
reaction
between
base
reaction
and
a
an
between
reactive
metal,
an
insoluble
carbonate
or
an
acid
a
soluble
base,
i.e.
an
alkali,
and
an
acid,
known
as
combination
composed
reacting
The
name
titration.
Direct
A
with
balanced
and
three
insoluble
8.4.2
nitrate
and
the
There
Figure
funnel
dry.
Preparation

barium
residue
to
5
of
lter
metal
anions.
two
of
two
simple
elements,
supplies
t he
a
ions,
metal
cations
such
and
of
a
t he
as
metal
chlorides,
non-metal,
salt
and
t he
directly
can
be
wit h
non-metal
prepared
each
ot her.
supplies
t he
Acids,
For
bases
and
example,
passing
glass
a
salts
aluminium
stream
tube
as
Salts
of
dr y
shown
in
chloride
chlorine
Figure
can
gas
be
prepared
over
heated
a
fume
cupboard
foil
in
a
by
long
8.4.3.
aluminium
dry
in
aluminium
foil
chlorine
unreacted
in
chlorine
out
heat

Figure
The
8.4.3
Preparation
equation
2Al(s)
for

t he
3Cl
of
aluminium
reaction
(g)
is:
2AlCl
2
Since
is
an
t he
aluminium
Reactions
Many
soluble
carbonate
●
occurs
salt.
chloride
with
or
in
This
and
absence
par ticularly
anhydrous
salts
can
be
of
any
moisture,
suitable
iron(III)
prepared
base
wit h
reactive metal
Mg(s)
t he
is
e.g.
an

an
●
met hod
is
Reacting
too
an
salt
formed
anhydrous
by
reacting
acid
as
a
cannot
or
reactive
shown
in
t he
metal,
insoluble
examples
below.
and an acid, e.g. to prepare magnesium chloride:
2HCl(aq)
potassium
acid
t he
preparing
chloride.
MgCl
(aq)

H
2
This
for
acids
insoluble
Reacting a
(s)
3
reaction
anhydrous
chloride
be
sodium
(g)
2
used
to
salts,
because
prepare
salts
t he
of
ver y
reaction
of
reactive
t hese
metals,
metals
wit h
violent.
insoluble
carbonate
and
an
acid,
e.g.
to
prepare
calcium
nitrate:
CaCO
(s)

2HNO
3
●
Reacting
an
(aq)
Ca(NO
3
insoluble
CuO(S)

H
SO
2
)
3
base
and
an
(aq)
acid,
e.g.
CuSO
4
(aq)
CO
(g)

H
2
to
(aq)

2
prepare

H
4
O(l)
2
copper(II)
sulfate:
O(l)
2
n t hese reactions, t he nal product will only be a pure solution of t he required
salt
if
t he
achieve
to
t he
t he
reaction
t his
acid
is
by
until
reactant
to
has
reached
using
some
react
a
completion
reactant
remains.
wit h
and,
which
This
is
and
indicates
since
it
is
no
acid
insoluble.
t here
is
insoluble,
remains.
This
no
t he
One
reactant
more
acid
excess
way
is
will
to
added
lef t
for
remain
✔
undissolved
in
t he
solution
of
t he
Exam
tip
salt.
Being
able
to
describe
the
Method
methods
is
very
used
to
important
prepare
for
salts
exams.
If
The following general met hod is used to prepare soluble salts using reactions
you
wit h
to
1)
are
asked
Choose
the
appropriate
reactive
metal,
insoluble
carbonate
or
base to provide the
prepare
cations
and the appropriate acid to provide the
t he
excess
used.
3)
acid
solid
This
speed
into
a
remains
indicates
up
t he
beaker
and
t hat
reaction
and
add
t he
effer vescence
all
t he
when
acid
has
using
a
metal,
stops
if
reacted.
metal
or
a
carbonate
a
metal
Heating
or
or
base
until
carbonate
may
a
soluble
be
with
an
is
required
idea
to
the
salt
acid
using
and
insoluble
cations
reactants,
choose
the
you
a
can
a
carbonate
it
doesn’t
the
and
it
is
a
good
appropriate
carbonate
since
to
supply
reaction
an
acid
the
between
is
rapid,
base.
need
heating
and
visible
Dip a piece of blue litmus paper into t he solution to ensure all t he acid has
effervescence
reacted.
The
Remove
t he
litmus
should
remain
excess,
unreacted
stops
when
the
blue.
reaction
4)
how
anions
choose
Place
to
describe
insoluble
reaction
2)
to
acids.
solid
by
has
reached
completion.
ltration.
139
Salts
Acids,
5)
Collect the
a
hydrated
ltrate
salt
is
bases
and
salts
and evaporate the water over a beaker of boiling water. f
required,
evaporate
some
of
the
water
to
concentrate
the
solution and leave the concentrated solution to cr ystallise.
T
o
prepare
Your
a
teacher
may
●
observation,
●
manipulation
Y
ou
will
beaker,
be
an
soluble
use
salt
this
recording
and
supplied
by
reacting
activity
and
to
a
base
with
an
acid
assess:
reporting
measurement.
with
evaporating
samples
dish,
a
of
lter
copper( II)
funnel
oxide
and
lter
and
sulfuric
acid,
a
paper.
Method
Add
the
the
copper(II)
sulfuric
heating
more
acid
gently,
will
oxide
to
3
1
Place
2
Add
20 cm
of
sulfuric
acid
into
the
beaker.
while
until
no
copper( II)
oxide
to
the
acid
a
spatula
at
a
time,
heating
and
stirring
dissolve
gently,
oxide
3
until
in
Using
4
Pour
Place
more
lter
funnel
ltrate
of
a
concentrated
6
Record
7
Write
8
T
o
a
lter
i.e.
until
you
can
see
excess
copper( II)
paper,
collect
evaporating
and
heat
and
leave
the
the
it
the
mixture
Place
the
solution
remove
crystallise
evaporating
becomes
evaporating
to
to
the
ltrate.
dish.
until
over
lter
the
dish
and
dish
a
concentrated.
containing
form
over
the
hydrated
crystals.
observations
balanced
chemical
anhydrous
evaporating
lter
and
paper
solution
your
produce
the
water
of
sulfate
all
react,
and
oxide
into
boiling
piece
copper(II)
will
beaker.
copper( II)
the
beaker
5
the
the
excess
no
dish
over
as
you
equation
copper( II)
a
prepare
beaker
for
the
sulfate,
of
the
reaction.
you
boiling
salt.
can
water
heat
until
the
all
ltrate
the
water
in
the
has
evaporated.
Filter
off
the
excess
copper(II)oxide
Titration
Potassium,
sodium
and
ammonium
salts
cannot
be
prepared
by
the
method
which you have just learnt for two reasons. Firstly, potassium and sodium react
in
a
violent
way
with
acids
making
the
reactions
too
dangerous.
Secondly,
potassium, sodium and ammonium carbonates and hydroxides are all soluble,
T
o
produce
copper(II)
so
hydrated
sulfate
allow
when
the
excess solid
crystals
days.
to
T
o
form
over
a
anhydrous
boiling
Figure
8.4.4
preparation
has
water
sulfate
Steps
of
alkali
reached
until
t he
solution
involved
hydrated
in
is
completion.
added
to
and
no
more
acid
remains,
the
For
is
just
potassium
example,
neutral,
hydroxide
to
indicating
prepare
t hat
solution
potassium
t he
reaction
until
t he
sulfate,
resulting
sulfuric
solution
is
the
copper( II)
just
neutral:
crystals
2KOH(aq)

H
SO
2
The
colour
point.
to
The
change
a
of
xed
solution
(aq)
K
4
technique
neutralise
carbonate
140
completion
beaker
acid

reached
sulfate
aqueous
of
a
has
and the solution of the salt will then not be pure.
Potassium, sodium and ammonium salts are prepared by adding an acid to an
copper(II)
over
dissolves
few
produce
evaporate
reaction
the
an
indicator
used
to
volume
may
SO
2
also
used
determine
of
be
is
aqueous
used
(aq)
in

2H
4
O(l)
2
to
determine
t he
exact
alkali
place
of
is
t he
volume
known
t he
neutralisation
of
as
aqueous
a
acid
needed
titration.
alkali.
A
Acids,
bases
and
salts
Salts
Method
The
1)
general
Choose
and
2)
an
met hod
an
for
performing
appropriate
appropriate
alkali
acid
to
or
a
titration
soluble
supply
t he
is
as
follows.
carbonate
to
provide
t he
cations
anions
Measure a xed volume of t he aqueous alkali or carbonate using a pipette.
Run
e.g.
it
into
a
conical
ask
and
add
a
few
drops
of
indicator
solution,
phenolpht halein.
3)
Place
4)
Add
t he
t he
point
is
5)
Take
a
6)
Repeat
acid
acid
in
to
a
burette
t he
and
aqueous
take
an
alkali
or
initial
burette
carbonate
reading.
until
t he
neutralisation
reached.
nal
burette
reading
and
determine
t he
volume
of
acid
added.
3
of
t he
each
titration
ot her.
until
Average
you
t hese
have
t hree
volumes
volumes
to
of
acid
determine
t he
wit hin
volume
0.1 cm
of
acid
needed.
7)
Add t his volume of acid to t he xed volume of aqueous alkali or carbonate
wit hout
8)
t he
Evaporate
T
o
t he
prepare
Your
indicator.
water
a
teacher
soluble
may
●
observation,
●
manipulation
from
use
salt
this
recording
and
t he
solution.
by
titration
activity
and
to
assess:
reporting
measurement.
3
Y
ou
will
be
supplied
with
3
0.1 mol dm
sodium
hydroxide
solution,
0.1 mol dm
hydrochloric
acid,
phenolphthalein
3
solution,
a
25 cm
pipette,
a
conical
ask
and
a
burette.
Method
1
Rinse
2
Rinse
the
burette
with
some
hydrochloric
acid
and
ll
it
with
the
acid.
3
the
pipette
3
Add
4
T
ake
5
Slowly
a
pipette
and
few
an
run
it
with
into
drops
initial
add
colourless.
of
the
the
sodium
conical
reading,
hydrochloric
The
hydroxide
solution
remembering
acid
neutralisation
solution.
Measure
25 cm
of
sodium
hydroxide
solution
in
the
ask.
phenolphthalein
burette
the
to
of
some
to
the
point
to
to
the
conical
take
conical
is
the
the
ask,
point
ask
reading
swirling
where
the
and
from
swirl
the
contents.
bottom
constantly,
colour
the
until
changes
of
the
the
meniscus.
solution
after
the
just
addition
turns
of
from
just
one
pink
drop
acid.
6
T
ake
7
Discard
8
Repeat
a
nal
burette
the
reading
contents
of
the
and
determine
conical
ask
the
and
volume
rinse
the
of
hydrochloric
ask
acid
thoroughly
added.
with
This
distilled
is
your
rough
titration.
water.
3
your
titration
until
you
have
three
volumes
of
acid
which
are
within
0.1 cm
.
Each
time
you
can
add
the
3
acid
tap
rapidly
and
until
add
the
you
have
added
acid
drop
by
about
drop
until
less
1 cm
the
than
you
neutralisation
added
point
is
in
your
rough
titration,
then
almost
close
the
reached.
3
9
Average
the
three
volumes
of
acid,
which
are
within
0.1 cm
.
This
is
the
accurate
volume
of
acid
needed
to
3
neutralise
10
Repeat
25 cm
your
determined
11
Place
the
of
the
titration,
in
step
solution
9,
sodium
but
this
add
into
an
hydroxide
time
the
acid
do
not
drop
evaporating
solution.
add
by
dish
the
drop
and
Y
ou
can
now
prepare
phenolphthalein
until
you
carefully
have
solution.
added
evaporate
the
all
the
the
salt.
When
correct
water
you
approach
the
volume
volume.
to
obtain
sodium
chloride.
141
Salts
Acids,
12
Record
your
results
in
a
table
like
the
one
opposite.
Titration
Burette
Write
a
chemical
equation
for
the
and
salts
number
reading
Rough
13
bases
1
2
3
reaction.
3
Final
reading/cm
3
Initial
reading/cm
3
Volume
of
acid
added/cm
safety
burette
filler
these
allow
fill
valves
you
and
the
to
empty
when
pipette
pipette
is
these
filled
to
this
graduations
mark
measure
it
contains
how
exactly
much
solution
3
25
cm
of
solution
has
been
added
tap
conical
flask
(a)

Figure
8.4.5
hydroxide
(a)
Using
solution
hydrochloric
and
a
pipette
(b)
using
to
a
measure
burette
a
to
xed
add
a
volume
varying
of
sodium
volume

Figure
of
pink
acid
Preparation
You
learnt
wit h
of
earlier
sulfuric
acid
in
acid
t his
(H
SO
2
The
formation
of
2NaOH(aq)
a
formation
of
H
NaOH(aq)

an
H
SO
●
to
at
t he
produce
hydroxide
●
to
produce
hydroxide
f
t he
acid
a
SO
1 mol
an
acid
t he
same,
changes
0 .1
mol
dm
(a)
acid
is
solution
hydroxide
(NaOH)
reacts
salt:
Na
SO
NaHSO
salt,
t he
t he
O(l)
2
(aq)

H
t he
t hese
of
O(l)
2
two
reactions:
reactants
is
2 mol
of
sodium
acid
ratio
sulfuric
can
for
ratio
sulfuric
of
we
2H
4
equations
of

salt:
(aq)
of
(aq)
4
of
reactants
is
1 mol
of
sodium
acid.
sodium
a p p ly
t he
hy d r ox i d e
ratio
to
solution
vo l u m e s .
and
Fo r
t he
sulfur ic
e xa mp l e ,
3
use
from
hydrochloric
hydroxide
sodium
2
salt,
1 mol
concentrations
are
when
possibilities:
4
normal
to
two
(aq)
acid
balanced
to
sodium
when
are
4
2
Looking
to
Phenolphthalein
colourless
4
2
The
t hat
t here
normal

(b)
salts
unit
)
8.4.6
to
added
(b)
if
we
3
sodium
hy d r ox i d e
solution
and
0 .1
mol
dm
sulfur ic
acid:
3
●
to
produce
a
normal
salt,
we
would
react
50 cm
of
sodium
hydroxide
3
solution
wit h
25 cm
of
sulfuric
acid
3
●
to
produce
an
acid
salt,
we
would
react
50 cm
of
sodium
hydroxide
3
solution
wit h
50 cm
of
sulfuric
acid.
Comparing t he two, to prepare t he acid salt we would need
of
142
acid
t hat
we
used
to
prepare
t he
normal
salt.
double t he volume
Acids,
bases
and
salts
Salts
Method
The
as
●
general
Determine
volume
●
Repeat
of
●
met hod
for
preparing
t he
acid
salt,
sodium
hydrogensulfate,
is
follows.
of
t he
sulfuric
Evaporate
t he
volume
sodium
titration
acid
t he
Summary
sulfuric
wit hout
acid
needed
solution
t he
using
indicator
to
a
neutralise
a
xed
titration.
and
adding
twice
t he
volume
determined.
water
of
of
hydroxide
from
salt
t he
solution.
preparation
You have just learnt t hat t here are several met hods t hat can be used to prepare
salts
and
it
is
impor tant
t hat
you
choose
t he
correct
met hod.
The
ow
char t
in Figure 8.4.7 outlines a series of questions to ask which will help you decide
which
met hod
to
choose.
Use
reactive
or
an
a
metal
insoluble

acid
carbonate
Is
NO

the
acid
or
an
base
an
insoluble
salt
Is

acid
anhydrous
NO
the
salt
a
chloride?
YES
potassium,
sodium
Is
YES
Use
or
the
direct
ammonium
salt
YES
combination
salt
soluble
?
in
Use
water?
NO
a
titration
Use
ionic
precipitation

Figure
Uses
8.4.7
of
Flow
chart
salts
in
for
the
preparation
everyday
of
salts
life
Salts play an extremely impor tant par t in our ever yday lives, from t he sodium
chloride
as

t hat
washing
T
able
we
soda.
8.4.2
use
to
Table
Uses
of
avour
8.4.2
our
gives
food
to
t he
sodium
some
of
t he
uses
carbonate
t hat
we
use
salts.
salts
Salt
Use
Explanation
Sodium
An
Baking
hydrogencarbonate
in
(NaHCO
powder
)
of
ingredient
baking
powder
is
used
to
hydrogencarbonate
and
in
the
the
cake
mixture,
make
an
cakes
acid.
two
rise.
When
It
contains
mixed
compounds
with
react
the
forming
sodium
liquid
carbon
3
dioxide:

Figure
8.4.8
Washing
soda
is
a
salt

HCO
(aq)

H
(aq)
CO
3
The
carbon
heating
Sodium
carbonate
(washing
T
o
soda)
soften
hard
water
Hard
dioxide
causing
water
calcium
forms
the
does
and
cake
not
)
added,
the

H
in
the
O(l)
2
cake
which
which
expand
some
of
us
have
in
our
homes
on
rise.
with
salts.
soap.
When
It
is
caused
sodium
by
dissolved
carbonate
is
2
and
Ca
bubbles
to
lather
magnesium
2
(NaCO
(g)
2
Mg
ions
precipitate
out
as
insoluble
3
calcium
and
magnesium
2
Ca
carbonate:
2
(aq)

CO
(aq)
CaCO
3
The
Calcium
carbonate
(limestone)
(CaCO
)
water
Manufacture
T
o
of
quantities
cement
make
becomes
cement,
of
and
calcium
other
(s)
3
soft
will
lather
carbonate
materials
such
as
is
with
soap.
heated
silicon
with
dioxide
small
(sand)
in
3
for
use
in
the
construction
a
kiln
to
forming
about
1400 °C.
calcium
oxide
The
calcium
carbonate
decomposes
(quicklime):
industry
CaCO
(s)
CaO(s)

CO
3
The
calcium
inside
small
the
kiln
amount
(g)
2
oxide
to
of
is
then
form
blended
clinker.
calcium
The
sulfate
with
the
clinker
is
(gypsum)
other
then
to
materials
ground
make
with
a
cement.
143
Salts
Acids,

T
able
8.4.2
?
you
Magnesium
know?
(Epsom
(MgSO
salt
derives
its
sulfate
salt)
.7H
4
Epsom
O)
Use
Explanation
Various
Added
medicinal
relax
the
uses
strain,
town
of
to
the
where
Epsom
the
salt
in
The
in
healing
a
bitter
power
saline
of
help
spring
heal
the
spring.
waters
chloride
and
were
realised
news
of
(NaCl)
Sodium
preservation
and
fish,
that
the
from
in
these
rapidly
.
Epsom
back
salt
is
pain
used
and
inflammation,
to
ease
aching
help
cure
stress
limbs,
skin
and
ease
muscle
problems
cuts.
T
aken
orally,
Epsom
salt
is
used
as
a
and
saline
to
help
also
chloride
by
is
eliminate
used
to
toxins
from
withdrawing
water
is
preserve
the
water
unavailable
withdraws
water
from
for
from
the
the
food
body.
their
items,
cells
reactions
such
by
as
meat
osmosis
that
microorganisms
cause
which
so
decay.
cause
about
preventing
them
from
growing.
powers
Sodium
spread
reduce
and
Food
decay,
1618
Epsom
soothe
first
It
the
water,
Surrey
,
was
Sodium
discovered
bath
body,
2
laxative
England
salts
name
help
from
and
(continued)
Salt
Did
bases
nitrate
Food
Sodium
preservation
chloride
nitrate
and
sodium
nitrite
are
often
used
with
sodium
quickly
)
(NaNO
and
to
preserve
meat.
They
destroy
certain
bacteria
that
3
developed
into
a
spa
town
and
sodium
people
travelled
from
far
and
wide
to
nitrite
(NaNO
cause
)
severe
rancidity.
food
Sodium
poisoning
nitrite
and
gives
an
retard
the
attractive
development
red
colour
to
of
the
2
visit
Epsom
and
‘take
the
meat,
waters’.
Sodium
H
(C
6
benzoate
COONa)
e.g.
Food
Sodium
preservation
e.g.
ham
and
benzoate
fizzy
drinks
bacon,
is
used
and
fruit
and
to
adds
preserve
juices.
At
a
flavour.
foods
pH
of
benzoate
is
converted
to
benzoic
acid
(C
H
6
Calcium
sulfate
(gypsum)
Did
?
you
.2H
4
inhibits
the
Manufacture
Plaster
of
of
which
of
plaster
O)
Paris,
and
back
it
gypsum
more
was
centuries
used
in
of
which
By
than
9000
through
many
the
parts
1700s,
of
the
became
known
years
used
bones
as
the
of
when
plaster
a
broken
paste
and
is
building
centre
as
for
the
were
time,
made
plaster
the
of
walls
the
of
its
to
of
Paris
fate
as
houses
was
make
Fire
of
did
not
and
1666.
heated
plaster)
to
is
about
made
300 °C
of
to
calcium
remove
sulfate
the
in
and,
used
them
suffer
had
in
Bandages
are
then
impregnated
with
water
the
Paris
powder.
When
water
is
added
to
the
dry
bandage,
forms
then
heat
wrapped
Plaster
an
of
to
is
around
orthopaedic
Paris
the
given
is
dry
also
the
off.
The
damaged
bandage,
limb,
with
where
it
its
hardens
cast.
used
plaster
to
as
a
building
make
a
material.
paste
which
is
Water
used
is
to
and
coat
ceilings.
of
salts
by
to
law,
While salts play such an impor tant role in our ever yday lives, some have also
cover
been
implicated
the
in
causing
various
healt h
problems.
Table
8.4.3
summarises
so
of
t hese
dangers.
same
T
able
8.4.3
Dangers
of
salts
Great
Salt
Dangers
Sodium
chloride
Sodium
nitrate
(NaCl)
(NaNO
)
Excessive
and
May
consumption
increase
a
person’
s
can
lead
risk
of
to
hypertension
developing
(high
blood
pressure).
cancer.
3
sodium
nitrite
(NaNO
)
Have
been
implicated
in
causing
brain
damage
in
children.
2
Sodium
H
(C
6
benzoate
Has
COONa)
May
1
Explain
2
What
3
Name
salts.
is
the
difference
of
most
each
the
increase
a
in
increasing
person’
s
risk
of
hyperactivity
developing
and
asthma
in
children.
cancer.
magnesium
anhydrous
Describe,
Describe
appropriate
salt
c
and
full
starting
we
calcium
c
magnesium
a
normal
method
the
write
a
two
salt
and
for
an
preparing
compounds
balanced
chloride
details,
with
use
sulfate.
you
magnesium
the
sulfate
how
following
you
chemical
chloride
giving
how
name
iron( III)
a
between
acid
salt.
crystallisation?
case
a
carbonate
5
implicated
questions
water
the
In
prepare
4
been
5
Summary
144
a
paste,
Paris
fireproof
the
and
it

London
which
Paris.
some
that
COOH)
5
microorganisms.
had
use
plaster
wood
Paris
of
forming
material
the
Paris
Dangers
At
of
(gypsum
been
crystallisation.
walls
become
growth
Paris
has
added
world.
pH,
sodium
plaster
setting
date
low
4.5,
2
is
origins
a
know?
(CaSO
The
with
below
5
each
equation
b
lead( II)
d
potassium
would
of
would
the
following
choose
for
the
to
reaction:
sulfate
prepare
nitrate.
magnesium
nitrate.
salts
in
b
our
everyday
sodium
lives:
hydrogencarbonate
Acids,
bases
A8.5
and
salts
Neutralisation
Neutralisation
n Unit 6.2 you learnt t hat a
a
base
and
an
acid.
n
a
reactions
Objectives
neutralisation reaction is any reaction between
neutralisation
reactions
reaction
a
salt
and
water
are
By
the
be
able
end
of
this
topic
you
will
to:
always
●
explain
●
describe
a
neutralisation
reaction
formed.
how
When a strong alkali reacts wit h a strong acid, t he reaction is complete when
neutralisation
neit her
an
alkali
nor
acid
is
present
in
excess.
At
t his
point
pH of 7
, i.e. t hey are neutral. This point is known as t he
or
end
t he
products
have
a
neutralisation point
point.
indicator,
temperature
●
describe
to
a
neutralisation
reaction
between
an
aqueous
alkali
and
an
acid,
t he
reaction
hydrogen
ions
remain
occurring
ions
in
of
t he
solution
is
between
acid.
as
These
spectator
t he
ions
ions.
hydroxide
react
For
to
ions
form
example,
of
t he
water
t he
alkali
and
t he
reaction
meter
using
and
change
how
we
use
reactions
in
our
t he
daily
actual
out
reactions
pH
neutralisation
n
carry
lives.
and
ot her
between
sodium hydroxide solution and hydrochloric acid can be summarised by t he
following
chemical
NaOH(aq)

equation:
Key
!
HCl(aq)
NaCl(aq)

H
O(l)
A
2
fact
neutralisation
reaction
reaction
between
a
base
is
a
and
an

The OH
ions from the sodium hydroxide and the H
ions from the hydrochloric
acid
to
form
a
salt
and
water.
acid react to form water, as shown in the following ionic equation:

OH
(aq)

H
(aq)
H
O(l)
2
Key

The
Na
and
Cl
ions
remain
in
solution
as
spectator
!
ions.
The reaction between t he hydroxide and hydrogen ions is described as being
The
an
point
exothermic
can
a
make
use
reaction
of
t his
fact
(see
Unit
when
12.1)
because
determining
t he
it
produces
heat
neutralisation
energy.
point
of
We
such
neutralisation
in
where
an
the
neither
reaction.
fact
point
acid–alkali
reaction
acid
nor
is
alkali
is
the
reaction
complete
is
and
present
in
excess.
Determining
acid–alkali
The
the
neutralisation
aqueous
acid
neutralisation
point
in
an
reaction
is
point
of
deter mined
a
by
reaction
between
perfor ming
a
an
aqueous
titration.
alkali
Dur ing
t he
and
an
titration,
t he volume of one solution required to neutralise a xed volume of anot her
solution
of
three
c hange.
using
is
deter mined,
ways:
We
using
will
now
temperature
Using
an
n
Unit
in
an
an
and
t he
neutralisation
indicator,
look
at
using
two
of
a
pH
t hese
point
meter
ways,
is
or
identied
using
using
an
in
one
temperature
indicator
and
c hange.
indicator
8.3
you
acidic
learnt
solution
t hat
and
an
ind icator
anot her
is
colour
a
in
substance
an
which
alkaline
has
one
colour
Did
?
performing
solution,
indicator
usually
are
a
t he
added.
titration
alkali,
The
is
using
placed
ot her
an
in
a
solution,
indicator,
a
conical
ask
usually
t he
know?
solution.
The
When
you
xed
and
acid,
a
is
volume
few
of
drops
added
one
of
t he
from
t he
neutralisation
determined
instead
is
of
added
using
an
in
point
a
pH
indicator.
small
can
be
meter
One
quantities,
solution
e.g.
3
2 cm
,
to
a
fixed
volume
of
the
burette and t he indicator will change colour at t he neutralisation point. This
other
point
is
determined
when
t he
colour
changes
on
t he
addition
of
a
solution
solution
drop
of
solution
from
t he
and
the
pH
of
the
single
changes
sharply
to
7
at
the
burette.
neutralisation
point.
Phenolpht halein and met hyl orange are t he most commonly used indicators
to
determine
t he
neutralisation
point
in
a
titration.
145
Neutralisation
reactions
Acids,
Using
temperature
When
using
a
 xed
a
of
and
salts
change
temperature
volume
bases
one
change
solution
is
to
deter mine
placed
in
an
t he
neutralisation
insulated
point,
container,
e.g.
a
polystyrene cup, and its temperature is recorded. The ot her solution is added
3
in
small
t he
is
quantities,
solution
is
recorded.
in
e.g.
2 cm
quic kly
The
temperature
,
procedure
have
from
stir red
been
t he
af ter
is
burette.
eac h
continued
recorded.
Using
addition
until
This
is
t he
and
several
known
t her mometer,
t he
temperature
successive
as
a
drops
thermometr ic
titration
A
graph
added
To
draw
t
are
and
of
is
t hen
from
t he
An
one
t hrough
intersection
example
of
of
showing
temperature
against
t he
volume
of
solution
burette.
graph,
drawn,
one
drawn
t he
t he
t he
t he
a
points
t hrough
points
two
graph
are
t he
plotted
points
where
lines
is
which
t he
the
and
t hen
where
t he
temperature
neutralisation
might
two
be
straight
temperature
is
lines
is
of
best
increasing
decreasing.
The
point
point.
obtained
when
hydrochloric
acid
3
is
added
to
25 cm
of
sodium
hydroxide
solution
is
shown
in
Figure
8.5.1.
3
The
graph
shows
t hat
1
1.0 cm
of
hydrochloric
acid
is
needed
to
neutralise
3
25 cm
of
sodium
hydroxide
solution.
neutralisation
the
temperature
point
increases
acid
is
as
more
added
the
temperature
decreases
)C°(
acid
is
as
more
added
erutarepme
T
0
2
4
6
8
10
12
14
16
18
3
Volume

Figure
8.5.1
Graph
of
hydrochloric
showing
acid
temperature
added
against
(cm
)
volume
of
hydrochloric
acid
3
added
to
25 cm
of
sodium
hydroxide
solution

The reaction between t he OH
in
t he
hydrochloric
acid
ions in t he sodium hydroxide and t he H
produces
ions
heat:

OH
(aq)

H
(aq)
H
O(l)
2

The
temperature
being
added
to
when
all
OH
This
is
reasons;
146
t he
t he
no
increases
react
wit h
ions
have
neutralisation
more
heat
completion,
acid
at
solution
heat
is
and
a
as
is
more
t he
reacted
point.
being
lower
being
acid
OH
is
ions.
and
The
t here
produced
to
t he
because
are
because
is
more
temperature
none
temperature
temperature
lost
added
The
t hen
t he
being
environment.
H
stops
lef t
in
t he
decreases
reaction
added
ions
solution.
for
has
which
are
increasing
t hree
reached
cools
t he
Acids,
T
o
bases
and
salts
determine
Your
teacher
the
may
observation,
●
Neutralisation
neutralisation
use
this
recording
activity
and
to
point
by
using
temperature
change
assess:
reporting
manipulation
●
and
measurement
3
Y
ou
will
be
supplied
polystyrene
cup,
a
with
burette
and
a
analysis
●
and
interpretation.
3
1.0 mol dm
reactions
sodium
hydroxide
solution,
3
1.0 mol dm
sulfuric
acid,
a
25 cm
pipette,
a
thermometer.
Method
1
Rinse
the
burette
with
some
sulfuric
acid
2
Rinse
the
pipette
with
some
sodium
hydroxide
and
ll
it
with
the
acid.
3
pipette
and
3
Using
4
Keeping
the
run
it
into
the
thermometer,
polystyrene
measure
and
solution.
Measure
25 cm
of
sodium
hydroxide
solution
in
the
cup.
record
the
temperature
of
the
sodium
hydroxide
solution.
3
solution
the
thermometer
with
the
in
the
thermometer
sodium
and
hydroxide
record
its
solution,
maximum
add
2 cm
of
acid
from
the
burette.
Quickly
stir
the
temperature.
3
5
Immediately
6
Repeat
step
quickly
as
7
Record
8
Use
5
another
until
you
2 cm
have
of
hydrochloric
recorded
four
acid,
quickly
successive
stir
drops
the
in
solution
and
temperature.
record
It
is
its
maximum
essential
that
temperature.
you
do
this
as
possible.
your
your
added.
add
results
results
Draw
to
two
in
a
table.
draw
a
straight
graph
lines
showing
of
best
the
temperature
of
the
solution
against
the
volume
of
sulfuric
acid
t.
3
9
10
Use
why
the
the
volume
of
sulfuric
acid
temperature
of
the
solution
increased
needed
(use
why
the
temperature
of
the
solution
stopped
why
the
temperature
of
the
solution
decreased.
Suggest
ant
T
able
Where
reasons
why
this
neutralisation
already
and
8.5.1
used
Antacids
studied
bee
neutralisation

determine
c
have
treat
to
b
Using
We
graph
to
neutralise
25 cm
of
sodium
hydroxide
solution.
Explain:
a
11
your
stings.
method
of
an
ionic
equation
to
help
you)
increasing
determining
the
neutralisation
point
is
less
accurate
than
using
an
indicator.
reactions
how
neutralisation
Table
8.5.1
reactions
summarises
t hree
can
be
ot her
used
ways
to
we
use
reactions.
Using
neutralisation
reactions
Action
Antacids
are
taken
to
treat
indigestion
and
acid
reflux.
They
may
contain
sodium
hydrogencarbonate
(NaHCO
),
magnesium
hydroxide
3
[Mg(OH)
]
2
excess
T
oothpaste
Acid,
aluminium
hydroxide
[Al(OH)
,
],
magnesium
carbonate
(MgCO
3
hydrochloric
produced
by
acid
in
bacteria
the
in
)
or
calcium
carbonate
(CaCO
3
).
They
work
T
wo
active
the
ingredients
in
mouth,
causes
toothpaste,
tooth
sodium
decay
by
reacting
hydrogencarbonate
with
the
and
calcium
sodium
hydroxyapatite
[Ca
monofluorophosphate
(PO
4
(Na
)
the
The
sodium
hydroxide
ions
hydrogencarbonate
in
the
calcium
neutralises
hydroxyapatite
any
acid
forming
in
the
calcium
mouth.
The
fluoroapatite
fluoride
ions
(PO
[Ca
10
Ca
(PO
10
Acids
Soil
treatment
Most
do
plants
)
4
not
(OH)
6
grow
(s)

2F
(aq)
Ca
2
react
best
(PO
10
with
calcium
if
the
soil
fluoroapatite
is
neutral.
hence
Finely
)
4
the
F
6
(s)
the
2OH
6
in
F
the
sodium
]
in
tooth
2
),
help
reduce
3
monofluorophosphate
displace
]:
2
(aq)
2
tooth
ground

)
4
(OH)
6
FPO
2
decay.
neutralising
stomach.
10
enamel.
by
3
enamel
calcium
does
not
carbonate
decay.
(limestone,
CaCO
)
or
lime
in
the
form
of
calcium
oxide
3
(quicklime,
CaO)
or
calcium
hydroxide
(slaked
lime,
Ca(OH)
)
can
be
added
to
soil
to
neutralise
any
acids
present.
However,
lime
cannot
2
be
added
beneficial
at
the
effects
same
of
time

an
ammonium
fertiliser
because
the
two
react
to
make
a
salt,
ammonia
gas
and
water
which
eliminates
the
both:

CaO(s)
as
2NH
4
2
(aq)
Ca
(aq)

2NH
3
(g)

H
O(l)
2
147
Volumetric
analysis
Acids,
Summary
1
What
2
Outline
a
By
the
be
able
end
of
an
this
topic
you
a
neutralisation
you
would
4
Why
should
time
to
three
salts
reaction?
perform
a
neutralisation
b
indicator
Give
and
questions
how
3
A8.6
Objectives
is
bases
uses
of
lime
neutralisation
and
an
reactions
ammonium
reaction
temperature
using:
change.
in
our
daily
fertiliser
not
be
lives.
added
at
the
same
soil?
Volumetric
analysis
will
Volumetric
analysis
involves
performing
a
titration
to
determine
t he
exact
to:
volume of one solution, usually an acid, required to neutralise a xed volume
●
explain
●
determine
volumetric
analysis
of
the
mole
ratio
anot her
t he
which
●
reactants
determine
the
and
of
a
can
usually
t hen
be
an
used
aqueous
alkali
quantitatively
in
or
carbonate.
one
of
two
The
results
of
ways:
combine
concentration
in
titration
●
to
determine
t he
mole
●
ratio
to
determine
t he
molar
of
t he
in
which
t he
two
reactants
combine
mass
concentration
used
solution,
in
concentration
and
mass
concentration
of
one
molar
one
reactants.
reactant
titration.
Determining
The
mole
ratio
mole
in
ratios
which
reactants
combine
can
be
determined
using
a
titration if t he mass or molar concentration of bot h reactants is known, i.e. if
t hey
are
bot h
standard
solutions.
Example
3
During
a
titration
it
was
found
t hat
25 cm
of
potassium
3
concentration
0.6 mol dm
hydroxide
of
molar
3
was
neutralised
by
10 cm
of
sulfuric
acid
of
3
molar
concentration
reactants
.
0.75 mol dm
Determine
t he
mole
ratio
t he
number
of
moles
of
potassium
hydroxide
t hat
3
concentration
3
i.e.
1000 cm
of
KOH(aq)
1 cm

0.6 mol dm
3
(1 dm
)
KOH(aq)
contains
0.6 mol
KOH.
0.6
_____
3
∴
KOH(aq)
contains
mol
KOH
1000
0.6
_____
3
and
25 cm
KOH(aq)
contains

25 mol
KOH
1000

Calculate
t he
number
of
moles
of
0.015 mol
sulfuric
acid
KOH
t hat
reacted:
3
Molar
concentration
of
H
SO
2
3
i.e.
1000 cm
(aq)

0.75 mol dm
4
3
(1 dm
)
H
SO
2
(aq)
contains
0.75 mol
4
H
SO
2
0.75
_____
3
∴
1 cm
H
SO
2
(aq)
contains
mol
4
H
SO
2
4
1000
0.75
_____
3
and
10 cm
H
SO
2
(aq)
contains

10 mol
H
4
SO
2
4
1000

0.0075 mol
H
SO
2
148
which
combine.
Calculate
Molar
in
4
4
reacted:
t he
Acids,
Use
bases
t he
and
salts
number
0.015 mol
of
KOH
Volumetric
moles
reacts
of
each
wit h
reactant
0.0075 mol
to
H
determine
2 mol
KOH
react
wit h
1 mol
H
SO
2
mole
ratio:
SO
2
∴
t he
analysiss
4
.
4
The mole ratio in which t he reactants combine is 2 mol potassium hydroxide
to
1 mol
sulfuric
acid.
Determining
The
t he
concentration
concentration
mass
or
standard
t hat
you
molar
solution.
followed
of
one
reactant
concentration
This
in
is
done
your
of
by
used
t he
in
a
following
calculations
titration
ot her
in
reactant
t he
Unit
same
can
is
be
determined
known,
four
steps,
i.e.
i.e.
if
1)
it
is
to
if
a
4),
7
.5.
Examples
1
A
student
solution
performed
of
a
titration
hydrochloric
acid.
to
determine
The
student
t he
used
concentration
a
standard
of
a
solution
of
3
potassium
hydroxide
wit h
a
concentration
of
0.1 mol dm
and
added
3
t he
hydrochloric
The
results
of
t he
acid
to
25 cm
experiment
of
are
Titration
Burette
t he
potassium
shown
in
t he
hydroxide
solution.
table.
number
reading
Rough
1
2
3
21.5
20.5
41.0
20.4
3
Final
reading/cm
3
Initial
reading/cm
0.0
0.0
20.5
0.0
21.5
20.5
20.5
20.4
3
Volume
of
acid
Determine
Calculate
added/cm
t he
t he
molar
average
concentration
volume
of
of
t he
hydrochloric
hydrochloric
20.5

acid
20.5

acid.
used:
20.4
__________________
average
volume
of
HCl(aq)

(
3
)
cm
3
3

20.5 cm
3
i.e. it takes 20.5 cm
3
of hydrochloric acid to neutralise 25 cm
of potassium
3
hydroxide solution, which has a concentration of 0.1 mol dm
The
balanced
chemical
KOH(aq)

equation
HCl(aq)
for
t he
reaction
KCl(aq)

H
is:
O(l)
2
1)
Calculate
t he
number
of
moles
of
potassium
hydroxide
t hat
reacted:
3
Molar
concentration
3
i.e.
1000 cm
of
KOH(aq)

0.1 mol dm
3
(1 dm
)
KOH(aq)
contains
0.1 mol
KOH.
0.1
_____
3
∴
1 cm
KOH(aq)
contains
mol
KOH
1000
0.1
_____
3
and
25 cm
KOH(aq)
contains

25 mol
KOH
1000

2)
Use
t he
KOH
balanced
and
1 mol
equation
to
0.0025 mol
determine
t he
KOH
mole
ratio
between
HCl:
KOH
reacts
wit h
1 mol
HCl.
149
Volumetric
analysis
Acids,
3)
Use
to
t he
number
calculate
0.0025 mol
4)
Use
t he
t he
of
moles
number
KOH
number
reacts
of
of
of
KOH
wit h
moles
from
moles
of
of
1)
and
HCl
from
3)
mole
ratio
and
from
salts
2)
reacting:
0.0025 mol
HCl
t he
bases
HCl
and
t he
volume
used
to
3
calculate
t he
number
of
moles
of
HCl
in
1 dm
:
3
Volume
of
HCl(aq)
used

20.5 cm
3
i.e.
20.5 cm
HCl(aq)
contains
HCl.
0.0025
_______
3
∴
0.0025 mol
1 cm
HCl(aq)
contains
mol
HCl
20.5
0.025
3
and
______
3
1000 cm
(1 dm
)
HCl(aq)
contains

1000 mol
HCl
20.5

0.122 mol
HCl
3
Therefore,
molar
concentration
of
HCl(aq)

0.122 mol dm
3
2
A
student
found
t hat
20.0 cm
of
hydrochloric
acid
of
unknown
3
concentration
were
required
to
neutralise
25 cm
of
sodium
carbonate
3
solution
wit h
a
concentration
The
balanced
Na
CO
2
concentration
of
t he

0.12 mol dm
hydrochloric
chemical
(aq)
of
equation
.
Calculate
t he
mass
acid.
for
t he
2HCl(aq)
reaction
2NaCl(aq)
is:

CO
3
(g)

H
2
O(l)
2
3
1)
Molar
concentration
of
Na
CO
2
3
i.e.
(aq)

0.12 mol dm
3
3
1000 cm
(1 dm
)
Na
CO
2
(aq)
contains
0.12 mol
Na
3
CO
2
3
0.12
_____
3
∴
1 cm
Na
CO
2
(aq)
contains
mol
Na
3
CO
2
3
1000
0.12
_____
3
and
25 cm
Na
CO
2
(aq)
contains

25 mol
Na
3
CO
2
3
1000

0.003 mol
Na
CO
2
2)
1 mol
Na
CO
2
3)
0.003 mol
reacts
wit h
2 mol
3
HCl.
3
Na
CO
2
reacts
wit h
2

0.003 mol
HCl
3

0.006 mol
HCl
3
4)
Volume
of
HCl(aq)
used

20.0 cm
3
i.e.
20.0 cm
HCl(aq)
contains
0.006 mol
HCl.
0.006
______
3
∴
1 cm
HCl(aq)
contains
mol
HCl
20.0
0.006
3
and
1000 cm
______
3
(1 dm
)
HCl(aq)
contains

1000 mol

0.3 mol
HCl
20.0
HCl
3
Therefore,
molar
concentration
of
HCl(aq)

0.3 mol dm
1
M(HCl)
i.e.
∴
mass
mass
of
of

1

1 mol
35.5
HCl
0.3 mol

HCl

36.5 g mol
36.5 g

0.3

36.5 g

10.95 g
3
Therefore,
150
mass
concentration
of
HCl(aq)

10.95 g dm
Acids,
T
o
bases
and
salts
determine
the
hydrochloric
Your
teacher
Volumetric
concentration
of
a
solution
analysis
of
acid
may
●
manipulation
●
analysis
use
and
and
this
activity
to
assess:
measurement
interpretation
3
Y
ou
will
be
supplied
hydrochloric
acid
with
of
0.2 mol dm
unknown
sodium
concentration,
hydroxide
methyl
solution,
orange
indicator,
a
3
25 cm
pipette,
a
conical
ask
and
a
burette.
Method
1
Rinse
2
Rinse
the
burette
with
some
hydrochloric
acid
and
ll
it
with
the
acid.
3
the
sodium
3
Add
the
4
a
with
hydroxide
few
drops
some
solution
of
sodium
in
methyl
the
hydroxide
pipette
orange
to
and
the
solution.
run
it
conical
into
Measure
the
ask
25 cm
conical
and
swirl
of
ask.
to
mix
contents.
Carry
This
out
time
orange
much
5
pipette
a
titration
add
on
the
as
described
acid
until
one
drop
adding
the
of
in
the
practical
solution
acid.
If
just
it
activity
turns
turns
red
from
you
on
page
yellow
have
141.
to
added
too
acid.
Record
your
results
in
a
table
as
outlined
in
the
practical
activity
on
page
3
6
142
and
Use
this
average
volume
concentration
help
or
vitamin
C
packaged
iodine
to
of
three
volumes
calculate
the
the
of
acid
molar
hydrochloric
which
were
concentration
acid.
Use
the
within
and
0.1 cm
.
mass
examples
above
to
you.
Determining
The
the
vitamin
(ascorbic
fr uit
solution.
juices
odine
C
acid)
can
acts
content
content
be
as
of
vitamin
determined
an
by
oxid ising
C
tablets,
fresh
performing
agent
(see
a
Unit
fr uit
juices
titration
using
9.3)
during
t he
titration and oxidises t he ascorbic acid to dehydroascorbic acid. The ascorbic
acid
is
acts
as
a
C
H
6
O
8
During
xed
is
(aq)
t he
t he
longer
starch
it
to
is
of
t he
of
(aq)
C
brown
juice
immediately
where
a
all
since
in
of
The
iodine
or
a
t he
O
6
iodine
(aq)
of
t he
1 mol
colour
t he
fr uit
of
by
colour.

ions.
The
reaction
ascorbic
in
The
is
added
vitamin
ascorbic
has
t he
end
2H(aq)
acid
from
C
acid
just
to
of
burette
As
t he
colourless
reacted,
solution
point
t he
tablet.
and
t he

iodine
reacts
a
ions.
will
wit h
titration
to
iodine
is
no
t he
when
forms.
iodine
juice
a
acid
remains
just
of
t he
ascorbic
iodine
to

6
solution
solution
reduced
t he
blue-black
blue-black
acid
H
6
concentration
calculated
reduces
equation:
2
fr uit
produce
ascorbic
and
dehydroascorbic
reduced.
permanent
f
agent
following


titration,
point
be
t he
acid
volume
added
At
in
6
ascorbic
a
reducing
summarised
solution
or
solution
acid
reacts
is
known,
of
wit h
a
t he
vitamin
1 mol
of
concentration
C
tablet
can
be
iodine.
151
Volumetric
analysis
Acids,
T
o
determine
Your
teacher
may
●
manipulation
●
analysis
and
be
the
Y
ou
will
e.g.
grapefruit
vitamin
use
and
this
C
content
activity
to
of
a
fruit
bases
and
salts
juice
assess:
measurement
interpretation.
supplied
with
a
sample
of
a
fruit
juice
without
pulp,
3
juice,
iodine
solution
of
concentration
0.005 mol dm
,
3
1%
starch
indicator
solution,
a
25 cm
pipette,
a
conical
 ask
and
a
burette.
Method
1
Rinse
the
burette
with
some
iodine
pipette
with
some
of
solution
and
ll
it
with
the
iodine
solution.
Summary
questions
3
2
3
1
A
volume
sodium
of
40 cm
carbonate
Rinse
juice
of
solution
of
3
Add
the
in
the
ten
pipette
drops
of
and
run
starch
it
the
into
fruit
the
indicator
to
juice.
Measure
conical
the
25 cm
of
the
fruit
ask.
conical
ask
and
swirl
to
mix
the
3
concentration
0.2 mol dm
contents.
3
reacts
with
20 cm
of
nitric
4
acid
of
Carry
out
a
titration
as
described
in
the
practical
activity
on
page
141.
concentration
This
time
add
the
iodine
solution
until
the
rst
permanent
trace
of
a
blue-
3
.
0.8 mol dm
Determine
black
the
mole
ratio
in
which
is
obtained.
the
5
reactants
colour
Record
your
results
in
a
table
as
outlined
in
the
same
practical
activity
combine.
on
page
142
and
average
the
three
volumes
of
iodine
solution
which
3
2
A
volume
sodium
of
30 cm
hydroxide
3
of
were
solution
within
0.1 cm
.
of
6
Use
this
volume
to
calculate
the
molar
concentration
and
mass
3
concentration
0.4 mol dm
concentration
of
ascorbic
acid
in
the
grapefruit
juice.
Use
the
examples
3
were
neutralised
by
20 cm
of
on
sulfuric
acid.
Determine
concentration
of
the
pages
149–50
to
help
you.
the
sulfuric
You could adapt t he experiment which you have just performed to determine
acid
in:
3
a
3
b
t he
effect
of
heat
on
t he
vitamin
C
content
of
a
fr uit
juice.
Planning
and
mol dm
designing
experiments
is
discussed
in
more
detail
in
t he
School-Based
g dm
Assessment
Key
section
on
t he
CD.
concepts

●
An
in
acid
●
An
●
Aqueous
to
●
acid
red,
substance
dibasic
An
●
We
which
pH
forms
of
react
water;
acids
acids
of
a
some
of
wit h
hydrogen
ions
(H
)
when
dissolved
be
or
of
t hese
7
taste,
and
metals
wit h
bases
change
conduct
to
as
to
form
that
organic
organic
form
organic
concentrated;
compound
variety
of
sour
hydrogencarbonates
classied
a
a
t han
reactive
react
dilute
is
donor.
have
less
and
and
may
tribasic;
across
proton
value
anhydride
use
a
carbonates
and
come
make
a
acids
or
acid
as
solutions
wit h
Aqueous
●
dened
have
dioxide
●
a
is
Aqueous
react
152
is
water.
in
in
a
salt
and
form
salt
strong
with
living
our
colour
electric
a
or
litmus
hydrogen;
carbon
water.
monobasic,
weak.
water
to
form
organisms
ever yday
of
current.
salt,
and
inorganic;
and
reacts
acids
acids
or
a
to
t he
an
an
and
acid.
we
activities.
Acids,
●
A
●
An
bases
base
and
salts
analysis
is dened as a proton donor.
alkali
is a base which dissolves in water to form a solution containing
hydroxide ions (OH
●
Volumetric
).
Aqueous solutions of alkalis have a bitter taste, change the colour of
litmus to blue, have a pH value greater than 7
, conduct an electric current
and feel soapy.
●
Bases react with acids to form a salt and water and react with ammonium
salts to form a salt, ammonia and water.
●
Amphoteric substances
●
Oxides
●
Strong acids and alkalis are fully ionised when dissolved in water.
●
Weak acids and alkalis are partially ionised when dissolved in water.
●
The strength of an acid or alkali is measured using the
ranges from
●
can react with acids and strong alkalis.
can be classied as acidic, basic, amphoteric and neutral.
pH scale
which
0 to 1
4
The stronger the acid, the lower the pH. The stronger the alkali, the higher
the pH.
●
Neutral substances have a pH of 7
.
●
Universal indicator or a pH meter is used to measure pH.
●
Other acid–alkali indicators have one colour in an acidic solution and
another colour in an alkaline solution.
●
A
salt
is a compound formed when some or all of the replaceable
hydrogen ions in an acid are replaced by metal or ammonium ions.
●
A
normal salt
replaced. An
is formed when all the hydrogen ions in an acid are
acid salt
is formed when only some of the hydrogen ions are
replaced.
●
Some salts contain water molecules trapped between their ions in the
cr ystal lattice. This is known as
water of crystallisation
●
nsoluble salts can be prepared by ionic precipitation.
●
Anhydrous binar y salts can be prepared by direct combination.
●
Potassium, sodium and ammonium salts can be prepared using a titration.
●
Other soluble salts can be prepared by reacting a reactive metal, an
insoluble carbonate or an insoluble base with an acid.
●
Salts play an extremely important part in our ever yday lives, but can also
be dangerous.
●
A
neutralisation reaction
is a reaction between a base and an acid to form
a salt and water.
●
The
neutralisation point
is the point in an acid–alkali reaction where the
reaction is complete and neither acid nor alkali is present in excess.
●
The neutralisation point of an acid–alkali reaction can be determined
during a titration by using an indicator, a pH meter or temperature
change.
●
Neutralisation reactions are used in various aspects of our daily lives.
●
Volumetric analysis
involves performing a titration to determine the
exact volume of one solution required to neutralise a xed volume of
another solution.
●
Results of a titration can be used to determine the mole ratio in which the
two reactants combine or to determine the concentration of one reactant.
●
The vitamin C content of a vitamin C tablet or fr uit juice can be
determined using a titration.
153
Practice
exam-style
questions
Acids,
9
Practice
exam-style
Multiple-choice
1
Which
of
t he
Magnesium
sulfate
can
be
prepared
bases
and
salts
by:
questions

reacting
magnesium
carbonate

reacting
magnesium
nitrate

reacting
magnesium
wit h
A

and

B

and

C
,
D

wit h
wit h
sulfuric
sulfuric
acid
acid
questions
following
is
not
a
proper ty
of
sulfuric
acid.
hydrochloric
only
acid?
A
t
turns
a
blue
B
t
is
C
t
reacts
strong
t
reacts
Which
of
magnesium
and
form
carbonate
dioxide
following
and
is/are
to
form
sodium

They
react
They
have
They
react

wit h
a
and

acids
pH
less
wit h
to
water.
a
salt
of
aqueous
and
hydrogen.
7
.
ammonium
salts
Which
an
proper ties
form
t han
only
to
form
a
of
t he
following
neutralisation
alkalis?


magnesium
10
sodium
carbon
t he
to
water.
wit h
chloride,
2
only
red.
electrolyte.
wit h
chloride
D
litmus
point
in
cannot
a
be
reaction
used
to
determine
between
an
acid
t he
and
alkali?
A
An
B
A
t hermometer
anemometer
C
A
pH
D
An
meter
indicator
salt,
3
11
ammonia
and
A
volume
of
of
25 cm
a
carbonate
solution
of
water.
3
concentration
A

and


C
,
and

D
3
A

neutralised
by
20 cm
of
3
acid
of
concentration
0.5 mol dm
.
The
mole
ratio
in
only
which

was
only
an
B
3
0.2 mol dm
and
t he
reactants
combine
is:

A
1 mol
of
carbonate
to
1 mol
of
acid
B
1 mol
of
carbonate
to
2 mol
of
acid
C
2 mol
of
carbonate
to
1 mol
of
acid
D
3 mol
of
carbonate
to
1 mol
of
acid.
only
weak
acid
A
is
B
ionises
C
has
is
one
which:
dilute
fully
in
aqueous
solution
3
12

a
low
concentration
of
A
volume
of
10 cm
of
sulfuric
acid
of
unknown
ions
H
3
concentration
D
does
not
ionise
in
aqueous
neutralised
25 cm
of
sodium
solution.
3
hydroxide
4
A
solution
which
has
a
pH
of
solution
concentration
A
is
more
B
is
less
C
is
more
alkaline
t han
a
of
concentration
.
0.4 mol dm
The
1
1:
solution
wit h
a
pH
of
of
t he
acid
is:
12
3
alkaline
t han
a
solution
wit h
a
pH
of
A
0.1 mol dm
B
0.25 mol dm
C
0.4 mol dm
D
0.5 mol dm
9
3
acidic
t han
water
3
D
is
less
alkaline
t han
a
sodium
hydroxide
solution
of
3
t he
5
The
same
actual
hydroxide
concentration.
change
which
solution
occurs
reacts
wit h
when
sodium
sulfuric
acid
is:
Structured

A
2Na
question
2
(aq)

SO
(aq)
Na
4
SO
2
(aq)
4

B
OH
C
2NaOH(aq) 
(aq)

H
(aq)
D
NaOH(aq)  H
H
13
O(l)
A
titration
is
used
to
determine
t he
volume
of
one
2
H
SO
2
Na
4
SO
2
(aq)
SO
2
(aq)
Na
4

2H
4
SO
2
(s)
O(l)
solution
Which
of
t he
following
acids
is
found
in
4
an
O(l)
solution.
Met hanoic
B
Et hanoic
neutralise
Titrations
a
xed
volume
of
can
be
used
as
a
means
of
soluble
salts
and
in
volumetric
analysis
t he
concentration
of
one
of
t he
solutions
acid
During
a
titration,
t he
neutralisation
point
C
Lactic
D
Hydrochloric
determined
by
using
an
indicator.
acid
a
acid
What
is
meant
by
t he
neutralisation
point
of
titration?
of
is
acid
usually
Which
to
sting?
used.
7
anot her
preparing
2
ant
determine
A
to
2
(aq)  H
cer tain
6
needed
t he
following
is
not
an
amphoteric
Lead(II)
B
Aluminium
n
order
to
ron(III)
Zinc
solution,
a
t he
concentration
student
is
of
provided
a
sodium
wit h
two
hydroxide
solutions
D
determine
oxide
hydroxide
C
marks)
substance?
b
A
a
(2
labelled
X
and
Y.
oxide
hydroxide
–
X
is
aqueous
sulfuric
acid
wit h
a
mass
3
concentration
8
A
pure
sample
of
lead(II)
chloride
can
be
prepared
of
19.6 g dm
by
–
Y
is
a
sodium
hydroxide
solution
of
unknown
reacting:
concentration.
A
lead
wit h
dilute
hydrochloric
B
lead(II)
hydroxide
C
lead(II)
nitrate
wit h
dilute
acid
hydrochloric
acid
To
determine
t he
concentration
of
Y,
t he
student
3
solution
wit h
sodium
chloride
titrates
t he
solution
X
against
readings
25.0 cm
from
t he
of
Y.
burette
The
gure
before
and
3
D
154
lead(II)
carbonate
wit h
hydrochloric
acid.
titration
using
25.0 cm
of
solution
Y.
shows
af ter
each
Acids,
bases
and
salts
Practice
c
0
17
2
19
4
Salts
can
be
prepared
i)
your
20
5
t he
before
wit h
answer
a
you
would
copper(II)
copper(II)
a
balanced
prepare
sulfate
a
in
variety
carbonate.
chemical
pure
t he
1
after
titration
nclude
would
before
to
your
(5
met hod
prepare
be
hydrated
different
if
i)
Using
t he
t he
table
in
for
copper(II)
2
marks)
you
sulfate
after
titration
(1
mark)
3
Total
Burette
sample
equation
cr ystals?
titration
of
laborator y
reaction.
How
wanted
after
by
23
ii)
before
how
anhydrous
star ting
3
laborator y
met hods.
Describe
of
18
t he
questions
22
different
1
in
exam-style
15
marks
readings
information
from
t he
gure,
complete
below.
Titration
number
1
2
3
needed
to
3
Final
burette
reading/cm
3
Initial
burette
reading/cm
3
Volume
of
solution
X
used/cm
(3
ii)
Calculate
t he
volume
of
X
marks)
neutralise
3
25 cm
iii)
of
Y.
Calculate
(1
t he
concentration
of
sulfuric
mark)
acid
in
3
solution
iv)
X
Calculate
used
v)
in
Write
in
t he
t he
a
mol dm
(1
number
of
moles
of
sulfuric
titration.
balanced
for
t he
Determine
t he
number
of
moles
mark)
reaction.
(2
vi)
acid
(1
equation
mark)
of
marks)
sodium
3
hydroxide
vii)
Calculate
in
t he
t he
of
25.0 cm
concentration
solution
of
Y
used.
(1
mark)
(1
mark)
sodium
3
hydroxide
c
How
in
b
i)
would
t he
in
solution
student
Y
use
in
t he
mol dm
.
titration
carried
to
prepare
a
pure
dr y
sample
of
sodium
sulfate
(2
ii)
to
prepare
a
pure
sodium
(1
Total
14
a
An
as
response
acid
a
can
proton
be
15
dened
acceptor.
as
a
proton
Explain
t he
donor
reason
and
for
acid
However,
t hey
marks
a
and
sulfuric
have
acid
different
are
pH
bot h
values.
base
EACH
(4
Carbonic
mark)
question
denition.
b
marks)
hydrogensulfate
solution?
Extended
out
above:
marks)
acidic.
You
are
3
supplied
i)
ii)
wit h
Suggest
Explain
a
a
solution
1.0 mol dm
pH
t he
value
reason
for
for
EACH
t heir
of
each
solution.
different
(2
pH
Give
one
way
suggested
pH
you
could
values
are
use
to
nd
correct.
out
if
marks)
values.
(2
iii)
acid.
marks)
your
(1
mark)
155
Oxidation–reduction
A9
reactions
Oxidation
and
reduction
reactions
form
a
very
important
Objectives
By
the
be
able
end
of
this
topic
you
will
part
of
our
everyday
photography,
●
describe
the
oxidising
action
and
of
common
in
dene
in
example,
in
batteries,
all
these
terms
of
oxidised
reduced
and
electron
the
electrons
and
are
the
rusting
being
of
cars.
transferred.
It
In
was
the
using
the
discovery
of
oxygen
that
the
chemistry
oxidation–reduction
reactions
was
understood.
reduction
transfer
reactant
and
reactions
after
behind
oxidation
identify
photosynthesis
everyday
activities
●
for
reducing
only
substances
●
lives,
to:
A9.1
being
reactant
electron
Oxidation
and
reduction
–
an
introduction
being
transfer.
The
discover y
stepping
when
metals
oxides.
and
stone
The
in
are
laborator y
chemistr y.
burned,
term
preparation
Antoine
t hey
oxid ation
combine
was
used
of
oxygen
Lavoisier
wit h
later
to
was
a
(1743–94)
oxygen
dene
ver y
from
any
impor tant
discovered
t he
air
reaction
to
in
t hat
form
which
a
reactant gains oxygen. An example, according to t his denition of oxidation,
is
t he
reaction
gained
between
oxygen,
2Mg(s)

magnesium
forming
O
and
magnesium
(g)
oxygen
where
t he
magnesium
has
oxide:
2MgO(s)
2
The
removal
reaction
of
oxygen
because
reduction
was
t he
used
from
metal
to
a
metal
oxide
dene
any
was
oxide
was
reduced
reaction
in
to
described
t he
which
a
pure
as
a
metal.
reactant
reduction
The
loses
term
oxygen.
An example, according to t his denition of reduction, is t he reaction between
iron(III)
oxide
and
carbon
where
t he
iron(III)
oxide
has
lost
oxygen
to
form
iron:
2Fe
O
2
These
(s)

3C(s)
4Fe(s)

3CO
3
(g)
2
denitions
were
later
extended
to
include
reactions
involving
hydrogen.
Hydrogen is chemically opposite to oxygen, therefore, oxidation was dened as
a loss of hydrogen and reduction was dened as a gain of hydrogen.
With
the
discovery
of
protons,
neutrons
and,
most
importantly,
electrons,
scientists rened their denitions of oxidation and reduction, and the denitions
were
rened
again
using
the
concept
of
oxidation
number
or
oxidation
state.
You will be studying these denitions in detail later in this unit.
Oxidation
We
and
encounter,
our
ever yday
Action
Bleach
used
and
of
is
and
lives.
reduction
make
We
use
will
of,
look
in
our
many
at
everyday
oxidation
some
of
t hese
and
activities
reduction
added
bleaches
oxygen

Figure
the
has
9.1.1
statue
oxidation
156
of
started
The
copper
Marcus
to
turn
from
Garvey
green
is
which
made
because
bleach
stain
to
to
are
clothes
chlorine
bleaches
remove
their
to
remove
bleaches
containing
coloured
containing
hydrogen
stains.
The
sodium
peroxide
most
stains
colourless
by
oxidising
form,
hence
the
the
coloured
stain
(H
O
summarises how the chlorate(I) ion (ClO
The
).
(aq)

coloured
dye
Cl
(NaClO)
Both
or
dyes,
equation
) in a chlorine bleach works:
(aq)

colourless
types
2
chemicals,
disappears.
commonly
chlorate(I)
of
ClO
in
bleaches
2
of
reactions
below.
dye
in
the
below
Oxidation–reduction
reactions
Oxidation
and
reduction
–
an
introduction
Rusting
When iron and its a lloy, ste el, co me into con t ac t w it h oxyg en an d mo isture
t he
iron
xH
O),
is
oxidised
by
t he
oxygen
to
fo r m
hydra te d
ir on (I II)
oxid e
(Fe
O
2
ot her wise
known
as
r ust .
Given
sufficient
t ime
a nd
3
ex po su re
to
2
oxygen
r ust
and
and
Browning
As
so on
suc h
t he
as
moist ure ,
of
as
cut
f ruits
cer t ain
pot atoes,
air.
a ny
iro n
ob j ec t
w ill
even tu ally
oxid ise
e n tir ely
to
disinteg ra t e .
fr uit s
a re
Enzymes
and
in
suc h
pee led
t he
vege tab les
as
or
plan t
a pple s
cut ,
c ells
an d
t he
on
cu t
t he
ban an as,
su r f ac e
su r f ac e
is
of
or
cer t ain
ex p ose d
t he
veget ables
to
fr u it
oxyg en
or
in
ve get ab le

begin
to
oxidise
cer t ain
c hemica ls
in
t he
ce lls
to
brown
Figure
on
known
tur n
n
as
melanins .
These
melanins
c a us e
t he
cut
or
9.1.2
da maged
su r f ac e
exposure
many
cases,
b rown in g
flavo ur,
is
qualit y
un desirab le
and
t aste.
b ec au se
Th e
it
me la n ins
cau se s
for med
c h an ges
a re
not
turns
in
the
brown
air
in
Did
?
you
in
some
case s
t h e ir
pro ductio n
is
use f u l
sinc e
it
con tr ib u tes
colour
and
flavour
of
ite ms
suc h
as
raisins,
pr u n es,
coffee,
t ea
to
and
are
pigments
to
of
eyes
skin,
of
hair,
and
scales,
animals.
ultraviolet
for
the
light
feathers
Exposure
stimulates
the
preservation
production
Sodium
sulfite
enhance
and
flavour,
discolouration
pot atoes
bacter ia
dr ied
brown
responsible
coc oa.
and
being
dark
t he
colour
Food
know?
tox ic
black
and
of
fo o ds
shr imp.
oxidising
de stroyed
pot ato
s ulfur
pre s e r ve
win e
by
The
bre at halyser
test
t he
te st ,
dic hromate(VI)
do
is
t he
as
used
dr ive r
c r y st a ls
(K
to
acid.
Any
et h an o l
test
O
2
)
t he
in to
vit amin
c hemicals
fr u it s,
Th ey
C
in
of
dic hromate(VI)
io n
t he
cr yst a ls
g re en
(se e
fr u it
dr ie d
oxidation
invo lve
reactio n s
electrons
electrons
to
was
was
t hat
sai d
said
to
to
a
in
)
lo ss
of
invo lved
h ave
produc e d
dur in g
leve l
have
of
in
t he
oran ge
be e n
b reat h
of
p ot assi um
t he
dr ive r ’s
acidified
b reat h
w ill
wit h
reduce
to
t he
green
c h romium(III)
io n
t he
(Cr
),
9.3).
Key
ele c tron s.
a
b ee n
be en
and
reduc t ion
can
fact
electrons
tran sfer
Th ey
of
oxid ised
develo ped
ele c tron s.
and
a
A
a
mo d el
su b st an c e
subst ance
t hat
for
by
an
is
in
a
being
t he
loss
of
loss
in
its
of
free
electrons
state
or
an
compound.
t h at
gained
reduced .
be
d ef ined
in
t er ms
of
ele c tron
Key
fact
t ran s fer,
Reduction
oxidation
the
element
element
!
Oxidation
skin
7
Un it
and
h ave
why
ju ic e
Oxidation
seemed
is
fr u its ,
By t h e tur n of t he 2 0t h ce nt ur y, c he mists realise d t h at ox id atio n reac tion s
always
which
sunlight.
dr ied
!
Oxidation–reduc tion
skin,
in
3
O
2
tur ning
human
darkens
pigments
7
vapo ur s
(Cr
in
melanin
p reven t
2
orange
to
and
of
for m.
sample
whic h
spoilage
dr ie d
b r own ing
a lco h o l
a
preservative s
preven t
ox id atio n .
t he
p reven t
reducing
food
or
j u ices,
c olo u rle ss
blow s
Cr
fr u it
p reven t
a lso
by
t h eir
as
r ed u c e
p reven ting
and
sh r imp
to
use d
and
by
They
2
sulfur ic
are
wine ,
t his
vine ga r
ba c k
te st
n
to
a nd
pro c e ss
breathalyser
dr iver s.
suc h
ox idat io n .
produc t s
browning
diox ide
fre sh ne ss
Th ey
The
lost
apple
oxygen
to
Melanins
t he
cut
to
brown.
appearance,
and
A
compounds
electrons
and
re duc tio n
b ein g
t he
gain
is
the
gain
of
electrons
of
by
an
element
in
its
free
state
or
an
electrons.
element
in
a
compound.
157
Oxidation
and
reduction
–
an
introduction
Oxidation–reduction
reactions
A substance will not lose electrons unless t here is anot her substance available
✔
Exam
to
tip
gain
t he
electrons,
i.e.
for
ever y
oxidation
reaction
t here
will
always
reduction reaction. These oxidation–reduction reactions are known as
You
must
oxidation
electron
be
able
and
transfer.
remember
to
define
reduction
these
remembering
An
in
easy
reactions.
terms
way
definitions
two
words:
is
of
to
t he
The
oxid ation
electrons
is
Oxidation
Is
RlG
Reduction
known
t hat
equation
as
t he
only
and
shows
t he
reduction
t he
loss
equation
half
of
t hat
electrons
only
is
shows
known
t he
gain
OlL
as
equation
RlG
of
redox
reactions
Loss
Is
1
Gain
Burning
magnesium
2Mg(s)
in

oxygen:
O
(g)
2MgO(s)
2
The
Key
!
redox
reaction
is
a
Each
consisting
magnesium
in
reduced
(MgO)
which
and
the
one
of
produced
Mg
in
atom
t he
reaction
is
an
ionic
2
ions
loses
and
two
O
ions.
electrons
to
During
form
a
t he
reaction:
magnesium
ion.
chemical
Magnesium
reaction
oxide
2
compound
●
A
magnesium
fact
reactant
other
is
(Mg)
is
oxid ised:
is
2
oxidised.
Mg
This
is

2e
more
Mg
correctly
written
as:
2
Mg
The
✔
Exam
Mg
overall
oxidation
2e
half
equation
is:
tip
2
2Mg(s)
When
and

writing
balanced
reduction
half
oxidation
equations
●
you
2Mg
Each
oxygen
form
an
atom
oxide
in
ion.
(s)
t he

4e
oxygen
Oxygen
(O
)
molecule
is
gains
two
electrons
to
reduced:
2
must
always
include
state
symbols
2
O
and
the
it
is
important
number
balance
at
of
to
ensure
atoms
each
side
and
of

2e
O
that
charges
The
overall
reduction
half
equation
is:
the
2
O
(g)

4e
2O
(s)
2
equation.
2
Adding
zinc
Zn(s)
to

copper(II)
CuSO
sulfate
(aq)
solution:
ZnSO
4
The
zinc
sulfate
displaces
and
copper
Writing
in
t he
t he
During
●

t he
Each
Cu
Cu(s)
copper(II)
ionic
2
Zn(s)

4
t he
copper.
(aq)
equation
sulfate
for
t he
to
form
zinc
reaction:
2
(aq)
Zn
(aq)

Cu(s)
reaction:
zinc
atom
loses
two
electrons
to
form
a
zinc
ion.
Zinc
(Zn)
is
oxid ised:
2
Zn(s)
●
Each
Zn
copper (II)
ion
(aq)
gains

two
2e
electrons
to
form
a
copper
atom.
The
2
copper(II)
ions
(Cu
)
are
reduced:
2
Cu
3
Bubbling
Cl
(aq)

chlorine
(g)

2e
gas
2Cu(s)
t hrough
2KBr(aq)
potassium
2KCl(aq)
bromide

Br
2
The
t he
(aq)
displaces
chloride
t he
and
bromine
bromine.
in
t he
potassium
Writing
t he
reaction:
(g)
2
158
gas
potassium
Cl
solution:
2
chlorine
form

2Br¯(aq)
2Cl¯(aq)

Br
(aq)
2
ionic
bromide
to
equation
a
of
by
Examples
OlL
equation
half
be
redox
for
Oxidation–reduction
During
t he
Each
●
reactions
Oxidation
numbers
reaction:
bromide
bromide
ions
ion
(Br
loses
)
are
2Br¯(aq)
one
electron
to
form
a
bromine
atom.
The
oxid ised:
Br
(aq)

2e
2
●
Each
chlorine
form
a
atom
chloride
in
ion.
t he
chlorine
Chlorine
(Cl
)
molecule
is
gains
one
electron
to
reduced:
2
Cl
(g)

2e
2Cl¯(aq)
2
onic
the
bonding
non-metal
always
atom.
involves
Any
a
transfer
reaction
in
of
electrons
which
ionic
from
bonds
the
are
metal
formed
atom
is
a
to
redox
reaction. Using the reaction between sodium and chlorine as an example:
2Na(s)

Cl
(g)
2NaCl(s)
2
Each
●
is
sodium
atom
loses
one
electron
to
form
a
sodium
ion.
Sodium
(Na)
oxid ised:

2Na(s)
Each
●
a
2Na
chlorine
chloride
atom
ion.
in
(s)
t he
Chlorine

2e
chlorine
(Cl
)
is
molecule
gains
one
electron
to
form
reduced:
2
Cl
(g)

2e
2Cl
(s)
2
Summary
1
Dene
2
State
questions
oxidation
whether
and
each
reduction
of
the
in
terms
following
half
of
a
transfer
equations
of
electrons.
shows
oxidation
or
reduction:
3
a
Fe
2
(aq)

3e
b
Fe(s)
Fe

c
Br
(aq)
2Br
(aq)

3
(aq)
Fe
(aq)

e
2
d
2e
Cu

2e
Cu(s).
2
3
In
the
has
following
been
Br
redox
reaction,
state
what
(aq)

2KI(aq)
2KBr(aq)

2
4
Why
A9.2
Redox
an
apple
turn
Oxidation
chemistr y
For
water,
oxidised
and
what
is
no
when
it
is
I
(aq)
cut
in
half?
numbers
in
Objectives
fur t her
reactions
example,
t here
brown
developed
oxidation–reduction
for m
been
2
does
electrons.
has
reduced:
t he
did
when
not
reaction
change
in
t he
chemists
always
between
number
of
involve
recognised
t he
hydrogen
valence
transfer
and
the
be
able
end
t he
atoms,
on
is
i.e.
t here
denitely
a
is
no
redox
transfer
reaction
of
valence
because
electrons.
t he
reaction
●
dene
●
determine
However,
involves
and
(g)

O
model
Oxidation
as
a
result
(g)
2H
2
of
development
number
oxidation
numbers
formulae
dene
oxidation
terms
of
and
oxidation
reduction
of
oxidation–reduction
t he
concept
indicates
chemical
identify
redox
number
change
in
identify
the
reactions
using
a
O(g)
2
number
of
oxidation
oxygen:
2
The
will
t he
●
2H
you
bot h
in
hydrogen
topic
any
●
reaction
this
to
from
of
of
to:
of
oxygen
electrons
By
t hat
of
t he
bonding.
reactions
oxid ation
number
of
was
number
electrons
expanded
or
lost,
by
oxid ation
gained
or
t he
state.
shared
●
oxidised
reduced
oxidation
reactant
and
the
using
oxidation
a
number
being
reactant
change
being
in
number.
159
Oxidation
numbers
Oxidation–reduction
Oxidation
Key
!
oxidation
fact
sign
The
oxidation
element
that
an
have
if
atoms
it
were
was
is
the
atom
all
in
the
the
ionic
number
of
theoretical
of
the
and
the
is
placed
1,
always
2,
can
of
an
before
and
be
t he
t here
positive,
element,
is
number
always
negative
unless
a
to
t he
or
zero.
number
indicate
number
af ter
impor tant
role
if
it
t he
is
When
zero,
is
a
positive
sign,
i.e.
writing
plus
or
t he
or
t he
minus
negative,
number
1
is
written.
would
between
compound
e.g.
charge
element
bonds
composed
an
numbers
number
reactions
the
containing
Oxidation
numbers
compounds
as
you
play
will
an
learn
in
sections
t hat
in
t he
naming
of
cer tain
follow.
compound
entirely
of
ions.
Rules
Before
for
you
determining
can
learn
how
to
oxidation
recognise
numbers
redox
reactions
using
t he
concept
of
oxidation number, you must learn how to determine t he oxidation numbers
of
●
elements.
The
For
To
do
oxidation
t his,
a
set
number
of
of
r ules
each
need
atom
of
to
an
be
followed.
element
in
its
free
state
is
zero.
example:
oxidation
number
of
an
oxidation
number
of
each
Al
atom
N
in
atom
Al
in

0
N

0.
2
●
The
oxidation
to
t he
in
Al
number
charge
on
t he
of
each
ion.
For
simple
ion
in
an
ionic
compound
is
equal
example:
3
O
2
:
oxidation
number
of
each
Al
ion

3
ion

2.
3
2
oxidation
●
number
The oxidation number of
of
each
O
hydrogen when present in a compound is always
1 except when bonded to a metal in a metal hydride where its oxidation
number is
1, e.g. in sodium hydride (NaH) and calcium hydride (CaH
).
2
●
The
2
oxidation
except
in
number
of
peroxides
oxygen
where
it
when
is
1,
present
e.g.
in
in
a
compound
hydrogen
is
peroxide
always
(H
O
2
●
The
sum
of
t he
compound
is
oxidation
zero.
For
numbers
example,
of
in
all
H
elements
O,
t he
present
oxidation
in
).
2
a
number
of
each
2
atom
must
add
up
2(oxidation
●
The
sum
of
OH
ion,

0

(2)

0
(2)

(2)

0
number
oxidation
ion
t he
zero:
2(1)
t he
polyatomic
to
is
equal
oxidation
(oxidation
of
H)

numbers
to
t he
of
O)
(2)
of
all
charge
number
number
(oxidation
of

elements
on
each
number
t he
ion.
atom
(oxidation

of
O)
present
For
must
add
number
in
a
example,
of
up
H)
(1)
to
in
t he
1:

1

1
Following these r ules, the oxidation number of any element can be determined
from
the
formula
of
the
compound
or
polyatomic
ion
in
which
the
element
occurs.
Examples
1
Determine
t he
oxidation
number
of
sulfur
in
sulfur
dioxide
(SO
).
2
(oxidation
number
of
S)

(oxidation
number
of
S)

(oxidation
number
of
S)

2(oxidation
∴
The
compound
sulfur
dioxide
number

0
2(2)

0
(4)

0

4
oxidation
(SO
)
can
be
of
number
called
O)
of
S
sulfur( IV)
oxide
2
because
160
t he
oxidation
number
of
sulfur
in
t he
compound
is
4.
Oxidation–reduction
2
Determine
t he
reactions
oxidation
Oxidation
number
of
nitrogen
in
t he
nitrate
ion
(NO
numbers
).
3
(oxidation
number
of
N)

(oxidation
number
of
N)

3(oxidation
3(2)

(oxidation
number
of
N)

(6)

∴
The
nitrate
ion
(NO
)
is
more
number
oxidation
correctly
of
number
called
t he
O)
of

N
1
1
1
5

nitrate( V)
ion
3
because
3
t he
Determine
carbon
in
oxidation
t he
number
oxidation
met hane
(CH
of
nitrogen
number
in
t he
ion
is
of
).
5.
C

4(1)

C

(4)

0
0
∴

4
4
The
4
oxidation
Determine
number
t he
manganese
in
of
oxidation
t he
carbon
is
number
MnO
ion
4
of
and
C
name
Mn

4(2)

1
Mn

(8)

1

7
4
t he
The
∴
ion.
oxidation
number
manganate( VII)
in
5
t he
t he
chromium
oxidation
in
K
Cr
2
name
of
manganese
because
of
t he
is
7.
The
oxidation
ion
is
called
number
of
t he
manganese
ion.
Determine
of
ion
Mn
t he
O
2
number
2(1)

2Cr

7(2)

(2)

2Cr

(14)

0
2Cr

12
Cr

6
and
7
compound.
∴
The
oxidation
The
compound
oxidation
6
number
is
called
number
Determine
t he
of
of
chromium
potassium
chromium
oxidation
in
number
is
0
6.
d ichromate( VI)
t he
because
of
t he
compound.
of
S

3(2)

2
S

(6)

2

4
2
sulfur
in
t he
sulte
ion
(SO
)
and
3
suggest
The
be
an
alternative
oxidation
called
t he
Oxidation
Cer tain
t his
elements,
name.
and

number
when
it
is
This
wit hout
When
is
its
9.2.3
give
9.2.1
containing
Compound
have
of
done
ions,
by
in
is
ion.
4.
∴
The
a
to
naming
t han
one
compound
include
placing
Roman
t he
t he
sulfur
more
impor tant
for
name
also
t he
t he
possible
or
ion
oxidation
oxidation
numerals
always
oxidation
t hat
in
ends
in
number.
contains
number
number
brackets
‘ ate’.
any
as
of
par t
t he
af ter
Tables
of
For
t hese
of
t he
element,
its
name.
9.2.1,
9.2.2
examples.
Names
of
compounds
manganese
Oxidation
of

T
able
ions
Name
9.2.2
Names
containing
Compound
of
compounds
and
nitrogen
Oxidation

T
able
ions
Name
of
manganese(IV)
NO
9.2.3
Names
containing
Compound
number
Mn
4
2
can
compounds
number
MnO
ion
S
ion
and
naming
charge,
naming
T
able
number
sulfate( IV)
elements
reason,
name
of
compounds
and
sulfur
Oxidation
Name
number
N
of
2
nitrogen(II)
oxide
4
nitrogen(IV)
3
nitrate(III)
ion
5
nitrate(V)
ion
SO
2
S
4
sulfur(IV)
oxide
6
sulfur(VI)
oxide
4
sulfate(IV)
ion
6
sulfate(VI)
ion
oxide
NO
2
KMnO
4
7
oxide
SO
3
potassium
2
NO
2
SO
3
manganate(VII)
2
NO
3
SO
4
161
Oxidation
numbers
Oxidation–reduction
Redox
Key
!
reactions
and
oxidation
reactions
number
fact
f we consider t he loss or gain of electrons and a change in oxidation number,
we
Oxidation
is
the
increase
oxidation
number
in
state
its
free
or
of
an
an
in
can
see
a
clear
link
between
t he
two.
the
element
element
in
Whenever
●
a
an
same
time,
atom
forms
atom
its
or
ion
oxidation
loses
electrons
number
it
has
increases.
been
For
oxidised.
example,
At
when
a
t he
sodium
compound.
increases
a
sodium
from
0
to
ion
1.
it
loses
The
one
sodium
electron
atom
has
and
its
been
oxidation
number
oxid ised:

Na
Key
!
oxidation
Reduction
is
the
oxidation
number
in
state
its
free
or
decrease
of
an
an
in
the
Whenever
●
element
element
in
time,
a
its
forms
compound.
a
an
numbers:
atom
oxidation
chloride
decreases
from
0
or
ion
is
Exam
easy
to
reduction
number,
ion
to
it
gains
1.
is
remember
a
you
electrons
decreases.
The
one
it
has
been
example,
electron
chlorine

For
and
atom
its
has
e
reduced.
when
a
t he
same
chlorine
atom
oxidation
been
At
number
reduced:
Cl
(0)
(1)
tip
when
make
it
it
that
decrease
because
anything,
Na
(1)
gains
number
numbers:
By considering t he
It
e
(0)
Cl
oxidation
✔

fact
in
oxidation
you
reduce
is
possible
to
change in oxidation number of each element in a reaction
determine
if
it
is
a
redox
reaction.
f
it
is
a
redox
reaction,
t he
oxidation number of one element will increase and t he oxidation number of
anot her
element
will
decrease.
less
Consider
t he
2Mg(s)
following

O
reaction
(g)
again:
2MgO(s)
2
We
can
write
magnesium
t he
ions
half
and
equation
show
t he
for
t he
oxidation
conversion
number
of
of
each
magnesium
to
below:
2
2Mg(s)
2Mg
(0)
(2)
Looking
atom
We
can
and
at
has
t his,
we
increased
write
show
t he
t he
can
see
from
half
(s)
0

t hat
to
t he
2.
equation
oxidation
4e
for
numbers
oxidation
Magnesium
t he
number
(Mg)
has
conversion
of
of
each
been
magnesium
oxid ised
oxygen
to
oxide
ions
below:
2
O
(g)

2
4e
2O
(0)
Looking
in
t he
(s)
(2)
at
t his,
oxygen
we
can
see
molecule
t hat
has
t he
oxidation
decreased
from
number
0
to
2.
of
each
Oxygen
oxygen
(O
)
has
atom
been
2
reduced
t is impor tant to note t hat in writing t he oxidation number of each element
we
disregard
number
of
a
any
Recognising
Changes
in
electrons.
subscripts
single
atom
redox
oxidation
The
or
or
ion
t he
are
not
numbers
We
element
reactions
number
oxidation
coefcients.
of
of
using
always
are
writing
t he
oxidation
only.
oxidation
brought
elements
in
about
covalent
numbers
by
a
transfer
substances
of
can
also change when t hey react to form ot her covalent substances. For example,
when
hydrogen
and
oxygen
react
2H
(g)
2
oxidation
162
numbers:
(0)
to

form
O
(g)
2
(0)
water:
2H
O(g)
2
(1)
(
2)
Oxidation–reduction
●
The
has
oxidation
increased
reactions
number
from
0
of
to
Oxidation
each
1.
hydrogen
Hydrogen
atom
(H
)
in
has
t he
been
hydrogen
numbers
molecule
oxid ised
2
●
The
oxidation
decreased
number
from
0
to
of
2.
each
oxygen
Oxygen
(O
)
atom
has
in
been
t he
oxygen
molecule
has
reduced
2
Redox
don’t
reactions
involve
which
a
transfer
number
by
1)
Write
t he
balanced
2)
Write
t he
oxidation
not
need
ions
3)
5)
to
is
t he
t he
f
t here
a
which
is
no
in
number
t he
which
of
has
increase
in
each
electrons
be
and
also
recognised
has
an
been
shows
been
a
t hose
using
which
oxid ation
reaction.
in
a
brackets
of
below
elements
in
it.
You
do
polyatomic
reaction.
increase
in
its
oxidation
number.
oxidised.
decrease
in
its
oxidation
number.
This
reduced.
oxidation
number
t he
numbers
during
shows
for
element
oxidation
element
which
of
can
equation
unchanged
oxidation
redox
transfer
below.
chemical
element
element
element
decrease
not
remain
a
electrons
outlined
which
Determine
is
steps
of
determine
which
Determine
This
4)
t he
involve
of
number
anot her
of
one
element
element,
t hen
and
t he
a
reaction
is
reaction.
Examples
1
Determine
been
which
reduced
in
CuO(s)
(2)(
element
t he
H

has
reaction
been
oxidised
between
(g)
Cu(s)
H

2
(0)
2)
and
copper(II)
which
oxide
element
and
has
hydrogen.
O(g)
2
(0)
(1)(
2)
reduced
oxidised
●
The oxidation number of each hydrogen atom in the hydrogen molecule
has increased from 0 to
1. Hydrogen (H
) has been oxidised.
2
2
●
The
oxidation
decreased
2
Determine
reduced
in
which
t he
CH
2
to
(g)
of
0.
element
reaction

4
(
number
from
2O
t he
Cu
ion
Copper(II)
has
been
between
(g)
t he
CO
2
and
and
(g)
has
oxide
been
which
has
reduced.
has
been
oxygen.
2H

2
(4)(
copper(II)
(CuO)
oxidised
met hane
(0)
4)(1)
in
oxide
O(g)
2
2)
(1)(
2)
oxidised
reduced
●
The
has
oxidation
increased
number
from
4
of
to
t he
4.
carbon
atom
Met hane
in
(CH
t he
)
met hane
has
been
molecule
oxid ised.
4
●
The
has
oxidation
decreased
number
from
0
of
to
each
2.
oxygen
Oxygen
atom
(O
)
in
has
t he
been
oxygen
molecule
reduced.
2
3
Determine
whet her
2AgNO
(aq)
3

(1)
Because
t he
following
MgCl
NO
(aq)
is
a
redox
2AgCl(s)

2
(2)(
t he
reaction
ion
1)
remains
(1)(
unchanged
in
1)
reaction
Mg(NO
or
)
3
not.
(aq)
2
(2)
t he
reaction,
i.e.
it
one
of
oxygen
is
in
3
t he
spectator
t he
ion
None
This
do
of
is
not
t he
not
ions,
a
t he
need
to
elements
redox
oxidation
be
has
numbers
of
t he
nitrogen
and
considered.
undergone
a
change
in
oxidation
number.
reaction.
163
Oxidising
and
reducing
agents
Oxidation–reduction
4
Determine
reduced
in
which
t he
Mg(s)
element
reaction
ZnSO

has
been
between
oxidised
and
which
magnesium
and
zinc
(aq)
MgSO
4
(0)
(aq)
been
sulfate.
Zn(s)

4
(2)
has
reactions
(0)
(2)
oxidised
reduced
2
Because
t he
SO
ion
remains
unchanged
in
t he
reaction,
t he
oxidation
4
numbers
of
t he
sulfur
and
oxygen
in
t he
ion
do
not
need
to
be
considered.
The
●
oxidation
Magnesium
number
(Mg)
has
of
t he
been
magnesium
has
increased
from
0
to
2.
oxid ised.
2
The
●
oxidation
from
2
to
0.
number
Zinc
of
each
sulfate
Zn
(ZnSO
ion
)
has
in
t he
been
zinc
sulfate
has
decreased
reduced.
4
Summary
questions
1
Dene
2
Determine
the
a
copper
in
b
sulfur
c
carbon
oxidation
in
and
reduction
oxidation
in
number
terms
of
oxidation
number.
of:
CuO
H
S
2
in
each
of
CO,
CO
,
H
2
d
nitrogen
in
each
of
NH
,
Mg
3
e
chlorine
in
each
of
AlCl
CO
2
N
3
,
and
C
3
H
2
and
NH
2
NaClO
and
KClO
3
3
Use
oxidation
reactions.
If
number
they
are
oxidised
and
a
Cl

b
4Al(s)

3O
c
Mg(s)

2HCl(aq)
d
BaCl
(g)
the
to
3
determine
redox
reactant
whether
reactions
which
2KI(aq)
4
Cl
4
has
give
been
2KCl(aq)

I
2
the
the
following
reactant
are
which
redox
has
been
reduced:
(aq)
2
(g)
2Al
2
O
2
(s)
3
MgCl
(aq)

H
2
(aq)

H
2
SO
2
(aq)
(g)
2
BaSO
4
(s)

2HCl(aq).
4
Objectives
By
the
be
able
end
of
this
topic
you
will
A9.3
n
●
dene
the
reducing
terms
agent
oxidising
dene
in
terms
any
redox
of
●
One
terms
oxidising
in
terms
oxidation
One
This
oxidising
as
t he
reactant
as
t he
can
brings
about
oxid ising
brings
occur
simultaneously.
t he
oxidation
of
t he
ot her
reactant.
This
is
reduction
of
t he
ot her
reactant.
This
is
agent
about
reducing
generally
oxidised
and
of
compounds
A

oxidised
can
oxidising
reduction
t he
agent
be
B
symbolised
is
t he
as
reactant
follows,
t hat
has
where
been
A
is
t he
reactant
reduced:
agents
examples
which
and
and
been
reducing
oxidation
number
recognise
give
agents
of
known
●
reducing
and
●
agent
reaction,
reactant
known
the
reducing
●
and
and
electrons
●
Oxidising
to:
act
as
agent
both
and
a
B
C

D
reduced
an
reducing
n
t he
above
reaction:
agent
●
describe
oxidising
164
tests
and
to
●
A
●
B
must
have
been
oxidised
by
B.
B
is
t he
oxidising
agent.
identify
reducing
agents.
must
have
been
reduced
by
A.
A
is
t he
reducing
agent.
t hat
has
Oxidation–reduction
Oxidising
Consider
and
t he
2Al(s)
reactions
reducing
example

Oxidising
of
aluminium
(g)
3Cl
agents
2AlCl
2
●
The
in
terms
reacting
wit h
of
chlorine
has
form
been
an
(s)
oxidised
aluminium
Key
!
gas:
An
because
ion
(Al
each
atom
agents
has
lost
t hree
by
fact
oxidising
the
3
to
reducing
electrons
3
aluminium
electrons
and
agent
oxidation
causing
of
an
brings
another
atom
or
about
reactant
ion
in
that
):
reactant
to
lose
electrons.
3
2Al(s)
The
2Al
chlorine
Chlorine
atoms
(Cl
)
is
(s)

brought
t he
6e
about
oxid ising
t his
loss
by
taking
t hese
electrons.
agent
2
●
The
chlorine
gained
one
3Cl
has
been
electron
(g)

reduced
to
form
6e
a
because
chloride
6Cl
each
ion
atom
(Cl
in
t he
molecule
Key
!
):
A
(s)
fact
reducing
agent
brings
about
2
the
The
aluminium
atoms
brought
about
t his
gain
by
donating
Aluminium
(Al)
is
t he
reducing
a
oxid ising
reducing
agent,
agent
Oxidising
t herefore,
causes
and
causes
anot her
reducing
anot her
reactant
to
agents
reactant
gain
in
another
reactant
causing
an
atom
or
ion
in
that
agent.
reactant
An
of
t hese
by
electrons.
reduction
to
lose
electrons
to
gain
electrons.
and
electrons.
terms
of
oxidation
Exam
✔
tip
number
It
Consider
t he
example
of
magnesium
burning
in
oxygen
can
learn
2Mg(s)

O
(g)
(0)
(2)(
agent
2)
to
reduced
magnesium
has
magnesium
been
atom
oxidised
has
because
increased
from
t he
0
to
oxidation
2.
confusing
number
Oxygen
(O
)
is
well
as
reducing
them
know
out
that
electrons
of
to
try
to
oxidation
those
agent.
when
Oxidation
(OIL).
of
An
It
and
oxidising
is
better
needed.
Is
the
oxidising
Loss
agent
of
must
each
as
and
work
Y
ou
of
The
very
definitions
reduction
oxidised
●
the
2MgO(s)
2
(0)
be
again:
cause
this
loss
by
taking
these
t he
2
electrons.
oxid ising
agent
because
it
is
t he
reactant
t hat
caused
t he
increase
The
oxygen
has
atom
been
reduced
because
t he
oxidation
number
of
has
decreased
An
ion
agent,
anot her
number
of
because
from
it
is
0
t he
to
2.
Magnesium
reactant
t hat
(Mg)
caused
t he
is
of
in
an
t herefore,
atom
or
to
ion
causes
increase.
in
A
anot her
t he
oxidation
reducing
reactant
number
agent
to
of
causes
an
t he
atom
decrease
which
in
CuO(s)
(2)(
reactant
t he

H
is
t he
reaction
oxdising
between
(g)
Cu(s)
2
(0)
2)
agent
and
copper(II)

(0)
H
which
oxide
is
and
the
reducing
this
gain
reducing
by
agent
giving
itself
fact
oxidation
agent
of
brings
another
about
reactant
t he
by
causing
the
oxidation
an
atom
ion
in
number
of
hydrogen.
O(g)
or
that
reactant
to
increase
2
(1)(
Is
electrons.
oxidising
the
agent
cause
The
Key
An
reducing
A
or
Examples
Determine
(RIG).
oxidation
!
1
must
electrons.
loses
reactant
Reduction
electrons
t he
decrease
number.
oxid ising
in
agent
that
each
agent
reducing
oxidation
itself
electrons.
know
Gain
oxygen
agent
number.
Y
ou
●
oxidising
in
gains
oxidation
The
2)
reduced
oxidised
Key
!
●
Copper (II)
t he
oxide
hydrogen
atom
to
by
increase
(CuO)
is
causing
from
0
t he
t he
to
oxid ising
oxidation
agent
number
because
of
each
it
hydrogen
A
reducing
reduction
1.
causing
●
Hydrogen (H
fact
oxidised
agent
of
the
brings
another
about
reactant
oxidation
the
by
number
of
) is the reducing agent because it reduced the copper(II)
2
an
atom
or
ion
in
that
reactant
to
2
oxide by causing the oxidation number of the Cu
ion to decrease from
decrease
2 to 0.
165
Oxidising
and
reducing
agents
Oxidation–reduction
2
✔
Exam
Determine
reducing
tip
Zn(s)
It
is
better
to
work
out
which
agent
H

of
oxidising
t he
SO
2
is
t he
reaction
oxdising
between
(aq)
ZnSO
4
agent
zinc
(aq)

4
and
and
which
sulfuric
H
is
t he
acid.
(g)
2
the
(0)
definitions
reactant
in
reactions
agent
(1)
(0)
(2)
and
oxidised
reducing
of
agent
oxidation
need
using
number
the
concept
when
reduced
you
them.
Sulfuric
●
acid
(H
SO
2
If
you
remember
involves
number,
an
an
that
increase
oxidation
in
oxidising
zinc
oxidation
agent
from
this
0
causing
to
is
t he
oxid ising
agent
because
it
oxidised
t he
4
t he
oxidation
number
of
t he
zinc
atom
to
increase
2.
must
Zinc
●
cause
by
)
(Zn)
is
t he
reducing
agent
because
it
reduced
t he
sulfuric
acid
increase.

by
If
you
remember
that
number,
a
a
decrease
reducing
in
this
oxidation
number
of
each
H
ion
to
decrease
from
1
0.
oxidation
agent
must
3
cause
t he
reduction
to
involves
causing
s
iron(III)
oxide
behaving
as
an
oxdising
agent
or
a
reducing
agent
when
decrease.
it
reacts
wit h
Fe
O
2
carbon
(s)
3CO(g)

3
(3)(
monoxide?
2)
(2)(
2Fe(s)
3CO

(g)
2
(0)
2)
(4)(
2)
oxidised
To
determine
t he
carbon
t he
behaviour
monoxide
has
of
iron(III)
been
oxide
oxidised
or
we
need
to
look
to
see
if
reduced.
The carbon monoxide has been oxidised. The iron(III) oxide (Fe
O
2
) is
3
behaving as an oxidising agent because it caused the oxidation number of
the carbon atom in the carbon monoxide (CO) to increase from
Substances
reducing
There
are
agents.
Sulfur
can
behave
as
both
oxidising
and
agents
some
Their
compounds
that
2 to 4.
compounds
behaviour
which
dioxide,
can
which
depends
behave
in
can
on
t his
act
t he
as
bot h
ot her
way
are
oxidising
reactant.
given
and
reducing
Examples
of
two
below.
SO
2
Sulfur dioxide usually acts as a
it
reacts
wit h
SO
(g)
2
reducing agent. This is seen, for example, when
chlorine:
Cl

(g)
2

2H
O(l)
H
2
SO
2
(aq)
4

2HCl(aq)
(0)
(
reduced
by
1)
SO
2
The
sulfur
each
dioxide
chlorine
When
it
sulde,
reacts
sulfur
2H
S(g)
2
(
reduced
atom
in
wit h
a
dioxide

SO
t he
t he
chlorine
chlorine
stronger
behaves
(g)
reducing
as
an
3S(s)
2
by
causing
molecule
agent
oxidising

to
2H
t he
oxidation
decrease
t han
from
itself,
0
such
number
to
as
of
1.
hydrogen
agent:
O(l)
2
(0)
2)
oxidised
by
SO
2
The
sulfur
dioxide
oxidised
t he
hydrogen
sulde
by
causing
t he
oxidation
number of t he sulfur atom in t he hydrogen sulde molecule to increase from
2
166
to
0.
Oxidation–reduction
reactions
Oxidising
and
reducing
agents

Acidified
hydrogen
peroxide,
H
/H
O
2
2
Acidied hydrogen peroxide is hydrogen peroxide solution to which sulfuric
acid
has
been
example,
added.
when
2K(aq) 
(
it
t
usually
reacts
H
O
2
wit h
(aq)
 H
2
behaves
SO
2
oxidising
(aq)

4
hydrogen
oxidation
it
agent.
This
is
seen,
for
2
(g)  K
SO
2
4
(aq)  2H
O(l)
2
(0)
by
H
O
2
When
an
iodide:
1)
oxidised
The
as
potassium
peroxide
number
reacts
of
wit h
oxidised
t he
a
2

ion
stronger
to
t he
potassium
increase
oxidising
from
agent
iodide
1
to
t han
by
causing
t he
0.
itself,
such
as
acidied
potassium manganate(VII), acidied hydrogen peroxide behaves as a
reducing
agent:
2KMnO
(aq)  5H
4
O
2
(aq)  3H
2
SO
2
(aq)
K
4
SO
2
(aq)  5O
4
(g)  2MnSO
2
(7)
reduced
by
H
t he
hydrogen
oxidation
T
ests
There
O(l)
2
O
2
The
(aq)  8H
4
( 2)
for
are
chemical
peroxide
number
reduced
of
t he
oxidising
cer tain
in
a
agents
ver y
potassium
manganese
chemicals
reaction
t he
2
to
and
which
distinct
from
reducing
undergo
way,
manganate(VII)
decrease
e.g.
to
by
causing
2.
agents
oxidation
they
7
may
or
reduction
change
to
a
in
a
distinct
colour, they may form a par ticular precipitate or they may give off a par ticular
gas. Chemists use these chemicals to determine whether unknown substances
are oxidising agents or reducing agents. They do this by reacting the unknown
substance with these chemicals and obser ving the products. These chemicals
form
the
basis
of
tests
for
oxidising
agents
and
reducing
agents.
Examples
Potassium
iod ide
Potassium
iod ide
agent.
brown
There
when
because
(
)
is
t he
which
a
t he
solution,
solution
distinct
K (aq)
is
potassium
oxidising
dissolves
used
colour
agent
forming
in
t he
change
iodide
is
laborator y
in
t he
oxidised.
oxidises
t he
a
solution.
brown
to
test
solution
The
colourless
for
from
colour
iodide
an
oxidising
colourless
change
ion
(
)
to
occurs
to
iodine
2
(

(aq)
2
(aq)
2

2e
(0)
1)
oxidised
The
potassium
iodide
is,
itself,
a
reducing
agent.

Acid ied
potassium
manganate(VII)
solution,
H
/KMnO
(aq)
4
Acid ied
test
for
from
The
a
potassium
reducing
purple
colour
to
manganate(VII)
agent.
colourless
change
There
when
occurs
is
a
t he
because
solution
distinct
is
potassium
t he
used
colour
in
t he
change
in
laborator y
t he
manganate(VII)
reducing
agent
reduces
is
to
solution
reduced.
t he
pur ple
2
manganate(VII)
ion
(MnO
)
to
t he
colourless
manganese(II)
ion
(Mn
).
4
2
MnO
(aq)
Mn
(aq)
4
(7)
(2)
reduced
The
acidied
potassium
manganate(VII)
is,
itself,
an
oxidising
agent.
167
Oxidising
and
reducing
agents
Oxidation–reduction
T
ests
for
oxidising
Table
9.3.1
chemicals
These

chemicals
T
able
9.3.1
Reducing
for
agents
summarises
which
can
are,
t he
be
agents
used
agent
iodide
as
used
Visible
test
Potassium
names
used
t hemselves,
Reducing
agent
reactions
solution
colour
reactants
reducing
to
test
change
is
and
t he
for
changes
to
test
of
for
t he
main
oxidising
two
agents.
agents.
the
when
presence
of
an
oxidising
agent
Explanation
oxidised
Colourless
to
brown
The
(KI(aq))
colourless
iodine
(I
)
iodide
which
ion
(I
dissolves
)
is
oxidised
forming
a
to
brown
2
solution
2
Iron(II)

Figure
9.3.1
Potassium
iodide
sulfate
solution
Pale
green
to
yellow-brown
The
(aq))
to
4
colourless
to
brown
green
iron(II)
ion
(Fe
)
is
oxidised
3
(FeSO
from
pale
turns
the
yellow-brown
iron(III)
ion
(Fe
)
when
oxidised
There
are
reactions,
oxidising

T
able
several
agent.
9.3.2
Reducing
ot her
alt hough
These
Other
chemicals
t hey
are
are
common
agent
given
sulfide
gas
(H
S(g))
reducing
A
which
usually
in
Visible
is
Hydrogen
not
Table
behave
used
to
as
test
reducing
for
t he
agents
presence
in
of
an
9.3.2.
agents
change
when
agent
Explanation
oxidised
yellow
precipitate
forms
Yellow
insoluble
sulfur
(S)
is
2
produced
Concentrated
hydrochloric
acid
A
yellow-green
gas
is
evolved
Yellow-green
chlorine
gas
(Cl
)
2
is
(HCl(aq))
Others:
hydrogen
gas
(H
);
carbon
(C);
carbon
monoxide
(CO);
reactive
produced
metals
2
T
ests
for
reducing
Table
9.3.3
chemicals
These

summarises
which
chemicals
T
able
9.3.3
Oxidising
agents
can
are,
used
agents
for
test
potassium
manganate(VII)
as
used
and
t he
colour
reactants
oxidising
to
Visible
is
Acidified
names
used
t hemselves,
Oxidising
agent
t he
be
test
for
change
changes
to
test
of
for
t he
main
reducing
two
agents.
agents.
the
presence
when
agent
of
a
reducing
agent
Explanation
reduced
Purple
to
colourless
solution
The
manganate(VII)
purple
(MnO
)
is
reduced
to
ion
the
4

(H
/KMnO
(aq))
colourless
manganese(II)
ion
4
2
(Mn
Acidified
potassium
dichromate(VI)
Orange
to
green
)
The
orange

solution
(H
dichromate(VI)
ion
2
/K
2
Cr
2
O
(aq))
(Cr
7
2
O
)
is
reduced
to
the
7
3
green

Figure
9.3.2
(a)
manganate( VII)
colourless
potassium
orange
to
Acidied
turns
when
purple
reduced.
dichromate( VI)
green
potassium
from
when
(b)
to
Acidied
turns
from
reduced
(a)
168
(b)
chromium(III)
ion
(Cr
)
Oxidation–reduction
reactions
Oxidising
and
reducing
agents
There are several ot her chemicals which behave as oxidising agents, alt hough
t hey
are

are
not
given
T
able
in
usually
Table
9.3.4
Oxidising
used
to
Other
common
agent
sulfate
for
oxidising
Visible
is
Iron(III)
test
t he
presence
of
a
reducing
agent.
These
9.3.4.
solution
agents
change
when
agent
Explanation
reduced
Yellow-brown
to
pale
green
The
yellow-brown
iron(III)
ion
3
(Fe
(SO
2
)
4
(aq))
)
(Fe
is
reduced
to
the
pale
3
2
green
Dilute
or
concentrated
(HNO
(aq))
nitric
acid
A
brown
gas
is
evolved
(NO
3
Hot
iron(II)
Brown
)
ion
(Fe
nitrogen
is
)
dioxide
gas
produced
2
concentrated
sulfuric
acid
A
pungent
gas
is
evolved
Sulfur
dioxide
gas
(SO
)
is
2
H
SO
2
(l))
which
turns
acidified
potassium
produced
4
manganate(VII)
Others:
sodium
chlorate( )
solution
(NaClO);
oxygen
colourless
gas
(O
);
chlorine
gas
(Cl
2
T
o
investigate
Your
teacher
the
may
reactions
use
this
activity
●
observation,
recording
●
analysis
interpretation.
Y
ou
will
be
and
supplied
dichromate( VI),
with
and
oxidising
to
manganese(IV)
oxide
(MnO
)
2
agents
and
reducing
agents
assess:
reporting
aqueous
potassium
of
);
2
iodide,
solutions
iron( II)
of
acidied
sulfate
and
potassium
acidied
manganate( VII),
hydrogen
peroxide
acidied
and
ve
potassium
test
tubes.
Method
3
1
Place
2 cm
solution,
of
acidied
shaking
as
potassium
you
add
the
manganate( VII)
solution,
until
solution
you
see
no
into
the
further
rst
test
colour
tube.
Slowly
add
3
2
Place
potassium
iodide
change.
3
2 cm
of
acidied
potassium
manganate( VII)
solution
into
the
second
test
tube,
2 cm
of
acidied
potassium
3
dichromate( VI)
iron(II)
as
sulfate
you
add
3
Record
in
4
Explain
the
T
ables
5
Dene
a
2
In
in
and
on
the
each
of
reducing
into
the
the
until
original
for
9.3.3
the
third
fth
you
behaviour
tube.
see
colour
colour
above
tube,
to
of
Slowly
no
of
the
2Fe
b
2NO(g)
each
O
Give
an
agent
acidied
colour
you
iodide
solution
hydrogen
into
peroxide
the
fourth
solution
to
tube
each
and
2 cm
tube,
of
shaking
change.
and
the
observed
hydrogen
nal
in
colour
each
after
reaction.
mixing.
Use
the
information
given
in
peroxide.
questions
of
the
oxidising
agent
and
b
electrons
following
reactions
reducing
in
terms
identify
the
(s)
agent
of
oxidation
oxidising
number.
agent
and
the

3C(s)
3CO
(g)

4Fe(s)
2

2CO(g)
N
(g)

2CO

2HCl(aq)
(g)
2
MgCl
(aq)

H
2
3
add
solution
that
acidied
3
Mg(s)
potassium
you.
2
c
of
further
change
help
3
2 cm
agent:
a
2
the
terms
terms
the
reason
9.3.1
into
solution,
table
Summary
1
solution
the
a
Comment
solution
example
and
as
a
of
a
compound
reducing
which
(g)
2
can
act
both
as
an
oxidising
agent.
169
Oxidising
and
reducing
agents
Oxidation–reduction
Key
●
concepts
We
encounter,
our
of
ever yday
fr uits,
and
lives.
and
breat halyser
make
We
make
use
Oxidation–reduction
●
Many
●
Oxid ation
state
or
an
or
an
Oxidation
oxidation
●
dened
element
is
of
t hem
and
involve
as
in
dened
element
oxidation
t hem
in
in
and
reduction
r usting
bleaches,
food
and
reactions
t he
in
browning
preser vation
and
t he
a
t he
a
a
known
transfer
loss
of
of
as
redox
reactions
electrons.
electrons
by
an
element
in
its
free
compound.
as
in
are
t he
gain
of
electrons
by
an
element
in
its
free
compound.
reduction
can
also
be
dened
using
t he
concept
of
number.
Oxid ation
would
of,
reactions
reactions
is
Reduction
state
●
redox
use
encounter
test.
●
●
reactions
number
have
containing
if
it
all
t he
were
is
t he
t heoretical
bonds
ionic
between
and
t he
charge
t he
t hat
atoms
compound
in
was
an
atom
t he
of
an
element
compound
composed
entirely
of
ions.
●
n
any
redox
numbers
●
Oxid ation
in
●
its
free
free
An
is
A
oxid ising
●
An
●
A
●
An
will
always
be
a
change
in
t he
oxidation
an
an
as
an
as
a
is
t he
in
a
in
a
in
oxidation
number
of
an
element
compound.
decrease
element
agent
increase
element
in
oxidation
number
of
an
element
reactant
t hat
brings
about
t he
oxidation
of
agent
is
t he
reactant
t hat
brings
about
t he
reduction
of
reactant.
oxidising
reducing
agent
agent
oxidising
causes
causes
agent
t he
t he
causes
ot her
ot her
t he
reactant
reactant
oxidation
to
to
lose
gain
number
electrons.
electrons.
of
anot her
element
to
increase.
●
A
reducing
agent
causes
t he
oxidation
number
of
anot her
element
to
decrease.
●
The
distinctive
reduction
when
●
●
of
to
for
for
170
a
presence
iron (II)
presence
potassium
of
changes
are
t hat
compounds
and
t he
dichromate(VI)
presence
t he
iodide
test
Acidied
colour
cer tain
testing
Potassium
used
in
compound.
reactant.
reducing
anot her
or
dened
or
t here
elements.
dened
is
state
anot her
●
reaction
two
state
Reduction
its
●
of
of
accompany
allow
oxidising
sulfate
of
an
reducing
agent.
are
or
agents
t he
and
reducing
to
or
be
used
agents.
agents
which
can
be
agent.
acidied
which
oxidation
compounds
reducing
oxidising
manganate (VII)
oxidising
t hese
can
be
potassium
used
to
test
for
t he
Oxidation–reduction
reactions
Practice
8
Practice
exam-style
n
t he
following

4HNO
is:
a
gain
of
oxygen

a
gain
of
electrons
a
A

only
decrease
B

and
C
,
D


in
B
oxidation
number
C
D
only
and
following
undergoes
Copper
(aq)
statements

oxidation
A
2
B
4
C
6
D
8
number
of
sulfur
in
t he
O
S
ion
Copper
Copper
n
its
oxidation
tr ue?
oxidation
and
its
oxidation
reduction
and
its
oxidation
oxidation
and
its
oxidation
increases.
undergoes
increases.
experiments,
acidied
acidied
following
obser ved
solutions
sulfur
of
potassium
pairs
in
Colour
dioxide
potassium
name
of
t he
BrO
ion
was
bubbled
dichromate(VI)
t he
of
manganate(VII).
correctly
describes
t he
Which
colour
of
t he
changes
experiment?
potassium
Colour
of
potassium
manganate(VII)
is:
A
orange
to
green
colourless
B
orange
to
green
pur ple
C
green
to
orange
colourless
D
green
to
orange
pur ple
to
pur ple
bromite(I)
bromate(I)
C
bromite(V)
to
colourless
to
to
pur ple
colourless
bromate(V)
10
4
is
and
3
and
B
D
copper
O(l)
2
decreases.
undergoes
separate
into
is:
3
A
about
2H

reduction
d ichromate(VI)
The
(g)
2
only
2
3
2NO

2
decreases.
undergoes
number
9
The
t he
number
2
2
of
Copper
number

)
3
number


Cu(NO
questions
A
Oxidation
reaction:
(aq)
3
which
1
questions
questions
Cu(s)
Multiple-choice
exam-style
Consider
t he
When
acidied
hydrogen
peroxide
solution
is
added
to
following:
iron(II)
sulfate
solution:
2
M(s)
n
t he
reaction

has
been

represented
has
increased
has
gained
A

only
B

and
C

D
,

above,
metal
M:
oxidised

and
(aq)
M
in
oxidation
number
5
6
and
Which
of
C
t he
oxidation
D
t he
acidied
Structured
following
t
causes
an
B
t
causes
a
C
ts
D
t
increase
loss
oxidation
which
iron(II)
green
solution
ion
is
number
formed
of
hydrogen
to
t he
t he
iron(III)
iron(II)
peroxide
is
ion
ion
decreases
acting
as
a
agent
question
a
The
gure
and
mineral
below
shows
t he
of
is
tr ue
in
about
oxidation
a
reducing
supplement
information
agent?
has
been
label
bottle.
on
a
multivitamin
lef t
Much
of
t he
out.
number.
electrons.
number
increases.
electrons.
of
t he
following
reactions
does
t he
oxidation
Each
number
is
oxidised

A
n
pale
only
t he
gains
t he
reducing
11

a
B
electrons
only

A
of
nitrogen
show
t he
greatest
tablet
contains
increase?
……………………………
A
2NO(g)
B
4NO

(g)
O
2NO
2
(g)

2
(g)
2
O
(g)

2H
2
……………………………
O(l)
4HNO
2
(aq)
……………………………
3
Potassium
C
N
(g)
D
2NH

3H
2
(g)
2NH
2
iodide
0.1 mg
(g)
3
……………………………
(g)

3CuO(s)
N
3
(g)

3Cu(s)

3H
2
O(l)
2
……………………………
7
Which
of
t he
A
2Na(s)
B
Fe(s)

C
MgO(s)
following
2H
reactions
O(l)
is
not
a
redox
2NaOH(aq) 
H
2

FeCl
(aq)

2
H
SO
2
A
(g)
(aq)
(g)
A
2
MgSO
4
H
(aq)
4

H
C(s)

O
(g)
2
and
mineral
supplement
bottle
solution
hydrogen
O(l)
CO
is
made
of
peroxide
is
one
of
added
t he
to
tablets
t he
and
acidied
solution.
2
i)
D
multivitamin
2
2HCl(aq)

reaction?
State
what
you
would
expect
to
obser ve.
(1
mark)
(g)
2
ii)
Write
an
ionic
half
equation
to
represent
reaction.
iii)
Wit h
a
Three
(2
reason,
represents
b
redox
t he
state
whet her
oxidation
reactions
are
or
t he
marks)
reaction
reduction.
represented
by
(1
mark)
t he
171
Practice
exam-style
questions
equations
given
substance
which
give
t he
reason
Oxidation–reduction
below.
has
for
For
been
your
EACH
reaction,
oxidised.
choice
n
based
name
EACH
on
t he
case,
oxidation
number.
i)
Zn(s)

2HCl(aq)
ZnCl
(aq)

H
2
(g)
2
(2
2
ii)
2Fe
marks)
3
(aq)

Cl
(g)
2Fe
(aq)

2Cl
(aq)
2
(2
iii)
(g)
2NH

3CuO(s)
N
3
(g)

marks)
3Cu(s)
2

3H
O(l)
2
(2
c
One
type
of
potassium
i)
For
t he
breat halyser
dichromate(VI)
what
pur pose
is
test
uses
marks)
acidied
cr ystals.
t he
breat halyser
test
used?
(1
ii)
Describe
t he
iii)
test
what
is
Explain
Using
would
obser ve
if
t he
t he
(1
chemistr y
oxidation
involved
in
(2
suggest
a
name
for
ion.
ClO
of
mark)
t he
test.
number,
mark)
result
positive.
breat halyser
d
you
marks)
t he
(1
mark)
2
Total
Extended
12
a
Dene
i)
ii)
b
response
oxidation
15
question
in
terms
of:
electrons
oxidation
Suppor t
Cl
number.
EACH
reference
to
(g)
t he

(2
denition
given
following
2Br
in a
above
marks)
by
reaction:
(aq)
2Cl
(aq)

Br
2
(g)
2
(4
c
‘Metals
are
oxidising
Use
your
reducing
agents
and
non-metals
marks)
are
agents.’
EACH
whet her
i)
marks
of
t he
t he
answers
2PbO(s)
reactions
above
based

below
statement
on
is
oxidation
C(s)
to
determine
tr ue.
Pb(s)
Give
reasons
for
number.

CO
(g)
2
(2
ii)
The
reaction
sulfate
d
You
are
an
respectively.
Describe
what
and
wit h
are
two
agents
tests
told
you
about
bottles
agent
are
a
and
carr y
Y.
X
Y
agent,
liquids.
out
to
conrm
(4
Total
172
marks)
and
reducing
colourless
could
X
labelled
and
marks)
copper(II)
(3
oxidising
Bot h
T WO
you
magnesium
solution.
provided
containing
between
marks)
15
marks
reactions
A10
Electrochemistry
is
Electrochemistry
the
study
of
the
relationship
Objectives
between
An
chemical
reactions
electrochemical
reaction
and
is
electrical
one
which
energy.
By
the
be
able
●
produces
electrical
energy
or
requires
electrical
energy
order
in
a
to
proceed.
From
the
reactions
that
to
produce
an
electric
current,
the
the
of
aluminium
oxide
to
to
the
is
important
in
produce
our
you
electrochemical
determine
reaction
will
series
metals
if
a
will
and
displacement
occur
their
between
compounds
aluminium,
based
electrochemistry
topic
common
metals
electrolysis
this
occur
●
battery
of
to:
give
of
in
end
either
lives.
on
positions
their
in
relative
the
electrochemical
series
●
determine
displace
A10.1
The
electrochemical
if
a
metal
hydrogen
on
its
position
electrochemical
electrochemical
series
of
an
acid
series
based
The
will
from
in
the
series
metals
●
give
the
electrochemical
series
n Unit 5.2 you learnt t hat when atoms bond ionically, t he metal atom always
of
loses
electrons
to
form
a
positive
metal
cation.
Some
metals
lose
more
easily
t han
ot hers.
When
metals
are
placed
in
order
of
ease
t hey
lose
electrons,
i.e.
ease
wit h
which
t hey
ionise,
a
series
determine
known
A
electrochemical
section
of
t he
series
of
metals
electrochemical
is
if
will
a
displacement
occur
non-metals
The
10.1.1.
more
forms.
which
back
are
at
to
easy
metals
when
t his
easily
Metals
conver t
Since
n
t hey
a
table,
metal
t he
top
atoms.
to
lose
react
t he
series
atom
of
t he
Metals
conver t
of
t he
common
ionisation
ionises,
at
t he
to
metals
is
given
their
compounds
their
relative
t he
form
increases
more
ver y
bottom
stable
stable
of
t he
going
are
ions
series
based
positions
in
on
the
in
series.
upwards.
t he
ions
which
form
are
t hat
hard
unstable
it
to
ions

T
able
series
10.1.1
of
the
The
electrochemical
common
metals
atoms.
when
ot her
of
series
back
electrons
wit h
ease
and
created.
electrochemical
Table
between
as
certain
t he
non-metals
wit h
reaction
which
common
electrons
●
much
some
t hey
ionise,
substances,
i.e.
t hey
t hey
act
give
as
reducing
electrons
to
agents
t he
Metal
Cation
potassium
K
calcium
Ca
sodium
Na
magnesium
Mg
aluminium
Al
zinc
Zn

ot her
2
reactant.
The
more
easily
t hey
give
electrons,
t he
stronger
t heir
reducing

power.
The
strengt h
as
a
reducing
agent,
t herefore,
increases
going
up
2
t he
series.
3
Potassium
is
highest
in
t he
series,
which
means
t hat
it
ionises
t he
most
2
easily,
forms
t he
most
stable
ions
and
is
t he
strongest
reducing
agent.
Silver
is
t he lowest in t he series, which means t hat it ionises t he least easily, forms t he
least
stable
ions
and
is
t he
weakest
reducing
2
iron
Fe
lead
Pb
hydrogen
H
copper
Cu
silver
Ag
agent.
2
We
can
make
chemical
use
of
t he
electrochemical
series
of
metals
to
predict
cer tain

reactions.
2

Displacement
A
met al
from
a
met al
ions
of
t he
been
displace
compound
is
of
will
a
stronger
t he
lower
lower
of
a
metals
met al
t hat
cont aining
reducing
met al.
met al
are
As
is
t he
agent,
a
it
in
met al.
t herefore,
result,
conver ted
below
lower
t he
to
electroc hemical
readily
higher
atoms,
t he
This
is
gives
met al
i.e.
t he
because
are
and
said
ser ies
higher
electrons
ionises
ions
t he
to
t he
to
t he
ions
have
d ischarged
173
The
electrochemical
series
Electrochemistry
Examples
1
Will
a
reaction
copper(II)
occur
sulfate
Magnesium
is
magnesium
can
Magnesium
is
if
a
strip
of
magnesium
ribbon
is
placed
in
solution?
higher
t han
copper
in
t he
electrochemical
series,
t herefore,
2
a
displace
stronger
t he
Cu
ions
reducing
from
agent,
t he
copper(II)
t herefore,
it
2
t he
Cu
ions
The
magnesium
d ischarged
Mg(s)

forming
CuSO
ionises
copper
(aq)
The
ionic
MgSO
sulfate
to
equation
Mg(s)

2
Mg
ions
and
t he
Cu
(aq)

Cu(s)
4
is:
2
copper(II)
forming
atoms:
4
blue
electrons
2
ions.
are
gives
sulfate.
Cu
2
(aq)
Mg
(aq)

Cu(s)
solution
The
transfer
of
electrons
is
shown
in
t he
ionic
half
equations:
magnesium
2
Mg(s)
Mg
(aq)

2e
2
Cu
colourless
As
t he
●
The
(aq)

reaction
2e
Cu(s)
proceeds
magnesium
t he
ribbon
following
gradually
are
gets
obser ved:
smaller
as
it
ionises
and
t he
magnesium
2
sulfate
pink

Figure
10.1.1
Mg
solution
copper
Magnesium
is
added
to
ions
●
A
pink
●
The
dissolve
solid
blue
in
builds
colour
of
t he
up
in
t he
solution.
t he
solution
copper (II)
as
copper
sulfate
is
solution
formed.
gradually
fades
as
2
copper( II)
sulfate
t he
solution
2
Will
a
blue
Cu
reaction
ions
occur
are
if
discharged
some
iron
from
lings
t he
are
solution,
placed
in
a
forming
solution
copper.
of
zinc
nitrate?
ron is
lower
than zinc in the electrochemical series.
Displacement
of
No
reaction will occur.
hydrogen

Metals
above
ions
an
in
hydrogen
acid,
in
forming
t he
electrochemical
hydrogen
gas
(H
).
series
Metals
will
below
displace
hydrogen
t he
will
H
not
2

displace t he H
ions. Metals above hydrogen are stronger reducing agents and

will
readily
give
electrons
to
t he
H
ions
of
t he
acid.
Metals
below
hydrogen

are
weaker
reducing
agents,
so
will
not
reduce
t he
H
ions.
Examples
1
Will
Zinc
a
reaction
is
higher
occur
t han
if
zinc
is
hydrogen
placed
in
t he
in
hydrochloric
electrochemical
acid?
series,
t herefore,

zinc
can
displace
t he
H
ions
from
t he
hydrochloric
acid.
Zinc
is
a

stronger
reducing
agent,
t herefore,
it
gives
2
zinc
ionises
hydrogen
forming
gas
(H
Zn
electrons
to
t he
H
ions.
The

ions
and
t he
H
ions
are
d ischarged
forming
):
2
Zn(s)

2HCl(aq)
ZnCl
(aq)

H
2
The
ionic
equation
is:

Zn(s)

2H
(g)
2
2
(aq)
Zn
(aq)

H
(g)
2
The
transfer
of
electrons
is
shown
in
t he
ionic
half
equations:
2
Zn(s)
Zn
(aq)

2e

2H
(aq)

2e
H
(g)
2
2
Will
a
reaction
Copper
will
174
is
lower
occur.
occur
t han
if
some
copper
hydrogen
in
turnings
t he
are
placed
electrochemical
in
sulfuric
series.
No
acid?
reaction
Electrochemistry
The
The
electrochemical
When
non-metal
electrons
to
electrons
atoms
form
much
a
series
bond
ionically,
negative
more
easily
of
series
non-metals
t he
non-metal
t han
electrochemical
ot hers.
non-metal
anion.
When
atom
Some
always
gains
non-metals
non-metals
are
gain
placed
in
order of ease wit h which t hey gain electrons, i.e. ease wit h which t hey ionise,
a
A
series
known
section
Table
The
of
10.1.2.
easier
forms.
hard
t he
n
a
to
electrochemical
t his
table,
non-metal
conver t
ions,
when
at
back
which
non-metals
agents
electrochemical
t he
Non-metals
unstable
Since
as
to
are
ease
atom
t he
gain
t hey
t he
top
t he
wit h
of
t he
some
at
stable
ver y
t he
to
t hey
is
created.
non-metals
increases
form
back
when
non-metals
more
series
conver t
ot her
of
ionisation
Non-metals
to
electrons
react
series
of
ionises,
of
atoms.
easy
series
going
are
stable
bottom
is
t he
ions
ions,
of
given
in
t he
t hat
which
series
ionise,
t hey
i.e.
t hey
act
as
form
oxid ising
remove
T
able
10.1.2
of
The
some
electrochemical
non-metals
Non-metal
Anion
fluorine
F
chlorine
Cl
bromine
Br
iodine
I
it
are
atoms.
substances,

series
upwards.
electrons
from t he ot her reactant. The more easily t hey remove electrons, t he stronger
t heir oxidising power. The strengt h as an oxidising agent, t herefore,
going
up
t he
Fluorine
forms
lowest
least
We
is
t he
in
can
cer tain
highest
most
t he
stable
in
series,
ions
make
and
use
chemical
non-metal
series
from
higher
will
a
t he
stable
series,
ions
and
which
is
of
t he
which
is
t he
means
weakest
t he
means
t hat
strongest
t hat
it
ionises
oxidising
electrochemical
it
ionises
oxidising
t he
t he
agent.
least
most
easily,
odine
easily,
is
forms
t he
t he
agent.
series
of
non-metals
to
predict
reactions.
Displacement
A
increases
series.
of
non-metals
displace
compound
non-metal
is
a
a
non-metal
containing
stronger
which
the
is
lower
oxidising
below
it
in
the
non-metal.
agent,
electrochemical
This
therefore,
is
because
readily
the
removes
electrons from the ions of the lower non-metal. As a result, the higher non-metal
ionises, and the ions of the lower non-metal are discharged forming atoms.
Examples
1
Will
a
reaction
occur
if
chlorine
gas
is
bubbled
into
sodium
iodide
solution?
Chlorine is
higher
than iodine in the electrochemical series of non-metals,
therefore, chlorine can displace the 
ions from the sodium iodide.
Chlorine is a stronger oxidising agent, therefore, it removes electrons from
the 
ions. The chlorine
discharged
ionises
forming iodine (
forming Cl
ions and the 
ions are
):
2
Cl
(g)

2Na(aq)
2NaCl(aq)

2
The
ionic
equation
(g)

2
is:
(aq)
2Cl
(aq)
2


(aq)
2
transfer
Cl
(aq)
2
Cl
The

(g)
of

electrons
2e
is
shown
2Cl
in
t he
ionic
half
equations:
(aq)
2
2
(aq)

(aq)

2e
2
175
Electrical
conduction
Electrochemistry
2
Will
a
reaction
potassium
Bromine
will
If
is
lower
zinc
is
Explain
b
Give
c
a
What
the
able
end
of
occur:
topic
you
the
b
silver
c
iodine
d
bromine
Which

chlorine
a
solution
reaction
added
to
a
solution
of
in
t he
electrochemical
series.
No
reaction
of
copper( II)
nitrate,
a
reaction
occurs.
occurs.
chemical
of
metal
lead(II)
equation
colour
of
and
a
balanced
ionic
equation
for
the
copper( II)
nitrate
solution?
Explain
to
in
of
the
a
displacement
reaction
solution.
electrochemical
zinc
when
three
series
will
release
hydrogen
acid?
displace
occurred
Arrange
not
solution
iodide
the
to
or
solution
hydrochloric
found
whether
solution
chloride
metals
was
ease
nitrate
potassium
added
predict
nitrate
sodium
displacement
of
the
following,


the
X
to
calcium

when
A10.2
this
of
aluminium
order
be
is
occurs.
a
solution.
By
in
a
happens
will
no
Objectives
why
this
each
A
solution
questions
balanced
For
gas
4
bromine
reaction.
why
3
t han
placed
a
the
2
if
occur.
Summary
1
occur
chloride?
it
from
was
metals,
X,
zinc
added
zinc
nitrate
to
and
solution
magnesium
magnesium
in
but
nitrate
decreasing
ionisation.
Electrical
conduction
will
n
Unit
5
you
learnt
t hat
in
order
for
a
substance
to
conduct
an
electric
to:
current, it must contain charged par ticles which are able to move t hrough t he
●
distinguish
conductor
between
and
a
a
substance.
non-
can
conductor
●
distinguish
between
electrolytic
distinguish
electrolyte,
and
give
a
Conductors
between
a
weak
a
strong
can
include
electrolyte
be
par ticles
groups
can
based
be
on
eit her
t heir
electrons
ability
or
ions.
to
conduct
to
pass
Materials
an
electric
substances
liquids
which
graphite,
and
aqueous
or
allow
solutions.
electricity
molten
acids
ionic
and
Examples
of
t hrough.
compounds,
conductors
solutions
of
ionic
alkalis.
non-electrolyte
examples
electrolytes,
of
Non-conductors
are
substances
which
do
not
allow
an
electric
current
strong
weak
pass
t hrough.
Non-conductors
can
be
solids,
liquids,
solutions
electrolytes
and
gases.
Examples
of
non-conductors
include
non-metals
(except
non-electrolytes.
graphite),
176
are
solids,
metals,
compounds
to
and
two
metallic
●
●
charged
into
conduction
They
●
These
classied
current.
●
and
be
plastics,
covalent
substances
and
solid
ionic
compounds.
Electrochemistry
T
o
Electrical
investigate
the
electrical
conductivity
of
conduction
various
substances
Circuit
1
switch
Your
teacher
may
●
observation,
●
manipulation
Y
ou
will
be
sulfate
a
and
e.g.
hydrochloric
with
rod,
and
to
assess:
reporting
circuit
wire,
a
sodium
acid,
activity
A
measurement.
copper
graphite
crystal,
this
recording
supplied
substances,
crystal,
use
components,
magnesium
plastic
chloride
ethanol
and
ruler,
a
samples
ribbon,
sodium
solution,
of
various
aluminium
chloride
copper( II)
foil,
crystal,
sulfate
an
a
iodine
copper( II)
solution,
solid
to
be
tested
dilute
kerosene.
Circuit
2
Method
1
switch
Draw
up
a
table
‘Prediction’
with
and
three
‘Results’.
columns
In
the
headed
rst
‘T
est
column
substance’,
write
down
the
name
of
A
each
test
column
a
substance
ll
in
your
that
you
prediction
have
of
been
whether
supplied
the
with.
substance
In
is
the
a
second
conductor
or
non-conductor.
beaker
2
Connect
the
circuit
as
shown
in
Figure
10.2.1.
If
the
test
substance
is
a
carbon
solid
use
Circuit
1
and
if
it
is
a
solution
or
a
liquid
use
Circuit
electrodes
2.
solution
3
Record
4
Compare
the
results
of
your
experiment
in
the
third
column
of
your
to
table.

your
predictions
with
the
Figure
10.2.1
When
and
ionic
created
electrolytic
compounds
contains
ions
melt
and
of
a
solid
and
to
a
test
the
liquid
conduction
or
is
circuits
tested
results.
conductivity
Metallic
T
wo
be
dissolve
known
in
as
water,
an
t he
liquid
electrolyte.
or
solution
Electrolytes
are
conductors.
There
are
cer tain
differences
between
conduction
in
a
metal,
known
Key
!
as
metallic
electrolytic
conduction ,
and
conduction
in
an
electrolyte,
known
An
conduction
electrolyte
that
forms
aqueous
Metallic
n
a
fact
as
ions
is
a
compound
when
molten
or
in
solution.
conduction
metal,
t he
delocalised
valence
electrons,
electrons
known
as
of
t he
mobile
atoms
are
electrons,
delocalised.
are
able
to
These
move
t hroughout t he metal. Metals are able to conduct an electr ic cur rent because
t hese mobile electrons
is
of
a
non-metal,
delocalised,
During
ionic
an
can move t hroughout t he metal. Alt hough graphite
conducts
an
electrons
(see
conduction,
t he
electr ic
Unit
metal
cur rent
because
of
t he
presence
5.5).
remains
chemically
unchanged
conduction
ionic
bonds
also
mobile
metallic
Electrolytic
When
it
and
compound
t hey
melts,
become
free
t he
to
ions
move
are
no
longer
t hroughout
t he
held
toget her
by
liquid:
heat

NaCl(s)
Na
(l)

Cl
(l)
177
Electrical
conduction
Electrochemistry
Similarly, when an ionic compound dissolves in water, t he ionic bonds break
and
t he
ions
are
free
to
move
t hroughout
t he
solution:
water

NaCl(s)
These
of
Na
electrolytes
mobile
ions
(aq)
conduct
which
are

Cl
an
able
(aq)
electric
to
current
move
because
t hroughout
t he
of
t he
liquid
presence
or
aqueous
solution.
During
electrolytic
chemically

T
able
10.2.1
Metallic
Mobile
through
The
Metallic
electrons
the
metal
electrolyte
and
electrolytic
conduction
carry
remains
can
is
decomposed,
i.e.
it
is
the
electric
current
Mobile
the
chemically
of
an
between
ions
Strong
electrolytes
Strong
electrolytes
strong
of
in
t he
are
alkalis
concentration
unchanged
The
ions
conduction
carry
the
electric
current
through
electrolyte
electrolyte
decomposes
electrolyte
distinguish
of
compared
Electrolytic
metal.
concentration
acids,
t he
conduction
Strength
We
conduction,
changed.
fully
and
ions
strong
in
and
weak
electrolytes
based
on
t he
electrolyte.
ionised
soluble
solution.
when
ionic
For
dissolved
in
compounds.
water,
These
e.g.
have
strong
a
high
example:

HCl(aq)
Molten
Weak
Weak
e.g.
H
ionic
(aq)
compounds

are
Cl
also
(aq)
classied
as
strong
electrolytes.
electrolytes
electrolytes
weak
solution.
acids
For
and
are
only
weak
parti ally
alkalis.
These
ionised
have
a
when
low
dissolved
concentration
in
of
water,
ions
example:

CH
COOH(aq)
CH
3

T
able
10.2.2
Examples
Strong
Acids
COO
(aq)

H
(aq)
3
of
electrolytes
electrolytes
Hydrochloric
acid
Weak
(HCl(aq))
electrolytes
Carbonic
acid
(H
CO
2
Nitric
acid
(HNO
(aq))
Ethanoic
3
Sulfuric
acid
(H
Potassium
Sodium
Salts
Molten
Sodium
Molten
hydroxide
178
solution
solution
(NaOH(aq))
(NaCl(aq))
bromide
bromide
(KOH(aq))
(NaCl(l))
solution
potassium
Potassium
(aq))
chloride
chloride
COOH(aq))
4
hydroxide
sodium
(CH
3
SO
2
Alkalis
acid
(aq))
3
(KBr(l))
solution
(KBr(aq))
Aqueous
ammonia
(NH
3
(aq))
in
Electrochemistry
Strong
Electrolysis
electrolytes
are
much
better
electrical
conductors
t han
weak
Summary
questions
electrolytes. The strengt h of an electrolyte can be tested wit h a simple circuit
which
has
a
light
bulb
(or
light
emitting
diode
(LED))
connected
to
a
batter y
1
and
two
electrodes
which
are
dipped
in
t he
electrolyte.
The
greater
Distinguish
a
strengt h
of
t he
electrolyte,
t he
more
brightly
t he
bulb
will
between:
t he
a
conductor
and
a
non-
glow.
conductor
A
non-electrolyte
liquid
any
state
ions.
or
is
a
substance
dissolved
in
Non-electrolytes
which
water.
are
The
remains
liquid
or
non-conductors.
as
molecules
solution
Examples
when
does
of
not
in
the
b
metallic
contain
and
electrolytic
conduction
non-electrolytes
c
a
strong
and
a
weak
include liquids such as kerosene and gasoline, molten covalent substances such
electrolyte.
as
wax
and
solutions
of
covalent
substances
such
as
ethanol
and
glucose.
2
Classify
as
Pure
water
a
each
strong
weak
of
the
following
electrolyte,
electrolyte
or
a
a
non-
electrolyte:
Pure
water
is
an
extremely
weak
electrolyte.
Water
undergoes
spontaneous

ionisation
into
H
ions
and
OH
ions.
At
any
one
time,
approximately
one
a
potassium
b
a
c
aqueous
d
kerosene
e
aqueous
chloride
solution
8
in
ever y
5.56

10
water
molecules
is
ionised:
solution
of
sucrose
ethanoic
in
water
acid

H
O(l)
H
(aq)

OH
(aq)
2

7
The concentration of H
ions and OH
As
next
you
will
learn
in
t he
unit,
ions in pure water is 1  10
t his
is
of
par ticular
3
mol dm
signicance
when
.
3
electric
current
is
passed
t hrough
an
aqueous
Why
is
pure
When
an
decomposed
current
into
is
simpler
passed
t hrough
substances,
i.e.
an
it
electrolyte,
undergoes
a
t he
electrolyte
chemical
is
By
the
be
able
as
end
takes
electrolytic
A
dene
batter y
or
place
cell
has
ot her
in
a
piece
three
d.c.
of
main
power
apparatus
known
as
an
electrolytic
cell.
●
the
Two
electrodes
components.
topic
you
will
terms
electrolysis,
supply
t hat
take
t he
connected,
electric
via
current
wires,
into
to
and
provides
t he
out
ions
anion
present
and
cation
in
electrolytes
t he
electric
current.
●
batter y
or
power
predict
of
t he
will
the
electrode
drift
during
to
which
an
electrolysis
supply,
●
which
this
cathode,
identify
ion
●
of
electrolysis
Electrolysis
●
electrolyte?
to:
anode,
An
weak
change
●
known
an
Objectives
Electrolysis
electric
acid.
water
electrolyte.
extremely
A10.3
nitric
an
electrolyte.
They
discuss
the
electrolysis
of
molten
must
electrolytes
be
able
to
conduct
an
electric
current
and
are
usually
made
of
an
iner t
●
material
such
as
graphite
(carbon)
or
platinum.
The
anode
is
explain
of
to
t he
positive
terminal
of
t he
batter y
and
t he
cathode
is
connected
negative
The
electrolyte,
compound
mobile
discharge
discuss
the
electrolysis
of
certain
terminal.
aqueous
●
preferential
ions
to
●
t he
the
connected
or
a
which
is
solution
a
molten
electrolytes.
ionic
containing
ions.
battery
Key
!
fact
Electrolysis
which
is
is
occurs
passed
the
chemical
when
through
an
an
change
electric
current
electrolyte.
electrolyte
!
anode

Figure
10.3.1
An
electrolytic
cell
Key
fact
The
anode
The
cathode
is
the
positive
electrode.
cathode
is
the
negative
electrode.
electrodes
179
Electrolysis
Electrochemistry
electrons
around
from
flow
the
Mechanism
of
electrolysis
circuit
anode
to
e

e

During
Light
electrolysis
bot h
anions
and
cations
are
d ischarged,
i.e.
bulb:
cathode

glows
t hey
brightly
lose
or
gain
electrons
to
form
neutral
atoms.
This
occurs
as
e
battery
if
the
is
electrolyte
follows.
strong
e

e
glows
the
e
dimly
if
The
●
electrolyte
anions
(negative
ions)
are
attracted
to
t he
anode
is
(positive
electrode).
The
anions
lose
electrons
to
t he
anode
weak
e
e
and
anode
()
cathode
(
form
atoms,
i.e.
t hey
are
discharged:
)
n
n
C
C
n
n
A
A
A

ne
n
C
n
n
A
C
n
A
Oxid ation occurs at t he anode (OL). The anode
electrolyte,
n
C
n
C
n
CA(l
A
n
A
→
A

or
aq)
acts
as
t he
oxid ising
The
electrons,
agent
ne
n
C
n
A
n
C

ne
→
C
n
n
A
●
C
lost
by
t he
anions
to
t he
positive
at
t he
anode,
travel
n
C
n
A
n
n
C
n
C
C
t hrough
n
They

Figure
10.3.2
Mechanism
of
●
Exam
tip
The
cations
electrode).
atoms,
It
can
be
confusing
to
try
to
circuit
terminal
of
t he
t hen
re-enter
t he
circuit
from
t he
negative
batter y.
terminal
of
electrolysis
t he
✔
t he
A
(positive
The
i.e.
batter y
ions)
cations
t hey
are
and
travel
are
gain
to
t he
attracted
t he
cat hode.
to
electrons
t he
cat hode
from
t he
(negative
cat hode
forming
discharged:
learn
n
which
electrode
which
is
is
negative.
positive
It
is
C
and
better

Reduction
work
it
out,
remembering
ne
C
to
that
occurs
at
t he
cat hode
(RG).
The
cat hode
acts
as
t he
reducing
the
agent
electrodes
which
•
are
You
are
named
attracted
know
negative
that
to
after
anions
charge.
the
ions
them.
have
Anions
a
must
Electrolysis
be
attracted
electrode.
must
be
to
The
called
the
positive
the
You
know
positive
that
electrode
cations
charge.
molten
electrolytes
Molten
electrolytes
contain
only
two
different
ions,
one
cation
and
one
anode
anion.
•
of
positive
have
Cations
Bot h
are
discharged
during
electrolysis.
a
must
Example
be
attracted
electrode.
electrode
to
The
must
the
negative
negative
be
called
Electrolysis
of
molten
(fused)
le ad(II)
bromide
using
inert
g raphite
the
electrodes
cathode
2
The
At
ions
the
present
in
t he
molten
lead(II)
bromide
are
Pb
(l)
and
Br
(l).
anode:
The
Br
lose
electrons
ions
immediately
2Br
move
to
towards
t he
bond
(l)
anode
t he
covalently
Br
(g)
anode
forming

where
bromine
forming
t hey
are
atoms.
bromine
discharged,
Pairs
of
i.e.
bromine
t hey
atoms
molecules:
2e
2
Brown
At
the
fumes
of
bromine
are
evolved
at
t he
anode.
cathode:
2
The Pb
gain
ions move towards t he cat hode where t hey are discharged, i.e. t hey
electrons
to
form
lead
atoms:
2
Pb
Molten
180
(l)

lead
2e
forms
Pb(l)
around
t he
cat hode
and
drips
off.
Electrochemistry
T
o
Electrolysis
electrolyse
(T
eacher
molten
lead( II)
bromide
using
graphite
electrodes
demonstration)
+
Your
teacher
may
observation,
●
use
this
recording
activity
and
to
reporting.
anode
Y
our
teacher
will
perform
the
−
assess:
following
()
(
)
cathode
experiment.
bromine
gas
The
experiment
must
be
performed
in
a
fume
cupboard.
molten
lead
Method
1
Place
2
Heat
3
Connect
the
circuit
4
Observe
the
product
some
the
lead( II)
lead( II)
bromide
bromide
as
into
until
it
shown
a
crucible.
melts.
in
Figure
bromide
10.3.3.
heat
formed
at
each
electrode.

5
Write
an
ionic
Electrolysis
During
those
the
of
half
of
equation
aqueous
electrolysis
the
for
solute.
of
an
the
occurring
at
each
electrode.
lead( II)
10.3.3
Electrolysis
of
molten
bromide
solutions
aqueous
Because
reaction
Figure
water
solution,
the
undergoes
ions
present
spontaneous
are
not
only
ionisation,
an

aqueous solution always contains H
ions and OH
ions from the ionisation of
water molecules as well as the ions from the solute. As a result, aqueous solutions
always contain at least
n
t he
will
electrolysis
be
discharged
of
in
two different cations and
an
aqueous
preference
solution,
to
t he
two different anions.
one
ot her.
type
This
is
of
ion
of
known
as
each
charge
preferenti al
d ischarge.
Preferential
discharge
of
anions
There are three main factors which inuence t he preferential discharge of t he
anions
The
t hat
you
position
Considering
will
of
the
t he
be
studying:
ion
in
the
electrochemical
electrochemical
series
of
series
anions
given
in
Table
10.3.1,
ions
discharge.
ons

T
able
series
at
t he
top
of
t he
series
are
t he
most
stable
and
t he
hardest
to
at t he bottom of t he series are t he least stable and t he easiest to discharge, i.e.
t he
ease
of
discharge
increases
10.3.1
of
The
electrochemical
anions
Anion
downwards.
F
2
The
lower
t he
ion
in
t he
electrochemical
series,
t he
more
likely
it
is
to
be
discharged.
SO
4
NO
3
Cl
This
is
seen,
for
example,
when
we
look
at
the
electrolysis
of
dilute
sulfuric
Br
acid,
dilute
sodium
chloride
inert electrodes; the OH
solution
and
copper(II)
sulfate
solution
using
ion is preferentially discharged from each solution.
I
OH
The
concentration
The
concentration
preferentially
to
be
of
the
electrolyte
t he
discharged.
preferentially
solutions
of
electrolyte
There
discharged.
containing
halide
ions,
is
a
has
However,
i.e.
an
tendency
Cl
impact
for
t his
ions,
Br
t he
r ule
on
more
really
ions
and

which
ions
concentrated
only
are
ion
applies
to
ions.
181
Electrolysis
Electrochemistry
This
is
seen
when
we
compare
t he
electrolysis
of
dilute
sodium
chloride
solution wit h t he electrolysis of concentrated sodium chloride solution, bot h
using
iner t
discharged
electrodes.
n
but
concentrated
in
t he
t he
dilute
solution,
t he
solution,
OH
t he
ion
Cl
is
ion
preferentially
is
preferentially
discharged.
The
type
of
electrode
The type of anode chosen for t he electrolysis can affect t he reaction occurring
at
t he
anode.
f
t he
anode
is
inert,
for
example
graphite
or
not affect t he reaction occurring. However, if t he anode is
copper,
it
happens
This
is
using
an
when
There
is
cations

T
able
series
Cation
10.3.2
of
The
wit h
is
t he
electrolysis
main
you
t he
of
factor
will
be
t he
its
used,
anode,
discharge
one
in
compare
anode
copper
t hat
we
anode
iner t
Preferential
par t
process
it
does
and
t his
affects
what
anode.
iner t
an
active
take
t he
seen
an
When
can
at
platinum,
active, for example
electrolysis
electrolysis
t he
OH
anode
ion
of
copper(II)
using
is
an
sulfate
active
preferentially
solution
copper
anode.
discharged.
Wit h
ionises.
cations
which
inuences
t he
preferential
discharge
of
t he
studying:
electrochemical
cations
The
position
of
the
ion
in
the
electrochemical
series

K
Considering
t he
electrochemical
series
of
cations
given
in
Table
10.3.2,
ions
2
Ca
at t he top of t he series are t he most stable and t he hardest to discharge. ons at

Na
2
Mg
t he
bottom
t he
ease
of
of
t he
series
discharge
are
t he
increases
least
stable
and
t he
easiest
to
discharge,
i.e.
downwards.
3
Al
The
lower
t he
ion
in
t he
electrochemical
series,
t he
more
likely
it
is
to
be
2
Zn
discharged.
2
Fe
This
is
seen,
for
example,
when
we
look
at
t he
electrolysis
of
dilute
and
2
Pb

concentrated
sodium
chloride
solution;
t he
H
ion
is
preferentially

H
discharged in bot h. Also when we look at t he electrolysis of copper(II) sulfate
2
2
Cu
solution;
t he
Cu
ion
is
preferentially
discharged.
We
will
now
look
at

Ag
examples
referred
to
above
in
greater
detail.
Examples
1
Electrolysis
Ions
of
d ilute
sulfuric
acid
using
inert
electrodes
present:

From
t he
H
SO
2
:
H
2
(aq)
and
SO
4
(aq).
4

From
t he
H
O:
H
(aq)
and
OH
(aq).
2
At
the
anode:
2
The
SO
ions
and
t he
OH
ions
move
towards
t he
anode.
The
4
OH
ions
are
preferentially
electrochemical
4OH
series
of
(aq)
discharged
182
occurs
2H
as
t hey
are
lower
anions:
O(l)

2
Effer vescence
because
oxygen
O
(g)

4e
2
gas
is
evolved
at
t he
anode.
in
t he
t he
Electrochemistry
At
the
Electrolysis
cathode:

The
H
ions
move
towards
t he
cat hode
where
t hey
are
discharged:

2H
(aq)

2e
H
(g)
2
Effer vescence
Relative
volumes
Comparing
from
are
occurs
t he
t he
anode
of
hydrogen
gases
two
to
as
is
evolved
at
t he
cat hode.
produced:
equations,
t he
gas
for
cat hode,
ever y
1 mol
of
4 mol
of
oxygen
electrons
and
transferred
2 mol
of
hydrogen
produced:
4OH
(aq)
2H
O(l)

O
2
(g)

4e
2

4H
(aq)

4e
2H
(g)
2
1
volume
Changes
of
in
oxygen
the
is
produced
for
ever y
2
volumes
of
hydrogen.
electrolyte:

The
sulfuric
OH
ions
acid
are
becomes
discharged
more
from
concentrated
it,
i.e.
water
because
is
being
H
ions
removed
and
from
t he

electrolyte.
Because
electrolysis
of
T
o
sulfuric
electrolyse
(T
eacher
of
t he
discharge
acid
dilute
is
of
referred
sulfuric
t he
to
acid
as
H
ions
t he
using
and
OH
electrolysis
inert
ions,
of
t he
water .
electrodes
demonstration)
oxygen
Your
teacher
may
use
this
activity
●
observation,
recording
●
analysis
interpretation.
Y
our
and
teacher
will
perform
and
the
to
hydrogen
assess:
reporting
following
experiment.
Method
platinum
foils
1
Set
up
the
sulfuric
Hoffmann’s
acid
2
Observe
3
T
est
the
as
the
gas
the
as
shown
in
Figure
10.3.4,
using
dilute
anode
electrolyte.
relative
given
voltameter
volume
off
at
the
of
gases
anode
to
given
off
see
it
if
at
is
each
splint.
The
splint
should
glow
brighter
oxygen
or
(–)
electrode.
by
using

a
Figure
10.3.4
showing
glowing
cathode
(+)
re-light
if
the
gas
the
Hoffmann’s
electrolysis
voltameter
of
dilute
is
sulfuric
acid
oxygen.
4
T
est
a
the
gas
burning
given
splint.
extinguished
if
off
The
the
at
the
splint
gas
is
cathode
should
to
see
make
a
if
it
is
hydrogen
squeaky
pop
by
and
using
?
be
Did
glowing
Explain:
relight
a
why
oxygen
b
why
hydrogen
c
why
the
was
produced
at
the
anode
(include
an
gas
6
What
volume
would
you
of
produced
hydrogen
expect
to
at
the
was
happen
cathode
greater
to
the
the
electrolyte
an
equation)
volume
as
to
because
the
glow
it
brighter
supports
or
the
equation)
(include
than
causes
splint
combustion,
was
know?
hydrogen.
Oxygen
5
you
the
of
i.e.
burning,
of
the
splint.
oxygen.
reaction
proceeds?
183
Electrolysis
Electrochemistry
2
Electrolysis
Ions
of
d ilute
sod ium
chloride
solution
using
inert
electrodes
present:

From
t he
NaCl:
From
t he
H
Na
(aq)
and
Cl
(aq).

O:
H
(aq)
and
OH
(aq).
2
At
the
The
are
anode:
Cl
ions
and
preferentially
lower
in
t he
4OH
t he
OH
ions
discharged
electrochemical
(aq)
2H
move
because
series
O(l)

At
the
occurs
as
O
anode.
a
dilute
The
OH
ions
solution
and
are
anions:
(g)

4e
2
oxygen
gas
is
evolved
at
t he
anode.

Na
ions
and
preferentially
series
in
are
cathode:

The
t he
of
2
Effer vescence
towards
t hey
of
t he
H

ions
discharged
move
because
towards
t hey
are
t he
cat hode.
lower
in
t he
The
H
ions
are
electrochemical
cations:

2H
(aq)

2e
H
(g)
2
Effer vescence
Relative
volumes
Comparing
from
are
occurs
t he
t he
anode
produced,
of
gases
two
to
i.e.
as
gas
is
evolved
at
t he
cat hode.
produced:
equations,
t he
1
hydrogen
for
cat hode,
volume
of
ever y
1 mol
of
oxygen
is
4 mol
of
oxygen
electrons
and
produced
2 mol
for
transferred
of
ever y
2
hydrogen
volumes
of
hydrogen.
Changes
in
the
electrolyte:

The
ions
3
sodium
and
chloride
OH
Electrolysis
inert
Ions
ions
of
solution
are
becomes
discharged
concentrated
from
sod ium
more
concentrated
because
H
it.
chloride
solution
(brine)
using
electrodes
present:

From
t he
NaCl:
From
t he
H
Na
(aq)
and
Cl
(aq).

O:
H
(aq)
and
OH
(aq).
2
At
the
The
ions
anode:
Cl
ions
are
and
t he
OH
preferentially
concentrated
2Cl
ions
move
discharged
towards
because
t he
t hey
anode.
are
The
halide
Cl
ions
in
a
solution:
(aq)
Cl
(g)

2e
2
Effer vescence
At
the
occurs
as
Na
gas
is
evolved
at
t he

ions
and
preferentially
series
chlorine
of
t he
H

ions
discharged
move
because
towards
t hey
are
t he
lower
cat hode.
in
t he
The
H
cations:
(aq)

2e
H
(g)
2
Effer vescence
occurs
as
hydrogen
gas
is
evolved
at
t he
ions
are
electrochemical

2H
184
anode.
cathode:

The
yellow-green
cat hode.
Electrochemistry
Relative
volumes
Comparing
from
are
Electrolysis
t he
t he
in
to
i.e.
the
gases
two
anode
produced,
Changes
of
produced:
equations,
t he
for
cat hode,
equal
ever y
1 mol
volumes
of
of
2 mol
of
electrons
chlorine
chlorine
and
and
transferred
1 mol
hydrogen
of
are
hydrogen
produced.
electrolyte:

The
electrolyte
becomes
alkaline
because
H
ions
and
Cl
ions
are

discharged
form
from
sodium
it
leaving
an
excess
of
Na
ions
and
OH
ions,
which
hydroxide.
test
T
o
investigate
the
effect
of
the
concentration
of
tubes
the
electrolyte
electrolyte
(T
eacher
Your
on
the
preferential
of
ions
demonstration)
teacher
may
use
this
activity
●
observation,
recording
●
analysis
interpretation.
Y
our
discharge
and
teacher
will
perform
and
the
to
assess:
reporting
following
experiment.
anode
cathode
Method
1
Set
up
an
electrolytic
electrodes
2
Place
an
and
dilute
inverted
cell
as
shown
sodium
test
tube
in
chloride
lled
with
Figure
10.3.5,
solution
dilute
as
using
the
sodium
inert
graphite
electrolyte.
chloride
solution

over
each
electrode
to
collect
the
gas
evolved
at
Figure
10.3.5
concentrated
3
T
est
the
4
T
est
the
gas
in
gas
the
in
tube
the
over
tube
the
over
anode
the
for
cathode
oxygen
for
Electrolysing
each.
using
hydrogen
a
glowing
using
a
splint.
(brine)
in
the
sodium
chloride
solution
laboratory
burning
splint.
5
Repeat
6
T
est
the
the
experiment
gas
in
the
using
tube
over
concentrated
the
anode
for
sodium
chloride
chlorine
using
a
solution.
piece
of
Did
?
moist
and
blue
then
litmus
paper.
If
the
gas
is
chlorine
the
paper
should
turn
Chlorine
white.
litmus
7
T
est
the
gas
in
the
tube
over
the
cathode
for
hydrogen
using
a
a
form
piece
of
red
litmus
paper
into
the
electrolyte.
it
How
were
your
observations
in
the
two
turns
red
moist
and
reacts
then
with
hydrochloric
chloric( )
acid
Cl
H
(g)

2
9
know?
acid
the
similar
b
different?
Which
were
the
dilute
b
in
the
concentrated
each
Which
case,
ions
Explain
were
why
electrolyte
sodium
explain
experiments?
12
preferentially
in
In
11
ions
the
a
the
in
sodium
why
and
preferentially
Give
a
reason
litmus
step
discharged
chloride
(HClO):
O(l)
HCl(aq)
2
at
the
acids
turn
chloric( )
litmus
acid
red
HClO(aq)
and
oxidises
it
to
colourless.
anode:
solution
chloride
include
solution?
the
discharged
and
paper
to
and
experiments:
The
10
white
water
(HCl)

a
blue
burning
splint.
Dip
gas
paper
because
8
you
red
a
relevant
at
relevant
changed
the
equation.
cathode
in
both
equation.
colour
when
dipped
into
the
8
185
Electrolysis
Electrochemistry
4
Electrolysis
Ions
of
copper( II)
sulfate
solution
using
inert
electrodes
present:
2
From
t he
CuSO
:
Cu
2
(aq)
and
SO
4
(aq).
4

From
t he
H
O:
H
(aq)
and
OH
(aq).
2
At
the
anode:
2
The
SO
ions
and
t he
OH
ions
move
towards
t he
anode.
The
4
ions
OH
are
preferentially
electrochemical
4OH
series
of
(aq)
discharged
2H
At
the
occurs
as
O(l)
lower
in
t he

O
(g)

4e
gas
is
evolved
at
t he
anode.
cathode:
Cu
ions
are
2
oxygen
2
The
t hey
anions:
2
Effer vescence
because

ions
are
and
t he
preferentially
electrochemical
H
2
ions
move
discharged
series
of
towards
because
t he
t hey
cat hode.
are
lower
The
in
Cu
t he
cations:
2
Cu
A
pink
(aq)
deposit
increases
Changes
in
in

2e
of
Cu(s)
copper
builds
up
around
t he
cat hode
because
t he
blue
and
t he
cat hode
size.
the
electrolyte:
2
The
electrolyte
becomes
paler
blue
Cu
ions
are
2
discharged
from
it.
t
also
becomes
acidic
because
Cu
ions

ions
are
discharged
leaving
an
excess
of
H
and
OH
2
ions
and
SO
ions,
which
4
form
5
sulfuric
Electrolysis
acid.
of
copper( II)
sulfate
solution
using
active
copper
electrodes
Ions
present:
2
From
t he
CuSO
:
Cu
2
(aq)
and
SO
4
(aq).
4

From
t he
H
O:
H
(aq)
and
OH
(aq).
2
At
the
anode:
2
The
SO
ions
and
t he
OH
ions
move
towards
t he
anode.
However,
4
t he
anode,
being
made
of
copper,
is
active
and
t he
copper
atoms
ionise,
2
forming
Cu
ions,
t his
requires
less
energy
t han
discharging
t he
OH
ions.
2
Cu(s)
Cu
(aq)

2e
2
The
✔
Exam
size.
At
the
you
are
ions
go
the
The
writing
reactions
t he
electrolyte
and
t he
anode
gradually
decreases
cathode:
Cu
are

ions
and
t he
preferentially
H
2
ions
move
discharged
towards
because
t he
t hey
cat hode.
are
lower
The
in
Cu
t he
equations
electrochemical
for
into
2
tip
ions
When
Cu
in
occurring
at
series
of
cations:
the
2
anode
always
and
cathode,
include
the
remember
correct
Cu
to
(aq)
2e
A
pink
deposit
of
symbols
increases
186
Cu(s)
state
in
size.
copper
builds
up
around
t he
cat hode
and
t he
cat hode
Electrochemistry
Changes
in
Electrolysis
the
electrolyte:
The electrolyte remains
unchanged. For ever y 2 mol of electrons transferred
2
from anode to cathode, 1 mol of Cu
ions enter the electrolyte at the
2
anode and 1 mol of Cu
T
o
investigate
on
the
the
ions is discharged at the cathode.
effect
electrolysis
of
of
using
copper( II)
inert
and
sulfate
active
electrodes
solution
anode
(T
eacher
Your
teacher
may
use
this
activity
●
observation,
recording
●
analysis
interpretation.
Y
our
()
(
)
cathode
demonstration)
and
teacher
will
perform
and
the
to
assess:
reporting
following
experiment.
oxygen
pink
gas
builds
is
copper
up
evolved
around
at
cathode
the
the
Method
anode
1
Set
up
an
electrolytic
cell
as
shown
in
Figure
10.3.6,
using
graphite
graphite
electrodes
2
Observe
the
electrode.
blue
and
Repeat
4
Observe
5
Classify
6
How
anode
Also
litmus
3
copper( II)
the
as
and
the
cathode,
taking
the
colour
the
into
the
experiment
the
solution
observe
paper
the
sulfate
anode
electrodes
note
of
what
electrolyte
and
occurs
dip
a
at
each
piece
of
the
as
copper
cathode
inert
or
anode
electrodes.
and
the
colour
of
the
your
observations
in
()
(
)
cathode
electrolyte.
active.
the
were
electrodes
electrolyte.
electrolyte.
using
and
of
the
the
two
anode
experiments:
pink
becomes
a
b
similar
different?
copper
builds
thinner
up
around
7
Why
was
the
reaction
experiments?
8
9
Why
Why
did
the
was
Include
litmus
there
experiment
a
but
occurring
the
paper
change
not
in
relevant
change
in
the
at
the
anode
in
the
two
of
in
the
step
copper
2?
electrolyte
in
the

rst
Figure
10.3.6
sulfate
solution
Dene
2
Give
the
term
3
formula
a
molten
b
dilute
Draw
a
4
sodium
labelled
Describe
solution
using
5
By
a
the
inert
anode
a
of
and
means
the
and
sulfuric
electrolysis
of
copper( II)
graphite
and
electrodes
state
the
in
the
electrolysis
graphite
graphite
of
sulfate
differences
an
of
chloride
diagram
when
symbol
acid
copper( II)
the
of
Exam
tip
electrolysis.
It
the
using
questions
✔
1
electrodes
Electrolysis
second?
copper
Summary
the
cathode
equations.
colour
colour
different
of
the
ions
present
c
copper( II)
d
potassium
apparatus
solution
used
using
electrolysis
of
concentrated
in
each
sulfate
in
of
the
dilute
sodium
is
line
important
diagrams
that
to
you
show
can
draw
electrolytic
cells
solution
laboratory
graphite
sodium
following:
solution
bromide
inert
the
for
the
electrodes.
chloride
chloride
solution
electrodes.
equation
in
copper( II)
anode
each
sulfate
case,
show
solution
b
a
is
the
reaction
electrolysed
copper
occurring
at
using:
anode.
187
Quantitative
electrolysis
Electrochemistry
A10.4
Objectives
By
the
be
able
end
of
this
topic
you
Quantitative
electrolysis
will
The
volumes
of
gases
and
masses
of
substances
produced
during
electrolysis
to:
can be calculated using t he mole concept t hat you studied in Unit 7
. Michael
●
●
dene
the
calculate
and
Faraday
the
masses
produced
constant
volumes
of
of
gases
(1791–1867)
quantity
t he
quantity
symbol
Q
Each
you
of
of
and
electrons
Did
t he
rst
person
to
propose
t hat
t he
mass
of
a
electricity
passing
t hrough
t he
electrolytic
cell.
electrolysis.
The
?
was
substance produced at an electrode during electrolysis is directly propor tional
to
substances
during
Faraday
ow
electron
electricity,
is
measured
from
t he
owing
or
in
quantity
units
anode
t hrough
of
called
to
t he
t hese
electrical
coulombs,
cat hode
wires
has
charge,
C.
t hrough
an
is
During
given
electrical
electrical
t he
electrolysis,
charge
wires.
which
is
know?
extremely small. n fact, t he electrical charge on one electron is so small t hat
18
when
The
electrical
charge
on
1 C
of
electrical
charge
ows
t hrough
a
circuit,
6.25

electrons
10
one
have
owed.
19
electron
means
is
1.6
that

1 C
10
of
C.
This
electrical
charge
The quantity of electricity or electrical charge owing t hrough an electrolytic
1
___________
is
equivalent
cell
to
during
electrolysis
depends
on
two
factors.
19
1.6

10
electrons.
●
The
the
rate
of
ow
symbol
I
of
and
the
is
electrical
measured
charge,
in
units
i.e.
the
called
current,
amperes
which
(also
is
given
known
as
18
amps),
A.
owing
●
The
The
t he
A
for
of
of
following
of
1
amp
is
equivalent
to
1 C,
or
6.25

10
electrons,
1 s.
lengt h
quantity
current
time,
t,
t hat
electricity
t he
or
current
electrical
ows
charge
for,
can
measured
t hen
be
in
seconds,
calculated
s
using
formula:
quantity
of
electrical
charge
(C)

current
Q

I
i.e.

(A)

time
(s)
t
Example
Calculate
t he
ows
circuit
in
a
Current
Time
∴
!
of
fact
can
for
of
electrical
charge
t hat
ows
when
a
current
seconds
of
relate
electrons

20

60
electrical
t his
has.
to

The
Faraday
of
the
of
electrons,
constant
electrical
charge
is
on
the
size
one
mole
if

we
10
charge
moles
You
will
if
owing
we

consider
recall
t hat
2

t he
1 mol
1200 C

electrical
of
2400 C
charge
electrons
is
which
1 mol
equivalent
to
19
electrons.
have
96 500 C.
2.0 A
1200 s
23
6.0
of
20 min.
2.0 A
quantity
We
Key
in

quantity
1 mol
This
of
The
charge
electrons,
value
is
known
on
one
t hese
as
t he
electron
electrons
Farad ay
is
1.6
would

10
have
a
C,
total
t herefore,
charge
of
constant
1
i.e.
96 500 C mol
.

Dur ing
electrolysis,
discharged
at
t he
a
cation
cat hode
wit h
a
according
to
single
t he
positive
following
charge,
i.e.
M
,
is
equation:

M

e
M

This
and
shows
form
t hat
1 mol
1 mol
of
M
of
or,
electrons
applying
is
required
t he
Faraday
to
discharge
constant,
1 mol
96 500 C
of
is
M
ions
required

to
discharge
discharging
96 500 C
188
is
1 mol
1 mole
of
of
required.
M
ions
anions
and
wit h
form
a
1 mol
single
of
M.
negative
This
also
charge
at
applies
t he
when
anode,
i.e.
Electrochemistry
The
to
following
calculate
and
examples
t he
electrolysis.
of
Molar
mass,
M
Molar
volume,
will
volumes
You
volumes
Quantitative
will
of
recall
show
gases
t he
how
and
we
can
masses
following
of
use
t he
Faraday
substances
quantities
t hat
constant
formed
relate
electrolysis
moles
during
to
mass
gases.

mass
V

of
1 mol
volume
of
of
a
substance.
1 mol
of
a
gas.
m
3
At
stp,
V

22.4 dm
3
,
at
r tp,
V
m

24.0 dm
m
Examples
1
Calculate
of
5
5.0 A
t he
ows
mass
of
lead
t hrough
produced
molten
at
lead(II)
t he
cat hode
bromide
for
when
16
a
current
minutes
and
seconds.
Determine
Current
Time
∴

in
t he
seconds
t he
of
electricity
t hat
ows:
5.0 A
quantity
Write
quantity
of

(16

60)
electricity
equation
for

t he

5

965 s
(5.0

965) C
reaction
at

t he
4825 C
cat hode:
2
Pb
From
t he
2 mol
∴
2
i.e.
(l)
of


2e
Pb(l)
equation:
electrons
96 500 C
193 000 C
are
required
form
form
1 mol
1 mol
to
form
1 mol
Pb.
Pb
Pb
1
________
∴
1 C
forms
mol
Pb
193 000
1
________
∴
4825 C
forms

4825 mol
Pb
193 000

0.025 mol
Pb
1
M(Pb)
i.e.
∴
2
f
2

207 g mol
mass
of
mass
an
of
34
at
Time
in

current
minutes
Determine
Current
t he
t he
207 g
Pb
of

0.025
2.5 A
and
24
at
quantity
is

207 g
passed
seconds,

5.175 g
t hrough
calculate
dilute
t he
sulfuric
volume
of
acid
for
oxygen
r tp.
of
electricity
t hat
ows:
2.5 A
quantity
for
4OH

anode
seconds
Equation
Pb
0.025 mol
electric
hours
produced
∴
1 mol
of
(2

60
electricity
t he
(aq)

reaction


at
2H
60)
(2.5
t he



60)
9264) C


24

9264 s
23 160 C
anode:
O(aq)
2
(34

O
(g)

4e
2
189
Quantitative
electrolysis
Electrochemistry
From
t he
4 mol
equation:
electrons
are
lost
in
forming
1 mol
O
2
∴
4

96 500 C
form
1 mol
O
2
i.e.
386 000 C
form
1 mol
O
2
1
________
∴
1 C
forms
mol
O
2
386 000
1
________
∴
23 160 C
forms

23 160 mol
O
2
386 000

0.06 mol
O
2
3
Volume
of
1 mol
O
at
r tp

24.0 dm
2
3
∴
volume
of
0.06 mol
O

0.06

24.0 dm
3

1.44 dm
2
3
A
solution
of
Determine
t hrough
t he
Determine
Current
Time
∴
in

copper(II)
t he
solution
t he
in
for
quantity
is
mass
32
of
electrolysed
of
t he
minutes
anode
and
electricity
10
t hat
using
if
a
copper
current
of
electrodes.
4.0 A
passes
seconds.
ows:
4.0 A
seconds
quantity
Equation
sulfate
decrease
for
of

(32

60)
electricity
t he

reaction

10
4.0
at


t he
1930 s
1930 C

7720 C
anode:
2
Cu(s)
From
t he
Cu
(aq)

2e
equation:
2
2 mol
electrons
are
lost
in
forming
1 mol
Cu
ions.
2
∴
2

96 500 C
form
1 mol
Cu
ions
2
i.e.
193 000 C
form
1 mol
Cu
ions
1
________
∴
1 C
forms
2
mol
Cu
ions
193 000
1
________
∴
7720 C
forms
2

7720 mol
Cu
ions
193 000
21

2
M(Cu
)
0.04 mol
Cu
ions
1

64 g mol
2
i.e.
mass
of
1 mol
Cu
ions

64 g
2
∴
mass
of
Therefore,
4
A
steel
0.04 mol
decrease
spoon
Calculate
the
electroplate
Calculate
needs
in
be
of
spoon
number
ions
mass
to
length
the
t he
Cu
of
0.04
t he

anode
electroplated
time
that
when
of

a
of

as
the

2.56 g
2.56 g
wit h
current
placed
moles
64 g
13 g
of
of
15 A
cathode
chromium
of
which
produced:
1
M(Cr)
i.e.

mass
52 g mol
of
1 mol
Cr

52 g
13
___
∴
number
of
moles
in
13.0 g

mol
52
190

chromium.
would
0.25 mol
have
the
to
ow
electrolytic
need
to
be
to
cell.
Electrochemistry
Equation
for
Industrial
t he
reaction
at
t he
applications
of
electrolysis
cat hode:
3
Cr
From
t he
3 mol
∴
3
i.e.
(aq)
electrons

3e
form
96 500 C
0.25

Therefore,
Calculate
quantity
Cr(s)
equation:
289 500 C
∴

1 mol
form
form
t he
t he
of
1 mol
1 mol
289 500 C
electricity
72 375 C

∴

of
taken
15 A
0.25 mol
Cr
electricity
for
(C)

Cr
Cr.
form
quantity
time
Cr.

time
72 375 C
required
72 375 C
current

to
(A)
ow


72 375 C
using
time
a
current
of
15 A:
(s)
(s)
72 375
______
time
s
15
t
would
take
Dene
2
Calculate
the
cathode
chloride
3
rtp
4
How
A10.5
hour
hour
for
20
2
is
●
extracting
●
purifying
minutes
of
magnesium
current
hours
the
a
a
40
volume
current
must
for
a
of
of
in
metals
51
25
25
seconds
seconds
chlorine
of
of
that
ows
and
to
electroplate
the
spoon.
would
28
ow
copper
at
ways
t heir
in
deposited
molten
on
the
magnesium
be
produced
concentrated
at
the
anode
sodium
seconds.
through
the
a
solution
of
copper( II)
cathode?
applications
many
be
seconds.
through
and
10.0 A
would
through
50
that
ows
minutes
25.6 g
from
5.0 A
2.5 A
current
produce
used
of
minutes
Industrial
Electrolysis
minutes
constant.
mass
solution
to
20
questions
the
long
sulfate
1
Faraday
when
chloride

when
Determine
at
4825 s
1
Summary
1

industr y
of
electrolysis
Objectives
By
the
be
able
i.e.
plating
one
metal
describe
wit h
anot her,
i.e.
used
coating
a
metal
wit h
its
oxide,
i.e.
now
look
at
will
how
each
of
t hese
in
to
electrolysis
extract
metals
can
from
ores
describe
be
will
you
anodising.
●
We
topic
electroplating
their
●
this
electrorening
be
●
of
to:
ores
●
metals,
end
including:
more
used
how
to
electrolysis
purify
can
metals
detail.
●
describe
the
process
of
electroplating
Extraction
of
metals
●
Ver y
few
metals
are
found
in
t heir
free
state
in
t he
Ear t h’s
cr ust.
Most
describe
the
process
of
are
anodising.
found
bonded
Minerals
from
to
ot her
which
elements
metals
can
in
be
ionic
compounds
extracted
are
known
known
as
as
ores.
minerals.
The
process
191
Industrial
applications
of
electrolysis
Electrochemistry
of
extracting
atoms,
i.e.
it
metals
is
a
from
t heir
reduction
ores
involves
conver ting
t he
metal
ions
to
process:
n
M

Metals
ions.
high
This
reason
from
in
t hese
t heir
t he
electrochemical
t hat
metals
ores.
and
is
where
example
oxide
(Al
is
O
2
a
to
of
of
ionise
met hod
the
molten
aluminium
t heir
molten
easily
difcult
to
of
form
to
reduction
ore
and
and
reduce
is
a
ver y
atoms.
to
extract
powerful
metals
above
stable
For
t his
t hem
met hod
aluminium
of
in
ores.
ore,
t he
metal
ions
move
towards
t he
discharged.
extraction
using
series
ver y
powerful
from
t he
are
are
extract
series
t hey
t he
),
need
ions
Electrolysis
electrolysis
cat hode
t heir
used
electrochemical
During
An
M
means
reduction
t he
ne
iner t
of
aluminium
graphite
from
its
molten
ore,
aluminium
electrodes.
3
The aluminium ions move towards t he cat hode where t hey are discharged to
form
molten
aluminium:
3
Al
(l)

The
molten
and
it
be
sinks
3e
aluminium
to
discussed
t he
in
is
which
bottom
more
Purification
Electrolysis
Al(l)
of
of
detail
forms
t he
in
is
denser
electrolytic
Unit
t han
cell
and
t he
is
molten
tapped
electrolyte
off.
This
will
18.2.
metals
ver y
useful
in
t he
production
of
pure
metals
from
impure
samples of t he metal. This process is known as electrorening. The principles
of
●
electrorening
The
impure
terminal
of
The
cat hode
●
The
electrolyte
●
The
●
anode,
The
metal
metal
●
The
t he
negative
is
as
is
follows.
made
t he
anode,
i.e.
it
is
connected
to
t he
positive
batter y.
a
ver y
is
an
t hin
sample
aqueous
of
t he
solution
pure
which
metal.
contains
ions
of
t he
metal
puried.
electrolyte
electrode,
t he
●
being
positive
are
metal
being
where
ions
which
are
are
ionises,
join
t he
discharged
builds
electrolyte
anode
active,
t hey
up
at
around
remains
removed
and
ot her
t he
t he
t hey
are
of
t he
metal
enter
t he
ions.
cat hode
where
t hey
form
t he
pure
cat hode.
unchanged
as
ions
metal
since
t he
discharged
metal
at
t he
ions
entering
it
at
cat hode.
power
electrode,
the
anode,
a
bar
supply
●
the
of
impure
Any
insoluble
impurities
present
in
t he
anode
fall
to
t he
bottom
of
t he
cathode,
copper
a
(1)
thin
sheet
(2)
of
cell
forming
a
sludge
which
can
be
removed.
pure
copper
An example of electrorening is t he purication of copper . This is illustrated
in Figure 10.5.1. The impure copper is t he anode (1) and t he cat hode is a t hin
2
sheet
of
sulfate
sludge
copper(II)
containing
The
pure
copper
(2).
The
electrolyte
copper
anode
of
copper
Cu(s)
Cu
(aq)

copper(II)
2e
2
ions,
The
Cu
ions
enter
t he
electrolyte
(aq)
forming
10.5.1
The
electrorening
pure
copper:
of
2
192
i.e.
ionises:
2+
Cu
copper
ions,
solution.
2
solution
flow
Figure
Cu
sulfate
impurities

contains
Cu
(aq)

2e
Cu(s)
and
are
discharged
at
t he
cat hode,
Electrochemistry
Electrore ning
hydrogen
in
t he
ions,
in
hydrogen
is
t he
ser ies
being
Industrial
only
suitable
for
electroc hemical
would
lower
in
not
t he
be
pur ifying
ser ies.
disc harged
ser ies,
would
Any
at
be
t he
metals
metal
whose
ions
cat hode
preferentially
ions
are
above
since
applications
of
electrolysis
below
hydrogen
t he
hydrogen
disc harged,
for ming
gas.
Electroplating
Electroplating
anot her
metal
from
object
be
made
of
The
t he
more
any
of
metal,
object
to
be
The
anode
●
The
electrolyte
The
is
used
The
metal
metal
The
●
t he
As
a
for
anode,
electrolyte
●
pure
is
ions
t he
sample
an
to
t hat
made
similar
made
to
t he
of
one
eit her
appearance
usually
is
layer
out
object
ver y
or
is
of
to
make
being
brass,
t hose
of
cat hode,
metal
protect
on
t he
a
top
cheap
metal
electroplated
copper
or
of
original
steel.
can
The
electrorening.
i.e.
it
is
connected
to
batter y.
of
aqueous
active,
t hey
are
t he
metal
solution
electrolyte
ionises,
join
t he
discharged
builds
up
as
remains
removed
electrorening,
electrochemical
of
t hin
which
which
is
being
contains
used
ions
for
of
plating.
t he
metal
plating.
being
are
is
are
its
The
electroplated
where
which
anode
wit h
it
a
carried
improve
but
terminal
●
●
to
is
valuable.
electroplating
negative
being
depositing
Electroplating
corrosion,
appear
principles
●
involves
metal.
series
a
at
t he
coating
t hey
only
be
are
of
t he
cat hode
since
where
t he
t he
whose
for
metal
enter
t he
ions.
at
ions
t hey
form
t he
pure
object.
metal
discharged
metals
used
ions
metal
around
unchanged
as
can
and
ot her
ions
t he
are
entering
it
at
cat hode.
below
hydrogen
in
t he
plating.
Examples of electroplating are chromium plating, silver plating, gold plating
and
nickel
plating.
Chromium
look
as
as
t he
plating ,
well
as
cat hode,
solution
of
or
chrome
protecting
t he
t hem
anode
is
chromium(III)
plating,
from
pure
sulfate
chromium
[Cr
(SO
2
The
chromium
anode
gives
steel
corrosion.
)
4
and
objects
The
t he
steel
a
shiny,
object
electrolyte
is
is
silver
placed
usually
a
].
3
ionises:
3
Cr(s)
Cr
(aq)

3e
3
The Cr
ions enter t he electrolyte and are discharged at t he cat hode forming

a
layer
of
chromium
on
t he
Figure
10.5.2
Chrome
plated
taps
object:
3
Cr
The
(aq)

3e
electrolytes
solutions
of
Cr(s)
used
nickel(II)
in
nickel
sulfate
plating
(NiSO
)
and
and
silver
silver
nitrate
plating
(AgNO
4
).
are
usually
During
t he
3
+
silver
process
of
silver
plating
illustrated
in
Figure
10.5.3,
t he
silver
anode
ionises:
nitrate
the
object
electrolyte

Ag(s)
Ag
(aq)

e
being
plated

The Ag
a
layer
(cathode)
ions enter t he electrolyte and are discharged at t he cat hode forming
of
silver
on
t he
silver
object:
anode

Ag
(aq)

e
Ag(s)

Figure
10.5.3
Electroplating
with
silver
193
Industrial
applications
of
electrolysis
Electrochemistry
Anodising
On
a
exposure
layer
of
to
air,
aluminium
aluminium
oxide
immediately
(Al
O
2
unreactive
a
result
The
it
and
adheres
protects
t hickness
objects
it
can
of
be
t he
t he
rmly
metal
aluminium
ar ticially
on
its
reacts
wit h
surface.
t he
This
oxygen
layer
is
to
form
relatively
3
to
from
)
t he
metal
attack
by
oxide
increased
by
below
and
oxygen
and
layer
a
on
process
t he
does
not
ake
moisture
surface
known
as
of
in
off.
t he
As
air.
aluminium
anod ising.
This
makes t he objects, such as window frames and saucepans, even more resistant
to
●
corrosion.
The
The
aluminium
hydroxide
●
The
t he
●
The
●
As
anodising
cleaned
terminal
electrolyte
as
to
to
t he
is
be
clean
aluminium
positive
soon
ar ticle
solution
process
of
anodised
and
ar ticle
t he
usually
a
electrolytic
involves
etch
is
is
following
pre-treated
t he
made
t he
steps.
using
sodium
surface.
t he
anode,
i.e.
it
is
connected
dilute
cell
is
solution
of
connected
sulfuric
up,
t he
acid.
aluminium
anode
3
begins
to
ionise,
forming
to
batter y.
Al
2
ions,
and
at
t he
same
time
t he
SO
ions
4
and
t he
OH
ions
in
t he
electrolyte
move
towards
t he
anode.
The
OH
3
ions
react
surface
of
wit h
t he
t he
Al
ions
forming
a
layer
of
aluminium
oxide
on
t he
aluminium:
3
Al(s)
Al
(aq)

3e
3
2Al

(aq)

3OH
(aq)
Al
O
2
The
silver-grey
attractively
aluminium
oxide
(s)

3H
(aq)
3
coating
readily
absorbs
dyes
cathode
anode
article
e.g.
a
()
to
–
be

Figure
Summary
Explain
why
Describe
3
the
Give
(
4
electrolysis
how
series
you
anodising
is
would
for
used
from
the
to
their
purify
occurring
equations
194
chromium
What
is
)
of
–
dilute
acid
aluminium
questions
reactions
the
The
at
a
the
extract
metals
high
plating
anodising?
in
the
ores.
sample
anode
reactions
that
of
silver.
and
the
occur
Include
b
nickel
the
equations
cathode.
at
the
during:
a
be
frame
10.5.4
electrochemical
for
can
coated,
window
sulfuric
2
it
aluminium
electrolyte
1
so
coloured.
plating.
anode
and
cathode
Electrochemistry
Key
●
The
electrochemical
The
t heir
A
atoms
higher
ionises
●
t he
and
metal
●
Metals
The
A
how
higher
from
not
it
t he
from
can
a
t he
an
in
t he
electrolysis
Electrolytes
are
to
a
list
of
metals
in
order
of
how
is
t he
ions
non-metals
in
gain
t he
stronger
series
is
gas;
from
more
easily
series
a
list
displace
metals
an
it
from
a
of
t he
below
acid.
non-metals
in
electrons.
electrochemical
are
its
non-metal
containing
to
t he
electrochemical
hydrogen
hydrogen
of
electricity
pass
in
electrochemical
t he
a
it
series,
powers.
metal.
forming
atoms
displace
allow
electricity
below
t he
series
compound
Conductors
is
reducing
lower
acid,
t heir
and
metals
electrochemical
its
metal
non-metal
ionises
of
t he
are
displace
easily
non-metal
allow
●
a
electrochemical
of
in
hydrogen
will
series
●
above
hydrogen
easily
●
is
stronger
displace
ions
order
●
of
electrons.
containing
hydrogen
The
series
lose
metal
t he
can
compound
●
applications
concepts
easily
●
Industrial
oxidising
below
t he
pass
it
lower
t hrough.
series,
t he
more
powers.
in
t he
electrochemical
non-metal.
Non-conductors
do
not
t hrough.
compounds
t hat
form
ions
when
molten
or
in
aqueous
solution.
●
Electrolytes
●
When
conduct
electricity
electricity
passes
because
t hrough
an
t hey
contain
electrolyte,
t he
mobile
ions
electrolyte
decomposes.
●
Metals
●
When
●
Strong
of
●
conduct
electricity
electricity
ions.
passes
electrolytes
Weak
of
Pure
ver y
is
fully
electrolytes
concentration
water
are
because
t hrough
a
a
t hey
ionised;
are
contain
metal,
t he
t hey
par tially
mobile
metal
contain
ionised;
electrons
remains
a
high
t hey
unchanged.
concentration
contain
a
low
ions.
weak
electrolyte
due
to
t he
ver y
low
concentration
of

H
●
and
●
is
of
t he
are
anode
lose
electrons.
The
cathode
Molten
Bot h
t he
chemical
t hrough
used
is
and
t he
during
positive
Oxidation
is
t he
gain
which
occurs
when
an
electric
electrolyte.
electrolysis
electrode.
occurs
negative
electrons.
electrolytes
are
change
an
to
conduct
electricity
in
to
and
electrolyte.
The
cat hode
●
is
passed
Electrodes
out
●
ions.
Electrolysis
current
●
OH
contain
discharged
during
at
Anions
t he
electrode.
Cations
Reduction
one
type
move
towards
t he
anode
and
anode.
occurs
of
move
at
cation
t he
and
towards
t he
cat hode.
one
type
of
anion.
electrolysis.

●
Aqueous
ions
electrolytes
from
t he
preference
●
Factors
●
The
t he
which
position
t he
to
of
water.
of
solute
type
of
ions
ion
of
as
well
each
as
H
charge
ions
will
be
and
OH
discharged
in
ot her.
anion
solution
position
preferential
One
inuence
t he
aqueous
contain
t he
in
t he
t he
and
whet her
cation
discharge
of
preferenti al
d ischarge
electrochemical
in
t he
t he
series,
anode
is
of
active
electrochemical
anions
t he
or
series
are
t he
concentration
of
iner t.
determines
t he
cations.
195
Industrial
applications
of
electrolysis
Electrochemistry
●
When
dilute
produced
●
When
if
t he
at
sulfuric
t he
sodium
is
at
●
●
t he
When
copper (II)
bot h
oxygen
is
sulfate
solution
produced
at
it,
Copper
is
produced
at
t he
volume
of
passing
t hrough
●
The
quantity
●
The
quantity
charge,
i.e.
Q
t

The
I
gas
electrolysis

of
of
t he
Farad ay
or
is
t he
at
using
t he
iner t
electrolysed
produced
at
t he
electrodes,
oxygen
is
cat hode.
at
using
t he
anode.
iner t
anode,
electrodes,
if
it
Hydrogen
is
is
produced
cases.
is
The
is
is
produced
oxygen
during
●
in
electrolysed
hydrogen
solution
dilute,
chlorine
cat hode
is
and
chloride
solution
concentrated,
acid
anode
if
mass
t he
cat hode
of
a
directly
electricity ,
current,
constant
I,
is
is
electrolysed,
in
is
made
bot h
substance
Q,
t he
if
t he
anode
copper,
it
is
iner t,
ionises.
cases.
to
t he
at
an
electrode
quantity
of
electricity
cell.
is
measured
dependent
and
of
produced
propor tional
electrolytic
electricity
is
anode
t he
size
time
of
on
t he
t he
in
coulombs,
t he
rate
current
electrical
of
C.
ow
ows
charge
of
for,
on
electrical
t,
i.e.
one
mole
of
1
●
electrons,
i.e.
ndustrial
uses
ores,
196
t he
96 500 C mol
of
electrolysis
purication
of
.
include
metals,
t he
extraction
electroplating
and
of
metals
anodising.
from
t heir
Electrochemistry
Practice
Practice
exam-style
Multiple-choice
1
Metal
X
was
containing
questions
to
displace
sulfate
of
Y.
metal
Y
However,
from
X
did
a
solution
not
displace
anode
metal
t he
Z
from
a
following
A
X
B
Z
is
solution
is
higher
containing
Z
sulfate.
Which
cathode
of
correct?
in
t he
electrochemical
series
t han
Z.
copper(II)
is
a
stronger
C
Y
is
higher
D
Y
is
a
in
reducing
t he
stronger
agent
t han
electrochemical
reducing
agent
series
t han
Which
of
t he
following
lists
consists
t han
X.
Z.
of
Electrolytic
State,
sodium
B
hydrochloric
chloride,
magnesium,
et hanol,
anode.
aqueous
D
kerosene,
sodium
hydroxide,
copper,
et hanoic
State,
During
electrolysis,
potassium
t he
a
what
you
relevant
would
obser ve
equation. (3
giving
a
reason,
what
you
would
chloride,
tap
reaction
which
takes
(2
f
a
current
of
5.0 A
ows
for
2
hours
8
minutes
water
place
at
40
seconds
t hrough
determine
t he
increase
Give
differences
t he
in
electrolytic
mass
of
t he
cell,
cat hode.
t he
B
reduction
C
oxidation
D
a
current
t hrough
would
electrolytic
cell
made
t he
anode
made
t he
cat hode.
a
be
A
2.7 g
B
5.4 g
of
5.0 A
silver
ows
nitrate
deposited
at
for
16
minutes
solution,
t he
what
and
mass
5
i)
of
Give
and
seconds
ii)
silver
you
would
obser ve
if
and
t he
t he
copper
electrode
graphite
C
10.8 g
D
27
.0 g
T WO
ONE
(2
What
a
0.75 mol
sodium
of
electricity
chlorine
molten
during
is
needed
t he
to
produce
electrolysis
of
answer
molten
b
chloride?
Using
t he
sodium
is
discuss
B
96 500 C
products
144 750 C
D
193 000 C
i)
a
electroplating
anodising.
is
a
chemical
relevant
The
of
of
to
t he
Which
of
t he
can
following
A
ron
B
Anodising
be
puried
is
used
statements
by
to
is
incorrect?
c
Suppor t
your
and
wit h
of
iner t
t he
(4
aluminium
items
from
t hem
position
of
ions
items
appearance
corrosion.
Cutler y
Electroplating
can
be
used
to
coat
steel
items
wit h
electrodes,
following
on
layer
of
in
t he
electrochemical
Magnesium
of
t he
electroplating
wit h
a
layer
resistant
and
made
of
to
make
of
steel
of
electrolyte.
can
be
anot her
corrosion,
t hem
is
marks)
(2
marks)
to
metal
more
coat
to
improve
appear
of ten
used
(2
make
t heir
valuable.
electroplated
of
nickel
followed
by
a
layer
of
wit h
a
silver.
silver.
i)
D
t he
a
layer
t hin
concentration
more
marks)
concentrated
electrolysis.
process
metal
electrolysis.
protect
The
The
marks
electrolysis
series.
ii)
15
mark)
how
equations.
dilute
EACH
Use
show
process.
ionic
solutions
effect
of
process.
bromide
electrolysis
t he
marks)
(1
question
chemical
chloride
72 375 C
C
was
marks)
(2
of
potassium
wit h
A
C
use
response
Electrolysis
of
of
between
Total
8
quantity
differences
anode?
electrolysis
6
in
was
electrode
anodising.
Give
Extended
5
t hat
decomposition
c
f
T WO
displacement
t he
4
marks)
is:
iv)
A
in
marks)
(4
anode
at
marks)
obser ve
electrolyte.
and
3
nclude
acid
iii)
molten
cell
reason,
aluminium
t he
C
a
graphite
ii)
acid,
giving
conductors?
t he
A
sulfate
solution
X.
i)
2
questions
questions
found
t he
exam-style
can
be
extracted
from
its
ore
Draw
a
labelled
diagram
to
show
t he
apparatus
by
you
could
use
to
electroplate
a
steel
spoon
wit h
electrolysis.
nickel
using
nickel
sulfate
solution
(NiSO
(aq))
as
4
Structured
7
a
b
Dene
An
electrolyte.
use
as
Clearly
indicate
what
you
would
question
t he
term
electrolytic
wit h
t he
cell
copper(II)
graphite
‘electrolysis’. (1
anode
was
sulfate
and
a
set
up,
as
solution
copper
ii)
mark)
shown
as
t he
cat hode.
in
t he
gure,
electrolyte,
a
How
t he
long
anode
must
t hrough
t he
9.44 g
nickel?
of
and
a
t he
steady
electrolyte
cat hode.
current
to
coat
(3
of
4.0 A
t he
spoon
(4
Total
marks)
ow
wit h
marks)
15
marks
197
A11
Rates
of
reaction
Chemical
reactions
reactions
can
proceed
at
different
speeds.
Some
Objectives
By
the
be
able
end
of
this
topic
you
will
while
●
take
years,
such
as
the
rusting
of
cars,
to:
dene
what
is
meant
by
rate
of
others
explosion.
happen
Other
in
less
reactions
than
take
a
second,
place
at
such
varying
as
an
speeds
reaction
between
●
explain
how
reaction
●
explain
the
can
the
be
rate
of
which
measured
collision
these
two
extremes.
Knowing
the
speed
at
a
theory
reactions
occur
is
extremely
important
in
industry
for
to
maximise
productivity
while
minimising
costs
and
the
reactions
●
interpret
rate
curves
risk
for
of
accidents.
reactions.
A11.1
The
t he
Measuring
study
rate
of
of
t he
concentration
increases.
f
of
we
t he
increase
in
t he
decrease
or
The
rate
of
speed
reaction ,
a
t he
can
is
rates
at
which
called
increase
reaction
to
can,
chemical
of
occur,
we
in
can
be
t he
in
product,
t herefore,
decrease
as
decrease
a
reaction
kinetics.
decreases
t he
concentration
reaction
chemical
reactants
measure
a
of
occurs,
During
a
concentration
concentration
and
know
determine
t he
determined
concentration
of
how
rate
known
reaction,
of
a
a
products
reactant
long
of
as
t he
it
took
or
for
reaction.
by:
of
a
reactant
____________________________________
rate
of
reaction

time
increase
taken
in
for
t he
decrease
concentration
of
a
product
____________________________________
or
rate
of
reaction

.
time
!
The
Key
rate
change
fact
of
in
reaction
the
is
a
measured
concentration
of
Changes
in
are
property
products,
or
product
with
time
at
t hat
changes
can
be
are
not
which
measured
always
depend
to
increase
easy
on
to
t he
determine
measure.
nature
t he
rate
of
of
a
However,
t he
t here
reactants
reaction.
and
Some
t hat
can
be
measured
of
are:
if
one
of
t he
products
is
a
gas,
t he
volume
of
gas
produced
over
time
temperature.
can
●
be
measured
metal
and
if
of
one
decrease
reaction
●
if
a
an
t he
in
if
products
precipitate
t here
is
reaction
e.g.
●
if
t here
of
a
a
is
t he
gas
syr inge,
a
gas,
if
t he
reaction
carbonate
for ms,
t he
e.g.
a
reaction
between
a
reactive
t he
gas
can
and
be
an
appearance
reaction
between
is
allowed
measured
to
escape,
over
t he
time,
e.g.
a
acid
of
t he
sodium
precipit ate
t hiosulfate
can
be
and
acid
c hange
between
is
reaction
a
a
acid
mass
hydroc hlor ic
●
using
between
measured,
198
changes,
t he
a
●
stated
concentration
for
a
t he
reactant
ot her
taken
in
colour
pot assium
distinct
proceeds,
c hange
any
of
intensity,
iodide
in
t his
and
pressure,
t hese
can
be
can
be
acidi ed
measured,
hydrogen
temperature
measured
or
over
pH
as
time.
e.g.
t he
peroxide
t he
Rates
of
reaction
Collision
Chemical
and
t he
take
Measuring
theory
reactions
formation
place,
all
of
for
t he
new
t he
breaking
bonds
following
the reactant particles must
●
of
reaction
reactions
involve
of
rates
in
must
t he
of
original
products.
bonds
in
order
for
n
t he
a
reactants
reaction
to
occur:
collide with each other in order to break the
original bonds in the reactants so that new bonds can form in the products
the
●
reactant
activation
reactants
products
t he
●
and
(see
reactant
energy
in
par ticles
energ y
enable
Unit
to
break
collide
Unit
the
with
12.1),
par ticles
to
to
enough
break
have
energy,
the
known
original
enough
as
bonds
energy
to
in
the
form
12.1)
par ticles
produced
order
must
(see
by
must
t he
collide
collision
wit h
can
t he
be
correct
passed
on
or ientation
to
t he
so
t hat
original
t he
bonds
t hem.
Not all collisions occur wit h t he required activation energy or wit h t he correct
orientation
of
par ticles.
Therefore,
not
all
collisions
result
in
a
reaction
occurring. Collisions which result in a reaction are called effective collisions .
The
For
rate
of
a
reaction
example,
2H
(g)
in

O
2
The
t he
depends
reaction
(g)
on
2H
break
will
t he
t hen
(H
)
and
oxygen
atoms,
and
collisions.
oxygen
to
form
new
(O
)
molecules
forming
H
between
covalent
bonds
water
bonds
must
to
atoms
collide
form
wit hin
wit h
t he
between
covalent
new
break
H

O
O
H
t he
must
O
O
2
Figure
11.1.1
To
be
effective
an
to
molecules
Rate
f
a
The
and
reaction
t he
t he
between
each
covalent
molecules
This
hydrogen
and
form
H
O
H
2H
2
collision,
break
ot her
covalent
bonds
2H

each
molecules.
molecules.
must
H
t he
H
energy
water:
O(g)
oxygen
bonds
original
H
hydrogen
effective
2
covalent
allow
of
2
2
to
number
between
2
hydrogen
t he
hydrogen
and
collision
bonds
must
be
O
2
oxygen
must
wit hin
correctly
generate
t he
enough
hydrogen
orientated
to
activation
and
each
oxygen
ot her.
curves
measured
proceeds
and
proper ty
t he
is
plotted
proper ty
on
changes,
a
a
graph
rate
against
curve
is
time
as
t he
reaction
obtained.
gas
syringe
volume
measures
of
the
hydrogen
Examples
1
The
reaction
between
magnesium
and
hydrochloric
acid:
dilute
Mg(s)

2HCl(aq)
MgCl
(aq)

H
2
(g)
2
hydrochloric
f
magnesium
ribbon
is
added
to
hydrochloric
acid,
t he
volume
acid
of
magnesium
hydrogen
gas
given
off
can
be
measured
in
a
gas
syringe
at
regular

inter vals
using
t he
apparatus
shown
in
Figure
1
1.1.2.
f
t he
volume
of
Figure
of
is
t hen
plotted
against
time,
t he
cur ve
in
Figure
1
1.1.3
may
be
11.1.2
Investigating
the
rate
gas
reaction
between
magnesium
and
obtained.
hydrochloric
acid.
199
Measuring

Figure
rates
11.1.3
gas
reaction
Graph
of
released
Rates
volume
against
of
of
reaction
50
time
45
mc(
3
)
hydrogen
of
40
sag
35
negordyh
30
25
fo
20
emuloV
15
10
5
0
0
60
120
180
240
300
Time
We
can
use
reaction
at
t he
values
different
on
t he
stages
graph
in
t he
increase
to
determine
reaction
in
360
420
480
(s)
by
volume
of
t he
using
average
t he
rate
general
of
formula:
hydrogen
______________________________
rate
of
reaction

time
To
●
determine
t he
average
taken
rate
of
for
t he
t he
increase
reaction
in
t he
rst
minute
(60 s):
3
volume
of
gas
produced
in
t he
rst
minute

28 cm
3
28 cm
_______
∴
average
rate
of
reaction
in
t he
rst
minute
3


0.47 cm
1
s
60 s
To
●
determine
t he
average
rate
of
t he
reaction
in
t he
second
minute:
3
olume of gas produced in the second minute
3
 (38  28) cm
 10 cm
3
10 cm
_______
∴
average
rate
of
reaction
in
t he
second
minute

60 s
3

This
clearly
decreases.
graph.
t he
The
discuss
2
wool
to
The
can
t hat
as
also
be
gradient
reaction
becomes
cotton
shows
This
is
rapid.
shallower
t his
in
reaction
is
t he
reaction
seen
steep
at
more
detail
between
in
as
calcium
at
t he
beginning
t he
t he
t he
proceeds,
looking
t he
However,
indicating
by
of
reaction
reaction
next
is
t he
0.17 cm
rate
of
gradient
t he
graph
progresses,
slowing
t he
or
1
s
reaction
slope
of
t he
indicating
t he
down.
gradient
We
will
section.
carbonate
and
hydrochloric
acid:
stop
CaCO
(s)

2HCl(aq)
CaCl
3
f
some
be
cur ve
in
CO
calcium
at
acid
regular
Figure
is
poured
carbonate
is
inter vals.
1
1.1.5
may
be
into
f
t he

H
2
a
added,
(g)
conical
t he
mass
ask,
mass
is
of
t hen
O(l)
2
which
t he
is
on
reaction
plotted
a
can
against
time,
obtained.
)g(
calcium
acid
carbonate
noitcaer
hydrochloric
(marble
and
measured
t he

2
hydrochloric
balance,
(aq)
chips)
fo
ssaM
direct-reading
balance
Time
on


Figure
11.1.4
reaction
and
200
Investigating
between
hydrochloric
calcium
the
rate
Figure
11.1.5
Graph
of
(s)
mass
of
reaction
against
time
of
carbonate
Looking
at
reaction
proceeds,
t he
gradient
of
t he
graph
we
can
also
clearly
acid
t he
rate
of
t he
reaction
decreases.
see
t hat
as
t he
Rates
of
reaction
Measuring
Explanation
We
can
steep
at
see
that
the
of
the
both
shape
rate
beginning
of
cur ves
the
of
rate
have
reaction
a
of
reaction
curves
ver y
and
rates
similar
gradually
shape.
The
becomes
gradient
shallower
is
until
the cur ve eventually becomes horizontal. This shows that the rate of a reaction
changes as the reaction proceeds. We will now look at the reasons for this.
●
The gradient is steepest at the beginning of the reaction indicating that
the rate of the reaction is at its
highest. This is because the concentration
of the reactant particles is at its highest at the beginning of the reaction.
The frequency of collision between the particles is at its highest at the
beginning.
●
As the reaction proceeds, the gradient becomes shallower indicating that
the rate of the reaction is
decreasing. This is because the concentration of
the reactant particles is decreasing as the reaction proceeds. The frequency
of collision between the particles is decreasing as the reaction proceeds.
●
After a period of time the cur ve becomes horizontal, i.e. the gradient
becomes zero, indicating that the reaction has reached completion and
has
stopped. One of the reactants has been used up and there are no more
of its particles left to collide. The reactant which is used up in a reaction
is known as the
limiting reactant. The quantity of the limiting reactant
determines the quantity of the products produced.
T
o
investigate
reaction
Your
the
change
in
rate
of
a
reaction
as
the
proceeds
teacher
may
●
observation,
●
manipulation
●
analysis
and
use
this
recording
and
activity
and
to
assess:
reporting
measurement
interpretation.
3
Y
ou
will
be
supplied
hydrochloric
through
it
to
acid,
a
a
gas
with
4.0 g
conical
syringe,
of
calcium
ask,
a
a
cork
measuring
carbonate
with
a
crystals,
delivery
cylinder
and
a
tube
0.3 mol dm
running
stopwatch.
Method
1
Place
the
calcium
carbonate
crystals
in
the
conical
ask.
3
2
Measure
3
As
conical
as
ask
syringe,
4
30 cm
quickly
as
of
with
in
hydrochloric
possible
the
Figure
Record
the
volume
volume
remains
Record
your
pour
cork
the
which
11.1.2.
of
gas
acid
acid
At
in
has
the
the
in
the
into
a
conical
delivery
same
gas
measuring
the
time,
syringe
tube
start
every
cylinder.
ask
and
running
the
15
cork
to
the
the
gas
stopwatch.
seconds
until
the
✔
5
constant
results
in
a
for
three
table
and
consecutive
use
them
to
Exam
plot
a
graph
of
volume
of
When
drawing
obtained
gas
against
time.
Draw
a
curve
of
best
t
between
the
from
Using
your
graph,
rst
minute
calculate
the
average
rate
of
the
reaction
the
b
the
second
minute.
Explain
than
in
why
the
the
average
second
rate
of
the
reaction
is
higher
in
the
Explain
why
the
you
rst
line
of
necessarily
data
it
draw
a
is
curve
best
join
curve
or
line
smooth
or
straight
of
all
fit.
You
the
best
fit
do
points.
must
be
minute
and
must
pass
minute.
between
8
that
straight
not
A
7
using
for:
or
a
graphs
experiments,
points.
important
6
tip
readings.
curve
of
your
graph
eventually
becomes
horizontal.
close
as
the
points
possible
to
so
all
that
the
it
is
as
points.
201
Factors
affecting
rates
of
reaction
Rates
Summary
Dene
2
Give
two
ways
3
Give
two
methods
of
reaction
changes
the
end
be
able
of
What
5
Explain
this
topic
you
rate
identify
the
factors
which
rates
explain
affect
●
that
between
rate
a
of
reaction.
the
rate
student
magnesium
of
could
a
reaction.
use
ribbon
to
and
determine
dilute
how
the
hydrochloric
rate
acid
time.
the
how
by
calculating
collision
the
rate
Factors
theory
of
a
for
a
reaction
reaction
changes
affecting
state?
as
rates
the
of
reaction
proceeds.
reaction
of
a
of
reaction
describe
different
rates
changing
the
a
will
is
dependent
be
st udyin g
on
several
whi c h
can
factor s.
a f fec t
There
t he
r ate
are
of
four
a
main
r eacti on .
are:
of
●
concentration
●
temperature
●
sur face
●
presence
factors
reaction
experiments
determine
we
reaction
how
the
t hat
affect
These
●
of
to:
facto r s
the
meant
will
The
●
is
with
does
A11.2
Objectives
By
4
reaction
questions
1
what
of
effect
factor
to
area
(par tic le
size)
of
on
the
rate
or
absen c e
of
a
ca t aly st .
of
Light and pressure also affect t he rate o f c e r t ain re act ion s. For e xa mple , t h e
a
reaction
reaction between met h a n e a n d c h lor ine (se e Unit 14.1) a n d p h otosynt h esis
●
interpret
graphical
are
representations
of
bot h
t he
obtained
in
initiated
by
ligh t ,
an d
as
t he
lig h t
in ten sity
in c rease s,
t he
r ate
of
data
studying
rates
reaction
incre a s e s.
Ch emic al
re ac tio n s
wh ic h
are
in it ia ted
or
sp eed ed
of
up
by
light
are
kn own
as
photochemic al
re actions .
reaction.
Pressure
affects
pressure
on
meaning
Did
?
you
know?
is
possibly
in
the
the
which
most
important
world.
green
It
is
the
plants
effective
carbon
make
The
plants
sunlight
reaction.
animals
and
to
dioxide
use
W ithout
would
both
bring
no
oxygen
t he
collis io n s ,
reactio n
the
(g)

3H
2
rea c t a n t
gase ou s
t h eir
p ar ticle s
p er
st ate.
volume
un it
f
t he
dec reas es ,
vo lume.
As
a
t h ereby
b etwee n
increasing
n itrog en
t he
and
rate
of
t he
hyd rogen
to
re a c t io n .
for m
This
is
a mmon i a:
(g)
2NH
2
(g)
3
will
now
look
in
det ail
at
h ow
eac h
of
t he
ot h er
four
factor s
affects
t he
and
of
a
reaction.
When
co nsider ing
a
p ar ticu la r
f ac tor,
it
is
of
a
assu med
t h at
energy
about
ot her
factor s
a re
ke pt
co nst a nt .
the
no
and
food
animals
to
eat
Concentration
would
The
have
t he
photosynthesis,
have
plants
mo re
in
in c rease d ,
by
all
from
in
N
by
food
rate
water.
are
r eac t an ts
is
reactions
process
We
combining
t h e re
bet we en
react ants
one
seen
of
t hat
gaseous
result, t h e par ticl e s c o llide mo re fre quen tly an d t h is inc rease s t h e c h an c es
of
Photosynthesis
re a c t io n s
t he
for
gene ral
r ule
is
t h at
t he
higher
t he
concentration
rea ct a nt ,
t he
respiration.
higher
This
is
t he
rate
applies
in creased,
volume.
t he
As
a
c hances
of
t he
reaction.
par t ic ula rly
t his
me an s
result ,
of
t he
to
so lution s.
t ha t
t h ere
pa r t icles
e ffe c t i ve
f
a re
c o llide
co llisio n s,
t he
con c en tratio n
mo re
mo re
r eac t an t
frequen tly
t h erefore,
t he
of
a
par ticle s
r ate
w h ic h
of
t he
r eac t an t
per
unit
inc r eas es
r eac tion
increases.
f we measure t he rate of a rea ctio n a t differen t con c en tratio n s o f on e o f t h e
react ants, and plot t h e rat e a gain st c on c en tratio n , we g et a g raph similar to
t he one in Figure 1
1. 2.1. The g raph
202
cle arly sh ows t h at a s t h e con c en trati on
Rates
of
reaction
t he
rate
increases.
t
also
shows
t h at,
for
t h is
reac tio n ,
t he
r ate
of
1
reaction
is
directly
propor tional
to
t he
rates
of
reaction
s(
t he
affecting
)
increases
Factors
concentrat io n .
noitcaer
fo
etaR
3

T
o
investigate
Your
teacher
the
may
●
observation,
●
manipulation
●
analysis
effect
use
this
recording
and
and
Figure
of
Rate
of
reaction
concentration
activity
and
11.2.1
to
on
against
the
Concentration
concentration
rate
of
a
will
be
)
reaction
assess:
reporting
measurement
interpretation.
3
Y
ou
(mol dm
supplied
with
0.005 mol dm
3
potassium
iodide
solution,
0.01 mol dm
sodium
thiosulfate
solution,
a
3
solution
of
acidied
hydrogen
peroxide
3
25 cm
and
starch
with
a
hydrogen
peroxide
concentration
of
0.085 mol dm
,
two
3
measuring
cylinders,
one
10 cm
measuring
cylinder,
a
burette,
a
small
beaker
and
a
stopwatch.
Method
1
Place
the
sodium
thiosulfate
solution
into
the
burette.
3
2
Measure
sodium
25 cm
3
of
thiosulfate
potassium
solution
iodide
from
the
solution
burette
in
a
and
measuring
swirl
to
cylinder
mix
the
and
pour
it
into
the
beaker.
Add
1 cm
of
solutions.
3
3
Measure
4
Add
the
piece
5
of
25 cm
of
acidied
mixture
to
the
white
Observe
the
hydrogen
beaker
and
at
peroxide
the
same
and
time
starch
start
mixture
the
in
another
stopwatch.
measuring
Swirl
the
cylinder.
beaker
and
place
it
on
a
paper.
solution
in
the
beaker
from
above
and
as
soon
as
a
blue-black
colour
begins
to
appear
stop
the
stopwatch.
6
Record
the
time
7
Repeat
the
experiment
table
8
taken
for
the
four
blue-black
more
times
colour
using
to
the
start
to
volumes
appear.
of
potassium
iodide
solution
and
water
given
in
the
below.
Calculate
the
concentration
of
potassium
volume
of
iodide
solution
for
each
concentration
of
KI(aq)
experiment
using
the
following
formula:
Kl(aq)
_______________

3

0.005 mol dm
25
9
Calculate
the
rate
of
reaction
for
each
experiment
using
the
following
1
______________________________________
rate
of
reaction

s
time
10
Record
your
against
the
Volume
results
a
Volume
iodide
25
of
of
distilled
3
solution/cm
taken
table
concentration
of
potassium
in
formula:
1
for
similar
the
blue-black
to
the
potassium
Concentration
potassium
of
0
dm
appear
below
solution.
Volume
of
and
Draw
sodium
thiosulfate
3
solution/mol
to
outlined
iodide
iodide
3
water/cm
one
colour
a
plot
a
graph
straight
Volume
of
hydrogen
1
to
of
show
best
acidified
peroxide
3
solution/cm
line
Time
and
the
t
rate
of
between
taken
blue/black
the
the
for
colour
Rate
mixture/cm
of
reaction/
3
starch
reaction
points.
1
to
appear/s
s
25
20
5
1
25
15
10
1
25
10
15
1
25
5
20
1
25
203
Factors
affecting
11
What
12
Explain
13
Use
can
rates
you
the
of
reaction
deduce
effect
Rates
about
that
the
effect
increasing
the
of
concentration
concentration
has
on
on
the
rate
the
of
rate
the
of
of
reaction
reaction?
the
reaction.
3
your
graph
to
determine
the
rate
of
the
reaction
at
potassium
iodide
concentrations
of
0.0022 mol dm
3
and
0.0044 mol dm
double.
Did
information
the
rate
given
.
In
of
theory,
your
below
to
if
the
reaction
help
concentration
double?
If
it
of
a
didn’t
reactant
double,
doubles,
can
you
the
rate
suggest
of
a
reaction
reasons
why?
should
Use
also
the
you.
During
t he
potassium
experiment,
iodide
to
t he
iodine
hydrogen
molecules
peroxide
(
oxidises
t he

ions
in
t he
):
2
2
(aq)

(aq)

2e
2
As
soon
back
to

as

an
iodine
molecule
is
formed
t he
sodium
t hiosulfate
reduces
it
ions:
(aq)

2e
2
(aq)
2
When all t he sodium t hiosulfate has reacted, iodine molecules remain in t he
solution
and
react
concentration
t he
same,
iodine
time
t he
has
t he
volume
blue-black
been
taken
wit h
and
for
concentrations
made
t he
of
starch
of
colour
each
same
produce
time.
n
of
iodide
a
blue-black
t hiosulfate
star ts
quantity
potassium
to
sodium
to
appear
your
solution
when
t he
experiment
iodine
to
be
colour.
used
same
you
Since
each
quantity
determined
produced
t he
time
using
is
of
t he
different
solution.
T
emperature
The general r ule is t hat t he
t he
f
higher
t he
t he
rate
of
temperature
par ticles
gain
t he
at
kinetic
t he
par ticles
move
●
t he
par ticles
collide
sufcient
Combining
effective
which
energ y
●
wit h
higher t he temperature at which a reaction occurs,
reaction.
faster,
wit h
activation
t hese
two
collisions
a
has
t herefore
more
as
occurs
t he
t hey
energy,
energy
effects,
increase,
reaction
which
for
t he
is
collide
temperature
t herefore
the
rate
of
to
collisions
occur
react.
increases,
t he
reactant
frequently
more
par ticles
t he
effects:
more
t herefore
t he
increased,
following
t he
reaction
chances
increases.
of
For
some chemical reactions which occur at room temperature, if t he temperature
increases
f
we
10 °C,
measure
against
The
by
the
t he
rate
temperature
graph
reaction
clearly
rate
of
we
a
but
it
t he
reaction
reaction
get
shows
increases,
of
a
at
graph
that
as
shows
different
similar
the
that
approximately
to
temperatures
the
one
temperature
the
rate
doubles
is
and
shown
in
increases,
not
directly
the
1
)
s(
noitcaer
fo
etaR

204
Figure
11.2.2
Rate
of
(°C)
reaction
against
the
rate
rate
1
1.2.2.
of
the
proportional
temperature.
T
emperature
plot
Figure
temperature
to
Rates
T
o
of
reaction
Factors
investigate
Your
teacher
the
may
●
observation,
●
manipulation
●
analysis
effect
use
this
recording
and
and
of
temperature
activity
and
to
on
the
rate
of
a
will
be
rates
of
reaction
reaction
assess:
reporting
measurement
interpretation
3
Y
ou
affecting
supplied
with
1.0 mol
3
dm
hydrochloric
acid,
0.05 mol dm
sodium
thiosulfate
solution
(Na
S
2
O
2
(aq)),
3
3
a
small
conical
ask,
a
50 cm
measuring
cylinder,
a
burette,
a
thermometer
and
a
stopwatch.
Method
1
Using
a
black
pen,
draw
a
cross
on
a
piece
of
white
paper.
Do
not
make
the
cross
too
dark.
3
2
Measure
50 cm
3
Pour
hydrochloric
4
Add
the
of
sodium
acid
thiosulfate
into
the
solution
using
the
measuring
cylinder
and
pour
it
into
the
conical
ask.
burette.
3
mix
5
1 cm
the
When
Look
6
of
the
two
down
7
the
before
8
the
to
the
and
to
the
are
conical
the
ask
mixed,
ask
conical
on
a
the
ask
of
the
precipitate
and
record
top
stop
the
and
at
of
sulfur
same
slowly
stopwatch
temperature
the
time
start
the
stopwatch.
Swirl
the
ask
to
cross.
of
the
as
forms
soon
mixture
as
in
which
the
the
gradually
cross
conical
is
no
ask
obscures
longer
and
the
cross.
visible.
record
the
time
taken
disappear.
experiment,
adding
Repeat
the
acid
place
measure
cross
Repeat
and
reactants
into
Immediately
for
hydrochloric
solutions
the
but
this
hydrochloric
experiment
three
time
heat
the
sodium
thiosulfate
solution
in
the
conical
ask
to
about
40 °C
acid.
more
times,
heating
the
sodium
thiosulfate
solution
to
about
50 °C,
60 °C
and
then
70 °C.
9
Record
your
results
in
a
table
and
calculate
the
rate
of
the
reaction
at
each
temperature
using
the
following
formula:
1
______________________________
rate
of
reaction

s
time
10
Plot
t
a
graph
between
11
What
12
Explain
13
Use
can
you
the
your
to
14
Given
that
chemical
deduce
graph
can
that
to
rate
of
for
the
about
if
the
suggest
products
equation
for
the
cross
to
reaction
effect
increasing
determine
double
you
the
the
taken
disappear
against
the
nal
temperature
of
the
mixture.
Draw
a
curve
of
best
points.
effect
approximately
double,
show
the
1
the
the
rate
of
of
the
temperature
the
temperature
reasons
the
of
temperature
why?
reaction
is
reaction
the
on
on
at
increased
Use
are
has
the
the
40 °C
by
and
10 °C.
information
sodium
rate
rate
chloride,
of
of
the
the
reaction?
reaction.
50 °C.
Did
given
the
In
rate
below
sulfur,
water
to
theory,
of
help
and
the
your
rate
of
reaction
a
reaction
double?
If
it
should
didn’t
you.
sulfur
dioxide,
write
a
balanced
reaction.
During t he experiment, t he sodium t hiosulfate reacted wit h t he hydrochloric
acid
to
form
Na
S
2
Since
each
t he
O
2
(aq)
each

sulfur,
which
slowly
2HCl(aq)
built
2NaCl(aq)
up

and
S(s)
obscured

H
3
t he
O(l)
t he

and
cross
time.
n
concentration
disappeared
your
of
when
experiment
t he
t he
you
two
solutions
same
were
quantity
(g)
2
used
of
cross:
SO
2
volume
time,
made
insoluble
was
sulfur
determining
t he
t he
same
had
time
been
taken
sulfur
for
t he
same
quantity
of
sulfur
to
be
produced
at
different
temperatures.
precipitate
cross

Figure
11.2.3
thiosulfate
Following
solution
and
the
reaction
hydrochloric
between
sodium
on
drawn
paper
acid
205
Factors
affecting
rates
of
reaction
Rates
Surface
area
The
general
rate
of
This
a
size
only
to
par ticles
n
of
t he
our
oxygen
t he
T
o
t he
size)
smaller
in
t he
t he
t he
ot her
par ticles
of
a
reactant,
t he
higher
t he
ne
coal
same
solid
solid.
mass
of
par ticles
reactant.
t he
As
state.
Small
large
have
a
chances
mines,
e.g.
which
par ticles
investigate
t he
t he
solid
a
par ticles.
t he
effective
solids
par ticles
greater
result,
of
When
solid
f
surface
react,
have
t he
area
par ticles
a
par ticle
exposed
collide
collisions,
t he
larger
more
t herefore,
t he
increases.
spark,
air
t he
in
of
smaller
increases
and
Any
surface
t han
reaction
mills
reactants
t he
t he
which
ammable.
of
area
of
to
on
decreased,
frequently
rate
t hat
applies
occurs
surface
is
is
reaction
reaction.
reaction
total
r ule
(particle
of
of
could
our
the
t he
from
a
be
and
effect
nely
divided
cigarette,
explosive
can
our
and
initiate
because
of
a
coal
are
reaction
t he
large
highly
wit h
surface
t he
area
coal.
of
surface
area
on
the
rate
of
a
reaction
Your
teacher
may
●
observation,
●
manipulation
●
analysis
Y
ou
will
be
use
this
recording
and
and
activity
and
to
assess:
reporting
measurement
interpretation.
supplied
with
5.0 g
of
small
calcium
carbonate
crystals,
5.0 g
of
3
large
calcium
ask,
a
cork
measuring
carbonate
with
a
crystals,
delivery
cylinder
and
a
tube
0.3 mol dm
running
hydrochloric
through
it
to
a
gas
acid,
a
conical
syringe,
a
stopwatch.
Method
1
Place
the
small
calcium
carbonate
crystals
in
the
conical
ask.
3
2
Measure
3
As
quickly
conical
as
ask
syringe,
4
30 cm
as
in
the
remains
5
Repeat
the
6
Record
your
the
7
8
Using
volume
of
of
gas
the
small
b
the
large
why
in
for
At
in
the
into
a
of
measuring
the
conical
delivery
time,
syringe
every
use
cylinder.
ask
tube
start
consecutive
large
and
set
the
same
gas
three
table
each
has
the
the
for
using
a
acid
in
and
running
the
30
cork
to
the
the
gas
stopwatch.
seconds
until
the
readings.
crystals.
them
crystals.
to
plot
Y
ou
a
can
graph
plot
of
both
volume
curves
axes.
graph,
a
Explain
time
the
acid
which
11.1.2.
constant
results
set
your
pour
cork
experiment
against
same
the
Figure
volume
gas
hydrochloric
possible
with
Record
of
of
calculate
the
average
rate
of
the
reaction
for:
crystals
crystals.
the
average
rate
of
the
reaction
is
higher
for
the
small
crystals.
9
Explain
of
206
gas.
why
both
sets
of
crystals
produced
almost
the
same
volume
on
Rates
of
reaction
Presence
Cer tain
t he
Factors
or
absence
chemical
reaction.
substances
These
of
a
can
chemically
in
substances
industr y
unchanged
to
at
be
are
added
to
reactions
known
as
catalysts
increase
t he
end
to
alter
and
t he
t hey
rate
are
of
of
t he
t he
rate
of
reactions.
Key
!
catalysts
providing
an
activation
of
t he
t he
added
to
alternative
energy
collisions
increases
For
are
t han
occur
number
example,
normal
wit h
hydrogen
up
pat hway
t he
of
speed
are
reaction.
t he
for
2H
O
2
into
water
peroxide
and
(aq)
reaction
catalyst
alters
energy
(H
O
)
a
reaction.
reaction
(see
for
in
a
the
reaction
of
Unit
t he
which
12.1).
As
par ticles
given
They
lengt h
decomposes
ver y
work
requires
a
result,
to
react,
of
time.
slowly
fact
is
a
rate
substance
of
a
without
permanent
which
chemical
itself
undergoing
chemical
change.
by
less
more
which
at
room
2
oxygen:
2H
2
t he
collisions
2
temperature
rate
pat hway
sufcient
effective
of
used
Catalysts
any
Most
rates
catalyst
A
extensively
affecting
O(l)

O
2
(g)
2
The reaction can be speeded up considerably by adding manganese(IV) oxide
(MnO
).
The
manganese(IV)
oxide
acts
as
a
catalyst
and
it
is
chemically
2
unchanged
mass
of
of
t he
at
t he
end
of
manganese(IV)
t he
oxide
reaction.
is
When
exactly
t he
t he
reaction
same
as
it
was
has
at
nished,
t he
t he
beginning
reaction.
Enz ymes are biological catalysts made of protein molecules. They are present
in
t he
t hat
cells
would
of
all
living
ot her wise
organisms
occur
too
where
slowly
t hey
for
life
speed
to
up
chemical
reactions
exist.
Did
?
catalytic
you
know?
conver ter
CO
2
T
etraethyl
lead(IV)
was
first
mixed
N
2
with
H
gasoline
in
the
1920s
as
an
2
inexpensive
way
to
increase
engine
gases
performance
and
fuel
economy
by
from
preventing
engine
uncontrolled
combustion
ceramic
known
suppor t
cavities
‘honeycomb’
in
through
matrix
it
as
and
covers
Pd
of
Figure
few
Hence
‘antiknock’.
toxic
inter nal
fuel
has
the
nature
been
use
of
of
lead
phased
leaded
out
almost
area
react
A
the
compounds,
worldwide.

knocking’.
as
pass
catalyst
large
surface
known
which
Because
gases
Pt
‘engine
became
11.2.4
A
together
catalysts
catalytic
forming
are
converter
harmless
added
in
a
car
exhaust
allows
harmful
pollutant
gases
to
in
the
USA
This
in
phasing
the
out
started
mid-1970s.
products
to slow
down
the
rate
of
a
reaction.
These
are
known
as
negative catalysts or inhibitors. They work by providing an alternative pathway
✔
Exam
tip
for the reaction which requires more activation energy than the normal pathway.
This decreases the number of effective collisions in a given length of time.
If
you
are
particular
An
example
of
a
negative
catalyst
is
tetraethyl
lead(IV)
((C
H
2
)
5
Pb),
to
be
added
prevented
to
gasoline
uncontrolled
(petrol)
for
combustion
use
of
in
the
internal
gasoline
combustion
so
that
to
explain
affects
the
how
rate
a
of
which
chemical
the
reaction,
your
answer
engines.
must
t
factor
4
a
used
asked
engine
be
based
on
the
collision
ran
theory
for
reactions.
more smoothly.
Effect
The
be
effect
shown
Figures
used
changing
of
changing
on
1
1.2.5
remains
is
of
t he
and
rate
in
a
any
factor
curve
1
1.2.6,
unchanged.
up
factors
t he
for
and
rate
which
t he
t hat
of
t he
determines
curves
alters
reaction.
number
Remember
reaction
on
t he
n
moles
limiting
t he
rate
of
each
of
t he
of
of
reaction
t he
is
t he
products
can
graphs
limiting
reactant
quantity
a
in
reactant
one
which
produced.
207
Factors
affecting
rates
of
reaction
Rates
B
A
Original
B
Rate
rate
curve
tcudorp
increased

A
fo
one
ytitnauQ
the
a
the
a
or
temperature
reaction,
adding
by:
concentration
reactant,
solid
an
caused
the
decreasing
of

rate
increasing
of

reaction
curve
showing
increasing
of

of
or
the
particle
reactant,
size
or
catalyst.
Time

Figure
a
n
of
Figure
●
B
higher
curve
showing
the
effect
of
any
factor
which
increases
the
rate
of
A
cur ve
any
one
is
single
t he
original
factor
as
cur ve
and
indicated.
B
cur ve
Looking
shows
carefully
t he
at
effect
what
t he
to
bot h
been
has
a
becomes
reach
cur ves
made
reactant
steeper
gradient
–
t his
is
because
t he
reaction
is
occurring
at
rate
B
cur ve
time
●
rate
shows:
cur ve
a
A
1
1.2.5,
changing
graph
●
11.2.5
reaction
–
hor izontal
become
t his
was
sooner
–
t his
is
because
t he
reaction
takes
less
completion
is
not
horizontal
because
t he
when
the
original
same
quantity
number
of
of
moles
product
of
t he
has
limiting
changed.
A
Original
C
Rate
rate
curve
tcudorp
decreased
curve
showing
rate
a
caused
by:
A

decreasing
the
concentration
C
fo
of
ytitnauQ

one
of

the
a
the
reaction,
increasing
of

reactant,
decreasing
solid
adding
a
the
or
temperature
or
particle
reactant,
negative
size
or
catalyst.
Time

Figure
a
n
of
Figure
Exam
tip
●
is
extremely
important
that
interpret
graphs
which
cur ve
cur ve
of
C
has
C
at
A
cur ve
one
is
single
a
a
shallower
slower
becomes
time
bot h
to
cur ves
made
t he
effect
original
factor
of
any
factor
which
decreases
the
rate
of
as
cur ve
indicated.
and
cur ve
Looking
C
shows
carefully
at
t he
effect
what
t he
gradient
hor izontal
reach
–
t his
is
because
t he
reaction
is
rate
later
–
t his
is
because
t he
reaction
takes
completion
–
become
t his
is
horizontal
because
reaction.
reactant
208
the
when
the
same
quantity
of
product
has
show
been
rates
showing
you
●
can
curve
shows:
more
It
rate
any
occurring
✔
A
1
1.2.6,
changing
graph
●
11.2.6
reaction
was
not
changed.
t he
original
number
of
moles
of
t he
limiting
Rates
of
reaction
Factors
Summary
1
Explain
a
2
3
how
decreasing
increasing
What
Explain
is
Describe
Key
The
rate
The
reaction
a
an
of
the
the
particle
size
of
concentration
increases
the
rate
of
a
reaction:
a
of
reactant
a
reactant.
catalyst?
a
catalyst
experiment
size
following
temperature
the
how
and
●
An
●
A
●
All
●
The
of
on
the
rate
reaction
or
product
collision
collide,
t he
t he
alters
you
of
effective
rate
of
a
a
a
the
could
rate
of
a
perform
reaction.
to
determine
the
effect
of
reaction.
t he
when
factors
temperature,
time
be
is
at
t hat
must
t he
t he
a
to
occur
one
t hat
same
as
t he
area
of
a
of
required
t he
reactants
activation
must
energ y
in
t he
formation
plotted
against
of
t he
product.
time.
shape.
t he
reaction
wit h
of
concentration
orientated.
time
reactant
rate
t he
par ticles
results
(par ticle
in
temperature.
t he
proper ty
decreases
affect
react,
wit h
basic
limiting
change
stated
correctly
changes
rate
surface
measured
measured
reaction
and
completion
main
have
a
states
must
shows
cur ves
rate
Four
t heor y
collision
curve
rate
is
wit h
collisions
par ticles
beginning
●
of
concepts
reactant
●
the
c
particle
●
each
b
a
rates
questions
increasing
b
affecting
a
is
proceeds.
until
used
chemical
size)
and
t he
is
fastest
at
t he
reaches
up.
reaction:
t he
t
reaction
concentration,
presence
or
absence
of
a
catalyst.
●
The
higher
t he
concentration
t he
temperature,
of
a
reactant,
t he
higher
t he
rate
of
a
reaction.
●
The
higher
●
The
smaller
●
A
catalyst
wit hout
●
Most
●
A
t he
is
a
itself
size,
substance
if
present,
catalyst,
if
t he
which
undergoing
catalysts,
negative
par ticle
t he
any
higher
alters
t he
up
t he
t he
slows
rate
t he
rate
rate
permanent
speed
present,
higher
of
a
a
a
of
t he
a
reaction.
reaction.
chemical
chemical
rate
down
of
of
reaction
change.
reaction.
rate
of
a
reaction.
209
Practice
exam-style
questions
Rates
6
Practice
exam-style
A
mass
of
5.0 g
of
powdered
zinc
will
react
of
t he
reaction
slowest
questions
wit h:
3
A
Multiple-choice
3
30 cm
questions
of
0.1 mol dm
of
0.2 mol dm
of
0.3 mol dm
of
0.4 mol dm
3
B
20 cm
C
20 cm
D
10 cm
3
1
Which
of
t he
following
would
not
result
in
an
increase
3
in
t he
rate
sulfuric
of
acid
reaction
and
between
excess
magnesium
of
0.1 mol dm
carbonate
cr ystals
acid
sulfuric
acid
3
3
3
25 cm
sulfuric
3
sulfuric
acid
sulfuric
acid
3
at
28 °C?
A
ncreasing
t he
temperature
B
ncreasing
t he
volume
C
Using
of
t he
acid
to
Structured
38 °C.
question
3
of
t he
acid
to
40 cm
7
t he
same
mass
of
magnesium
a
An
experiment
was
set
up
to
investigate
what
effect
carbonate
changing
various
factors
has
on
t he
rate
of
reaction
powder.
between
D
ncreasing
t he
concentration
of
t he
acid
calcium
carbonate
and
hydrochloric
acid.
to
The
reaction
was
carried
out
at
30 °C
in
a
conical
3
0.2 mol dm
ask
2
An
aqueous
solution
of
hydrogen
peroxide
t hat
calcium
was
was
placed
carbonate
on
was
a
balance.
placed
in
A
mass
t he
ask
of
10.0 g
and
of
excess
3
decomposed
a
gas
t he
and
syringe.
total
t he
Which
volume
of
oxygen
of
t he
produced
following
oxygen
as
was
collected
graphs
measured
at
hydrochloric
in
added.
represents
various
regular
time
as
inter vals?
The
acid
ask
inter vals
shown
in
t he
of
concentration
and
and
its
contents
t heir
mass
was
1.0 mol dm
were
weighed
plotted
against
at
time,
gure.
306
)g(
emuloV
noitcaer
emuloV
A
B
ssaM
Time
304
303
fo
Time
305
302
301
300
emuloV
emuloV
0
0
30
Time
Time
C
D
i)
The
rate
catalyst
is
best
described
as
a
substance
of
of
proceeds.
A
90
120
150
Time
Mass
3
60
against
reaction
Using
determine
which:
a
reaction
t he
t he
180
210
time
decreases
data
average
240
(s)
from
rate
of
as
t he
t he
t he
reaction
graph,
reaction
1
A
speeds
B
slows
C
takes
D
alters
up
t he
down
no
t he
par t
t he
rate
in
rate
of
rate
a
of
a
of
chemical
a
chemical
chemical
a
reaction
reaction
chemical
:
in g s
reaction
ii)
reaction
–
in
t he
rst
–
in
t he
second
Why
is
second
4
The
rate
of
a
chemical
reaction
independent
of
t he
size
of
rate
minute.
faster
in
(4
t he
rst
minute
minute?
marks)
t han
(2
t he
marks)
is:
iii)
A
t he
minute
t he
par ticles
of
a
What
effect
would
repeating
rate
t he
t he
reaction
at
40 °C
solid
have
on
t he
of
reaction?
(1
mark)
reactant
iv)
B
independent
C
dependent
D
unaffected
of
t he
concentration
of
t he
By
referring
t he
to
t he
collision
t heor y
for
reactions,
reactants
explain
on
your
answer
to
par t iii)
above.
temperature
(3
by
a
v)
5
f
t he
wit h
temperature
sodium
following
A
The
at
which
t hiosulfate
is
hydrochloric
raised
by
acid
10 °C,
of
of
t he
reaction
is
increased
by
a
factor
The
rate
of
t he
reaction
is
decreased
by
a
factor
of
i)
210
The
rate
of
t he
reaction
is
doubled.
D
The
rate
of
t he
reaction
is
halved.
any,
would
using
excess
have
on
t he
your
answer.
acid
rate
of
of
concentration
t he
reaction?
0.5 mol dm
Give
a
reason
(2
for
What
is
a
catalyst?
marks)
(1
mark)
10.
ii)
C
if
10.
b
B
effect,
hydrochloric
t he
of
What
3
reacts
which
occurs?
rate
marks)
catalyst
Explain
how
a
catalyst
works.
(2
Total
marks)
15
marks
Rates
of
reaction
Extended
8
The
response
graph
which
below
was
reaction
acid
Practice
between
varies
over
out
t he
to
results
n
of
determine
magnesium
time.
questions
question
shows
carried
exam-style
t he
an
experiment
how
ribbon
t he
and
experiment,
rate
of
a
hydrochloric
excess
3
magnesium
ribbon
was
added
to
25 cm
of
hydrochloric
o
acid
at
35
regular
C
and
t he
volume
of
gas
was
measured
at
inter vals.
mc(
3
)
sag
fo
emuloV
Time
a
i)
ii)
b
Write
a
balanced
Account
Draw
a
could
for
labelled
be
set
up
t he
(min)
equation
shape
diagram
to
carr y
of
to
out
for
t he
reaction.
cur ve.
show
t he
t he
how
t he
(2
marks)
(4
marks)
apparatus
experiment.
(3
c
i)
Copy
on
t he
your
graph
expected
at
25 °C.
your
ii)
f
graph
draw
results
Make
onto
if
a
your
second
t he
sure
answer
cur ve
experiment
t hat
you
paper
to
show
was
distinguish
between
(2
experiment
was
repeated
again
t he
repeated
cur ves.
t he
marks)
and
marks)
wit h
o
magnesium
powder
what
if
effect,
any,
–
t he
maximum
–
t he
rate
Explain
of
instead
would
volume
evolution
your
answer
of
in
of
t his
of
gas
t he
each
ribbon
have
at
35
C,
on:
evolved
gas?
case.
(4
Total
marks)
15
marks
211
A12
Energetics
Chemical
energetics
is
the
branch
of
chemistry
that
Objectives
By
the
be
able
end
of
this
topic
you
will
deals
and
●
with
distinguish
between
exothermic
reaction
an
chemical
accompany
and
give
and
examples
of
exothermic
endothermic
explain
physical
processes
bond
reactions.
all
Energy
chemical
changes
reactions.
In
usually
fact,
in
some
reactions
the
energy
produced
is
more
important
than
the
products
of
the
chemical
reaction,
reactions
exothermic
endothermic
on
during
reaction
e.g.
●
changes
an
chemical
endothermic
●
energy
to:
reactions
breaking
the
burning
of
fuels.
Energy
changes
can
take
many
and
and
based
forms,
e.g.
changes
in
heat,
light
and
electricity.
bond
forming
A12.1
●
explain
what
enthalpy
●
explain
is
meant
change,
H
exothermic
endothermic
enthalpy
changes
during
reactions
Exothermic
and
Whenever
is
endothermic
reactions
and
reactions
t here
a
chemical
reaction,
t here
tends
to
be
a
change
in
energy
based
of
on
Energy
by
t he
system.
The
energy
changes
in
chemical
reactions
are
usually
in
t he
change
form of heat energy, however, t hey may also be in t he form of light, electrical
●
draw
energy
prole
or
diagrams
for
exothermic
nuclear
on
endothermic
show
the
t he
energy
effect
of
adding
can
distinguish
which
between
two
types
of
reaction
based
occur.
If
t he
reaction
using
energy
produces
heat,
causing
t he
reaction
mixture
and
its
a
surroundings
catalyst
We
changes
reactions
●
●
energy.
and
to
get
hotter,
t he
reaction
is
said
to
be
an
exothermic
prole
reaction.
Exot hermic
reactions
transfer
energy
to
t heir
surroundings.
diagrams.
●
If
the
its
reaction
reaction.
!
An
Key
to
its
reaction
surroundings
to
get
!
heat,
causing
colder,
Endothermic
the
reactions
the
causing
reaction
absorb
is
the
said
energy
to
reaction
be
from
an
mixture
their
surroundings.
causing
investigate
fact
teacher
exothermic
may
●
observation,
●
manipulation
and
endothermic
reactions
use
this
recording
and
activity
and
to
assess:
reporting
measurement.
3
Y
ou
An
endothermic
reaction
will
from
the
its
supplied
hydroxide
with
3
2.0 mol dm
solution,
zinc
hydrochloric
metal,
potassium
acid,
2.0 mol dm
nitrate,
sodium
hydroxide
surroundings,
pellets,
causing
be
absorbs
sodium
energy
and
endothermic
hotter.
Your
Key
get
releases
surroundings,
T
o
the
to
fact
exothermic
energy
absorbs
surroundings
surroundings
to
ammonium
chloride,
distilled
water,
a
polystyrene
cup
supported
in
get
a
beaker,
two
measuring
cylinders
and
a
thermometer.
colder.
Method
3
1
Measure
pour
it
25 cm
into
the
of
hydrochloric
polystyrene
cup.
acid
using
Record
a
the
measuring
cylinder
temperature
of
the
and
acid.
3
2
Measure
cylinder
and
25 cm
and
record
of
add
the
it
sodium
to
the
hydroxide
acid.
maximum
or
Stir
solution
the
minimum
in
solutions
the
other
with
the
measuring
thermometer
temperature.
3
3
Measure
another
polystyrene
amount
212
of
cup.
zinc.
25 cm
Record
Stir
and
of
hydrochloric
the
acid
temperature
record
the
of
and
the
maximum
or
pour
acid
it
and
into
add
minimum
the
a
cleaned
small
temperature.
Energetics
Energy
changes
during
reactions
3
4
Measure
pour
it
water
25 cm
into
and
Repeat
or
step
ammonium
Make
sure
6
Record
7
Classify
of
distilled
cleaned
add
maximum
5
the
a
small
4
using
you
your
amount
minimum
chloride
each
sodium
reaction
of
a
cleaned
cup.
measuring
Record
potassium
hydroxide
place
the
in
in
the
nitrate.
cylinder
temperature
Stir
and
and
of
record
the
the
temperature.
in
wash
results
water
polystyrene
a
of
the
pellets
potassium
polystyrene
cup
and
again
nitrate
between
in
using
each
each
case.
experiment.
table.
as
exothermic
or
endothermic.
zinc
is
added
sodium
polystyrene
hydroxide
cup
solution
hydrochloric

Figure
12.1.1
solution
is
Sodium
added
to
acid
hydrochloric
hydroxide

Figure
hydrochloric
12.1.2
hydrochloric
Zinc
is
acid
added
to
acid
acid
Examples
of
exot hermic
●
burning
●
neutralisation
of
between
reactions
include:
fuels
reactions
sodium
●
reactions
●
respiration,
between
hydroxide
between
reactive
which
releases
and
acids
and
bases,
hydrochloric
metals
energy
and
e.g.
t he
reaction
acid
acids
from
food
in
t he
cells
of
all
living
organisms
●
dissolving
sulfuric
Examples
●
t he
cer tain
substances
in
water,
e.g.
sodium
hydroxide
and
acid.
of
endot hermic
decomposition
decomposition,
decompose
into
●
photosynt hesis
●
dissolving
of
e.g.
reactions
calcium
calcium
in
cer tain
include:
compounds
oxide
plants,
salts
in
when
carbonate
and
which
water,
heated,
must
carbon
absorbs
e.g.
known
absorb
as
heat
thermal
in
order
to
dioxide
sunlight
ammonium
energy
chloride
and
potassium
nitrate.
Bond
breaking
and
bond
forming
In Unit 1
1.1 you learnt t hat a chemical reaction involves breaking t he original
bonds
in
t he
reactants
●
When
t he
●
When
new
original
bonds
energy
are
is
making
bonds
are
reactants
bonds
and
broken
absorbed
are
new
broken
formed
in
t he
bonds
in
t he
in
t he
products.
reactants,
products,
energy
energy
is
is
absorbed
released
products
bonds
are
energy
is
formed
released
213
Energy
changes
during
reactions
Energetics
In
●
Did
?
you
an
t he
Average
bond
found
chemical
in
energies
data
can
be
amount
of
energy
in
new
absorbed
during
can
be
a
bonds
In
an
the
all
up
bonds
the
the
in
bond
bonds
in
in
new
t he
the
for
and
products
following
change
energies
all
bond
in
the

sum
in
extra
of
t he
to
break
released
energy
is
in
t he
released
surroundings
existing
forming
to
t he
increases.
reaction ,
is
t he
greater
energy
t han
absorbed
t he
energy
to
break
released
t he
in
existing
forming
in
t he
and
products.
t he
The
temperature
extra
of
t he
energy
is
absorbed
surroundings
from
t he
decreases.
Ever y
chemical
bond
has
a
specic
amount
of
energy,
no
matter
what
and
it
is
in,
known
as
its
bond
energ y.
The
amount
of
energy
which
formula:
of
reactant
energies
The
absorbed
energy
all
for
has
energy
t he
temperature
reactants
bonds
compound
applying
products.
t he
energy
t han
by
energies
reactants
the
t he
less
chemical
calculated
the
t he
endothermic
surroundings
adding
in
and
is
books.
t he
reaction
reaction ,
reactants
released
bonds
or
t he
surroundings
●
The
exothermic
bonds
know?
the
all
bond
sum
to
be
released
absorbed
when
to
t hat
break
bond
is
t hat
bond
is
t he
same
as
t he
amount
of
energy
formed.
of
products
Enthalpy
The
energy
symbol
but
change
it
H.
is
content
The
of
energy
possible
to
a
substance
content
measure
reaction. This is known as
of
t he
a
is
called
its
substance
change
in
enthalpy change
enthalpy
cannot
ent halpy
be
and
is
given
measured
t hat
occurs
t he
directly,
during
and is given t he symbol
a
H and
1
is
usually
The
expressed
ent halpy
change
ent halpy
i.e.
in
of
change
H

kilojoules,
of
In
an
i.e
of
t he
reaction

kilojoules
summarised

per mol,
by
t he
kJ mol
following
(total
ent halpy
of
products)
(total
ent halpy
of
reactants)
.
formula:

H
reactants
reaction

H
energy
t he
ent halpy
of
t he
products
is
less
t han
t he
reactants:
H
products
extra
is
or
reactions
H
Therefore,
a
products
exothermic
ent halpy
reaction
H
reaction
Exothermic
a
kJ,
reactants
has
is
a
value
released
which
to
t he
is
less
t han
zero,
surroundings
and
i.e.
t he
H
is
negative.
temperature
of
The
t he
surroundings increases. Anot her way to t hink of t his is t hat since t he reaction
loses
energy,
H
is
negative,
i.e.
H
energy
of
ve.
content
reactants
ygrenE
H
ve
energy
of
Progress

An
example
value
of
H
of
is
an
Figure
12.1.3
exot hermic
given
af ter
t he
An
of
content
products
reaction
exothermic
reaction
is
t he
reaction
combustion
of
met hane
(t he
equation):
1
CH
(g)

2O
4
The
is
214
value
(g)
CO
2
for
completely
H
tells
burned
(g)

2
us
in
t hat
891 kJ
oxygen.
2H
O(g)
H

891 kJ mol
2
of
energy
is
lost
when
1 mol
of
met hane
Energetics
Energy
Endothermic
In
an
t he
i.e.
of
t he
H
reaction
t he
ent halpy
of
t he
products

from
is
greater
reactants
t he
surroundings
and
t he
H is positive. Energy
temperature
of
t he
surroundings
decreases. Anot her way to t hink of t his is t hat since t he reaction
H
is
positive,
i.e.
H
of
ygrenE
H
energy
of
example
of
an
Figure
content
products
ve
content
reactants
Progress

and
gains energy,
ve.
energy
An
t han
H
Therefore, H has a value which is greater t han zero, i.e.
absorbed
reactions
reactants:
products
is
during
reactions
endothermic
ent halpy
changes
12.1.4
endot hermic
An
of
reaction
endothermic
reaction
is
t he
reaction
reaction
between
hydrogen
iodine:
1
H
(g)

I
2
The
value
hydrogen
by
t he
(s)
2HI(g)
H

26.5 kJ mol
for
H
iodide
reaction
tells
is
us
made
t hat
26.5 kJ
during
represented
in
t he
t he
of
energy
reaction.
equation
is
The
would
gained
overall
be
when
energy
double
t his
1 mol
since
Reversible
In
a
it
shows
of
It
may
a
reaction
of
hydrogen
iodide
being
be
very
confusing
value,
which
causes
to
think
an
of
increase
i.e.
made.
temperature
as
having
and
vice
that
an
a
of
its
surroundings
negative
versa.
Try
value
to
for
H
remember
reactions
reversible
reverse
2 mol
tip
absorbed
in
53 kJ,
Exam
✔
2
reaction ,
reaction
is
if
t he
for ward
endot hermic
and
reaction
vice
versa.
is
exot hermic,
The
H
value
t hen
given
t he
for
a
losing
and
exothermic
energy
if
you
minus
it,
to
lose
i.e.
its
reaction
anything
H
is
is
surroundings
–ve.
you
are
Similarly,
the
reversible reaction is for t he for ward reaction, i.e. t he reaction which proceeds
endothermic
from
lef t
to
right.
For
example,
t he
reaction
between
nitrogen
and
energy
to
form
ammonia
reaction
is
gaining
hydrogen
from
its
surroundings
and
is:
if
you
gain
anything
you
are
plus
it,
1
N
(g)

3H
2
(s)
2NH
2
(g)
H

–46.1 kJ mol
i.e.
3
H
is
ve.
This shows t hat t he for ward reaction which produces ammonia is exot hermic.
Therefore,
1 mol
of
t he
reverse
ammonia
is
reaction
made
is
endot hermic.
during
t he
reaction,
It
also
46.1 kJ
shows
of
us
energy
t hat
is
when
released.
!
Energy
profile
Key
fact
diagrams
Activation
The
energy
change
in
a
chemical
reaction
can
be
illustrated
wit h
an
energ y
amount
must
prole
d i agram.
The
diagram
shows
t he
energy
content
or
ent halpy
of
and
products,
H
and
t he
activation
energy.
Most
reactions
energy
to
get
t hem
star ted.
This
minimum
amount
of
energy
is
given,
normally
activation
energ y .
This
activation
energy
can
be
t hought
of
the
minimum
reactants
excess
possess,
in
of
what
order
bonds
to
start
breaking
in
the
called
reactants
t he
in
is
that
need
for
some
be
energy
energy
t he
they
reactants
of
as
and
products
to
start
t he
forming.
energy
The
for
amount
t he
The
barrier
of
of
reaction
are
reaction.
activation
reaction
general
a
and
energy
shown
is
prole
in
energy
not
does
included
diagrams
Figure
not
in
of
affect
t he
an
t he
overall
calculation
exot hermic
of
and
energy
t he
an
change
value
of
H.
endot hermic
12.1.5.
215
Energy
changes
during
reactions
Energetics
(a)
(b)
activation
energy
tnetnoc
tnetnoc
AB + C
reactants
activation
ygrenE
ygrenE
–ve
H
A + BC
products
energy
H
A + BC
AB + C
products
Course

Figure
(a)
An
12.1.5
When
Energy
exothermic
Drawing
you
impor tant
of
prole
energy
are
you
Course
an
an
endothermic
energy
include
t he
t he
formulae
of
t he
reactants
t he
formulae
of
t he
products
●
arrows
●
t he
An
example
hydrogen
is
of
H.
of
how
shown
t he
t his
in
prole
activation
can
be
Figure
reaction.
diagram
following
●
indicating
energy
done
for
a
and
t he
specic
on
your
reaction
it
is
diagram:
H
reaction
between
nitrogen
and
12.1.6.
tnetnoc
(g) + 3H
2
for
information
activation
N
reaction
diagrams
●
value
of
diagrams.
(b)
profile
drawing
t hat
reactants
reaction
reaction,
+ve
energy
(g)
2
ygrenE
–1
=
H
– 46.2 kJ mol
2 NH
(g)
3
Course

Catalysts
In
Unit
rate
has
is
of
a
effect
in
of
energy
t he
up
a
diagram
catalyst
energy,
an
energy
t he
t he
t han
because
catalyst
for
is
a
the
a
formation
substance
reaction
same
t he
of
t he
can
normal
are
to
more
products)
be
shown
t hat
which
ammonia
for
when
effective
in
on
t he
pat hway.
react
t he
can
a
wit hout
pat hway
energy
t here
in
reaction
alternative
required
of
reaction
diagrams
t han
formation
using
prole
a
of
provides
have
speeds
t hat
terms
activation
par ticles
result
In
Energy
profile
learnt
catalyst
reaction
t hat
you
activation
a
less
reactant
12.1.6
energy
reaction.
lower
requires
The
and
1
1.2
a
because
t he
Figure
of
a
is
As
a
t hey
lengt h
prole
t he
used
catalyst.
reaction
This
which
result,
more
collide,
collisions
same
energy
increase
catalyst
and
(collisions
of
time.
diagrams.
It
is
impor tant to note that although the reaction has a lower activation energy, as
shown in the diagrams in Figure 12.1.7
, the energy values for the reactants and
products
216
remain
unchanged,
therefore,
the
value
for
H
remains
the
same.
Energetics
Calculating
activation
energy
activation
activation
without
a
without
a
energy
catalyst
activation
a
changes
energy
catalyst
with
energy
energy
catalyst
with
a
catalyst
reactants
tnetnoc
tnetnoc
ygrenE
ygrenE
H
ve
H
ve
products
reactants
Course

Figure
(a)
an
of
12.1.7
reaction
Energy
exothermic
Summary
1
Explain
Course
prole
reaction,
diagrams
(b)
an
with
and
endothermic
without
a
of
reaction
catalyst.
reaction.
questions
what
is
meant
by
an
exothermic
reaction
and
an
endothermic
reaction.
2
Explain
exothermic
a
bond
b
enthalpy
3
Give
4
Draw
breaking
the
a
formula
on
endothermic
bond
reactions
by
reference
to:
forming
change.
fully
Indicate
and
and
used
labelled
your
to
calculate
energy
diagram
enthalpy
prole
what
diagram
effect
change.
for
adding
a
the
following
catalyst
reaction.
would
have.
1
2H
(g)

O
2
(g)
2H
2
O(g)
H

241.8 kJ mol
2
Objectives
A12.2
Calculating
energy
changes
By
the
be
able
●
In
t he
laborator y,
t he
energy
c hange,
or
ent halpy
c hange,
in
a
end
of
be
deter mined
dene
by
measur ing
t he
heat
c hange
t hat
occurs
dur ing
known
as
t he
he at
of
re action .
We
cannot
measure
t he
or
ent halpy,
of
t he
react ants
and
products
directly.
the
calculate
t he
heat
of
reaction
by
measur ing
t he
c hange
However,
in
occurs
dur ing
a
terms
heat
the
of
solution
to
calculate
change
of
a
heat
unit
calculate
heat
you
will
learn
neutralisation
changes
from
reaction.
how
to
determine
heats
of
reaction
such
as
explain
why
data
the
and
t he
heat
of
solution
experimentally.
In
heat
of
t he
neutralisation
of
reaction
temperature
●
t his
heat
heat
neutralisation
formula
experimental
In
specic
of
we
●
whic h
heat
give
the
can
will
energy
●
content,
you
t he
and
reaction,
topic
reaction
capacity,
can
this
to:
for
the
reaction
t hese
between
a
strong
acid
and
experiments you will measure t he change in temperature which accompanies
strong
t he
neutralisation
reaction
between
a
strong
acid
and
a
strong
alkali
and
●
dissolving
of
a
solid
in
water.
You
can
t hen
use
what
is
known
as
t he
describe
capacity
to
determine
t he
change
in
ent halpy
for
t he
is
speci c
heat
capacity
of
a
substance,
c,
is
t he
the
same
experiments
determine
the
heat
of
reaction.
neutralisation
The
always
specic
to
heat
alkali
t he
quantity
of
heat
and
heat
of
required
solution
to
raise
t he
temperature
of
a
unit
mass
of
t he
substance
by
1 °C
or
1 K.
We
●
usually
take
t he
unit
mass
of
t he
substance
as
1 g
and
measure
give
the
when
in
deg rees
Celsius.
This
being
t he
case,
speci c
heat
capacity
is
given
joules
per
g ram
per
deg ree
Celsius
or
J g
calculating
.
Using
1
t he
speci c
heat
capacity
of
water
is
made
heat
neutralisation
and
heat
of
1
°C
water
as
an
solution
example,
the
t he
of
1
units
assumptions
temperature
4.2
J g
o
from
experimental
1
C
.
This
means
data.
t hat
it
takes
4.2
J
of
heat
energy
to
raise
t he
temperature
of
1 g
of
water
by
1 °C.
217
Calculating
energy
changes
Energetics
If
Key
!
we
heat
fact
t he
The
specific
heat
capacity
know
of
substance
heat
energy
is
quantity
required
temperature
substance
the
of
by
a
to
unit
1 °C
temperature
q,
of
t he
from
change,
substances
t he
specic
T,
using
reacting,
heat
t he
m,
capacity
following
we
of
can
t he
determine
substances,
c,
t he
and
formula:

m

c

T
of
raise
mass
or
mass
of
q
a
t he
reaction,
the
of
the
Measuring
1 K.
To
measure
heats
t he
heat
apparatus
known
container
whic h
sur roundings
being
The
a
general
xed
be
heat
reaction
t he
is
out
is
and
used.
released
of
if
a
t he
heat
A
by
exot her mic,
reaction
made
met hod
volume
it
into
of
maximum
or
of
solution
calor imeter
a
reaction
or
heat
reaction
polystyrene
above
determining
water
reactants
minimum
to
or
calorimeter
The
temperature
given
for
solution
t he
t hermometer.
The
neutralisation
c alor imeter
is
cup
is
a
an
piece
escaping
from
t he
into
t he
sur roundings
endot her mic.
because
of
insulated
A
simple
polystyrene
is
a
insulator.
pouring
a
by
can
of
a
reaction
prevents
t he
absorbed
calor imeter
good
if
as
of
are
to
can
t he
t hen
t hen
heat
of
of
be
reaction
used
measuring
temperature
change
calculate
and
heats
be
t he
its
mixed
reached
in
involves
t he
t he
calculated
cylinder,
temperature
calorimeter
reaction
and
measuring
measuring
initial
in
in
a
used
in
is
using
and
t he
measured.
t he
formula
reaction.
Assumptions
In
t he
experiments
you
will
be
carr ying
out
to
determine
t he
heat
of
neutralisation and heat of solution, you will make t hree assumptions in your
calculations.
●
The
density
of
a
dilute
aqueous
solution
is
t he
3
1 g cm
●
The
This
specic
means
heat
t hat
●
i.e.
4.2
Negligible
J g
heat
surroundings
Heat
!
Key
of
t he
capacity
1
water,
same
as
water,
i.e.
3
.
of
a
mass
of
dilute
1 cm
of
aqueous
solution
solution
is
is
1 g.
t he
same
as
1
°C
is
lost
during
to
t he
t he
surroundings
or
absorbed
from
t he
reaction.
neutralisation
fact
The
neutralisation
reaction
between
a
strong
acid
and
a
strong
alkali
is
an
exot hermic reaction. The amount of heat produced per mole of water formed
The
heat
heat
of
change
1 mol
of
neutralisation
which
water
is
occurs
produced
is
the
when
in
in
t he
In
reaction
between
an
acid
reaction
is
known
as
t he
heat
of
neutralisation
a
and
calculating
t he
heat
of
neutralisation,
t he
initial
temperature
of
an
bot h
solutions
must
be
measured
and
averaged
to
determine
t he
initial
alkali.
temperature,
must
be
and
t he
number
of
moles
of
water
produced
in
t he
reaction
calculated.
Example
3
A
volume
of
50 cm
of
sodium
hydroxide
solution
of
3
1.0 mol dm
concentration
3
and
temperature
26.0 °C
is
added
to
50 cm
of
hydrochloric
3
acid
t he
of
concentration
maximum
neutralisation
218
temperature
and
and
1.0 mol dm
draw
an
of
t he
temperature
solution
energy
prole
is
33.2 °C.
diagram
for
27
.0 °C.
Af ter
Determine
t he
mixing,
t he
reaction.
heat
of
Energetics
The
Calculating
balanced
equation
NaOH(aq)

for
t he
reaction
HCl(aq)
energy
changes
is:
NaCl(aq)

H
O(l)
2
Determine
t he
number
of
moles
of
water
made
in
t he
reaction:
3
1000 cm
of
NaOH(aq)
contain
1.0 mol
NaOH
1.0
_____
3
∴
50 cm
of
NaOH(aq)
contain

50 mol
NaOH

0.05 mol
NaOH
1000
3
And
1000 cm
of
HCl
contains
1.0 mol
HCl
1.0
_____
3
∴
50 cm
of
HCl(aq)
contain

50 mol
HCl

0.05 mol
HCl
1000
From
t he
1 mol
equation:
NaOH
reacts
wit h
1 mol
HCl
forming
1 mol
H
O
2
∴
0.05 mol
NaOH
reacts
wit h
0.05 mol
HCl
forming
0.05 mol
H
O
2
i.e.
0.05 mol
H
O
is
produced
in
t he
reaction.
2
Determine
t he
heat
of
neutralisation:
3
Total
∴
volume
mass
of
of
solution 
solution,
m

50

50

100 cm
100 g
26.0

27
.0
___________
Average
initial
temperature,
T

°C

26.5 °C
1
2
Final
temperature,
T

33.2 °C
2
∴
temperature
increase,
T

T
–
T
2

(33.2
–
26.5) °C
1
Specic
Using
q
heat

heat
m

c
evolved
capacity

in
of
t he

6.7 °C
1
solution,
c

4.2 J g
1
°C
T,
forming
0.05 mol
H
O

(100

4.2

2814

2.814 kJ

6.7) J
2
J
2.814
______
∴
heat
evolved
in
forming
1 mol
H
O 
kJ
2
0.05

56.28 kJ
1
i.e.
The
heat
t herefore,
The
heat
of
neutralisation,
neutralisation
t he
energy
of
reaction
prole
was
diagram
is
H

negative
56.28 kJ mol
because
t he
is
shown
increased,
below:
activation
NaOH(aq)
temperature
exothermic

energy
HCl(aq)
tnetnoc
ygrenE
1
H

56.28 kJ mol
NaCl(aq)

H
O(l)
2
Course
of
reaction
219
Calculating
energy
changes
Energetics
T
o
determine
Your
teacher
the
may
●
observation,
●
manipulation
●
analysis
heat
use
this
recording
and
and
of
neutralisation
activity
and
to
assess:
reporting
measurement
interpretation.
3
Y
ou
will
be
hydroxide
and
a
supplied
solution,
with
a
3
1.0 mol dm
calorimeter
sulfuric
(polystyrene
acid,
2.0 mol dm
cup),
a
potassium
measuring
cylinder
thermometer.
Method
3
1
Measure
the
2
dry
50 cm
of
sulfuric
acid
in
the
measuring
cylinder
and
pour
it
into
calorimeter.
Measure
and
record
the
temperature
of
the
acid
using
the
thermometer.
3
3
Measure
50 cm
measuring
4
Pour
the
solution
Record
6
Calculate
7
to
the
the
the
the
reaction
calculation
The
an
the
hydroxide
of
solution
temperature
the
initial
density
as
prole
for
cleaned
the
calorimeter
the
and
temperature
stir
the
change.
reached.
of
the
to
heat
the
and
for
the
the
two
solutions
and
use
increase.
acid
diagram
neutralisation
into
specic
page
in
temperature.
watching
calculate
sulfuric
previous
its
temperature
and
water,
solution
record
while
temperature
between
energy
heat
the
same
on
hydroxide
and
thermometer
average
that
both
9
Measure
maximum
are
Draw
the
calculate
Assuming
8
potassium
potassium
with
5
this
of
cylinder.
capacity
heat
of
potassium
help
the
of
the
solution
neutralisation
hydroxide.
for
Use
the
you.
reaction.
reaction
should
be
approximately
1
56.3 kJ mol
.
If
your
value
is
lower
than
this,
can
you
suggest
reasons
why?
The
heat
of
neutralisation
for
t he
reaction
between
any
strong
acid
and
any
acids
and
1
strong
alkali
is
always
about
56.3 kJ mol
.
This
is
because
strong
strong alkalis are fully ionised in aqueous solution and t he common reaction
t hat
releases
heat
in
all
cases
is:

OH
(aq)

H
1
(aq)
H
O(l)
H

56.3 kJ mol
2
The equation for t he neutralisation reaction between sodium hydroxide and
sulfuric
acid
is:
2NaOH(aq)

H
SO
2
(aq)
Na
4
SO
2
(aq)

2H
4
O(l)
2
In this reaction, 2 mol of water are produced. The heat of neutralisation is still
1
about 56.3 kJ mol
in
the
The
equation
heat
of
is
, however, the overall heat change for the reaction shown
about
1
12.6 kJ,
neutralisation
thermometric
temperatures
titration
of
t he
acid
can
i.e.
also
explained
and
double
be
in
alkali
t he
heat
determined
Unit
must
8.5.
be
In
of
neutralisation.
from
t his
t he
results
met hod,
measured
and
t he
t he
of
a
initial
point
of
intersection of t he two lines of best t on t he graph represents t he maximum
temperature
220
recorded
during
t he
reaction.
Energetics
Heat
When
Calculating
of
a
energy
changes
solution
solid,
liquid
or
gas
dissolves
in
a
solvent,
t here
is
usually
a
change
in
Key
!
fact
ent halpy. This ent halpy change which occurs when 1 mol of solute dissolves
The
in
In
a
solvent
is
known
calculating
be
measured
t he
and
as
heat
t he
heat
of
of
solution
solution,
exact
t he
quantity
initial
of
heat
change
temperature
solute
dissolving
of
t he
must
water
be
of
solute
t he
number
of
moles
of
solute
can
be
solution
of
solvent
is
occurs
dissolves
in
the
heat
when
such
1 mol
a
volume
must
known
that
further
dilution
by
the
so
solvent
t hat
of
which
produces
no
further
heat
calculated.
change.
Example
3
A
student
water.
The
minimum
heat
for
of
t he
dissolves
initial
5.35 g
solution
of
Determine
t he
ammonium
temperature
temperature
solution
of
of
of
16.4 °C
ammonium
t he
is
chloride
water
recorded
chloride
and
is
by
in
100 cm
22.5 °C.
t he
draw
student.
an
of
Af ter
energy
distilled
mixing,
Determine
prole
a
t he
diagram
process.
number
of moles
of
NH
Cl
dissolved:
4
1
M(NH
Cl)

53.5 g mol
4
i.e.
mass
of
1 mol
NH
Cl

53.5 g
4
5.35
_____
∴
number
of
moles
in
5.35 g

mol

0.1 mol
53.5
Determine
t he
Mass
heat
of
Initial
of
water,
solution:
m

100 g
temperature,
T

22.5 °C
1
Final
temperature,
T

16.4 °C
2
∴
temperature
decrease
( T)

T
–
T
1

22.5
–
16.4 °C
1
Specic
Using
q
heat

heat
m

capacity
c

absorbed
of
t he

6.1 °C
2
solution,
c

4.2
J g
1
°C
T,
in
dissolving
0.1 mol
NH
Cl

100

2562

4.2

6.1
J
4
J

2.562 kJ
2.562
______
∴
heat
absorbed
in
dissolving
1 mol
NH
Cl

kJ

25.62 kJ
4
0.1
heat
of
solution,
H

Exam
✔
1
i.e.
25.62 kJ mol
It
is
essential
tip
that
you
give
The heat of solution is positive because t he temperature decreased, t herefore,
the
t he
reaction
was
correct
unit
neutralisation
The
energy
for
the
heat
of
endothermic
prole
diagram
is
shown
below:
are
for
or
calculating
producing
dissolving
solution.
the
heat
1 mol
1 mol
of
of
(aq)

Cl
(aq)
4
you
change
water
solute,

NH
Since
or
the
unit
1
will
tnetnoc
It
is
always
also
be
J mol
essential
1
or
that
kJ mol
you
.
indicate
activation
whether
energy
1
H

or
ygrenE
negative
your
NH
Cl(s)

the
reaction
endothermic
by
is
exothermic
putting
a
25.62 kJ mol
or
positive
sign
before
value.
water
4
Course
of
reaction
221
Calculating
energy
changes
Energetics
T
o
determine
Your
teacher
may
●
observation,
●
manipulation
●
analysis
Y
ou
will
use
and
of
this
solution
activity
and
to
assess:
reporting
measurement
interpretation.
supplied
calorimeter
heat
recording
and
be
the
with
(polystyrene
potassium
cup),
a
nitrate,
measuring
distilled
cylinder
water,
and
a
a
balance,
a
thermometer.
Method
3
1
Measure
into
the
dry
2
Measure
3
Using
water
4
Stir
100 cm
and
the
in
the
of
distilled
water
in
the
measuring
cylinder
and
pour
it
calorimeter.
record
balance,
the
the
temperature
weigh
12.1 g
of
of
the
water.
potassium
nitrate
and
add
it
to
the
calorimeter.
solution
with
the
thermometer
while
watching
the
temperature
change.
Summary
questions
5
Record
6
Calculate
7
Assuming
as
1
Dene
the
the
water,
the
that
a
heat
of
neutralisation
b
heat
of
solution
Is
specic
heat
the
to
in
specic
the
heat
heat
of
capacity
solution
of
of
the
solution
potassium
is
the
nitrate.
same
Use
an
a
the
previous
potassium
reason
for
your
page
nitrate
to
an
help
the
you.
exothermic
or
endothermic
reaction?
answer.
Draw
an
energy
prole
diagram
for
the
solution
process.
assumptions
10
made
decrease.
capacity.
9
are
on
dissolving
Give
What
the
reached.
following:
8
2
temperature
temperature
calculate
calculation
c
minimum
By
reference
for
the
to
bonds
breaking
and
bonds
forming,
explain
the
reason
experiment
determine
the
heat
enthalpy
change
which
occurred
when
potassium
nitrate
of
dissolved
in
water.
neutralisation?
3
Why
is
the
heat
of
When
neutralisation
between
and
for
sodium
hydrochloric
the
a
solute
●
hydroxide
Bonds
the
acid
break
same
as
the
heat
in
between
surroundings.
which
the
dissolves
a
solvent
t he
following
events
occur.
reaction
break,
e.g.
In
the
the
when
par ticles
case
of
sodium
of
the
ionic
solute;
this
compounds,
chloride
dissolves
it
in
absorbs
is
the
water
energy
ionic
it
is
from
bonds
the
ionic
of

bonds
neutralisation
for
the
between
covalent
between
potassium
sulfuric
It
was
found
that
of
and
the
Cl
ions
which
break.
In
the
case
substances,
it
is
the
intermolecular
forces
between
the
of
molecules
break,
e.g.
between
when
the
ethanol
ethanol
dissolves
molecules
in
water
that
it
is
the
intermolecular
break.
when
●
4.0 g
ions
acid?
forces
4
Na
hydroxide
that
and
the
reaction
ammonium
The
intermolecular
also
absorbs
forces
between
t he
solvent
molecules
also
break;
t his
nitrate
energy
from
t he
surroundings.
3
dissolved
in
50 cm
of
distilled
●
water,
the
Attractions
t he
decreased
from
27.4 °C
molecules
Determine
solution
for
the
heat
ammonium
energy
energy
reaction
absorbed
is
to
for
the
ions
or
process
to
t he
molecules
is
called
of
t he
solute
solvation
and
and
it
surroundings.
exot hermic
break
t he
if
more
bonds
in
energy
t he
is
released
solute
if
more
energy
is
absorbed
process.
solvent
222
t he
This
and
during
solvent.
solvation
The
t han
reaction
is
prole
endot hermic
diagram
between
solvent.
nitrate
is
an
t he
of
The
draw
formed
of
to
releases
21.6 °C.
and
are
temperature
t han
is
released
during
solvation.
to
break
bonds
in
t he
solute
and
Energetics
Key
●
Exothermic
reactions
mixture
its
and
Endothermic
t heir
●
bonds
are
an
an
The
The
energy
t han
energy
an
broken
in
heat
to
in
get
t he
in
of
t he
released
a
is
energy
forming
reaction,
energy
change
The
H

exot hermic
H
a
reaction
The
is
A
proceed
to
The
●
The
H
t he
The
heat

of
To
heat
is
is
absorbed.
to
absorbed
called
can
from
When
new
break
bonds
is
less
new
to
break
bonds
is
bonds.
enthalpy
and
is
given
t he
be
measured
and
is
given
t he
H
,
is
t herefore,
H
is
less
t han
reactants
H
>
chemical
t he
H
, t herefore,
H
is
greater
reactants
reaction
minimum
from
c
in

a
of
can
be
illustrated
by
an
amount
of
energy
required
for
a
a
of
is
can
in
t he
route
required
for
t he
for
a
reaction
to
substance
in
t he
quantity
mass
be
enables
us
to
determine
temperature.
of
heat
heat
from
t he
capacity
using
energy
substance
calculated
T,
of
t he
t he
by
required
1 °C
masses
of
t he
or
of
to
1 K.
t he
substances,
c,
formula:
T
in
solution
determine
energy
alternative
specic
neutralisation
produces
a
unit
t he
activation
energy.
change
q,
m,
of
an
temperature,
produced
of
less
capacity
reaction ,

amount
providing
capacity
heat
dissolves
solvent
t he
by
reacting,
of
heat
solute
●
m
a
is
requires
change
water
in
temperature
t he
The
energy
positive.
energ y
change
heat
q
●
reaction
d i agram
occur
specic
and
of
t he
absorb
bonds.
forming
<
reaction,
change
which
substances
●
t hey
reactants
is
reduces
specic
raise
to
occur.
to
ent halpy
●
H
activation
catalyst
The
energy
negative.
prole
reaction
●
i.e.
ent halpy
reaction
●
reaction
H
reaction
endot hermic
zero,
energ y
●
causing
absorbed
new
products
●
t he
transfer
released.
energy
in
substance
in
products
i.e.
an
t han
t hey
i.e.
energy
energy
products
In
energy
colder,
reactants
products
reaction,
content

zero,
●
causing
i.e.
H.
H
In
energy
hotter,
H
reaction
●
get
absorb
released
t he
ent halpy
symbol
●
are
formed
endot hermic
symbol
●
heat
to
surroundings
exot hermic
t he
greater
●
reactions
its
bonds
In
produce
surroundings
surroundings.
t han
●
and
When
In
changes
surroundings.
mixture
●
energy
concepts
t heir
●
Calculating
is
such
no
a
is
t he
a
heat
of
heat
change
between
change
volume
fur t her
heat
t he
reaction
heat
of
an
which
acid
which
solvent
occurs
and
occurs
t hat
an
when
fur t her
when
1 mol
alkali.
1 mol
dilution
of
by
t he
change.
neutralisation
or
heat
of
solution
we
assume
3
t hat
1 cm
of
a
dilute
aqueous
solution
has
a
mass
of
1 g
1
heat
capacity
negligible
●
The
heat
which
heat
of
is
is
lost
t he
to,
same
or
neutralisation
as
water,
absorbed
for
t he
i.e.
from,
reaction
4.2
t he
J g
and
a
specic
1
°C
,
and
t hat
surroundings.
between
a
strong
acid
and
a
1
strong
alkali
is
always
t he
same,
about
56.3 kJ mol
223
Practice
exam-style
questions
Energetics
3
6
Practice
exam-style
When
water,
t hat
Multiple-choice
0.2 mol
sodium
nitrate
dissolved
in
100 cm
of
questions
t he
t he
questions
temperature
specic
1
4.2 J g
heat
decreased
capacity
of
by
7
.2 °C.
t he
Assuming
solution
is
1
°C
,
t he
heat
of
solution
of
sodium
nitrate
is:
1
1
Which
of
t he
following
statements
best
describes
A
an
604.8 J mol
1
endot hermic
reaction?
B
3024 J mol
C
15.12 kJ mol
D
151.2 kJ mol
1
A
The
ent halpy
of
ent halpy
of
B
Energy
released
C
The
ent halpy
D
The
temperature
is
t he
t he
reactants
is
greater
t han
t he
1
products.
to
t he
change
of
is
t he
surroundings.
Structured
negative.
surroundings
7
a
The
a
2
When
sodium
hydroxide
is
added
to
question
decreases.
water
at
28 °C,
gure
reaction
below
and
shows
t he
an
effect
energy
of
a
prole
catalyst
on
diagram
t he
for
reaction
t he
pat hway.
temperature
t he
B
energy
C
t he
D
t he
ent halpy
is
change
released
reaction
more
solution
is
energy
to
is
increases
to
40 °C
because:
positive
t he
surroundings
tnetnoc
A
of
endot hermic
is
absorbed
to
break
t he
ionic
bonds

during
3
Which
I
II
of
t he
Na
ion
and
OH
ions
t han
is
released
solvation
t he
breaking
following
of
solvation
a
of
processes
releases
B
C
ygrenE
between
A
energy?
bond
an
ion
Course
III
formation
A
I
only
B
I
and
C
II
of
a
Energy
i)
II
III
State,
III
wit h
a
prole
reason,
diagram
if
t he
reaction
is
exot hermic
endot hermic.
(2
Identify
t he
par ts
labelled
A,
B,
and
C
on
diagram.
The
diagram
below
shows
t he
energy
prole
diagram
How
(3
does
a
catalyst
work
to
speed
up
t he
reaction.
Which
letter
in
t he
diagram
represents
necessar y
for
t he
reaction
to
take
(2
of
a
marks)
t he
b
energy
marks)
rate
of
reaction?
a
t he
only
iii)
4
marks)
only
ii)
D
reaction
only
or
and
of
bond
The
dissolving
of
ammonium
nitrate
in
water
may
be
place?
represented
by
t he
(s)

following
equation:

NH
NO
4
A
water
NH
3
(aq)

4
D
NO
(aq)
H
ve
3
tnetnoc
In
order
to
distilled
water
ygrenE
stirred
at
t he
regular
t he
t he
value
ammonium
at
room
Course
of
room
of H,
nitrate
a
student
in
75 cm
temperature
(30.0 °C).
of
He
i)
following
sodium
equation
hydroxide

H
PO
3
and
for
t he
reaction
phosphoric
(aq)
Na
4
O(l)
PO
H
(aq)

4

168.9 kJ
t he
following
A
The
reaction
B
The
heat
C
The
reactants
D
The
temperature
is
statements
is
incorrect?
exot hermic.
1
of
neutralisation
have
more
is
168.9 kJ mol
energy
t han
t he
On
erutarepme
T
2
of
between
recorded
all
t he
The
t he
t he
its
mixture
largest
initial
temperature
solid
had
had
dissolved
returned
difference
temperature
he
and
temperature
t he
axes
in
was
t he
below,
15 °C.
sketch
solution
a
graph
temperature
to
show
wit h
t he
time.
acid
3
3H
Which
of
temperature.
variation
)C°(
3NaOH(aq)
and
until
reaction
solution
t he
mixture
inter vals
temperature
obser ved
between
of
C
to
Consider
16.0 g
B
and
5
determine
3
dissolved
50
40
30
20
10
products.
0
224
of
t he
surroundings
would
increase.
Time
(min)
(2
marks)
Energetics
ii)
Practice
Calculate
t he
assuming
t hat
energy
t he
change
specic
1
solution
iii)
t he
t hat
Determine
t he
reaction,
capacity
°C
.
number
of
moles
of
heat
(2
of
solution
of
8
a
i)
ii)
Dene
(2
‘heat
Account
for
Give
a
acid
of
neutralisation’.
t he
fact
for
and
relevant
t hat
t he
any
t he
reaction
strong
ionic
(2
heat
A
student
between
alkali
equation
is
to
determine
between
She
was
marks)
t he
any
same.
suppor t
your
(2
was
required
t he
heat
of
potassium
provided
marks
of
answer.
b
marks)
15
question
neutralisation
strong
marks)
ammonium
Total
response
t he
marks)
ammonium
nitrate.
Extended
of
(2
dissolved.
t he
questions
1
4.2 J g
Determine
nitrate
iv)
is
for
heat
exam-style
to
carr y
out
an
neutralisation
hydroxide
wit h
t he
and
in
t he
sulfuric
following
marks)
experiment
to
reaction
acid.
materials
and
equipment:
3
of
50 cm
potassium
hydroxide
solution
3
50 cm
of
sulfuric
acid
of
concentration
3
0.6 mol dm
a
a
She
t hermometer
polystyrene
recorded
solutions,
recorded
mixed
t he
temperature
Initial
Initial
initial
t hem
temperature
in
maximum
recordings
temperature
solution

Determine
assuming
are
ii)
State
T WO
made
iii)
From
of
t he
t he
potassium
of
sulfuric
ot her
specic
Draw
t he
a
two
cup
reached.
and
Her
hydroxide
fully
acid 
for
t he
heat
37
.1 °C
reaction,
capacity
.
of
(3
assumptions
to i)
given
in i)
t he
above,
t hat
t hat
labelled
energy
you
marks)
have
above.
(2
calculate
t he
t he
sulfuric
reactant.
reaction.
29.5 °C
mixing 
1
calculation
answer
limiting
af ter
change
°C
4.2 J g
your
your
t he
below:
of
heat
neutralisation
t he
iv)
in
given
temperature
t hat
is
of
polystyrene
temperature
1
solution
t he
29.5 °C
temperature
Maximum
i)
cup.
t he
heat
acid
(4
prole
marks)
diagram
(2
Total
is
marks)
for
marks)
15
marks
225
Section
B
Introduction
Objectives
the
end
be
able
of
Organic
this
topic
you
will
chemistry
compounds
give
is
the
containing
branch
carbon
of
chemistry
atoms,
in
known
which
as
organic
to:
compounds,
●
organic
chemistry
B13
By
to
examples
of
are
studied.
Studying
organic
compounds
organic
is
very
important
since
they
are
all
around
us
and
form
compounds
●
give
the
main
containing
an
compounds
integral
oil,
●
give
the
carbon
●
electron
of
gasoline,
and
can
form
illustrate
double
bonds,
single
that
form
explain
and
of
fats
are
branched
chains
for
example
plastics,
diesel
and
alcohols.
Organic
compounds
a
the
major
food
part
we
of
eat.
the
bodies
Proteins,
of
living
organisms
carbohydrates
and
all
organic
compounds.
and
the
term
certain
represent
Organic
compounds
functional
All
identify
using
lives,
structures
functional
groups
●
daily
unbranched
group
●
our
bonds,
B13.1
●
of
a
also
carbon
ringed
structure
atom
understand
chains,
part
carbon
organic
compounds
contain
carbon.
Most
also
contain
hydrogen
and
many contain oxygen. Ot her elements may also be present such as nitrogen,
sulfur and phosphor us. Organic compounds which contain only carbon and
organic
molecular,
compounds
fully
hydrogen
are
known
as
hydrocarbons
displayed
A vast number of organic compounds exist and t hey are used in all aspects of
and
condensed
structural
our
lives.
Some
examples
of
organic
compounds
t hat
we
use
in
our
ever yday
formulae.
lives
●
are
given
Met hane,
below.
CH
,
is
t he
main
component
of
natural
gas
which
is
used
as
4
a
●
fuel
to
generate
pur poses
and
as
Et hanoic
acid,
electricity,
a
fuel
CH
for
as
a
fuel
vehicles
COOH,
is
t he
in
for
domestic
some
main
heating
and
cooking
countries.
component
in
vinegar
which
is
3
used
●
to
preser ve
Et hanol,
C
H
2
●
Glucose,
C
●
H
Protein
is
an
and
is
for
The
great
,
is
an
of
of
t he
carbon
●
metal
●
fossil
●
carbohydrates,
●
organic
●
diamond
dioxide
of
basis
of
bot h
a
of
and
of
in
wines
and
spirits.
plants
and
animals
as
one
of
t heir
atom.
(see
Unit
man-made
polymer
bags
and
compounds
Carbon
which
which
cling
is
in
t he
found
in:
monoxide
oil,
and
natural
lipids
ascorbic
graphite
16)
is
used
by
grow.
hydrogencarbonates
cr ude
as
a
to
sandwich
organic
proteins
such
polymer
t hem
is
widely
used
wrap.
compounds
carbon
and
as
natural
enable
carbon
such
and
by
example
carbonates
acids,
to
carbon
●
fuels,
used
example,
abundance
chemistr y
t he
energy.
example
as
plastic,
food.
6
of
Polyet hene
a
forms
animals
Formation
226
O
12
sources
plants
●
OH,
avour
5
6
main
and
which
(fats
acid
are
gas
and
pure
and
and
coal
oils)
citric
acid
carbon.
world
is
because
of
t he
Introduction
The
atomic
and
has
to
organic
number
chemistry
of
carbon
is
Organic
6.
A
carbon
atom
t herefore
has
six
compounds
electrons
×
an
electronic
conguration
of
C
(2,4).
The
shell
diagram
of
a
carbon
××
atom
is
shown
in
Figure
13.1.1.
6p
×
×
6n
Looking
This
can
at
t he
means
form
electron
t hat
four
str ucture,
carbon
covalent
can
a
carbon
share
bonds
wit h
four
atom
has
electrons
ot her
atoms.
four
wit h
These
valence
ot her
ot her
electrons.
atoms,
atoms
i.e.
it
×
include
12
hydrogen,
oxygen,
nitrogen
and
t he
halogens.
carbon,
C
6
It is impor tant to note t hat not all carbon-containing compounds are organic

Figure
13.1.1
Electron
structure
of
carbon
compounds. Carbon dioxide, carbon monoxide, metal carbonates and metal
hydrogencarbonates
are
classied
as
inorganic
compounds
Did
?
Bonding
As
a
result
wit h
vast
in
of
ot her
organic
carbon
carbon
number
of
having
atoms
different
Carbon
compounds
four
in
valence
an
almost
organic
electrons,
unlimited
compounds
carbon
way.
exist
compounds. The simplest of t hese is met hane (CH
atoms
Because
compared
to
can
of
bond
t his,
a
inorganic
). If we look at t he met hane
you
is
the
know?
sixteenth
abundant
element
crust
the
and
element
after
neon
by
sixth
mass
hydrogen,
and
in
Earth’
s
most
in
the
helium,
nitrogen.
most
the
It
is
abundant
Universe
oxygen,
present
in
4
molecule
in
t he
ball
and
stick
model
in
Figure
13.1.2,
we
can
see
t hat
carbon
all
forms
most
is
bonded
to
four
hydrogen
atoms
arranged
in
a
tetrahedron
around
it.
angle
Organic
between
covalent
molecules,
bonds
t herefore,
is
life
and
abundant
is
the
element
second
by
mass
in
The
the
bond
of
human
body
after
oxygen.
109.5°.
have
ver y
distinctive
t hree-dimensional
str uctures.
When
carbon
Single
bonds
Single
bonds
atoms
bond
wit h
each
ot her
a
variety
of
str uctures
can
form.

Figure
13.1.2
Ball
and
stick
model
of
methane
a
carbon
leaves
ot her
can
atom
t hree
atoms.
form
shares
ot her
For
between
one
pair
electrons
example,
of
adjacent
electrons
per
carbon
et hane
(C
H
2
carbon
atoms,
represented
by
carbon
t he
wit h
atom
)
has
a
atoms.
anot her
bonds
Double
bonds
a
carbon
leaves
atom
two
atoms.
For
can
containing
saturated
form
shares
ot her
H
between
two
pairs
electrons
example,
per
represented
et hene
by
two
H
)
6
single
bonds
between
adjacent
carbon
compounds
of
adjacent
electrons
carbon
(C
H
2
atoms,
only
two


Double
as
t he

known
between
This
wit h
H

(C
2
compounds
bond
atom.
bonding
H  C  C  H
H
et hane
are
for
bond,
line:
or
atoms
single
6
single
H
Organic
a
carbon
available
single
In
)
atom
has
a
carbon
wit h
atoms.
anot her
available
double
for
bond
In
a
double
carbon
bonding
between
bond,
atom.
wit h
two
This
ot her
carbon
4
lines:
227
Organic
compounds
Introduction


(C
H
2
chemistry

C  C
H
et hene
organic
H

H
or
to
H
)
4
Organic compounds containing one or more double bonds between adjacent
carbon
atoms
Unbranched
known
chains
butane
(C
of
H
4
single
bonds
as
unsaturated
compounds
chains
Unbranched
example,
are
carbon
)
is
an
atoms
of
different
unbranched
chain
of
lengt hs
four
can
carbon
form.
atoms
For
wit h
10
between
adjacent
atoms:
H
H
H
H




H  C  C  C  C  H




H
H
H
butane
(C
H
H
4
Branched
)
10
chains
Branched chains of carbon atoms of different lengt hs can form. For example,
met hylpropane
(C
H
4
carbon
atom
)
is
a
chain
of
t hree
carbon
atoms
wit h
t he
four t h
10
branching
off
from
t he
middle
H
atom
of
t he
chain:
H
H



H  C  C  C  H



H
H
H  C  H

H
met hylpropane
(C
H
4
)
10
Rings
Rings
of
carbon
atoms
can
form.
For
example,
cyclohexane
(C
H
6
of
six
carbon
)
is
a
ring
12
atoms:
H
H
H




H

C


C


H
C
H


H
C



H

H
H

C

C
H
H
cyclohexane
(C
H
6
)
12
The ability of carbon atoms to form covalent bonds wit h ot her carbon atoms
forming
It
is
t he
long
chains
impor tant
drawings
to
note
above
Functional
compounds
a
par ticular
two
of
wit h
each
carbon
t he
atoms
exception
molecule
in
is
known
of
t he
as
ball
catenation.
and
two-dimensions
stick
models,
only.
groups
group
between
rings
t hat,
show
Organic
is
and
contain
atom,
carbon
a
atoms
one
or
more
par ticular
wit hin
functional
group
t he
of
groups .
atoms,
molecule.
or
The
a
A
functional
par ticular
functional
bond
group
determines t he chemical proper ties of t he compound containing it. Organic
228
Introduction
to
compounds
on
t he
organic
are
chemistry
classied
functional
into
group
Organic
groups
t hat
t hey
known
contain
as
homologous
(see
Unit
13.2).
series
Some
based
of

T
able
groups
we
will
be
studying
are
given
in
Table
Functional
groups
t he
Name
functional
13.1.1
compounds
of
Structure
functional
13.1.1.
group
of
functional
group
carbon–carbon
The simplest organic compounds t hat you will be studying can be t hought of
single
bond
C
as
●
being
t he
composed
of
hydrocarbon
two
C
par ts:
part
which
is
composed
of
carbon
and
hydrogen
carbon–carbon
atoms
●
t he
only.
double
functional
bond
group
hydroxyl
group
O
H
or
Formulae
of
organic
compounds
carboxyl
The
formulae
of
organic
OH
compounds
can
be
written
in
a
variety
of
group
O
different
C
ways.
Using
butanoic
acid
as
an
example,
t he
most
common
met hods
are:
O
●
The
molecular
each
for
element
butanoic
formula .
in
one
acid
is
atoms
●
The
chemistr y
are
fully
joined
H
compound
O
8
since
form
(Figure
.
of
actual
number
compound.
Molecular
formulae
The
of
atoms
molecular
have
a
limited
don’t
give
any
information
about
formula
use
or
t he
how
group
O
t he
C
formula .
atoms
COOH
in
molecule.
structural
are
This
shows
arranged
in
in
one
H
of
ester
t he
how
t he
t he
2
t hey
wit hin
d isplayed
diagrammatic
shows
molecule
C
4
organic
This
or
two-dimensional
molecule
of
O
COO
t he
13.1.3).
H
H
H
O
The fully displayed formula has t he limitation t hat it is a two-dimensional
C
C
C
drawing of a t hree-dimensional molecule, i.e. t he molecule is straightened
out
and
t he
attened.
actual
The
molecule
ball
in
and
stick
model
t hree-dimensions.
in
Figure
However,
13.1.4
you
represents
would
not
H

required
●
The
to
draw
condensed
arrangement
t hat
t he
shown
nature
wit hout
written
bonded
t his.
atoms
and
to
it.
in
The
formula .
one
position
actually
separately
Figure
13.1.3
formula
structural
of
and
of
in
t he
sequence,
shows
t he
CH
3
CH
2
of
followed
t he
sequence
compound
t he
molecule.
str uctural
CH
of
attachment
drawing
condensed
This
molecule
by
t he
for
carbon
ot her
a
of
may
atoms
t he
be
and
shor tened
total
molecule,
fur t her
number
of
atoms
is
t hat
acid
are
is:
COOH

Figure
13.1.4
How
2
What
is
a
3
What
is
the
many
Ball
and
stick
model
of
2
by
showing
hydrogen
H
3
1
structural
acid
t he
atoms
in
total
t he
number
of
hydrocarbon
acid
carbon
par t
of
i.e.
C
Summary
displayed
is
butanoic
This
Fully
butanoic
way
group
atom
butanoic
H
and
such
functional
Each
formula
in
H
be
COOH
7
questions
bonds
can
a
carbon
atom
form
with
other
atoms?
hydrocarbon?
difference
between
a
saturated
and
an
unsaturated
organic
compound?
4
What
5
Give
and
is
a
the
functional
condensed
molecular
group?
structural
formula
of
formula
H
H
H
H
H
C
C
C
C
H
H
H
H
this
H
compound:
H
229
Homologous
series
Introduction
Objectives
By
the
end
be
able
of
B13.2
this
topic
you
organic
chemistry
series
will
We can classif y compounds into groups based on t he functional group which
to:
t hey
dene
●
Homologous
to
the
term
contain.
These
groups
are
known
as
homologous
series
homologous
series
Characteristics
list
●
of
the
a
the
given
write
●
of
a
general
series
formulae
given
The
formula
homologous
the
of
of
the
characteristics
●
All
members
●
All
members
for
chain
common
determine
series
to
the
●
Each
homologous
a
its
●
compound
name
or
dene
structural
t he
the
of
group
All
homologous
series
series
t he
isomer
and
members
of
a
have
can
series
by
series
decreases
as
molecule
increases.
All
molar
members
increases,
series
are
given
below.
t he
be
same
functional
represented
by
the
group.
same
general
formula.
differs
relative
from
t he
molecular
member
mass
of
before
or
af ter
it
by
a
14.
as
of
a
series
t heir
melting
possess
mass
similar
increases,
show
molar
point,
a
mass
i.e.
chemical
as
gradual
t he
change
increases.
boiling
point
In
proper ties.
number
in
t heir
general,
and
of
density
as
Reactivity
carbon
atoms
per
physical
molar
mass
increase.
and
●
structural
of
of
member
proper ties
formula
●
a
2
homologous
which
from
of
series
members
●
belongs
series
members
series
●
homologous
series
homologous
straight
a
a
CH
name
●
of
characteristics
homologous
write
●
general
All
members
of
a
homologous
series
can
be
prepared
by
t he
same
general
isomerism
met hod.
explain
●
can
be
how
structural
isomers
formed
Naming
name
●
branched
chain
straight
chain
members
of
a
homologous
series
isomers.
Because
of
t he
great
variety
of
organic
compounds,
a
set
of
r ules
for
naming
t hese compounds has been developed by t he International Union of Pure and
Applied
Key
!
is
fact
Chemistr y
known
as
nomenclature
A
of
homologous
organic
series
compounds
is
a
that
group
is
no
the
same
is
ambiguity
to
as
ensure
to
The
process
nomenclature .
t hat
which
when
chemical
a
of
naming
The
main
person
reads
compound
it
chemical
function
a
compounds
of
chemical
chemical
name
t here
refers.
all
The
possess
(IUPAC).
chemical
functional
names
of
straight
chain
members
of
a
homologous
series
consist
of
group.
two
●
par ts:
The
rst
present
par t,
in
compounds
●
or
one
prex,
is
molecule.
up
to
ten
related
Table
carbon
to
t he
13.2.1
total
gives
number
t he
of
carbon
prexes
for
atoms
organic
atoms.
The second part which is based on the homologous series to which the
compound belongs and relates to the
functional group
present. For example,
if the compound belongs to the alkane series, its name ends in ‘-ane’.
T
otal

T
able
13.2.1
organic
Prexes
for
number
of
carbon
atoms
Prefix
1
meth-
2
eth-
3
prop-
4
but-
5
pent-
6
hex-
7
hept-
8
oct-
9
non-
10
dec-
naming
compounds
Table 13.2.2 gives t he main homologous series you will be studying, toget her
wit h
230
an
example
of
a
member
of
each
series
containing
two
carbon
atoms.
Introduction

T
able
Name
to
13.2.2
organic
The
main
chemistry
Homologous
homologous
series
series
of
Example
General
Functional
formula
present
group
Condensed
homologous
Naming
containing
carbon
Alkane
C
carbon–carbon
H
n
two
Structural
formula
formula
series
single
bond
prefix

atoms
ethane
ane
CH
2n2
H
CH
3
H
3
or
C
C
C
C
H
H
2
6
H
Alkene
C
H
n
carbon–carbon
double
bond
prefix
2n

ethene
ene
CH
H
CH
2
H
H
2
or
C
or
C
H
n
hydroxyl
OH
group
prefix

ethanol
anol
CH
3
alkanol
O
H
4
CH
2n1
H
H
2
Alcohol
H
OH
H
2
H
or
C
OH
C
H
2
OH
5
H
Alkanoic
acid
or
C
H
n
carboxyl
COOH
group
prefix

anoic
ethanoic
acid
acid
CH
COOH
H
3
2n1
H
O
carboxylic
acid
O
C
C
H
O
H
O
H
COOH
Determining
The
you
out
homologous
homologous
are
t he
deduce
given
t he
formula
its
series
t hat
name
of
of
name
if
a
a
compound
t he
have
belongs
compound
compound
you
series
if
been
you
or
have
given
its
its
to
can
formula.
been
given
be
determined
You
its
can
name
also
or
if
work
you
can
formula.
Examples
●
To
determine
name,
par t
look
of
t he
at
t he
homologous
t he
name
second
is
‘-ene’
ser ies
par t
of
t hen
t hat
t he
t he
a
compound
name.
For
compound
belongs
example,
belongs
if
to
to
t he
t he
from
t he
second
alkene
series.
●
To
work
out
determine
t he
prex
butane
of
t hen
carbon
formula
t he
t he
t he
it
name.
belongs
atoms.
of
t he
homologous
The
For
to
to
alkane
formula
from
which
example,
t he
general
compound
series
if
t he
series.
of
an
it
t he
name,
belongs
name
Its
of
t he
prex
alkane
is
and
is
butane
must
be
C
‘but-’
To
determine
formula,
t he
look
t he
functional
belongs
to
t he
so
it
The
has
four
formula
2n2
10
homologous
and
.
at
is
H
4
●
look
compound
H
C
n
of
rst
t hen
see
group
what
present
alcohol
ser ies
t hat
functional
is
t he
a
compound
group
O
H
is
belongs
present.
group,
For
t hen
to
from
example,
t he
t he
if
✔
It
series.
is
can
●
To
deter mine
t he
name
of
t he
compound
from
t he
Exam
for mula,
very
important
work
out
t he
homologous
ser ies
to
whic h
t he
compound
t hen
look
at
t he
tot al
number
of
carbon
atoms
in
t he
name
example,
if
t he
for mula
of
t he
compound
is
C
H
2
to
t he
alkanoic
acid
ser ies
so
t he
second
COOH
t hen
be
‘-anoic
acid’.
It
has
a
tot al
of
t hree
par t
carbon
so
t he
pre x
must
be
‘prop-’.
The
name
that
of
of
t he
been
have
of
a
been
you
can
given
deduce
a
compound
atoms
in
of
t he
given
the
if
you
formula.
T
o
do
name
of
these,
you
must
be
able
to
t he
compound
the
homologous
series
to
is
which
propanoic
or
name
identify
molecule
you
it
either
must
if
5
have
belongs
you
molecule.
the
For
that
formula
belongs
its
and
the
 r st
compound
deter mine
tip
compound
the
compound
belongs.
acid.
231
Homologous
series
Introduction
Structural
!
Key
organic
str uctural
Structural
isomers
compounds
isomers
which
formula
compounds
formulae,
have
the
each
element,
but
t he
same
molecules
molecular
contain
t he
formula
same
but
different
number
of
but
t hese
atoms
are
bonded
toget her
atoms
differently.
are
called
structural
isomers
and
t his
phenomenon
These
is
called
isomerism
formulae.
Str uctural
isomers
homologous
Key
If
●
fact
t hey
Structural
isomerism
occurrence
of
compounds
two
with
or
the
is
the
more
have
organic
contain
belong
to
t he
same
homologous
series
or
to
different
t he
same
series.
similar
functional
Because
chemical
differently
t hey
t hey
group
have
proper ties,
have
t hey
t he
must
same
however,
different
physical
belong
functional
because
to
t he
group,
t heir
same
t hey
atoms
are
proper ties.
same
If
●
formula
ver y
bonded
can
series.
homologous
but
t hey
contain
different
functional
groups
t hey
belong
to
different
different
homologous
structural
have
t heir
different
structural
molecular
i.e.
same
compounds
!
chemistry
are
of
structural
organic
fact
Many
molecular
to
series.
Because
of
t his
t hey
have
different
chemical
and
formulae.
physical
Each
different
Str uctural
by
proper ties.
t he
isomers
chain
functional
Forming
Carbon
str uctural
of
has
chain
atoms
a
different
name.
molecules
becoming
can
branched
be
or
formed
by
t he
in
two
position
ways,
of
t he
atoms.
For
changing.
isomers
example,
straight
carbon
group
chains
of
isomer
by
can
pentane
branching
have
(C
side
H
5
)
branches
has
t hree
of
one
isomers,
or
more
one
of
carbon
which
is
t he
straight
12
chain isomer and two of which are formed by branching of t he carbon chain
as
is
shown
given
in
Figure
below
t he
13.2.1.
The
condensed
str uctural
formula
of
each
H
H
C
H
H
H
C
H
H
H
H
H
C
C
C
H
C
H
H
CH

Figure
13.2.1
Isomers
of
pentane
H
CH
3
Straight
It
is
always
twisted
a
CH
2
version
C
C
C
H
H
H
H
H
H
H
C
H
CH
CH
3
3
CH(CH
2
)CH
3
CH
3
note
t hat
t he
of
t he
of
t he
when
longest
Care
straight
straight
drawing
t he
continuous
must
c hain
c hain
also
be
isomer.
isomer
C(CH
3
Branched
hor izontally .
versions
bent
H
C
isomer
to
H
H
H
compound,
drawn
H
C
H
H
H
CH
2
chain
impor tant
organic
is
H
CH
2
isomer
isomer.
chain
str uctural
c hain
t aken
For
of
)
3
CH
2
3
isomers
of
not
to
example,
pentane
for mula
carbon
draw
t he
and,
of
an
atoms
bent
is
or
following
t herefore,
is
incor rect:
CH
CH
3
CH
2
CH
2
2
CH
3
Forming
isomers
by
changing
the
position
of
the
functional
group
The functional group is usually situated at t he right-hand end of t he molecule.
However,
232
t he
position
of
t he
functional
group
can
change.
Introduction
to
organic
chemistry
Homologous
series
Examples
Butene
(C
H
4
double
)
has
two
isomers
because
t he
position
of
t he
carbon–carbon
8
bond
can
change
H
as
H
shown
in
Figure
13.2.2.
H
H
H
H
H
C
C
H
C
C
C
C
H
H
H
H
H
H

Figure
13.2.2
Isomers
of
butene
When drawing t he str uctural formulae of alkenes, t he carbon–carbon double
H
bond
is
always
alkenes
in
Butanol
Unit
(C
H
4
group
(
drawn
hor izontally.
You
will
learn
more
about
t he
isomers
C
14.2.
OH)
has
two
isomers
because
t he
position
of
t he
hydroxyl
9
OH)
can
H
change
as
shown
in
Figure
branched
chain
H
C
C
H
H
H
H
H
H
H
H
C
C
O
H
13.2.3.
C
Naming
H
of
H
isomers
H
H
The side chains which branch off from t he longest chain of carbon atoms in a
H
molecule
C
H
n
known
Alkyl
as
groups
alkyl
are
groups.
named
by
These
adding
groups
t he
have
sufx
t he
‘ -yl’
general
to
t he
formula
prex.

Figure

T
able
13.2.3
Isomers
of
butanol
2n1
The
●
.
are
name
t he
of
rst
a
branched
par t
chain
indicates
t he
molecule
number
of
is
made
t he
up
carbon
of
t hree
atom
to
par ts:
which
t he
Formula
chain
is
13.2.3
Naming
alkyl
groups
side
of
the
Name
attached
alkyl
●
t he
second
●
t he
t hird
par t
is
t he
name
of
t he
side
chain,
i.e.
t he
alkyl
group
–
CH
–
C
–
C
group
methyl
3
par t
compound
is
derived
belongs
and
from
t he
t he
homologous
longest
series
continuous
to
chain
which
of
t he
carbon
2
atoms.
3
To
name
should
1)
be
Find
branched
chain
molecules,
t herefore,
t he
following
four
H
ethyl
5
H
propyl
7
steps
used.
the
number
of
the
carbon
atom
to
which
the
side
chain
is
attached.
2)
Determine
t he
name
3)
Determine
t he
homologous
and
t he
carbon
4)
Put
t he
total
of
number
t he
of
side
chain.
series
carbon
to
which
atoms
in
t he
t he
compound
longest
belongs
continuous
chain.
information
separating
t he
from
number
steps
from
1)
t he
to
3)
name
toget her
by
a
to
name
t he
compound,
hyphen.
Examples
1
Determine
t he
name
of
t he
following
branched
chain
isomer
of
C
H
5
H
H
C
H
H
C
C
H
12
H
H
C
H
C
H
233
Homologous
series
Introduction
1)
Find
t he
Number
t hat
longest
t he
t he
side
continuous
carbon
chain
atoms
is
at
chain
from
t he
lowest
H
H
C
H
of
t he
carbon
end
to
organic
atoms
closest
to
in
chemistry
t he
t he
str ucture.
side
chain
so
number:
H
H
C
C
H
H
H
C
H
2)
The
side
chain
is
attached
The
side
chain
is
an
methyl
3)
The
The
4)
2
to
t he
longest
name
The
is,
has
only
alkane
group
atom
wit h
one
number
carbon
2
atom.
It
is
t he
of
t he
t he
carbon–carbon
bonds.
Therefore,
it
carbon
chain
has
four
carbon
atoms
in
it.
Its
butane
compound
name
single
series.
continuous
t herefore,
name
Determine
carbon
group.
compound
belongs
alkyl
to
of
t he
is
2-methylbutane
following
branched
chain
isomer
of
C
H
6
H
H
C
H
H
C
C
H
14
H
H
C
H
C
H
1)
Number
t hat
t he
t he
carbon
side
chains
atoms
are
at
in
t he
H
t he
longest
lowest
H
C
continuous
carbon
chain
so
numbers:
H
H
C
C
H
H
H
C
H
C
H
There
are
two
side
chains.
One
is
attached
to
carbon
atom
number
2
and one is attached to carbon atom number 3. When writing t he name
we
write
2,3-
because
bot h
side
chains
are
t he
same,
i.e.
CH
3
2)
Bot h
t he
‘di-’,
234
side
chains
met hyl
i.e.
we
are
group
write
alkyl
and
groups
because
d imethyl
wit h
t here
one
are
carbon
two
of
atom.
t hem
we
They
use
are
t he
bot h
prex
Introduction
3)
The
to
compound
belongs
The
3
to
t he
longest
name
4)
organic
The
is,
has
t he
t he
carbon–carbon
bonds.
Therefore,
it
carbon
chain
has
four
carbon
atoms
in
it.
Its
butane
compound
name
single
series
series.
continuous
of
Homologous
only
alkane
t herefore,
name
Determine
chemistry
of
t he
is
2,3-d imethylbutane
following
branched
chain
isomer
of
C
H
4
8
H
H
H
H
H
H
1)
Number
t hat
t he
t he
carbon
side
chain
atoms
is
at
t he
in
t he
longest
lowest
continuous
carbon
chain
so
number:
H
H
H
H
H
H
The
2)
side
chain
is
attached
to
carbon
The side chain is an alkyl group wit h
atom
number
2
one carbon atom. It is t he
methyl
group.
3)
The compound has a carbon–carbon double bond; t herefore, it belongs
to
t he
The
longest
name
4)
The
Ot her
alkene
is,
series.
continuous
t herefore,
name
of
examples
t he
are
carbon
chain
has
three
carbon
atoms
in
it.
Its
propene
compound
given
is
2-methylpropene
below:
H
C
H
H
H
H
C
C
C
C
H
H
H
H
CH
H
C
CH
3
CH
2
CH
2
2
3
H
CH
2
H
C
CH
3
H
3-ethylhexane
2,2,3-trimethylpentane
235
Homologous
series
Summary
1
Give
four
2
Give
the
3
Introduction
characteristics
name
an
alcohol
c
an
alkanoic
a
C
the
and
with
of
a
homologous
condensed
one
acid
following
carbon
with
three
b
6
4
Dene
5
Name
formula
structural
series.
of
each
of
the
following
atom
carbon
C
H
4
the
chemistry
atoms
straight
chain
isomers:
b
an
alkene
with
four
d
an
alkane
with
two
c
CH
carbon
carbon
atoms
atoms.
compounds:
H
3
organic
questions
a
Name
to
OH
9
d
C
4
H
2
COOH
5
isomerism.
following
isomers:
a
H
H
C
H
H
H
C
C
C
CH
b
3
H
CH
CH
3
H
H
H
C
CH
3
3
H
CH
3
C
H
6
Draw
the
structural
formula
of
2,3-dimethylhexane.
Key
concepts
●
Organic
●
All
many
A
●
Carbon
carbon
ot her
and
A
atom
carbon
●
●
The
str uctural
names
two
par ts,
carbon
of
ways,
by
position
Each
atoms
bonds
form
also
contain
hydrogen
and
single
form
wit h
and
straight
ot her
atoms.
double
chains,
bonds
wit h
branched
chains
two
can
be
a
par ticular
atoms
t he
wit hin
chemical
represented
or
a
into
group
series
t he
by
condensed
classied
chain
par t,
in
wit h
t he
t he
or
all
same
group
t he
of
atoms
or
t he
a
molecule.
proper ties
a
molecular
str uctural
groups
t hat
known
t hey
possess
general
members
prex,
molecule
is
t he
same
compounds
chain
different
atom,
carbon
of
t he
formula,
a
fully
formula.
as
homologous
contain.
t he
same
formula
functional
and
have
group,
cer tain
of
which
and
a
is
t he
homologous
related
second
to
series
t he
par t
total
which
consist
of
number
is
related
group.
isomers
t he
par ticular
by
isomerism
The
of
also
characteristics.
rst
functional
Str uctural
compounds
Most
it.
are
straight
t he
Structural
a
homologous
common
The
to
functional
represented
formulae.
236
a
t he
of
compounds
●
on
can
be
organic
carbon.
covalent
can
formula
compounds
based
all
of
determines
Members
t he
●
group
compound
of
●
is
between
An
Organic
four
ability
They
containing
ot her
●
t he
group
functional
series
●
form
compound
organic
study
contain
str uctures.
bond
displayed
●
can
have
atoms.
functional
par ticular
t he
oxygen.
atoms
ringed
is
compounds
contain
●
●
chemistr y
organic
of
of
occurrence
molecular
are
known
of
two
formula
as
or
but
more
organic
different
structural
straight
chain
molecules
can
carbon
atoms
becoming
branched
functional
str uctural
group
isomer
be
changing.
has
a
different
str uctural
isomers
name.
formed
or
in
by
two
t he
to
Introduction
to
organic
chemistry
Practice
6
A
compound
has
t he
formula
C
H
3
Practice
exam-style
1
Members
of
a
I
have
similar
have
t he
chemical
same
series:
proper ties
molecular
differ
from
The
name
of
7
A
et hanoic
B
propanoic
C
propanol
D
butanoic
is:
acid
succeeding
acid
acid
formula
7
III
compound
questions
homologous
II
COOH.
questions
questions
t he
Multiple-choice
exam-style
members
by
Which
of
t he
following
is
t he
correct
formula
of
CH
2
pentanol?
A
I
and
II
B
I
and
III
only
A
C
B
C
C
C
H
5
H
5
C
II
and
III
I,
II
and
1
1
H
C
H
5
To
which
OH
12
III
D
2
OH
only
5
D
OH
10
only
homologous
series
does
C
H
4
alkanes
B
alkenes
C
alcohols
D
alkanoic
13
belong?
8
8
A
OH
What
is
t he
name
of
t he
following
isomer?
CH
3
3
CH
acid
CH
3
Isomers
always:
A
have
t he
B
have
similar
chemical
C
have
similar
physical
D
have
different
3
CH
CH
3
same
functional
A
4
Which
of
t he
2,2,3-trimet hylbutane
proper ties
B
2,3,3-trimet hylbutane
C
2,3,3-trimet hylheptane
D
2,2,3-trimet hylheptane
proper ties
str uctural
following
3
group
formulae
formulae
do
not
represent
isomers?
I
II
H
C
H
H
H
Structured
H
C
H
H
9
H
a
The
question
fully
displayed
compounds
C
C
H
H
str uctural
formulae
of
ve
organic
H
H
H
C
C
H
H
are
given
below:
H
H
H
H
H
H
C
H
H
C
C
H
H
H
H
H
H
H
A
III
H
IV
H
B
H
H
O
H
C
H
H
C
H
C
H
H
H
O
H
H
C
C
C
H
H
C
C
H
H
H
C
H
A
I
and
II
B
I
and
III
H
H
H
H
H
D
H
H
H
H
H
C
C
C
C
C
H
H
H
H
H
H
H
H
E
C
II
D
III
and
III
and
IV
i)
5
The
general
A
C
B
C
H
n
C
C
D
C
alkane
Which
compounds
homologous
is:
ii)
Name
t he
belong
to
t he
same
series?
homologous
(1
series
to
which
mark)
t he
compounds
reason
for
you
named
placing
t hem
in a
in
i)
t he
belong
same
and
give
a
series.
2n2
H
n
an
2n1
H
n
of
2n
H
n
formula
2n3
(2
marks)
237
Practice
exam-style
questions
iii)
Give
t he
names
iv)
Give
t he
name
Introduction
of
compounds B
and
D
(2
formula
carbon
same
of
t he
atoms
and
fully
displayed
compound
in
its
homologous
which
molecule
series
as
has
and
marks)
str uctural
FOUR
belongs
to
(2
v)
Draw
t he
isomers
isomer
b
Name
t he
following
t he
fully
fully
of
displayed
compound E.
you
have
str uctures
Give
any
name
series
to
str uctural
which
belongs
formula
EACH
and
of
marks)
T WO
of
(4
compounds
displayed
t he
of
drawn.
homologous
organic
t he
compound D
EACH
marks)
of
t he
draw
EACH
compound:
i)
ii)
propene
2,2-dimet hylpentane.
(4
Total
Extended
10
a
response
Explain
fully
marks)
15
marks
question
how
t he
electronic
conguration
of
12
t he
carbon
atom,
C,
can
account
for
t he
fact
t hat
6
carbon
can
form
such
a
wide
variety
of
organic
compounds.
b
Organic
(5
compounds
homologous
i)
List
can
be
classied
series.
FOUR
characteristics
of
a
homologous
(4
ii)
A
compound
has
t he
formula
H
C
2
–
To
which
homologous
compound
–
c
i)
Give
What
t he
do
Explain
t he
why
same
chemical
physical
COOH
5
does
t he
of
t he
compound.
understand
by
t he
term
(2
(2
str uctural
homologous
proper ties,
proper ties.
isomers
series
but
of
have
t hey
marks)
‘str uctural
marks)
members
ver y
have
of
similar
different
(2
Total
238
series.
marks)
belong?
name
you
series
isomerism’?
ii)
marks)
into
marks)
15
marks
to
organic
chemistry
Hydrocarbons
–
alkanes
B14
and
alkenes
Hydrocarbons
are
organic
compounds
which
consist
Objectives
By
the
be
able
end
of
this
topic
you
entirely
will
of
carbon
hydrocarbons
identify
●
and
hydrogen.
The
majority
of
to:
natural
petroleum
as
gas
and
natural
of
sources
dead
are
marine
naturally
organisms
formed
under
by
the
the
decomposition
effects
of
high
of
pressures,
heat
and
bacteria
deep
under
the
sea,
hydrocarbons
describe
●
the
distillation
converting
fractional
of
are
list
●
the
main
fractions
the
them
into
oily
liquids
or
gases.
Hydrocarbons
petroleum
uses
of
obtained
fractional
one
of
the
most
important
energy
sources
on
Earth.
the
from
distillation
of
B14.1
Sources
Sources
of
and
extraction
of
hydrocarbons
petroleum
describe
●
catalytic
the
thermal
cracking
of
and
alkanes.
hydrocarbons
Hydrocarbons
atoms
only.
hydrocarbons.
under
t he
organic
or
Natural
compounds
include
Naturally
Ear t h’s
petroleum,
drilling
are
They
oil,
where
and
t he
exist
gaseous
in
bot h
form,
carbon
alkenes
hydrocarbons
t hey
t he
containing
alkanes,
occurring
surface
cr ude
t he
are
t he
as
hydrogen
t he
extracted
liquid
known
and
and
form,
natural
ringed
from
deep
known
gas
rig
Natural gas is a mixture of four alkanes: met hane (CH
), et hane (C
4
impervious
H
2
),
6
rock
propane
(C
H
3
natural
as
gas.
)
and
butane
(C
8
H
4
).
Met hane
makes
up
about
80%
10
gas
of
natural
gas
and
t he
ot her
t hree
hydrocarbons
make
up
20%.
The
petroleum
propane and butane are removed before natural gas is sold commercially.
water
impervious

Figure
14.1.1
Diagram
showing
Commercial
natural
et hane.
natural
of
petroleum
and
This
natural
be
piped
the
surface
of
the
t herefore,
can
t hen
is
be
a
mixture
used
to
of
met hane
generate
and
electricity,
to
homes
and
used
for
cooking
and
heating,
or
it
can
it
be
gas
liqueed
under
gas
the
can
occurrence
gas,
rock
under
pressure
to
produce
liqueed
natural
gas,
or
LNG.
LNG
Earth
is
Af ter
and
used
in
removal,
used
‘bottled
to
place
t he
and
petrol
propane
produce
gas’
of
of
vehicles
and
liqueed
many
in
you
butane
it
for
some
are
petroleum
use
in
also
gas,
or
countries,
liqueed
LPG.
LPG
e.g.
Germany.
under
is
also
pressure
known
as
cooking.
Petroleum
?
Did
you
know?
Petroleum
is
an
hydrocarbons,
Petroleum
renewable
the
is
a
finite,
resource
existing
supplies
crust
have
once
not
be
which
and
is
a
complex
ringed
mixture
hydrocarbons.
of
The
many
smallest
within
gaseous
hydrocarbons
t he
liquid.
been
and
t he
largest
solid
hydrocarbons
are
dissolved
in
all
oily
The
mixture
can
contain
hydrocarbons
wit h
as
many
as
70
must
be
the
used
more
carbon
atoms
in
t heir
molecules.
To
be
useful,
petroleum
they
separated
will
liquid
alkanes
non-
and
or
Earth’
s
oily
mainly
into
its
different
components,
or
fractions,
as
t hey
are
called.
This
replaced.
is
done
by
fractional
Fractional
When
it
is
have
is
to
be
heated
t he
removed
Before
it
removed.
to
lower
distillation
rst
impurities.
about
par t
d istillation
of
can
from
be
Once
400 °C
a
of
at
an
t he
under
t he
liquid
fractionating
ground,
into
impurities
t he
rener y.
petroleum
separated
and
oil
its
have
and
tower .
petroleum
components,
been
vapour
The
contains
t hese
removed,
t he
produced
fraction
are
which
many
impurities
petroleum
piped
remains
into
as
a
239
Sources
and
extraction
of
hydrocarbons
refinery
bubble
Hydrocarbons
viscous
gas
liquid
at
400 °C
sinks
to
t he
bottom
of
t he
–
alkanes
tower
and
and
is
alkenes
tapped
off
caps
forming
bottled
bitumen
or
asphalt.
gas
25 °C
and
chemicals
The
petrol
(gasoline)
petrol
tray
vapours
jet
oil
(paraffin)
larger
hydrocarbons
wit h
in
lower
lower
tower
of
wit h
par t
of
boiling
and
t he
t he
pass
tower
higher
t he
tower,
points
rise
t hrough
decreases
boiling
and
series
points
t hose
fur t her
a
and
of
upwards.
of
bubble
The
condense
t he
on
smaller
condense
at
caps
vapours
t he
and
of
t he
bubble
hydrocarbons
higher
levels.
The
fuel
tower.
diesel
produced
Gases
diesel
oil
t hat
do
tapped
not
off
from
condense
at
t he
t he
trays
at
t he
different
temperatures
wit hin
levels
t he
in
t he
tower
as
renery
gas
at
t he
top
of
t he
are
tower.
fuel
Each
fuel
are
oil
removed
crude
t he
temperature
t he
t he
liquids
heated
up
The
caps
kerosene
rise
trays.
oil,
and
fraction
boiling
lubricating
waxes
Petrol
is
points
is
a
mixture
wit hin
tapped
off
a
of
hydrocarbons
specic
from
t he
temperature
top
trays,
of
similar
range
kerosene
as
molecular
shown
and
in
diesel
size
Table
oil
are
and
14.1.1.
tapped
oil
off
from
t he
middle
trays
and
fuel
oil,
lubricating
t he
fractions
oil
and
waxes
are
tapped
400 °C
fuel
for
off
ships
from
t he
lower
trays.
bitumen
Table
14.1.1
distillation
roads

T
able
Name
of
Refinery
Petrol
14.1.1
Uses
of
the
fraction
Diesel
different
fractions
Number
carbon
below
(paraffin

Boiling
gas
oil
roofing
point/°C
obtained
of
14.1.2
from
and
oil,
lubricating
oil
Fuel
for
domestic
for
internal
170–250
10–14
Fuel
for
cooking,
250–350
14–20
Fuel
for
diesel
350–400
18–30
Fuel
waxes
oils
into
are
Lubricating
Waxes
above
400
more
than
30
Road
are
you
largest
world.
the
is
a
Lake
natural
lake
over
tourist
in
covers
75 m
in
T
rinidad
deposit
Located
e.g.
heating,
engines,
smaller
used
oils
as
are
used
are
obtained
by
fractional
uses.
petroleum
cooking
to
kerosene
e.g.
and
engines,
cars,
heating.
e.g.
lamps
lorries,
cars
and
T
o
and
jet
buses,
manufacture
light
aircraft.
engines.
trains,
a
variety
As
Cracked
trucks
and
of
petrochemicals.
solvents.
into
smaller
hydrocarbons.
generators.
hydrocarbons.
fuel
used
for
to
make
factory
boilers,
lubricate
polishing
ships
mechanical
waxes,
wax
and
power
parts
paper,
in
stations.
machinery
petroleum
and
jelly
vehicles.
and
candles.
Roofing.
hydrocarbons
petroleum
problems
Pitch
of
which
t heir
know?
When
The
use,
combustion
surfacing.
Cracking
Did
?
distillation
of
Uses
Fuel
Bitumen
some
atoms
1–4
oil)
and
petroleum
Cracked
Fuel
Fractional
5–10
oil
25
Figure
petroleum
25–170
(gasoline)
Kerosene
and
summarises
of
of
is
asphalt
south-west
about
deep.
attraction
40
The
and
is
in
●
fractionally
distilled
into
its
different
fractions,
two
The fractions which contain the smaller hydrocarbon molecules,
e.g. petrol, are in much greater demand in today’s world than the fractions
and
serves
also
the
T
rinidad,
hectares
lake
is
arise.
the
containing the larger hydrocarbon molecules, e.g. diesel oil. However, the
as
distillation of petroleum produces an excess of the larger hydrocarbons
mined
and insufcient of the smaller ones to meet modern demands.
for
its
asphalt.
Sir
Walter
Raleigh
was
●
introduced
to
the
lake
by
Most
of
carbon
guides
in
1595
and
he
its
potential
and
his
ships
with
the
energy,
we
to
use
Bot h
fact
t hese
is
long-chain
the
process
by
hydrocarbons
which
are
into
known
as
shorter-chain
ever y
are
day,
which
fairly
t he
t hey
have
petroleum
and,
unreactive.
great
need
To
variety
to
be
apar t
be
have
from
used
of
ot her
conver ted
carbon–carbon
can
molecules
only
carbon–
burning
in
t he
in
air
to
petrochemical
organic
be
into
overcome
smaller,
double
by
more
into
compounds
more
reactive
bonds.
breaking
useful
down
molecules
t he
by
a
larger
process
cracking
can
be
carried
hydrocarbons.
catalytic
240
from
molecules
broken
Cracking
down
t hey
problems
hydrocarbon
Cracking
obtained
t heir
manufacture
compounds
Key
in
tar
.
t hat
!
bonds
started
industr y
caulking
hydrocarbons
single
immediately
release
recognised
t he
Amerindian
cracking
out
in
one
of
two
ways,
thermal
cracking
and
Hydrocarbons
Thermal
During
larger
to
thermal
alkanes
break.
fairly
alkanes
and
alkenes
Sources
cracking
into
Thermal
are
high
temperatures
smaller
ones.
cracking
broken
up
propor tion
of
Under
an
alkane
in
a
fairly
of
alkene
of
above
t hese
700 °C
molecule
random
and
conditions,
way
molecules.
t he
always
so
For
pressures
forms
thermal
a
t hree
H
of
t hese
are
illustrated
in
Figure
to
70
alkane
shor ter-chain
cracking
example,
up
long-chain
octane
always
(C
H
8
ways,
and
extraction
of
hydrocarbons
cracking
molecules
a
–
atmospheres
molecules
alkane
gives
)
can
a
and
mixture
be
are
used
vibrate
cracked
at
least
of
in
to
one
variety
t he
enough
alkene.
products
a
break
strongly
The
containing
of
different
18
14.1.3.
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
H
H
H
C
C
H
H
H

C
H
H
octane
C
H
pentane
H
8
H
C
18
propene
H
5
C
12
H
3
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
H
H
6
H
H
H

C
H
H
octane
C
H
butane
H
8
C
18
butene
H
4
C
10
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
4
H
H
C
C
8
H
H

H
C
H
H
octane
C

Figure
14.1.3
Catalytic
C
18
Thermal
cracking
of
H
H
propene
H
3
H
H
propane
H
8
H

C
8
et hene
H
3
C
6
H
2
4
octane
cracking
During catalytic cracking t he long-chain alkanes are heated to temperatures
of
about
catalysts
dioxide
of
500 °C
are
known
petrol
and
Natural
at
fairly
normally
as
raw
gas
low
pressures
synt hetic
zeolites.
Catalytic
materials
and
for
oil
in
in
mixtures
t he
t he
of
presence
cracking
is
t he
petrochemical
the
of
aluminium
most
a
catalyst.
oxide
and
impor tant
The
silicon
source
industr y.
Caribbean
The Republic of Trinidad and Tobago is t he leading Caribbean producer of
oil and natural gas, wit h t hese accounting for about 40% of gross domestic
product
and
a
large
percentage
of
expor ts.

The
oil
rener y
in
Trinidad
is
found
at
Pointe-à-Pierre
and
accounts
Figure
14.1.4
Pointe-à-Pierre
oil
for
renery
most
of
t he
prosperity
domestically.
ammonia
More
plants
of
t han
and
to
t he
region.
two-t hirds
t he
All
of
electricity
t he
it
is
natural
piped
to
gas
produced
met hanol,
is
used
urea
and
Did
?
sector.
The
Summary
1
Name
two
List
the
natural
main
Pointe-à-Pierre
sources
of
only
oil
with
a
refinery
wildlife
uses
of
three
of
of
the
fractions
obtained
from
the
Wild
Describe
cracking
4
Give
the
what
and
is
meant
catalytic
formulae
cracking
refinery
world
reserve.
to
is
the
The
co-exist
Fowl
T
rust
is
Pointe-
a
environmental
not-for-
organisation
petroleum.
and
by
‘cracking’
cracking
names
of
of
and
distinguish
between
thermal
alkanes.
two
products
which
could
be
and
pentane
(C
H
5
to
environmental
conservation
waterfowl.
It
and
25
about
of
education
wetlands
consists
of
hectares
two
of
and
lakes
land
within
obtained
the
by
oil
the
fractional
dedicated
3
in
hydrocarbons.
profit
distillation
know?
questions
à-Pierre
2
you
oil
refinery
.
).
12
241
Alkanes:
C
H
n
Hydrocarbons
2n

B14.2
Objectives
Alkanes:
C
the
end
be
able
of
this
topic
you
form
a
homologous
series
wit h
t he
general
formula
C
H
n
Alkanes
the
alkenes
2n  2
to:
give
and
will
Alkanes
●
alkanes
H
n
By
–
2
names
and
are
saturated
hydrocarbons .
This
means
t hat
t hey
2n  2
contain
only
structural
single bonds between carbon atoms. Alkanes are relatively unreactive because
formulae
of
unbranched
and
of
branched
alkanes
up
to
t he
t he
carbon
●
relate
to
●
reactivity
presence
describe
reaction
●
carbon–carbon
single
the
of
describe
of
of
alkanes
single
Alkanes
bonds
combustion
t he
alkanes
series
given
substitution
are
named
by
using
t he
prex
in
do
not
Figure
show
str uctural
and
in
number
of
formulae
are
et hane
H  C  C  C  H
H
H
(C
H
2
)

)
H

H
(CH
H

met hane
H
propane
H
(C
6
H
3
)
8
properties

●
total

to
H
H  C  C  H
H
alkanes
H
4
their
names

of
t he

H  C  H
undergo
reactions
uses
Their

the
alkanes
indicates

why
H

relate
bonds
reactions
halogens

explain
with
which
isomerism.

alkanes
substitution
●
carbon–hydrogen
14.2.1.

●
and
carbon atoms in t he molecule and t he sufx ‘ -ane’. The rst t hree alkanes in
H
of
bonds
molecules.
atoms
the
the
strong
six
describe
the
production
Alkanes
biogas.
from
page
H
H
H
H
Figure
14.2.1
Structural
formulae
of
the
rst
three
alkanes
of
H
C
C
C
H
H
H
H
233
H
4
C
t heir
14.2.4
(C
wit h
or
ability
for
show
),
four
more
to
form
naming
t he
pentane
H
5
and
)
atoms
branched
branched
names
(C
10
carbon
chain
hexane
Figures
formulae
H
6
isomerism
Following
isomers,
(C
12
str uctural
chains.
str uctural
and
show
of
t he
steps
1)
14.2.2,
resulting
to
4)
14.2.3
isomers
of
on
and
butane
).
14
H

H
H  C  H

pentane
H
H
H
H
H
H






H
H  C  C  C  C  H
H
H
H
H
butane
C

H
H

H

H
H  C  C  C  H

H
H

H
C


H
C

C
Figure
14.2.2
2-met hylpropane
The
structural
isomers
of
butane
(C
H
4
)
10
H
H
H
H
H
H
2-met hylbutane
H
H
H
H
H
H
H
C
C
C
C
C
H
H
H
H
H
H
C
H
H
H
C
C
C
C
H
H
H
H
H
H
C
H
H
H
H
C
H
H
H
H
H
C
H
hexane
2-met hylpentane
H
H
C
H
H
H
C
H
H
H
H
C
H
H
H
H
H
2,2-dimet hylpropane
C
H
C
H

Figure
14.2.3
pentane
(C
The
H
5
structural
isomers
H
Figure
hexane
H
H
C
C
H
)
12
14.2.4
(C
H
6
The
C
structural
isomers
H
C
C
C
H
H
C
C
C
C
H
H
of
C
H
of
H
H
H
H
H
H
H
H
H
H

H
H
H
H
H
H
)
14
3-met hylpentane
2,2-dimet hylbutane
The melting and boiling points of t he alkanes
2,3-dimet hylbutane
increase wit h an increase in t he
size of t he molecules, i.e. wit h an increase in molar mass. The rst four alkanes,
met hane,
242
et hane,
propane
and
butane,
are
gases
at
room
temperature.
Hydrocarbons
–
alkanes
and
alkenes
Alkanes:
C
H
n
2n

2
Alkanes wit h 5 to 16 carbon atoms in t heir molecules are liquids, while t hose
wit h 17 or more carbon atoms are solids. Alkanes become less volatile as t heir
molecular
size
Did
?
namely
are
relatively
combustion,
described
in
know?
increases.
The
Alkanes
you
Unit
unreactive
and
substitution
14.1.
We
will
only
and
now
undergo
cracking.
look
at
t he
a
The
few
types
cracking
ot her
two
of
of
reaction,
alkanes
was
prefix
name
chain
reactions.
reactions
of
when
called
alkanes
used
of
The
butane
normal
Similarly,
or
the
‘n-’
before
naming
isomers.
isomer
Combustion
‘normal’
sometimes
is
the
the
straight
straight
is
chain
sometimes
butane
straight
or
n-butane.
chain
isomer
Alkanes burn ver y easily in air or oxygen. The reaction is exot hermic producing
of
large
amounts
fuels.
The
oxygen
of
heat
products
supply.
combustion,
if
f
it
energy,
of
t he
is
t he
which
oxygen
limited,
is
why
combustion
supply
t hey
is
alkanes
are
reaction
var y
plentiful,
t hey
undergo
incomplete
used
extensively
depending
undergo
on
as
pentane
pentane
alkanes
burn
t hey
do
so
wit h
a
clear
blue
remains
to
to
carbon
give
t he
dioxide
ame
a
or
carbon
ame
yellow,
monoxide
smoky
a
ver y
low
soot
content.
Alkanes
are
and
because
no
appearance.
regarded
as
t he
ratio
unreacted
The
ame,
Exam
tip
It
important
that
is
fully
displayed
and
names
clean
of
you
can
structural
give
the
formulae
carbon
of
unbranched
and
t herefore,
burning
chain
isomers
of
any
fuels.
atoms
combustion
n-pentane.
of
alkane
Complete
normal
complete
branched
has
called
combustion.
carbon to hydrogen atoms in t he molecules is low. All t he carbon is t herefore
conver ted
or
be
t he
✔
When
can
containing
if
you
are
up
to
given
six
its
carbon
molecular
alkanes
formula.
When
t he
undergo
of
oxygen
supply
complete
alkanes
are
combustion
CH
of
is
plentiful,
combustion .
always
carbon
met hane
(g)

2O
(g)

7O
4
and
The
products
dioxide
et hane
is
(g)
CO
(g)
4CO
2
alkanes
and

of
t he
water
shown
(g)
burn
2H
2
in
as
t he
completely,
complete
steam.
O(g)
H
t hey
combustion
The
following
i.e.
complete
✔
equations:
Exam
Balancing
ve
H
2
6
2
(g)

6H
2
O(g)
H
of
by
t he
oxygen
combustion.
carbon
The
met hane
is
shown
supply
products
monoxide
and
in
is
of
limited,
t he
water
t he
balancing
followed
as
incomplete
steam.
following
alkanes
The
undergo
combustion
incomplete
incomplete
of
alkanes
are
combustion
of
until
and
you
last.
the
(g)

3O
4
by
(g)
2CO(g)

4H
2
O(g)
H
the
After
be
difficult.
the
carbon
hydrogen
oxygen
balancing
hydrogen,
have
atoms
equation:
Leave
on
an
odd
the
coefficient
2CH
can
the
alkanes
atoms.
When
combustion
alkanes
2
atoms
combustion
of
ve
Begin
Incomplete
the
2
reactions
2C
tip
if
you
of
multiply
(including
the
carbon
find
number
right,
atoms
the
that
oxygen
each
unwritten
ve
2
1)
by
2,
before
balancing
the
oxygen.
Substitution
Under
t he
right
molecules,
hydrogen
reactions
t he
conditions,
carbon
atoms
of
alkanes
atoms
possible.
alkanes
are
When
a
can
react
bonded
reaction
to
wit h
t he
occurs
halogens.
maximum
between
an
n
alkane
number
alkane
of
and
a
halogen, t he hydrogen atoms are replaced by halogen atoms. These reactions
are
of
known
t he
time.
They
Energy
light
takes
in
place
Light
●
The
t he
substitution
can
t he
works
●
form
t he
in
atoms
also
be
of
best,
stages
intensity
reactivity
reaction.
rapid
●
as
hydrogen
in
reactions
t he
called
light
but
and
is
required
speed
of
–
t he
brighter
t he
t he
halogen
–
reaction.
odine
being
does
for
sunlight
of
Fluorine,
halogen
molecules,
atoms
one
take
hydrogen
t he
place
atom
at
a
halogenation
of ten
t he
because
alkane
not
t he
t he
t he
more
most
react
reactions
sufcient.
reaction
light,
t he
t he
is
A
to
occur.
depends
on
three
faster
t he
reaction.
reactive
t he
halogen,
reactive
wit h
halogen,
alkanes
Ultraviolet
substitution
to
has
any
reaction
factors.
t he
t he
faster
most
extent.
The reactivity of the alkane – the smaller the alkane molecule, the faster the
243
Alkanes:
C
H
n
Hydrocarbons
2n

–
alkanes
and
alkenes
2
reaction.
This
No
is
Methane, being the smallest molecule, has the most rapid reaction.
seen
in
reaction
light
a
slow
replaced
reaction
occurs
in
t he
substitution
by
produces
t he
one
between
dark.
n
reaction
chlorine
chloromet hane
bright
occurs
atom
and
met hane
at
a
light
in
The
is
rapid.
hydrogen
stage
of
n
atom
t he
dim
being
reaction
gas:
Cl
UV
H
reaction
one
rst
chloride
H
chlorine.
t he
stages,
time.
hydrogen
and
C
H
light

H
H
H

H
met hane
chlorine
monochloromet hane
hydrogen
chloride
or
U
CH
(g)

Cl
4
light
(g)
CH
2
Cl(g)

HCl(g)
3
As t he reaction continues, t he hydrogen atoms are replaced one by one until
tetrachloromet hane
(CCl
)
is
produced:
4
U
CH
Cl(g)

Cl
3
light
CH
(g)
Cl
2
2
(l)
HCl(g)

2
dichloromet hane
U
CH
Cl
2
(l)

Cl
2
light
CHCl
(g)
(l)
HCl(g)

3
2
trichloromet hane
Did
?
you
know?
U
CHCl
(l)

Cl
3
Trichloromethane
(or
light
CCl
(g)
(l)
HCl(g)

4
2
chloroform)
tetrachloromet hane
and
tetrachloromethane
carbon
tetrachloride)
are
(or
both
The
volatile,
At
one
used
‘sweet’
time,
as
a
because
smelling
trichloromethane
general
the
reaction
can
was
be
U
CH
anaesthetic
vapours
overall
summarised
by
t he
following
(g)

4Cl
4
light
(g)
CCl
2
(l)

4HCl(g)
4
depress
The products of t he halogenations of alkanes are called
the
nervous
system,
tetrachloromethane
in
fire
extinguishers
equation:
liquids.
haloalkanes or alkyl
and
was
and
used
as
halides
a
The reaction of bromine vapour or bromine solution wit h met hane is similar,
solvent
in
dry
cleaning.
Their
uses
but
were
discontinued
when
it
since
slowly.
discovered
how
toxic
they
bromine
is
less
reactive
t han
chlorine,
t he
reaction
proceeds
more
was
Once
again,
energy
in
t he
form
of
ultraviolet
light
is
required
for
t he
of
t he
both
reaction
to
proceed.
were.
During
t he
reaction
between
bromine
and
any
alkane,
t he
colour
bromine slowly fades from red-brown to colourless. The rst step in t he reaction
between
et hane
H
and
bromine
is
shown
t he
equation
H
UV
H
in
C
C
H
H
et hane

Br
C
C
H
H
light
H
bromine
H
below:
H
monobromoet hane

hydrogen
bromide
244
Hydrocarbons
–
alkanes
and
alkenes
Alkanes:
C
H
n
Uses
of
Because
t heir
related
Alkanes
●
are
burn
–
t hey
release
t he
t hey
–
t hey
to
t hey
are
parafn
Biogas
fuels
for
when
large
several
amount
of
low
an
a
variety
given
of
uses.
The
main
uses
of
below.
reasons:
of
energy
alkane
fuels,
soot
easily
have
are
ignited
burning
ver y
stored
are
used
as
is
an
i.e.
when
t hey
undergo
exot hermic
t hey
burn
combustion,
reaction
wit h
a
clear
blue
ame
content
liquids
in
containers,
which
makes
t hem
easy
are
glues
a
as
solvents.
variety
used
and
of
as
are
non-polar
non-polar
solvents
ot her
solid
Alkanes
ot her
in
t he
adhesives,
solutes.
molecules
For
manufacture
petroleum
jelly
t herefore
example,
of
is
hexane
fast-dr ying
oil
dissolved
in
alkane.
production
of
any
a
wax,
refers
absence
crop
a
dissolve
lacquers,
from
a
clean
has
heptane
Biogas
2
transpor t.
Alkanes
and
as
easily
alkanes
proper ties,
combustion
are
which
t heir
used
t hey
–
●
proper ties,
to
–
i.e.

alkanes
of
alkanes,
2n
to
a
gas
oxygen.
organic
residues,
t
produced
is
matter
sewage,
a
by
the
renewable
including
garden
breakdown
energy
manure
waste,
food
of
source
and
other
waste
organic
which
and
matter
can
farmyard
organic
be
in
the
produced
animal
waste
waste,
from
food
industries.
The
organic
occurring
oxygen
waste
is
anaerobic
into
biogas.
put
into
a
sealed
microorganisms,
Biogas
is
a
anaerobic
e.g.
mixture
of
bacteria,
digester
digest
approximately
it
where
in
60%
the
naturally
absence
methane,
of
40%
carbon dioxide and traces of other contaminant gases such as hydrogen sulde.
Summary
The exact composition depends on the nature of the original organic matter.
Biogas
or
it
can
can
be
be
used
directly
conver ted
to
as
a
fuel
almost
to
pure
provide
heat
met hane,
and
of ten
generate
called
electricity
1
Give
the
names
removal
of
t he
ot her
gases.
This
biomet hane
can
t hen
be
piped
to
natural
gas
or
liqueed
under
pressure
to
produce
liqueed
natural
for
use
in
vehicles
designed
to
r un
on
lef tover
indigestible
material
and
three
isomers
Write
a
balanced
dead
microorganisms,
known
show
the
can
t hen
be
used
as
a
fer tiliser.
The
production
of
biogas
on
non-renewable
fossil
fuels,
equation
as
recycles
soil
nutrients
and
of
butane.
reduces
3
demands
hexane.
complete
combustion
d igestate,
of
LNG.
to
The
fully
formulae
gas
2
(LNG)
structural
homes
of
wit h
and
biomethane,
displayed
by
questions
Propane
reacts
with
chlorine
reduces
gas.
t he
amount
of
waste
going
to
garbage
dumps
and
landlls.
a
What
condition
necessary
to
slurry
and
manure
b
for
is
the
reaction
occur?
What
is
the
name
given
to
power
gas
grid
this
c
anaerobic
biogas
food
Use
of
reaction?
structural
formulae
to
biomethane
digester
show
the
rst
step
in
the
reaction.
and
amenity
type
waste
d
Name
rst
transport
the
step
products
in
the
of
the
reaction.
fuel
digestate
crops
and
residues
4
Explain
why
the
main
use
of
heat
alkanes

Figure
14.2.5
Production
of
is
as
fuels.
biogas
245
Alkenes:
C
H
n
Hydrocarbons
B14.3
Objectives
Alkenes:
C
the
be
able
●
end
of
give
alkenes
of
you
alkenes
relate
the
a
by
form
Alkenes
the
2n
a
homologous
series
wit h
t he
general
of
up
double
and
to
six
are
unsaturated
hydrocarbons .
C
the
of
of
a
atoms
alkenes
Alkenes
carbon
carbon–
t he
bond
are
series
given
named
atoms
in
do
in
not
Figure
by
t he
using
t he
molecule
show
They
prex
and
str uctural
which
t he
sufx
isomerism.
indicates
‘ -ene’.
Their
hydrogen,
●
the
hydrogen
alkane
relate
their
to
H
H
(C
H
)
propene
(C
4
H
3
)
6
Figure
14.3.1
Structural
formulae
of
the
rst
two
alkenes
halides
which
distinguish
and
the
 C
Alkenes wit h four or more carbon atoms show str uctural isomerism. Str uctural
reactions
an
in
are
the
water
used
formulae
of

with

be
and
alkenes
reactions
2
describe
number
two

H
et hene
and
names

addition
halogens,
total
rst
H
H  C  C

undergo
H
alkenes
t he
The



alkenes
reactions
describe
bond
H

H

alkenes
why
addition
double
carbon–carbon
14.3.1.
C  C
explain
one
C
H
of
contain
2n
combustion
H
●
H
bond:
structural
carbon
reactivity
double
describe
of
C
unbranched
presence
reaction
●
formula
between two carbon atoms, i.e. t heir functional group is t he
carbon–carbon
names
the
carbon
●
alkenes
will
bond
the
formulae
●
and
n
recognise
to
topic
Alkenes
double
●
this
to:
presence
●
alkanes
H
n
By
–
2n
an
uses
isomers
can
between
●
alkene
of
alkenes
t he
of
alkenes
change
position
to
of
however,
in
result
from
position
t he
t hat
of
t he
t he
functional
carbon–carbon
t he
bond
must
following:
double
always
group,
bond
be
(it
i.e.
is
t he
change
impor tant
to
in
note,
horizontal)
properties.
●
branching
When
H
H

t he
molecule.
isomers
carbon
of
alkenes:
atoms
 C  C
t he
double
bond
so
t hat
in
t he
t he
longest
double
chain
bond
is
from
closest
t he
to
end
t he
closest
lowest
to
number



 C
naming
number
t he
H



H  C
●
H
of
and
indicate
t he
position
of
t he
double
bond
in
t he
name
using
t he
H
H
H
●
but-1-ene
(or
lowest
possible
follow
steps
to
4)
on
page
233
for
naming
branched
chain
isomers.
1-butene)
Using
H
1)
number
H
t he
r ules
above,
t he
str uctures
and
names
of
t he
unbranched
and
H
H




branched isomers of butene (C
H
4
H  C  C  C  C  H
isomers
of
hexene
(C
H


6
)
are
) and pentene (C
8
H
5
given
in
Figures
14.3.2,
) and t he unbranched
10
14.3.3
and
H
H
14.3.4.
12
H
but-2-ene
H
(or
2-butene)
H
H
H
H
H
H
H
H
H
C
C
C
C
C
H
H
H
H
H
H
H
H

C
C
H
H
C
C
H
H
C
C
H  C  H
H
H
H
H
H
H
H



H
pent-1-ene
pent-2-ene
2-met hylbut-1-ene
H  C  C  C  H

(or
1-pentane)
(or
2-pentene)
(or
2-met hyl-1-butene)
H
H
H
2-met hylpropene
H
H

Figure
butene
14.3.2
(C
H
4
The
structural
isomers
H
H
H
H
C
C
H
H
H
of
H
)
8
H
C
C
H
H
C
C
H
C
C
H

Figure
14.3.3
pentene
(C
H
5
246
The
)
10
structural
isomers
of
3-met hylbut-1-ene
(or
3-met hyl-1-butene)
H
2-met hylbut-2-ene
(or
2-met hyl-2-butene)
Hydrocarbons
–
alkanes
and
alkenes
Alkenes:
C
H
n
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
H
H
H
H
H
H
H
H
C
C
C
C
C
H
H
2n
H
C
C
C
C
C
H
H
H
H
H
H
hex-1-ene
H
(or
H
1-hexene)
hex-2-ene
H
(or
H
2-hexene)
H
hex-3-ene

The
presence
of
t he
double
bond
makes
alkenes
more
reactive
t han
(or
Figure
3-hexene)
14.3.4
The
straight
isomers
of
hexene
(C
H
6
Alkenes
looking
undergo
at
are
a
variety
combustion
of
different
and
reactions.
addition
The
ones
t hat
we
will
reactions
of
be
burn
ver y
easily
in
air
or
oxygen.
The
complete
an
alkene
produces
carbon
tip
is
important
that
dioxide
and
water
as
steam.
The
unbranched
exot hermic,
combustion
of
producing
et hene
is
a
large
shown
in
amount
t he
of
heat
equation
energy.
The
complete
below:
containing
atoms.
you
It
can
is
H
2
(g)

3O
4
(g)
2CO
2
(g)

2H
2
O(g)
H
require
more
oxygen
cor responding
alkane
wit h
alkenes
higher
ratio
have
a
for
t he
of
not
carbon
and
bur n
as
soot
steam.
wit h
a
wit h
As
smoky
clean
complete
same
number
carbon
and
a
 ames.
sometimes
result
of
t he
atoms
combustion
of
to
carbon
t han
atoms
hydrogen
atoms
t he
because
atoms
in
formula.
t heir
When
carbon
presence
t hey
bur n
monoxide
of
t he
soot
t hey
as
in
well
t he
release
as
unreacted
carbon
ame,
can
if
you
It
is
name
are
reactions
wit h
one
called
molecule.
hydrogen
The
of
of
14.3.5,
two
reaction,
t he
t he
Did
in
addition
Hexene
(C
single
its
essential
branched
any
six
not
H
6
involve
adding
extra
atoms
to
t he
t he
double
reactions
substitution
reaction
where
atoms
which
A–B
or
covalent
bond
carbon
bond
being
broken
in
t he
to
because
two
reactions,
t he
molecules
alkene
react
does
not
to
form
lose
any
Figure
Alkenes
as
an
represents
small
bond
double
forming
atom
t he
at
carbon
reaction
alkene
a
groups
between
bond
a
one
of
A
also
undergoes
molecule
atoms
and
B
breaks.
saturated
side
atom
undergo
to
with
a
wit h
in
a
breaks
The
a
is
summarised
single
covalent
molecule.
and
one
double
of
bond
is
compound
and
A
has
thirteen
the
chain
three
isomers
chain
could
isomers.
see
how
and
For
ten
of
t he
original
double
practice,
many
of
and
at
t he
ot her
each
This
The
atoms
carbon
always
in
t he
atom
following
at
a
nickel
●
a
pressure
●
a
temperature
you
draw.
t he
C
C

C
C
A
B
in
conver ted
small
saturated
B
bonded
product
becomes
Figure
14.3.5
Summary
of
addition
side.
addition
eit her
an
reaction
hydrogenation,
hydrogen
of
alkenes
side
molecule
of
t he
wit h
t he
breaks
original
hydrogen
single
and
bond
one
double
gas
atom
bond
known
between
in
is
t he
bonded
t he
alkene.
alkane
conditions
●
of
During
produces
you
these
in
bonds
becomes
bond
shown
branched
bond
During
t he
)
12
hydrogen
type
hydrogenation.
hydrogen
of
know?
isomers,
14.3.4
reactions
Addition
you
process.

bonded
that
isomers
molecule
to
carbon
molecular
t he
can
carbon–carbon
a
of
to
given
you
alkene
to
up
bur n
atoms.
between
unbranched
isomers
dioxide
alkenes
alkenes
alkenes
bond
Unlike
addition
Figure
of
that
alkenes.
in
one
any
carbon
displayed
are
the
unbranched
They
six
ame
reactions
molecules,
to
fully
formulae
containing
structural
Add ition
up
important
the
branched
alkene
?
Addition
name
ve
molecules. Because of t his higher ratio of carbon to hydrogen atoms, alkenes
do
of
2
and
Alkenes
also
draw
structural
C
can
isomers
reaction
alkene
is
you
combustion
the
of
Exam
alkenes
It
Alkenes
)
12
reactions.
✔
Combustion
chain
alkanes.
are
required
for
t he
reaction:
catalyst
of
about
of
5
atmospheres
about
150 °C.
247
Alkenes:
C
H
n
Hydrocarbons
For
Did
?
you
alkanes
example,
et hene
reacts
wit h
hydrogen
to
fats
is
used
and
in
oils,

industry
i.e.
H
H
H
catalyst
H
C
atm,
150
melting
points.
hydrogenating
can
the
be
H
For
et hene
margarine
H
°C
H
H
their
example,
by
alkenes
et hane:
H
5
‘harden’
increase
and
H
Ni
Hydrogenation
form
know?
H
to
–
2n
hydrogen
et hane
made
carbon–
or
carbon
double
bonds
in
vegetable
Ni
oils.
This
hardens
the
oils
making
C
H
2
(g)

H
2
2
5
the
margarine
it
also
If
margarine
butter,
has
it
more
possible
is
used
reduces
spreadable
health
in
the
animal
fats
150
(g)
6
°C
benefits.
place
of
amount
in
atm,
and
Addition
the
reaction
with
halogens
of
Alkenes
saturated
catalyst
H
4
undergo
a
type
of
addition
reaction
wit h
halogens
known
as
diet.
halogenation.
atoms
in
t he
During
molecule
halogenation,
breaks
and
t he
one
single
atom
is
bond
between
bonded
to
each
t he
halogen
carbon
atom
at eit her side of t he original double bond in t he alkene. This always produces
a
haloalkane
n
contrast
reaction
to
does
temperature.
reaction
For
t hat
t he
not
halogenation
need
The
reaction
occurs
example,
light
wit h
reactions
energy;
is
also
a
it
can
rapid
which
take
alkanes
place
reaction
in
in
undergo,
t he
dark
contrast
to
at
t his
room
t he
slow
alkanes.
propene
reacts
wit h
bromine
vapour
to
form
1,2-dibromopropane:
H
H
H
H
H
C
C
H
C

C
Br
Br
H
H
H
H
propene
bromine
Br
Br
1,2-dibromopropane
or
C
H
3
n
t his
bot h
wit h
reaction,
cases,
+
Br
H
2
bromine
red-brown
3
can
be
in
bromine
t he
is
form
rapidly
of
a
Br
6
(l)
2
vapour
decolour ised
as
or
a
t he
solution.
alkene
n
reacts
it.
Addition
Alkenes
reactions
undergo
hydrogen
to
t he
(g)
6
hydrogen
addition
chloride
produce
with
(HCl)
halides
reactions
and
wit h
hydrogen
hydrogen
bromide
halides,
(HBr),
at
for
room
example,
temperature
haloalkanes
For example, ethene reacts with hydrogen chloride to form monochloroethane:
H
H
H
H
H

H
Cl
C
H
et hene
hydrogen
H
2
248
H
4
H
H
monochloroet hane
chloride
or
C
Cl
2
Cl(l)
5
Hydrocarbons
–
alkanes
and
alkenes
Alkenes:
C
H
n
Addition
Alkenes
steam
a
reactions
undergo
known
hydrogen
t he
as
double
carbon
The
bond
atom
in
at
following
type
and
atom
is
t he
t he
of
of
a
catalyst
t he
●
a
pressure
●
a
temperature
alkene
ot her
example,
60–70
of
During
oxygen
to
and
side.
are
phosphoric
of
addition
bonded
conditions
●
For
a
water
hydration.
atom
hydrogen
with
2n
reaction
atom
t he
t he
This
in
in
t he
carbon
for
sand
of
water
at
OH
in
t he
t he
bonds
molecule
one
side
group
produces
t he
water
one
atom
remaining
always
required
acid
wit h
hydration,
an
is
of
form
of
between
breaks
t he
and
original
bonded
to
t he
alcohol
reaction:
(silica)
atmospheres
about
ethene
300 °C.
reacts
with
water,
in
the
form
of
steam,
to
form
ethanol:
H
H
H
H
H

H
PO
3
O

ethene
H
C
70
H
300 °C
catalyst
4
atm,
300

+
°C
H
60–70
atmospheres
steam
H

H
phosphoric(V) acid
catalyst
et hene
water
et hanol
cooling
unreacted
of
or
gases
gases
recycled
H
PO
3
C
H
2
(g)
+
catalyst
4
H
4
H
2
2
70
atm,
300
OH(l)
5
°C
ethanol
to
Et hanol
and
ver y
to
is
steam
low
produced
using
so
increase
t he
preparation
Addition
t he
of
yield.
i.e.
example,
et hene
ow
t he
is
addition
above.
recycled
diagram
in
reaction
The
back
Figure
yield
into
14.3.6
between
of
t he
t he
et hene
reaction
reaction
shows
t he
is
ethanol
vessel
industrial

acidified
an
an
by
potassium
addition
The
t he
alcohol
et hene
Figure
14.3.6
preparation
solution.
oxidised
d i alcohol,
For
with
undergo
is
The
by
listed
et hanol.
manganate(VII)
alkene
conditions
unreacted
reaction
Alkenes
industrially
t he
acidied
wit h
reacts
two
wit h
is
a
wit h
redox
potassium
–OH
The
of
industrial
ethanol
manganate(VII)
reaction
reaction
turns
liquid
acidied
reaction
in
manganate(VII)
potassium
which
to
t he
form
a
groups.
acidied
potassium
manganate(VII)
to
form
et hane-1,2-diol:
H
H
H
H
H
H

O
[O]

2
H
C
H
et hene
from
H
oxidising
H
et hane-1,2-diol
agent
or
Exam
✔
C
H
2
(g)
+
H
4
H
2
2
(OH)
4
It
is
very
write
Dur ing
t he
changes
colour
and
reduces
reaction,
from
t he
t he
purple
pur ple
potassium
to
colourless.
manganate(VII)
The
manganate(VII)
alkene
ion
tip
(l)
2
acts
(MnO
solution
as
)
a
to
for
that
the
you
can
addition
rapidly
reducing
t he
important
equations
reactions
of
can
the
alkenes
and
that
you
agent
state
conditions
required
colourless
4
for
the
reactions
to
occur.
2
manganese(II)
ion
(Mn
).
249
Alkenes:
C
H
n
Hydrocarbons
Reactions
Did
?
–
alkanes
and
alkenes
2n
you
to
distinguish
between
an
alkane
and
an
know?
alkene
Alkenes
in
can
addition
also
add
reactions.
These
very
molecules
large
to
themselves
You
polymerisation
reactions
but
make
known
have
slow
We
will
be
more
detail
in
Unit
learnt
t hat
saturated
bot h
whereas
reactions
alkanes
alkenes
because
t hey
and
are
alkenes
are
unsaturated.
contain
only
hydrocarbons,
Alkanes
undergo
carbon–carbon
single
as
looking
at
whereas
alkenes
undergo
rapid
addition
reactions
because
of
t he
this
presence
in
are
substitution
bonds
polymers.
already
alkanes
of
a
carbon–carbon
double
bond.
16.
The difference bet we e n t he re ac tion s of a lk an es a n d a lken es w it h bro min e
solution
or
laborato r y
see
if
t he
acidifie d
to
p ot a ssium
dist in g uish
compo un d
man gan ate(VI I)
b etwee n
c o nt ain s
a
t he
t wo.
solutio n
B ot h
c arbon – c arb o n
is
r eac tio n s
dou ble
u se d
a re
in
t he
t est in g
bo n d ,
i. e.
if
to
it
is
uns aturated
The tests used to distinguish between an alkane and an alkene are summarised
in

T
able
14.3.1
Distinguishing
between
an
Table
alkane
Observations
and
and
14.3.1.
an
alkene
explanation
T
est
Alkane
Add
acidified
potassium
manganate(VII)
The
Alkene
solution
remains
purple.
The
solution
solution
changes
colour
rapidly
from
purple
to
colourless.
Alkanes
do
not
react
with
acidified
potassium
Alkenes
rapidly
reduce
the
purple
MnO
ion
to
the
4
2
manganate(VII)
Add
a
water
solution
(bromine
of
bromine
water)
or
in
The
solution
remains
colourless
red-brown.
The
in
tetrachloromethane
under
standard
conditions
Mn
solution
ion.
changes
colour
rapidly
from
red-brown
to
colourless.
Alkanes
laboratory
solution.
do
laboratory
not
react
with
bromine
solution
under
standard
conditions.
t
●
is
impor tant
n
t he
in
water
brown
●
to
note
presence
or
to
of
alkanes
red-brown
and
ultraviolet
and
due
light,
to
t he
to
t he
decolour ise
t his
reaction
to
rapid
addition
conditions,
alkanes
slowly
slow
react
colourless.
due
a
any
reaction
including
with
bromine
darkness.
following.
alkenes
to
light
rapidly
reaction
under
ultraviolet
colourless
from
Alkenes
undergo
solution
tetrac hloromet hane
Bot h
in
t he
Alkenes
substitution
wit h
bromine
Alkanes
slow
t he
does
cause
c hange
slowly
not
due
need
solution
colour
light,
reaction
t he
bromine
red-
occur r ing.
c hanging
decolour ise
to
of
from
reaction
vapour,
substitution
vapour
a
rapid
t herefore
t he
it
vapour
occur r ing.
addition
it
will
occur
in
darkness.
These
reactions
distinguish
T
o
teacher
will
be
and
test
use
with
acidied
tubes.
an
this
recording
supplied
cyclohexene,
however,
and
between
may
observation,
Y
ou
250
are,
alkane
distinguish
Your
●
an
not
usually
used
as
laborator y
tests
alkene.
an
alkane
activity
and
to
and
an
alkene
assess:
reporting.
samples
potassium
of
two
hydrocarbons
manganate( VII)
cyclohexane
solution,
bromine
and
solution
to
Hydrocarbons
–
alkanes
and
alkenes
Alkenes:
C
H
n
2n
Method
3
1
Place
A
2 cm
and
of
cyclohexane
into
each
of
two
test
tubes.
Label
the
tubes
of
cyclohexene
into
each
of
two
test
tubes.
Label
the
tubes
B.
3
2
Place
C
3
and
Add
A
2 cm
a
D.
few
and
drops
of
acidied
4
Shake
5
Add
6
Shake
and
7
Which
hydrocarbon
Uses
of
a
a
and
few
of
Alkenes
reactions
manganate( VII)
solution
to
tubes
observe
drops
any
of
colour
bromine
observe
any
is
changes
solution
colour
to
which
test
occur.
tubes
B
and
D.
changes.
saturated
and
which
is
unsaturated?
alkenes
are
wide
potassium
C.
extremely
range
due
of
to
impor tant
chemicals
t he
starting
because
presence
of
of
t he
mater ials
t heir
for
ability
t he
to
manufacture
undergo
carbon–carbon
double
addition
bond.
Did
?
The
example,
t hey
are
used
to
manufacture
et hanol
and
ot her
alcohols
you
combustion
undergo
addition
reactions
wit h
steam
and
to
of
alkenes
is
an
because
exothermic
t hey
know?
For
manufacture
reaction,
therefore,
various
alkenes
could
be
used
as
fuels.
haloalkanes because of t heir addition reactions wit h halogens and hydrogen
However,
they
are
far
too
important
halides. They are also used to manufacture antifreezes, such as et hane-1,2-diol
as
and
synt hetic
t hemselves
plastics.
r ubbers.
t hey
You
will
Give
the
straight
2
a
to
more
t hey
can
undergo
manufacture
about
plastics
a
in
wide
Unit
addition
variety
reactions
of
starting
materials
for
making
wit h
polymers,
other
organic
them
by
products
to
waste
or
using
them
as
fuels.
16.
questions
names
chain
Describe
used
learn
Summary
1
are
Because
and
fully
isomers
what
you
of
displayed
structural
formulae
of
the
three
hexene.
would
observe
when
bromine
solution
is
added
to
ethene.
b
3
4
Give
Give
a
the
balanced
conditions
a
hydrogenation
b
hydration
Describe
an
distinguish
Key
●
of
under
of
to
experiment
between
which
ethene
ethane
an
for
to
the
the
that
following
produce
produce
you
alkane
reaction
structural
reactions
formulae.
occur:
ethane
ethanol.
could
and
using
an
perform
in
the
laboratory
to
alkene.
concepts
Hydrocarbons
hydrogen
are
atoms
●
Natural
●
Natural
gas
et hane,
propane
●
equation
gas
Petroleum
and
is
is
organic
petroleum
composed
a
compounds
composed
of
carbon
and
only.
and
are
mainly
natural
of
sources
met hane
of
wit h
hydrocarbons.
small
amounts
of
butane.
complex
mixture
mainly
of
alkanes
and
ringed
hydrocarbons.
251
Alkenes:
C
n
H
Hydrocarbons
–
alkanes
and
alkenes
2n
●
Separation
of
distillation
●
The
of
●
of
oil
the
are
as
The
molecules
larger
broken
Thermal
Catalytic
catalyst
Cracking
●
Alkanes
components
is
done
by
fractional
down
obtained
the
uses
the
of
fractional
distillation
petrochemicals,
as
roads.
produced
into
from
manufacture
during
smaller,
high
fractional
more
useful
temperature
distillation
molecules
and
pressures
by
to
of
petroleum
cracking
break
the
down.
cracking
to
●
in
surfacing
cracking
its
fractions
fuels,
and
be
in
into
rener y.
lubricants
molecules
●
an
uses
petroleum
can
●
main
petroleum
at
break
of
an
are
uses
the
fairly
high
molecules
alkane
produces
saturated
temperatures,
low
pressures
and
a
down.
at
least
hydrocarbons
one
with
alkene.
the
general
formula
C
H
n
●
Alkanes
with
●
Alkanes
burn
●
The
●
in
complete
or
air
more
or
carbon
oxygen
combustion
of
produces
carbon
dioxide
produces
carbon
monoxide
Alkanes
of
●
four
undergo
atoms
with
a
clear
alkanes
and
water
and
substitution
display
is
as
blue
an
str uctural
ame.
exothermic
steam.
2n2
isomerism.
The
reaction
incomplete
and
combustion
steam.
reactions
with
halogens
in
the
presence
light.
Substitution
replaced
●
Alkanes
●
Biogas
by
are
is
a
reactions
one
used
mainly
renewable
are
take
halogen
●
Alkenes
●
Alkenes
have
the
●
Alkenes
with
four
●
Alkenes
burn
●
The
place
atom
as
fuels
source
unsaturated
in
at
of
a
stages,
one
hydrogen
atom
being
time.
and
organic
solvents.
methane.
hydrocarbons
with
the
general
formula
C
H
n
complete
produces
●
Alkenes
the
●
addition
an
●
The
a
t
atoms
with
a
alkenes
water
is
as
with
one
a
an
in
functional
str uctural
2n
group.
isomerism.
ame.
exothermic
which
in
is
nickel
their
reaction
and
steam.
bond
hydrogen
requires
as
display
smoky
reactions
process
bond
the
other
double
known
catalyst,
as
a
atoms
bond
are
added
hydrogenation
pressure
to
breaks.
of
5 atm
and
and
a
150 °C.
reaction
with
the
halogens
is
known
as
halogenation
and
it
haloalkane.
●
The addition reaction with the hydrogen halides also forms a haloalkane.
●
The
addition
hydration
catalyst,
●
Alkenes
a
●
Alkenes
Alkenes
a
wide
it
from
are
addition
to
of
the
t
and
of
a
as
star ting
of
a
steam
temperature
solution
of
known
for
their
as
acid
in
sand
300 °C.
red-brown
whereas
to
alkanes
do
manganate (VII)
alkanes
materials
because
of
from
potassium
whereas
is
phosphoric
conditions,
acidied
chemicals
form
requires
bromine
colourless,
mainly
reactions.
in
laborator y
colour
other
water
alcohol.
60–70 atm
colour
pur ple
of
an
standard
the
used
range
of
the
under
with
forms
pressure
change
solution
●
reaction
and
change
colourless
252
of
and
addition
the
reaction
of
addition
forms
n
double
carbon
oxygen
dioxide
alkane.
temperature
more
or
combustion
undergo
forms
or
air
carbon
molecule.
The
it
in
carbon–carbon
do
the
not.
manufacture
ability
to
of
undergo
not.
Hydrocarbons
–
alkanes
and
alkenes
Practice
7
Practice
exam-style
The
process

Natural


sources
of
hydrocarbons
include:
petroleum
natural
gas

coal
A

and

B

and

C

only
2
4

and
Which
of
t he
following
could
not
be
obtained
by
hexane?
met hane
B
propene
and
and
C
butane
D
met hane,
and
t he
pentene
hydration

addition
A

and

B

and

C

D
,
and

Which
only
only

and
only

of
t he
following
from
could
best
be
used
to
distinguish
propene?
are
As
a
main
B
To
manufacture
C
As
a
roong
D
As
a
lubricant
and
different
Burn
B
React
bot h
bot h
in
wit h
air.
bromine
C
React
bot h
wit h
hydrogen
D
React
bot h
wit h
acidied
vapour.
gas.
potassium
manganate(VII)
solution.
et hane
propene
A
fuel
A
propane
What
separated
and
uses
for
as
fractions
and
a
to
which
and
surface
roong
fully
displayed
as
a
up
A
str uctural
and
B
are
formulae
given
of
fuel.
H
H
H
H
H
C
C
C
C
C
H
H
H
H
H
H
H
H
cr ude
oil
are
H
H
C
C
C
C
C
H
H
H
H
H
H
t heir
different
melting
B
t heir
different
boiling
C
t heir
different
densities
D
t heir
different
solubilities
B
points
points
a
To
which
homologous
reacts
wit h
in
water
b
bromine
vapour
which
of
is/are
does
EACH
compound
Draw
(2
THREE
str uctures
to
represent
isomers
A.
marks)
of
(3
marks)
t he
c
following
series
belong?
compound
et hane
H
on:
A
When
two
below:
roads.
material.
make
The
question
hydrocarbons,
roads.
petrochemicals
and
9
bitumen?
surfacing
material
based
of
Structured
et hene
A
5
be

A
The
can
only
cracking
3
et hane
hydrogenation
propane
,
to
only
8
D
et hene
as:
questions

1
conver ting
questions
questions
described
Multiple-choice
of
exam-style
A
and
B
bot h
react
wit h
chlorine
but
under
different
tr ue?
conditions.

a
substitution
reaction
occurs
i)

t he
bromine
is
rapidly
Give
ONE
condition
necessar y
for B
to
react
chlorine.

only
A

one
product
is
(1
Draw
t he
fully
displayed
str ucture
of
t he
only
compound
B

and

C

and

formed
when A
reacts
wit h
chlorine.
only
(1

and

Draw
t he
following
are
all
str uctural
isomers
of
pentene
H
H
displayed
H
H
H
H
H
produced
reaction
except:
d
H
fully
str ucture
of
t he
organic
only
product
The
mark)
only
iii)
6
mark)
produced
ii)
D
wit h
decolourised
H
Describe
a
chemical
distinguish
during
between B
and
test
between A
t hat
and
t he
rst
step
of
chlorine.
could
be
t he
(1
used
B.
marks)
to
(1
marks)
H
e
C
C
C
C
C
C
C
C
Give
t he
reagent
and
t he
reaction
conditions
H
necessar y
to
conver t A
to
B.
(2
marks)
H
f
H
H
H
H
H
Bot h
and
B
ii)
H
H
H
H
H
C
C
Write
t he
f
equal
which
H
C
C
H
H
or
oxygen.
balanced
chemical
combustion
equation
volumes
would
of A
you
of B.
for
or
B
expect
(2
t he
are
to
burnt
produce
marks)
separately,
Give
a
reason
for
your
choice.
t he
more
(2
marks)
C
H
Total
15
marks
H
H
H
air
H
soot?
C
in
B
complete
H
burn
H
i)
A
A
C
H
C
H
H
C
H
H
D
253
Practice
exam-style
Extended
10
a
One
man
i)
response
of
t he
is
main
is
Name
a
T WO
main
sources
of
hydrocarbons
used
by
i)
dentify
uses
fractions
of
of
few
t he
demands
supplies
alkanes
t he
of
are
represent
(1
obtained
of
from
petroleum
smaller
of
world.
smaller
cracked.
one
petroleum
alkanes
and
to
an
way
increase
equation
of
ii)
marks)
cracking
iii)
t he
can
be
and
reaction
used
to
conver t:
–
compound
A
to
compound
B
–
compound
A
to
compound
D.
Describe
what
would
formation
of
Under
right
wit h
larger
to
t he
be
obser ved
compound C
from
(4
during
compound A
conditions,
compound D
Name
–
Write
rst
t he
a
type
of
chemical
step
in
t he
reaction
equation
reaction.
taking
to
answer
study
t he
t he
reaction
questions
which
scheme
below
(3
follow.
(g)
2
CH
3
CH
2
OH
2
CH
CH

CH
2
B
A
CH
CH
3
CHBrCHBr
3
C
CH
2
D
254
CH
3
3
t he
marks)
marks)
and
Br
CH
mark)
reacts
place.
represent
Total
Carefully
marks)
t he
chlorine.
–
hexane.
(2
b
alkenes
(1
meet
hydrocarbons,
Write
possible
To
t he
reagents
which
produces
hydrocarbons
today ’s
t hese
give
(4
of
mark)
t he
and
each.
distillation
too
suitable
conditions
distillation
Fractional
–
question
hydrocarbon?
fractional
iii)
Hydrocarbons
petroleum.
What
ii)
questions
15
marks
Alcohols,
alkanoic
acids
B15
and
Alcohols,
alkanoic
acids
and
esters
esters
are
organic
Objectives
compounds
contain
that
oxygen,
because
of
the
all
contain
their
way
oxygen.
properties
the
oxygen
Although
and
they
reactions
atoms
are
all
differ
bonded
By
the
be
able
of
molecules.
Because
of
their
varied
properties
have
members
widespread
of
these
uses
in
three
industry
homologous
and
our
daily
you
will
of
the
by
the
hydroxyl
and
group,
reactions,
topic
alcohols
presence
the
this
to:
identify
●
in
end
series
give
●
–OH
the
names
formulae
lives.
alcohols
of
and
structural
unbranched
with
up
to
six
carbon
atoms
B15.1
Alcohols:
C
H
n
OH
relate
●
the
solubility
Alcohols
have
are
t he
also
known
hydroxyl
as
group,
alkanols.
–OH,
as
They
t heir
are
organic
functional
compounds
which
general
formula
of
alcohols
which
group.
contain
one
of
presence
and
alcohols
of
the
to
polar
the
–OH
group
describe
●
The
volatility
2n  1
hydroxyl
group
the
reactions
of
is
ethanol
C
H
n
OH.
This
can
also
be
written
R–OH,
where
R
represents
C
2n  1
H
n
,
2n  1
explain
●
i.e.
an
alkyl
Alcohols
are
named
by
using
t he
prex
which
indicates
t he
total
number
t he
atoms
in
t he
molecule
plus
t he
ending
‘ -anol’.
The
rst
two
series
given
in
do
not
show
str uctural
isomerism.
Figure
describe
fermentation
Their
names
and
the
by
H
describe
H
three
isomers
15.1.1
(CH
OH
)
et hanol
(C
or
more
H
2
Structural
formulae
carbon
of
the
of
alcohols
result
atoms
from
t he
t he
change
in
position
of
t he
functional
OH
●
of
branching
t he
of
hydroxyl
t he
group,
show
alcohols
tip
must
not
confuse
group,
i.e.
t he
change
in
alcohols
with
is
present
in
molecule.
H
H
H
number
and
indicate
t he
position
t he
chain
of
group
from
t he
is
at
t he
hydroxyl
t he
end
closest
follow
steps
1)
to
4)
on
page
233
for
naming
group
branched
in
t he
chain
t he
r ules
above,
t he
str uctures
and
names
of
H
propan-1-ol
name
of
propanol
(C
H
3
given
in
Figures
OH)
and
butanol
7
15.1.2
(C
H
4
and
Figure
15.1.2
(C
H
H
H

H  C  C  C  H
H
OH

H


H



H

H  C  C  C  O  H
H
H
H

butan-1-ol
(or
1-butanol)
butan-2-ol
(or
2-butanol)
of
H  C  H
H


OH

H


H
H

H  C  C  C  C  H
isomers
H

H


H

H

H



H
H





H  C  C  C  C  O  H
H
structural
OH)
7

H

H
The
H
OH)

H
2-propanol)
9
15.1.3.
H  C  H
H
(or
t he
3
are
H
propan-2-ol
1-propanol)
propanol
isomers
OH
isomers.

Using
H
lowest
(or
●
H

longest
t hat

t he
so

in
group

atoms
functional
H
H  C  C  C  H

carbon

t he
–OH
H

alcohols:

of

isomers

t he
ion
hydroxides.
–OH
H
to
–OH
OH
in

number
the
the
following:
H  C  C  C  O  H
●
and
isomerism.

naming
making
manufacture.
Exam
✔
str uctural
H
When
processes
wine
)
two
that
position
the
in
5
rst
group
●
is
carbohydrates
H
You
Str uctural
from



H
3
Figure
rum
H  C  C  O  H
H
met hanol
involved



H  C  O  H
wit h
ethanol
formulae
●

which
15.1.1.
H
Alcohols
the
alcohols
produced
are
of
test
process
in
principles
breathalyser
of
●
carbon
the
group.
2-met hylpropan-1-ol
(or
2-met hyl-1-propanol)
2-met hylpropan-2-ol
(or
2-met hyl-2-propanol)
Figure
15.1.3
structural
of
The
isomers
butanol
(C
H
4
OH)
9
255
Alcohols:
C
H
n
OH
Alcohols,
alkanoic
acids
and
esters
2n  1
H
H
H
H
The
H
C
C
C
C
H
H
H
H
straight
given
in
H
H
chain
isomers
of
pentanol
(C
H
5
are
Figures
H
H
15.1.4
and
H
H
H
H
C
C
C
C
H
H
H
H
OH)
and
hexanol
(C
1
1
H
6
OH)
13
15.1.5.
H
H
H
H
H
H
C
C
C
C
C
H
H
H
pentan-1-ol
(or
1-pentanol)
H
H
H
H
H
H
H
H
hexan-1-ol
(or
C
C
H
C
H
H
C
hexan-2-ol
1-hexanol)
(or
OH
2-hexanol)
H
H
H
OH
H
H
H
H
H
H
C
C
C
C
C
H
OH
H
H
pentan-2-ol
(or
H
H
2-pentanol)
H
H
H
H
C
C
C
C
H
H
H
H
H
hexan-3-ol
(or
3-hexanol)
H

Figure
15.1.5
The
straight
chain
isomers
of
hexanol
(C
H
6
H
H
OH
OH)
13
pentan-3-ol
General
(or

Figure
15.1.4
isomers
of
The
straight
pentanol
(C
H
5
chain
OH)
Alcohol
Recall
molecules
t hat
is
Exam
tip
important
that
bot h
you
a
are
polar
molecule
negative
It
of
alcohols
polar
molecule
due
to
is
covalent
a
t he
presence
of
t he
molecule
in
polar
–OH
which
one
group.
par t
of
11
t he
✔
properties
3-pentanol)
can
has
charge.
related
to
a
slightly
The
t he
positive
volatility
polar
of
nature
charge
alcohols
of
t heir
and
and
anot her
t heir
par t
has
solubility
a
in
slightly
water
are
molecules.
name
Volatility
the
unbranched
alcohol
atoms.
you
isomers
containing
It
can
is
also
draw
structural
up
to
of
six
important
the
fully
formulae
of
any
carbon
that
displayed
unbranched
Alcohols
number
higher
point
are
of
less
t han
of
volatile
carbon
t hat
et hanol
up
to
of
six
any
alcohol
carbon
containing
atoms.
It
is
89 °C.
This
that
you
can
name
corresponding
t he
H
isomers
of
OH)
is
boiling
78 °C
and
point
of
an
alkane.
t he
alkanes
alcohol
For
boiling
wit h
is
example,
point
of
t he
always
t he
et hane
same
much
boiling
(C
5
H
2
because
t he
polar
–OH
groups
cause
t he
forces
of
)
is
6
attraction
t he
alcohol
molecules
to
be
stronger
t han
between
t he
non-polar
the
alkane
branched
corresponding
of
(C
t he
not
between
essential
is
t heir
i.e.
2
isomers
t han
atoms,
molecules.
As
a
result,
all
alcohols
are
eit her
liquids
or
solids
at
room
alcohols.
temperature.
The
boiling
molecules
molecules
Solubility
The
point
of
alcohols
increases.
increase
in
general
This
as
t he
is
increases
because
size
of
t he
as
t he
t he
number
of
carbon
intermolecular
molecules
forces
atoms
water.
water
r ule
The
completely
of
carbon
on
(–OH)
atoms
of
solubility
states
t hat
polar
solutes
dissolve
in
of
as
alcohols,
in
t he
a
variety
n
of
as
met hanol,
t he
et hanol
solubility
and
decreases
propanol,
as
t he
are
number
increases.
reactions
t his
however,
contain
t he
such
however,
molecules
group.
et hanol,
all
water,
polar
soluble
ethanol
undergo
t hey
decreases
256
in
functional
reactions
since
small
soluble
Reactions
Alcohols
t he
t he
increases.
solvents. Water is a polar solvent, t herefore alcohols, being polar, are
in
in
between
number
t he
of
section
t he
ot her
hydroxyl
carbon
due
we
to
will
be
alcohols
group.
atoms
t he
in
The
t he
presence
looking
undergo
strengt h
alcohol
of
t he
hydroxyl
specically
similar
of
t he
molecules
at
t he
reactions
reactions
increases.
Alcohols,
alkanoic
acids
and
esters
Alcohols:
C
n
Combustion
of
H
OH
2n  1
ethanol
Ethanol burns ver y easily in air or oxygen producing carbon dioxide and water
as steam. The reaction is exothermic, producing a large amount of heat energy.
The
complete combustion
C
H
2
OH(l)

3O
5
in
dioxide
t he
and
Reaction
Et hanol
(g)
2CO
2
Et hanol burns wit h a
atoms
of ethanol is shown in the equation below:
of
clear blue ame
molecule
no
reacts
is
low.
unreacted
ethanol
All
t he
carbon
with
wit h
(g)

3H
2
O(g)
H
ve
2
because t he ratio of carbon to hydrogen
carbon
remains
is
to
t herefore
produce
conver ted
When
effer vescence
of
sodium
between
2C
sodium
piece
occurs
as
et hoxide
et hanol
H
2
a
to
and
OH(l)

of
t he
in
carbon
sodium
produce
sodium
et hoxide
(C
H
2
hydrogen.
to
soot.
sodium
metal
hydrogen
alcohol
sodium
is
is
gas
is
is
evolved
formed.
given
The
into
and
a
ONa)
colourless
equation
for
and
5
et hanol
steady
solution
t he
reaction
below:
2C
2Na(s)
dropped
H
2
5
H
ONa(alc
sol)
H

5
sodium
(g)

2
C
C
H
2
O
et hoxide
.
The
is
fully
an
ionic
displayed
compound
str ucture
of
containing
sodium
t he
et hoxide
et hoxide
is
The
in
15.1.6.
reaction
sodium
and

Figure
15.1.6
structure
between
water.
n
sodium
bot h
and
et hanol
reactions,
Na
t he
is
similar
sodium
to
t he
reaction
d isplaces
H
ion,
represented
5
Figure
O
et hoxide
H
Sodium
H
of
The
fully
sodium
displayed
ethoxide
between
hydrogen
from
t he et hanol or t he water, forming hydrogen gas. However, t he strengt h of t he
reaction
between
Dehydration
When
et hanol
heated
in
one
to
of
two
is
passing
t he
bot h
i.e.
a
t he
t he
wit h
et hanol
oxide
met hods,
atom
of
wit h
170 °C,
et hanol
formation
carbon
of
hydroxyl
hydrogen
t he
mixed
t he
et hanol
aluminium
n
water
is
much
more
vigorous
(see
Unit
17
.2).
concentrated
is
sulfuric
dehydrated
to
acid
et hene.
and
This
t he
can
mixture
be
is
achieved
ways:
temperature
●
and
ethanol
170 °C,
heating
●
of
sodium
a
excess
where
vapour
acts
as
water
a
a
over
acid
acts
heated
as
sulfuric
a
acid
catalyst
aluminium
in
at
t he
oxide,
a
reaction
where
t he
catalyst.
molecule
functional
is
concentrated
t he
is
group
removed
from
carbon–carbon
removed
is
from
removed
t he
ot her
double
each
from
carbon
bond
et hanol
one
carbon
atom.
between
This
t he
molecule,
atom
and
results
two
in
adjacent
atoms.
The
equation
acid
is
given
for
t he
dehydration
of
et hanol
using
concentrated
sulfuric
below:
H
H
conc.
H
H
H
H
H
SO
2
4

C
170
H
H
O
°C
H
H
et hanol
et hene
water
or
conc.
H
SO
2
C
4
H
2
H
5
2
170
4
(g)

H
O(g)
2
°C
257
Alcohols:
C
H
n
OH
Alcohols,
alkanoic
acids
and
esters
2n  1
Oxidation
When
of
et hanol
potassium
solution,
can
ethanol
be
is
heated
t he
et hanol
represented
C
H
2
wit h
manganate(VII)
OH(l)
is
by
powerful
oxid ised
t he
to
following
2[O]

5
a
solution
or
oxidising
acidied
et hanoic
such
acid.
The
as
acidied
dichromate(VI)
oxidation
of
et hanol
equation:
CH
COOH(aq)
3
et hanol
agent,
potassium
from
et hanoic
H

O(l)
2
acid
oxidising
agent
n t he above reaction, et hanol is behaving as a reducing agent. f t he reaction
occurs
wit h
changes
acidied
from
pur ple
potassium
to
manganate(VII)
colourless
because
t he
solution,
et hanol
t he
reduces
solution
t he
purple
2
manganate(VII)
ion
(MnO
)
to
t he
colourless
manganese(II)
ion
(Mn
).
f
4
t he
reaction
solution
occurs
changes
wit h
from
acidied
orange
potassium
to
green
dichromate(VI)
because
t he
solution,
et hanol
reduces
2
orange
dichromate(VI)
(Cr
Reaction
Et hanol
of
reacts
discussing
T
o
investigate
Your
●
teacher
may
observation,
Y
ou
will
be
the
oxidation
use
this
recording
supplied
with
of
activity
and
ethanol
wit h
t his
in
with
)
to
t he
green
chromium(III)
ion
(Cr
).
7
alkanoic
alkanoic
greater
t he
3
O
2
t he
acids
detail
in
acids
to
form
Unit
an
ester
and
water.
We
will
be
15.3.
ethanol
to
assess:
reporting.
ethanol,
acidied
potassium
dichromate( VI)
solution
and
a
test
tube.
Method
3
1
Place
2
Add
3
Observe
about
an
2 cm
equal
the
of
ethanol
volume
colour
of
of
into
acidied
the
the
test
tube.
potassium
solution
dichromate( VI)
periodically
The
The
for
about
solution
15
of
breat h.
dichromate(VI)
acidied
The
to
mix.
test
potassium
colour change is used in t he
driver’s
shake
minutes.
breathalyser
reduction
and
driver
cr ystals.
blows
f
dichromate(VI)
and
t he
accompanying
breathalyser test to test t he alcohol content of a
t he
over
a
sample
driver’s
breat h
of
orange
contains
acidied
et hanol
potassium
vapour,
t he
2
et hanol
will
reduce
t he
orange
dichromate(VI)
ion
(Cr
O
2
)
to
t he
green
7
3
chromium(III)
ion
Production
(Cr
of
).
As
a
ethanol
result,
by
t he
cr ystals
turn
green
fermentation
Fermentation is t he chemical reaction in which carbohydrates are conver ted
into
et hanol
oxygen.
down
yeast
Yeast
any
t hen
simple
258
is
yeast
a
anaerobic
fungus
carbohydrates
produces
into
under
unicellular
complex
sugars
anaerobic
by
anot her
et hanol
respiration ,
into
enzyme
and
releases
conditions,
which
carbon
energy
i.e.
produces
simple
called
sugars,
which
This
t he
t he
mainly
zymase
dioxide.
in
enzymes
which
process,
yeast
cells
absence
t hat
glucose.
conver ts
also
use.
of
break
The
t he
known
as
Alcohols,
alkanoic
acids
and
esters
Alcohols:
C
H
n
The
equation
for
t he
fermentation
zymase
C
H
6
O
12
in
of
t he
about
given
below:
✔
(aq)
2C
6
H
2
OH(aq)
2CO

5
(g)
H
2
Exam
it
begins
to
of
et hanol
destroy
t he
in
t he
fermentation
zymase
enzyme
and
mixture
t he
reaches
fermentation
It
is
a
line
very
used
important
diagram
to
carry
distillation
reaction
stops.
fractional
et hanol
is
tip
ve
et hanol
concentration
14%,
is
yeast
glucose
When
glucose
OH
2n  1
The
et hanol
d istillation
collected
at
can
(Unit
78 °C
t hen
2.4).
and
is
be
separated
During
about
t he
96%
from
t he
distillation
mixture
process,
to
that
show
you
the
can
out
fractional
the
laboratory
.
in
draw
apparatus
by
t he
pure.
conical
cork
flask
T
o
prepare
a
sample
of
ethanol
glucose,
(T
eacher
Your
demonstration)
teacher
may
observation,
●
use
this
recording
activity
and
to
water
lime
and
water
yeast
assess:
reporting.

Figure
15.1.7
Production
of
ethanol
by
fermentation
Y
our
teacher
will
perform
the
following
experiment.
Method
thermometer
3
1
Place
and
2
10 g
mix
Make
a
of
to
glucose
make
paste
a
into
a
glucose
with
1g
of
3
250 cm
conical
ask.
Add
100 cm
of
water
solution.
dried
yeast
and
a
small
quantity
of
water.
Add
water
the
paste
to
the
glucose
out
solution.
condenser
3
Place
a
cork
on
the
ask
with
a
delivery
tube
leading
to
a
beaker
fractionating
containing
lime
water.
Ensure
that
all
the
connections
are
properly
column,
sealed.
The
bacteria
lime
which
water
can
acts
cause
as
the
an
airlock
formation
to
of
prevent
ethanoic
the
entry
acid
of
aerobic
(vinegar).
packed
with
The
water
glass
in
beads
lime
the
water
also
formation
shows
of
a
when
white
the
production
of
carbon
dioxide
starts
by
precipitate.
distillate
4
Leave
5
Pour
the
the
reaction
mixture
until
into
a
fermentation
distillation
has
ask
stopped.
and
fractionally
distill
it,
point
of
fermentation
collecting
the
fraction
which
distils
at
78 °C,
the
boiling
ethanol.
mixture
containing
ethanol
heat
Fermentation
such
as
wine
produced
r um
is
used
and
during
making
in
in
r um.
t he
more
t he
t
is
also
process
detail
production
used
makes
in
t he
in
t he
next
of
different
baking
dough
alcoholic
where
rise.
We
t he
will
beverages
carbon
look
at
dioxide
wine
and
sections.

Figure
15.1.8
fractional
Separation
of
ethanol
by
distillation
Winemaking
Wine
to
is
form
wine
made
a
t he
primarily
mixture
skins
of
are
from
pulp,
grapes
skins
removed.
in
and
The
a
winer y.
juice
vintner
The
known
grapes
as
are
‘must’.
(winemaker)
To
t hen
rst
cr ushed
make
adds
white
yeast
?
Did
must
in
fermentation
tanks
and
t he
yeast
ferments
t he
sugars
or
et hanol
and
carbon
dioxide.
When
fermentation
is
complete
are
removed
and
t he
wine
is
ltered
to
clarify
it.
The
wine
is
t hen
red
storage
wines
is
tanks
or
between
oak
10%
barrels
and
before
bottling.
The
et hanol
content
of
most
are
14%.
colour.
from
vary
Great
care
must
be
taken
t hroughout
t he
winemaking
process
to
and
are
the
used
to
grape
present
throughout
aged
fermentation
in
grapes
wine
any
skins
skins
black
present
make
forming
know?
to
Red
t he
you
White
‘white’
in
to
give
wine
grapes,
colour
from
the
is
wine
made
which
green
its
mainly
actually
to
pale
minimise
yellow.
t he
exposure
of
t he
wine
to
air.
This
is
because
cer tain
aerobic
bacteria
may
259
Alkanoic
acids:
C
H
n
COOH
Alcohols,
alkanoic
acids
and
esters
2n  1
be
present
in
t he
air,
in
t he
t hese
wine
from
bacteria
t he
original
oxid ise
t he
aerobic
C
H
2
OH(aq)

O
5
grapes
et hanol
to
and,
et hanoic
Rum
Rum
t hen
acid,
CH
COOH(aq)
t he
wine
to
become
H

3
causes
or
to
oxygen
vinegar:
O(l)
2
acid
sour
and
undrinkable.
manufacture
is
which
acid
exposure
bacteria
(g)
2
et hanoic
The
on
et hanoic
made
is
from
produced
t he
black
during
t he
treacle-like
extraction
substance
of
sugar
from
known
sugar
as
molasses,
cane
(Unit
2.5).
The molasses is rst diluted wit h water and yeast is added. The yeast ferments
t he
sugar
in
t he
molasses
forming
et hanol
produced is t hen sent to t he still where it is
a
distillate
wit h
an
et hanol
content
of
and
carbon
dioxide.
The
fractionally d istilled
between
70%
and
mixture
to produce
95%.
The distillate is then diluted and transferred to oak barrels to be aged. This process
can
take
20
years
or
more.
The
oak
barrels
are
charred
on
the
inside
to
impart
a
variety of avours to the rum, give it a smoother taste and add colour. More water
is then added to reduce the ethanol content to about 40% and a master blender

Figure
of
the
15.1.9
oak
A
master
Summary
2
Explain
3
Ethanol
burns
4
Ethanol
can
the
names
how
a
Give
b
Draw
be
a
is
front
and
the
fully
for
blending
various
rums
of
different
oxygen
the
group
with
a
structural
of
blue
fully
required
displayed
chemical
for
the
formulae
alcohols
ame.
the
structural
equation
and/or
from
different
Give
of
affects
a
three
their
balanced
straight
solubility
equation
chain
and
for
isomers
boiling
the
of
pentanol.
points.
reaction.
for
reaction.
formulae
the
of
the
products
fermentation
of
formed
glucose
and
in
the
give
reaction.
two
ways
in
which
the
reaction
may
used.
B15.2
Objectives
Alkanoic
acids:
C
H
n
By
the
be
able
end
of
this
topic
you
acids
are
also
known
as
carboxylic
acids .
They
are
organic
to:
compounds
identify
the
COOH
2n  1
will
Alkanoic
●
ages
dehydrated.
conditions
balance
displayed
functional
in
be
the
responsible
questions
Give
Give
in
barrels to produce the unique brands of the different rum manufacturers.
1
5
blender
barrels
alkanoic
presence
of
acids
the
group.
by
The
which
have
carboxyl
t he
group
carboxyl
can
also
be
group,
–COOH,
represented
as
t heir
functional
as:
O
carboxyl

 C
–COOH

group,
O  H
●
give
the
names
formulae
alkanoic
of
and
structural
unbranched
acids
with
up
to
The
six
is
general
C
H
n
carbon
atoms
C
H
n
●
relate
the
volatility
of
alkanoic
presence
of
,
i.e.
acids
part
of
the
the
polar
functional
the
which
written
contain
one
R–COOH,
carboxyl
where
R
group
represents
an
alkyl
group.
acids
of
are
carbon
named
atoms
by
in
using
t he
t he
prex
molecule
plus
which
t he
indicates
sufx
‘-anoic
t he
total
acid’.
to
remember
t hat
t he
functional
group
contains
one
t
is
carbon
which
must
be
taken
into
account
when
naming
alkanoic
acids,
i.e.
of
prex
is
not
derived
directly
from
‘ n’
in
t he
general
formula,
it
is
derived
acid.
by
adding
formula
1
to
CH
t he
value
COOH
3
260
be
group
reactions
t he
ethanoic
acids
also
–OH
atom
describe
can
to
impor tant
●
alkanoic
2n  1
number
the
of
This
and
Alkanoic
solubility
formula
COOH.
2n  1
is
of
‘ n’.
et hanoic
For
example,
acid
and
not
t he
name
met hanoic
of
t he
acid.
acid
wit h
t he
Alcohols,
alkanoic
acids
and
esters
Alkanoic
acids:
C
H
n
COOH
2n  1
The names and formulae of t he straight chain isomers of t he rst six alkanoic
acids
are
shown
in
Figure
15.2.1.
H


H
H
H
Organic
acid
et hanoic
H
(HCOOH)
(CH
propanoic
acid
(C
COOH)
H
2
3
acid
butanoic
COOH)
(C
5
H
H
H
H
3
H
be
natural
bee


H
acid,
O  H
H
4
COOH)
(C
9
H
5
Figure
15.2.1
Structural
formulae
of
the
rst
six
in
of
alkanoic
Alkanoic acid molecules are
the
venom
while
vinegar
found
its
in
of
ant
ethanoic
sour
citrus
carboxyl
found
is
and
acid
taste.
fruits,
Citric
has
in
groups
and
tamarinds,
tartaric
has
COOH)
1
1
alkanoic
acids
functional
acetylsalicylic
reduce
Properties
the
acid
H
two

Methanoic
acid
acid,
(C
throughout

H
hexanoic
found
world.
stings
gives
three
acid
or
O

H
H


H
pentanoic
one
groups
7
H


O  H


H
H
H  C  C  C  C  C  C





H
H
H


H  C  C  C  C  C
H





O
containing
functional
acid
COOH)
found
H
acids
carboxyl
H
can
met hanoic
know?
O  H
more
H
you



O  H
Did
O
H  C  C  C  C




 C
?
H



O  H
H

O
H  C  C

 C


H  C
O  H



H  C
O
H
H

H
O
acids
pains,
fever
has
groups.
acid,
and
one
Aspirin,
which
relieve
carboxyl
is
or
used
aches
to
and
group.
polar due to the presence of the polar –OH part of
the carboxyl functional group. Like alcohols, the volatility of alkanoic acids and
their solubility in water are both related to the polar nature of their molecules.
Volatility
Alkanoic
same
acids
number
always
much
boiling
are
of
less
higher
point
of
volatile
carbon
than
atoms,
than
ethanoic
that
i.e.
of
acid
the
(CH
their
the
corresponding
boiling
point
corresponding
COOH)
is
1
12 °C
of
alkanes
an
alkane.
and
with
alkanoic
For
the
example,
boiling
the
acid
is
the
point
of
3
ethane
(C
H
2
)
is
89 °C.
This
is
because
the
forces
of
attraction
between
the
6
polar alkanoic acid molecules are stronger than between the non-polar alkane
molecules. All alkanoic acids are either liquids or solids at room temperature.
The
in
boiling
t he
molecules
Solubility
Alkanoic
such
point
molecules
as
soluble
of
increase
in
as
t he
acids
increases
because
size
of
t he
t he
as
t he
number
intermolecular
molecules
of
carbon
forces
atoms
between
t he
increases.
water
acids,
being
met hanoic
in
alkanoic
increases
water,
atoms
in
t he
When
alkanoic
polar,
acid,
however,
molecules
acids
are
soluble
et hanoic
t he
acid
in
water.
and
solubility
The
propanoic
decreases
as
small
acid
t he
alkanoic
are
acids
completely
number
of
carbon
increases.
dissolve
in
water,
they
also
ionise
to
a
very
small
degree

to
form
hydrogen
ethanoic
acid
(H
)
dissolves
ions,
in
hence
water
they
about
are
1%
weak
of
the
acids.
For
ethanoic
example,
acid
when
molecules
ionised at any one time, i.e. the solution contains 1% ethanoate ions (CH
are
COO
)
3

and hydrogen ions (H
) and 99% ethanoic acid molecules (CH
COOH).
3
The
ionisation
of
et hanoic
acid
is
shown
in
t he
following
equation:

CH
COOH(aq)
CH
3
COO
Reactions
Aqueous
acids
of
aqueous
solutions
such
oxides,
(aq)

H
(aq)
3
et hanoate
as
metal
of
alkanoic
hydrochloric
hydroxides
ethanoic
acids
acid
and
ion
react
when
metal
acid
in
they
a
ver y
react
carbonates.
similar
with
The
way
reactive
reactions
to
inorganic
metals,
are
metal
slower
than
they would be with inorganic acids because the alkanoic acids are weak acids.
261
Alkanoic
acids:
C
H
n
COOH
Alcohols,
alkanoic
acids
and
esters
2n  1
n
t his
acid.
all
section
However,
contain
number
Salts
of
t he
Reactive
Using
by
with

group.
et hanoic
react
2CH
looking
alkanoic
atoms
reaction
Mg(s)
be
reactive
metals
t he
will
ot her
carboxyl
carbon
formed
Reaction
we
t he
in
The
t he
acid
specically
acids
strengt h
molecules
are
at
undergo
known
of
t he
reactions
similar
t he
of
reactions
reactions
et hanoic
since
decreases
t hey
as
t he
increases.
as
ethanoates
metals
wit h
et hanoic
between
acid
magnesium
to
produce
and
(CH
COOH(aq)
COO)
3
3
a
salt
et hanoic
and
acid
as
Mg(aq)
gas.
example:
H

2
magnesium
hydrogen
an
(g)
2
et hanoate

t is important to note that since the magnesium has displaced the H
ion from

the
–COOH
functional
group,
it
is
written
in
the
place
of
this
H
ion
in
the
formula of the salt. However, in the name of the salt, the metal still comes rst.
Reaction
Metal
with
oxides
reactions
oxide
react
are
and
metal
wit h
et hanoic
neutralisation
et hanoic
ZnO(s)
oxides

acid
2CH
as
an
acid
to
reactions .
produce
Using
a
t he
salt
and
reaction
water.
These
between
zinc
example:
(CH
COOH(aq)
COO)
3
3
zinc
H
Zn(aq)

2
H
O(l)
2
et hanoate
O
Reaction
C
with
metal
hydroxides

O
Metal
Na
hydroxides
react
wit h
et hanoic
acid
to
produce
a
salt
and
water.
These
H
are

Figure
15.2.2
The
fully
also
neutralisation
of
sodium
Using
t he
and
et hanoic
 CH
acid
as
an
CH
COONa(aq)
fully
Figure
name
following
a
C
H
3
of
each
of
C
an
H
compounds:
Reaction
with
metal
and
carbonates
why
acid.
methanoic
As
part
of
acid
your
as
water.
an
Using
sodium
et hanoate
is
represented
in
carbonates
write
chemical
shows
in
is
a
et hanoic
acid
acid
water.
CaCO
to
produce
calcium
(s)  2CH
(CH
COOH(aq)
a
salt,
carbonate
COO)
3
3
Ca(aq)
carbon
and

2
calcium
dioxide
et hanoic
acid
CO
(g)

H
2
O(l)
2
et hanoate
Esterification
Alkanoic acids react with alcohols to produce an ester and water. The reaction
acid
less
is
known
acid
than
between
which
methanoic
ethanoic
volatile
wit h
reaction
balanced
equation
how
ionises
react
t he
example:
3
Why
of
COOH
11
answer
3
str ucture
COOH
Explain
is
displayed
15.2.2.
7
5
2
O(l)
2
the
Metal
b
H
et hanoate
questions
The
the

3
sodium
Give
sodium
example:
COOH(aq)
3
1
between
ethanoate
NaOH(aq)
Summary
reaction
displayed
hydroxide
structure
reactions .
and
as
esterication
heat
in
order
to
and
take
it
requires
place.
Since
a
catalyst
two
of
concentrated
molecules
are
reacting
sulfuric
together
ethane?
with the loss of a water molecule from between them, the reaction may also be
4
Give
a
balanced
chemical
referred to as a condensation reaction. The alkanoic acid and alcohol must be
equation
for
the
reaction
between
ethanoic
in the pure liquid form and not in aqueous solution for the reaction to occur.
acid
and:
Using
a
calcium
t he
reaction
between
et hanoic
acid
conc.
H
potassium
COOH(l)
3
Give
the
conditions
the
reaction
acid
example:
C
acid
H
3
OH(l)
CH
7
COOC
3
propanol
propyl
H
3
(l)
7

et hanoate
H
O(l)
2
water
between
and
et hanoate
ethanol.
t he
262
an
heat
Propyl
ethanoic

necessary
et hanoic
for
as
4
carbonate.
CH
5
propanol
SO
2
b
and
oxide
next
unit.
is
an
ester.
We
will
be
looking
at
esters
in
more
detail
in
Alcohols,
alkanoic
B15.3
acids
Esters:
and
esters
Esters:
RCOOR
RCOOR
Objectives
By
the
be
able
end
of
this
topic
you
will
An ester is a compound formed when an alkanoic acid reacts wit h an alcohol.
The
smaller
sweet
bot h
esters
fr uity
are
smells.
animals
and
volatile
Esters
plants,
liquids
are
which
widespread
especially
in
usually
in
have
nature
owers
and
ver y
where
fr uits,
distinctive
t hey
giving
occur
t hem
in
identify
●
of
t heir
are
esters
of
long-chain
alkanoic
acids
and
an
alcohol
called
esters
ester
describe
●
glycerol.
the
by
the
presence
functional
group,
–COO–
distinctive smells and avours. Naturally occurring animal fats and vegetable
oils
to:
how
esters
are
formed
Esters
are
used
extensively
as
ar ticial
perfumes,
food
avourings
and
write
●
essences,
e.g.
ar ticial
avourings
such
as
banana,
strawberr y
and
of
are
esters.
solvents
from
They
for
t he
are
also
making
reaction
of
used
paints
fats
in
t he
and
wit h
manufacture
varnishes.
of
soap
Biod iesel
is
and
an
as
ester
have
group
can
t he
also
ester
be
names
and
formulae
esters
industrial
●
explain
the
hydrolysis
●
explain
the
saponication
of
esters
produced
of
met hanol.
fats
Esters
the
apple
group,
–COO–,
represented
as
t heir
functional
group.
The
ester
and
oils
distinguish
●
soapless
as:
between
soapy
and
detergents.
O
C
O
Did
?
The
general
formula
of
a
simple
ester
is
C
H
n
COOC
2n  1
H
x
where
‘n’
‘x’ may be t he same or different numbers. This can also be written R–COO–R ,
Some
where
in
R
and
R
represent
alkyl
groups
which
may
be
t he
you
same
or
different.
esters
animal
produce
play
of
chemical
same
are
made
by
a
condensation
reaction
known
as
esterication.
an
alkanoic
acid
is
heated
wit h
an
alcohol
in
t he
presence
sulfuric
acid.
The
reaction
is
reversible
and
produces
in
an
natural
of
the
For
example,
these
are
3-methylbutyl
which
of
is
the
the
main
banana
aroma,
water.
reaction
can
be
summarised
by
t he
following
general
word
H
also
the
equation:
a
conc.
the
honeybee.
bee
is
acid

alcohol
ester

●
it
acts
●
it
is
a
as
a
increases
Using
catalyst
powerful
produced
sulfuric
t he
yield
str uctural
speed
is
ester
formulae
t he
attacked
released
by
a
of
when
which
for
two
aggression
in
predator
the
other
to
bees
provokes
them
to
sting.
reasons:
reaction
agent,
reaction
of
added
up
dehydrating
during
t he
to
acid
is
water
heat
concentrated
It
pheromone
4
trigger
alkanoic
alarm
SO
2
The
Some
of
ester
is
The
members
species.
component
and
called
trigger
of
ethanoate,
concentrated
signals
which
role
Animals
During
esters.
esterication,
important
esters
responses
Esters
an
communication.
pheromones
Formation
know?
and
2x  1
t herefore,
which
favours
it
removes
t he
t he
for ward
water
reaction
and
produced.
to
represent
t he
reaction
between
et hanoic
acid
and et hanol to produce et hyl et hanoate, we can see t he str ucture of t he et hyl
et hanoate
H
t hat
is
formed.
O
H
H



+
H  O



H
H
H
et hanol
equation
for
t he
et hyl
reaction
H
is

C
H
2
OH(l)
given
et hanoate
H
water
below:
4
CH
5
H
SO
2
COOH(l)
3
H
H  C  C  O  C  C  H
heat
conc.
CH
O

H
acid
chemical
4
lost
2
et hanoic
SO
2


O
H
H  O  C  C  H

H
H
conc.

+
H




H  C  C  O  H
The
H
COOC
3
H
2
(l)
5

H
O(l)
2
heat
et hanoic
acid
et hanol
et hyl
et hanoate
water
263
Esters:
RCOOR
Alcohols,
Formulae
When
writing
comes
t hat
H
O
H
H
and
t he
from
t he
formed
t he
names
str uctural
alkanoic
of
acids
and
esters
esters
formula
acid
alkanoic
and
of
t he
an
ester,
second
t he
par t
rst
par t
comes
of
t he
from
formula
t he
alcohol
ester.
H





The
name
of
an
ester
is
also
derived
from
t he
alkanoic
acid
and
t he
alcohol.
H  C  C  O  C  C  C  H
Figure
propyl

H
propyl




H
H
However, t he rst par t of t he name is derived from t he alcohol and t he second
H
par t
To
ethanoate
15.3.1
Structural
formula
of
of
t he
Exam
acid
Formula:
tip
The
writing
reaction
an
the
equation
between
alcohol,
formula
of
the
an
always
acid
for
alkanoic
write
first.
In
of
when
ester,
alkanoic
acid.
alcohol
par t
second.
you
you
write
will
the
part
Some
rst
wit h
t he
ending
‘yl’;
acid
par t
second
wit h
of
propyl
et hanoate
is
shown
in
Figure
15.3.1
(T
eacher
more
examples
of
t he
formulae
and
names
of
esters
are
given
a
in
Figure
H
write
COOCH
5
HCOOC
3
H
4
C
9
H
3
COOC
7
H
2
5
of
the
propanate
butyl
methanoate
ethyl
butanoate
sample
of
ethyl
Figure
15.3.2
Other
examples
of
esters
ethanoate
demonstration)
teacher
may
use
this
activity
to
out
assess:
condenser
observation,
Y
our
an
this
water
●
as
first.
prepare
Your
t he
15.3.2.
the
formula
always
par t
the
acid

T
o
rst;
formula
methyl
acid
t he
t his.
2
the
from
‘anoate’.
C
way,
par t
alcohol
str uctural
example
and
derived
ethanoate
ending
When
is
summarise:
Name:
✔
name
teacher
recording
will
perform
and
the
reporting.
following
reflux
water
experiment.
in
the
position
in
Method
3
1
Place
10 cm
3
of
ethanoic
acid
into
a
round-bottomed
ask.
Add
10 cm
of
mixture
of
ethanol
3
ethanol
and
2
Attach
a
3
Gently
boil
4
Pour
the
the
ester
2 cm
of
condenser
the
concentrated
to
mixture
mixture
formed
into
by
a
its
the
for
ask
5
in
sulfuric
the
acid.
reux
and
position
as
shown
in
Figure
of
the
acid
15.3.3.
minutes.
small
beaker
half
characteristic
lled
odour
with
and
cold
oily
water
and
appearance
identify
on
the

Figure
of
surface
ethanoic
15.3.3
ethyl
Preparing
a
sample
ethanoate
water.
The
reaction
proceeds
between
relatively
et hanoic
slowly.
As
acid
t he
and
et hanol
reaction
is
to
produce
heated,
bot h
et hyl
et hanoate
reactants
and
any
ester produced boil forming vapours which must be retained. The condenser
is
placed
et hanol
in
condense
are
dense
264
reux
et hyl
and
returned
resulting
dissolve
t he
and
return
for
in
t he
t han
to
fur t her
mixture
is
it
t he
reaction
Et hyl
oats
i.e.
ver tically,
vapours
ask.
poured
water.
water,
position,
et hanoate
into
n
t his
and
t he
way,
no
an
is
t hat
et hanoic
on
et hanoic
acid
is
unreacted
slightly
layer
t he
condenser
et hanoate
any
only
oily
so
t he
t he
et hyl
water,
et hanoate
forming
enter
and
lost.
acid
soluble
t he
where
of
t hey
et hanol
When
and
and,
surface
acid,
being
t he
t he
alcohol
less
water.
Alcohols,
alkanoic
Hydrolysis
During
a
acids
of
and
hydrolysis
reaction
by
reacting
Esters
be
hydrolysed
can
products
Acid
of
Esters:
RCOOR
esters
molecules
The
esters
wit h
by
hydrolysis
molecules
are
broken
down
into
smaller
water.
heating
depend
wit h
on
a
dilute
whet her
acid
an
or
an
aqueous
or
an
alkali
acid
is
alkali.
used.
hydrolysis
During
dilute
acid
alkanoic
Using
hydrolysis,
hydrochloric
acid
t he
and
acid
or
an
t he
ester
sulfuric
is
acid.
heated
The
wit h
an
products
of
acid
acid
catalyst
such
hydrolysis
are
as
an
alcohol.
hydrolysis
of
et hyl
et hanoate
as
an
example:

H
CH
COO
3
et hyl
Alkaline
During
H
2
(l)

H
5
ions
CH
O(l)
COOH(aq)
3
2
et hanoate
et hanoic

C
H
2
acid
OH(aq)
5
et hanol
hydrolysis
alkaline
hydroxide
hydrolysis ,
solution.
potassium
salt
of
an
The
t he
ester
products
alkanoic
acid
of
is
heated
alkaline
and
an
wit h
sodium
hydrolysis
alcohol.
The
are
or
potassium
t he
reaction
sodium
occurs
in
or
two
stages.
Using
t he
alkaline
hydroxide
Stage
1:
hydrolysis
solution
et hanoic
as
acid
an
of
et hyl
and
et hanol
are
OH
CH
COOC
3
et hyl
Stage
2:
to
CH
(l)
COOH(aq)

overall
is
H
2
is
(l)
it
t hen
in
COOH(aq)
acid

sodium
hydrolysis:
C
H
2
acid
neutralised
NaOH(aq)
OH(aq)
5
et hanol
by
t he
sodium
CH
COONa(aq)
hydroxide
in
t he
following
NaOH(aq)
O(l)
2
et hanoate
equation:
CH
COONa(aq)
3
et hanoate
H

3

wit h
et hanoate:
shown
5
as
3
sodium
COOC
3
et hyl
CH
acid
reaction
reacting
ions
O(l)
acid
sodium
by
rst
et hanoic
3
CH
H
2
et hanoic
form
et hanoic
The

5
formed
et hanoate
t he
solution
H
2
et hanoate
example:
sodium

C
H
2
et hanoate
OH(aq)
5
et hanol
?
Saponification
of
esters
Glycerol
for
S aponi c ation
refers
animal
veget able
to
t he
Did
alkaline
hydrolysis
of
large
esters
found
you
is
the
know?
common
propane-1,2,3-triol
in
1,2,3-propanetriol.
fats
and
oils.
Saponi cation
is
used
in
t he
soap.
Dur ing
t he
manufactur ing
process,
fats
and
oils
The
structural
manufacture
formula
of
name
or
are
boiled
of
glycerol
is
drawn
for
you
wit h
below:
concentrated
sodium
The
salts
ot her
pot assium
of
or
long-c hain
product
of
t he
sodium
hydroxide
alkanoic
reaction
is
acids,
t he
solution
also
alcohol,
known
to
as
glycerol,
produce
fatt y
C
H
3
t he
for mula
shows,
glycerol
is
an
alcohol
wit h
t hree
hydroxyl
t he
(OH)
5
H
acid s .
.
As
3
functional
g roups.
A
simplied
equation
for
t his
reaction
is:
heat
H
fat
or
oil

NaOH
sodium
salt
of
a
long-chain
alkanoic
acid

glycerol
265
Esters:
RCOOR
Alcohols,
alkanoic
acids
and
esters
Example
One
example
of
a
fat
is
glycer yl
octadecanoate
((C
H
17
Glycer yl
acid (C
octadecanoate
H
17
is
an
ester
of
COOH) and glycerol (C
35
by
boiling
octadecanoate
wit h
(C
H
17
octadecanoate
is
one
form
t he
H
3
hydrolysed
sodium
is
fatty
(OH)
5
acid
COO)
35
known
as
C
3
H
3
).
5
octadecanoic
). When glycer yl octadecanoate
3
concentrated
COONa)
and
sodium
glycerol
hydroxide
are
solution,
produced.
Sodium
35
of
soap.
heat
(C
H
17
COO)
35
glycer yl
C
3
H
3
(l)

5
3NaOH(aq)
3C
H
17
octadecanoate
sodium
COONa(aq)

35
C
H
3
octadecanoate
(fat)
(OH)
5
(aq)
3
glycerol
(soap)
When t he soap has been produced, t he mixture is added to saturated sodium
chloride
solution
to
precipitate
out
and
solidify
t he
soap.
O

CH
CH
3

Figure
15.3.5
Model
of
a
CH
2
Figure
T
o

CH
2
CH
2
15.3.4
prepare
CH
2
A
a
CH
2
soap
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
+
Na
 C  O
CH
2
2
molecule
sample
of
soap
soap
(T
eacher
demonstration)
molecule
Your
●
teacher
may
observation,
Y
our
teacher
use
this
recording
will
perform
activity
and
the
to
assess:
reporting.
following
experiment.
Method
3
1
Büchner
Place
3
10 cm
of
cooking
oil
into
a
beaker
and
carefully
add
15 cm
of
funnel
3
ethanol
and
15
cm
mixture
thoroughly.
3
of
5.0 mol dm
sodium
hydroxide
solution.
Stir
the
soap
filter
paper
perforated
plate
2
Continue
about
and
it
much.
to
vacuum
be
the
–
mixture
the
fairly
overheat
T
op
or
thick.
foam
mixture
while
mixture
up
During
and
a
no
the
it
gently
longer
heating,
that
with
heating
must
make
volume
solution
on
a
hot
separate
sure
that
doesn’t
containing
plate
into
the
two
mixture
decrease
equal
for
layers
too
volumes
of
pump
ethanol
3
Büchner
the
minutes
must
doesn’t
cork
stirring
30
When
and
thick,
water
let
if
the
necessary.
mixture
cool
for
a
while,
but
do
not
let
it
cool
flask
completely.
3
4
filtrate
Add
stir

Figure
15.3.6
separate
Suction
soap
from
ltration
the
the
to
mixture
to
precipitate
100 cm
out
the
of
saturated
sodium
chloride
solution
and
soap.
to
reaction
5
mixture
Filter
the
paper
as
mixture
the
using
suction
ltration
and
collect
the
soap
in
the
lter
residue.
3
6
Rinse
the
during
soap
ltration
with
and
two
separate
continue
the
10 cm
suction
portions
ltration
of
to
iced
dry
distilled
the
water
soap.
3
7
Place
a
distilled
266
small
portion
water.
Place
of
a
the
cork
soap
on
in
the
a
test
tube,
tube
shake
and
add
about
thoroughly
and
4 cm
of
observe.
Alcohols,
alkanoic
Soapy
A
detergent
surfaces
wit h
●
and
and
two
One
hating.
●
The
a
t he
say
This
organic
added
t his
is
end
of ten
of
t he
carbon
substances
or
is
‘head’,
referred
as
oils
water-hating
hydrocarbon
to
is
as
ionic
t he
dir t
of
from
long
RCOOR
is
readily
dissolves
grease.
end
We
oil-loving.
and
in
oil-
head
covalent
This
clot hing,
molecules
proper ties.
water-loving
ionic
‘tail’,
and
and
or
atoms.
and
and
remove
composed
str uctures
t he
hydrogen
such
to
are
hydrophilic
molecule,
and
water
different
t he
end
to
molecules
ver y
molecule,
end
of
have
Esters:
detergents
Detergent
t hat
hydrophobic
t he
esters
chemical
which
opposite
composed
in
is
of
We
and
soapless
oors.
ends
end
water.
acids
say
This
and
readily
t hat
end
is
is
dissolves
t his
end
referred
is
to
as
tail
Dirt often consists of oily or greasy substances that do not dissolve in water. This
makes them difcult to remove. Detergents help to remove this dirt by lowering
the surface tension of water, loosening the dirt molecules and dispersing them
in the water, i.e. they help to make the greasy dirt mix with the water.
When
a
detergent
is
added
to
oily
or
greasy
dir t
on
fabrics
or
t he
skin,
t he
hydrophobic (oil-loving) tail of t he detergent molecule dissolves in t he greasy
dir t and t he hydrophilic (water-loving) head sticks out. The head dissolves in
t he
water
This
is
Figure
and
helped
15.3.7
t he
by
dir t
is
lif ted
agitation
shows
how
from
such
greasy
as
t he
fabric
occurs
dir t
can
in
be
a
or
skin
washing
removed
and
is
washed
away.
machine.
from
fabric.
detergent
molecule
greasy
dirt
fabric
The
hydrophobic
molecules
The
in
hydrophilic
the
tails
dissolve
in
of
the
the
heads
detergent
greasy
remain
The
dirt.
off
greasy
the
dirt
is
lifted
The
fabric.
by
dissolved
into
water.
greasy
smaller
with
water.
which
Detergent
t heir
molecules
be
classied
into
soapy
or
soapless
can
is
surrounded
molecules
droplets
This
be
depending
and
that
forms
washed
an
broken
can

mix
emulsion
away.
Figure
How
15.3.7
detergent
remove
greasy
molecules
dirt
on
str ucture.
Soapy
detergents
Soapy
detergents
animal
fats
hydroxide
soap
can
dirt
detergent
or
solution,
molecule
Soapy
is
of ten
as
calcium
do
just
oils
known
wit h
described
shown
detergents
dissolved
are
vegetable
in
not
and
in
Figure
lat her
as
soap.
They
concentrated
t he
previous
are
made
potassium
section.
The
by
or
boiling
sodium
str ucture
of
a
15.3.4.
easily
magnesium
in
salts
hard
such
water.
as
Hard
calcium
water
and
contains
magnesium
hydrogencarbonate (Unit 21.1). The calcium and magnesium ions in t he hard
water displace t he sodium ions in t he soap forming an insoluble precipitate of
calcium
or
magnesium
octadecanoate.
This
precipitate
is
known
as
scum
2
2C
H
17
COONa(aq)
35
soap

Ca

(aq)
(C
H
17
COO)
35
Ca(s)
2

2Na
(aq)

Figure
15.3.8
Scum
forms
when
soap
scum
and
hard
water
react
267
Esters:
RCOOR
Alcohols,
Scum
removes
t he
soap
from
t he
solution
which
alkanoic
prevents
acids
it
and
from
esters
doing
t he
job of removing greasy dir t. t is only when all of t he calcium and magnesium
ions have been precipitated out of t he water as scum t hat any remaining soap
molecules
Soapless
Soapless
called
will
form
lat her
and
do
t heir
job
of
removing
t he
dir t.
detergents
detergents
detergents.
soapless
a
detergent
are
also
They
known
are
molecule
as
formed
is
shown
synt hetic
from
in
detergents
petroleum.
Figure
and
The
of ten
str ucture
just
of
a
15.3.9.
O

+
CH
CH
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
CH
2
 O  S O
CH
2
2
Na

3
O

Figure
Soapless
15.3.9
A
soapless
detergents
detergents.
t herefore,
This
t hey
is
do
detergent
lat her
much
because
not
t heir
form
molecule
more
easily
calcium
and
wit h
hard
water
magnesium
t han
salts
are
soapy
soluble,
scum.
Apar t from t heir different lat hering abilities in hard water, soapy and soapless
detergents

T
able
Soapy
They
they
do
not
are
broken
Soapy
differences
and
soapless
which
lather
a
easily
etc.
grey,
and
in
therefore,
by
they
greasy
not
sewerage
systems
lakes
rivers.
and
or
layer
detergents
in
Instead
They
wastes
around
they
do
do
not
not
contain
their
they
the
are
Some
environment,
foaming
waterways,
build
in
foam
e.g.
phosphates,
are
up
therefore,
in
hard
calcium
Some
can
damage
non-biodegradable
the
environment
and
are
manufactured
resource,
and
oils
T
o
not
and
run
Most
contain
improve
not
form
salts
scum
are
soluble.
the
treatment
for
of
aquatic
the
cause
foam
waterways.
difficult
and
organisms
modern
phosphates
cleaning
environments
them
on
prevents
resulting
soapless
to
This
in
detergents
biodegradable.
their
rapid
These
and
growth
turns
which
ability.
by
of
are
causing
green
added
Phosphates
eutrophication,
algae
waterways
to
pollute
(Unit
green
20.5).
and
eventually
stagnant.
will
be
renewable
supply
of
They
fats
the
effects
of
are
manufactured
resource,
will
may
use
a
this
recording
supplied
water,
pipettes.
a
The
a
i.e.
eventually
soapy
from
petroleum.
run
and
The
a
non-renewable
supplies
of
petroleum
out.
a
soapless
detergent
water
teacher
soft
from
oils.
out.
observation,
Y
ou
of
will
fats
hard
Your
●
i.e.
compare
on
268
do
soapless
They
are
They
magnesium
systems
sewage
dissolving
however,
makes
15.3.10
and
sewerage
Eutrophication
detergents
water.
non-biodegradable.
in
death.
They
pollution.
i.e.
Figure
15.3.1.
detergents
makes
oxygen
aquatic

Table
sinks,
their
cause
in
compared
lather
since
are,
They
summarised
clothes.
i.e.
cause
on
water.
which
discolours
bacteria
do
hard
scum
biodegradable,
down
are
Soapless
unpleasant
forms
showers,
They
15.3.1
ot her
detergents
form
soap,
have
with
sample
of
activity
and
a
soapy
hard
to
assess:
reporting.
detergent,
water,
four
a
soapless
boiling
tubes
detergent,
and
two
a
sample
dropping
Alcohols,
alkanoic
acids
and
esters
Esters:
RCOOR
Method
3
1
Label
the
boiling
tubes
A,
B,
C
and
D.
Place
20 cm
of
soft
water
into
3
each
2
Using
in
3
of
a
tube
Allow
A.
Observe
Place
test
2.
the
6
Record
7
Compare
to
form
a
2
Name
a
the
C
3
3
Give
the
tube
and
on
for
1
of
the
adding
soapy
a
and
a
is
no
note
to
how
C
D.
to
for
the
10
lather
many
water
seconds.
permanent
permanent
permanent
detergent
of
the
and
lather
in
contents
the
number
each
lather,
forms.
drops
of
lather.
and
soapless
of
each
of
drops
tube
of
when
a
detergent
needed
tube.
necessary
for
C
H
2
equation
formation
formation
of
an
ester.
esters:
b
hydrolysis
the
of
butyl
of
COOC
5
H
3
7
for:
ethanoate
ethyl
from
methanoate
ethanoic
using
acid
sodium
and
butanol
hydroxide
solution.
saponication?
a
soapy
effects
hard
detergent
and
a
soapless
detergent
by
referring
to
on:
b
water
the
environment.
concepts
Alcohols
have
t he
general
formula
C
H
n
●
The
●
Alcohols
●
Alcohol
●
Alcohols
t he
●
a
and
detergent
vigorously
there
until
C
table.
formed
following
the
Compare
If
of
questions
balanced
5
form
each
soapy
shake
2
step
mixture
to
3
What
of
minute.
repeating
required
in
permanent
the
Key
drop
into
D.
conditions
4
water
one
COOCH
is
hard
add
stand
appearance
lather
b
a
4
to
and
7
a
were
a
their
●
2
the
the
H
to
results
Summary
Give
cork
Continue
B
your
permanent
pipette,
a
of
20 cm
appearance
steps
detergent
1
and
tube
detergent
Repeat
to
B,
dropping
step
soapy
5
and
the
repeat
4
A
The
functional
wit h
molecules
are
polar
less
nature
smaller
polar
group
t hree
are
of
t he
of
t he
alcohols
more
is
t he
carbon
hydroxyl
atoms
group,
display
–OH.
str uctural
isomerism.
polar
volatile
alcohols
nature
of
or
OH
2n  1
t han
t heir
corresponding
alkanes
because
of
molecules.
are
completely
molecules.
soluble
Solubility
in
water
decreases
as
because
t he
of
t he
molecular
size
increases.
●
Ethanol
dioxide
burns
and
in
air
water
●
Et hanol
reacts
●
Et hanol
can
wit h
be
concentrated
as
or
oxygen
steam.
sodium
dehydrated
sulfuric
wit h
The
to
to
a
clean
reaction
form
is
sodium
et hene
by
blue
ame
to
form
carbon
exot hermic.
et hoxide
being
heated
and
to
hydrogen.
170 °C
wit h
acid.
269
Esters:
RCOOR
Alcohols,
●
Et hanol
can
be
oxidised
manganate(VII)
●
The
reaction
The
reduction
and
t he
t he
produces
of
breat halyser
acidied
Et hanol
reacts
●
Et hanol
can
●
Fermentation
is
conver ted
et hanol
●
Wine
and
wit h
r um
●
Alkanoic
●
The
●
Alkanoic
acid
●
Alkanoic
acids
it
acidied
wit h
acidied
potassium
acid
and
potassium
colour
alkanoic
produced
t he
are
acids
reacting
of
●
t he
The
polar
smaller
polar
by
acids
by
from
have
t he
to
orange
produce
reaction
yeast
by
group
of
under
solution.
to
cr ystals
by
green
used
is
et hanol
in
an
are
less
of
general
alkanoic
t he
are
and
water.
in
which
anaerobic
carbohydrates
are
conditions.
formula
acids
is
C
H
COOH
2n  1
t he
carboxyl
group,
–COOH.
polar
volatile
t he
ester
fermentation.
alkanoic
molecules
of
potassium
fermentation.
chemical
made
nature
nature
esters
water.
n
functional
and
dichromate(VI)
dichromate (VII)
change
acids
test.
●
into
or
et hanoic
accompanying
be
by
solution
alkanoic
t han
t heir
corresponding
alkanes
because
molecules.
acids
are
completely
molecules.
Solubility
soluble
in
decreases
water
as
t he
because
of
molecular
t he
size
increases.
●
Alkanoic
●
Aqueous
acids
hydroxide
●
Et hanoic
●
An
ester
par tially
ethanoic
and
acid
is
a
ionise
acid
metal
reacts
in
reacts
carbonates
wit h
compound
water
wit h
in
alcohols
formed
making
reactive
t he
to
same
way
produce
when
an
t hem
metals,
an
as
weak
metal
inorganic
ester
alkanoic
acids.
oxides,
and
acid
metal
acids.
water.
reacts
wit h
an
alcohol.
●
The
as
reaction
which
esterication.
t
makes
an
requires
ester
a
is
a
catalyst
condensation
of
reaction
concentrated
sulfuric
known
acid
and
heat.
●
Esters
of ten
vegetable
●
The
●
Acid
●
Alkaline
have
oils
are
functional
distinctive
esters
group
hydrolysis
of
an
hydrolysis
of
of
esters
ester
of
sweet
an
fr uity
long-chain
is
t he
forms
ester
smells.
alkanoic
ester
an
group,
alkanoic
forms
t he
Animal
acids
salt
and
glycerol.
–COO–.
acid
of
fats
and
and
an
an
alcohol.
alkanoic
acid
and
an
alcohol.
●
Saponication
hydrolysis
is
Soapless
●
Soapy
detergents
scum.
Soapless
Soapy
detergents
not
detergents
contain
some
are
t he
animal
●
●
270
of
do
process
fats
are
not
or
do
not
which
produced
lat her
detergents
phosphates.
by
vegetable
do
easily
pollute
and
is
made
by
t he
alkaline
in
in
petroleum.
hard
t hey
detergents
t hey
water,
instead
t hey
form
water.
because
Soapless
non-biodegradable
from
lat her
soap
oils.
are
can
contain
biodegradable
cause
and
pollution
phosphates.
do
because
Alcohols,
alkanoic
acids
and
esters
Practice
a
Practice
exam-style
Draw
t he
fully
scheme
When
type
1
and
2
refer
answering
of
t he
to
t he
following
question,
select
types
t he
of
most
reaction.
Name
i)
ii)
D
shown
in
of
each
t he
of
reaction
(4
type
A
to
of
reaction
involved
in
marks)
t he
of:
Glucose
to
A.
C.
B
reduction
C
substitution
State
t he
reaction
necessar y
i)
D
(1
mark)
(1
A
to
to
conditions
and
any
mark)
reagents
conver t:
B
(2
A
(2
marks)
marks)
(2
marks)
oxidation
ii)
iii)
The
process
by
which
et hanol
is
produced
C
to
D
to
d
Write
a
process
by
which
et hanol
is
and
B
balanced
between
The
A
from
carbohydrates.
2
and
fermentation
c
1
C
above.
t he
conversion
appropriate
reaction.
A
A,
questions
b
Questions
str uctures
questions
questions
compounds
Multiple-choice
displayed
exam-style
conver ted
to
B
and
chemical
equation
magnesium
and
for
name
t he
reaction
compound E
et hanoic
(3
marks)
acid.
Total
3
During
t he
et hanol
on
breat halyser
a
driver’s
test
to
breat h,
detect
t he
t he
presence
oxidises
t he
green
to
t he
orange
Cr
O
2
reduces
t he
orange
C
reduces
t he
green
Cr
O
2
ion
to
t he
green
Cr
t he
orange
Cr
8
a
Describe
t he
orange
Cr
O
ion
of
7
et hanol
ion
t he
green
Cr
ion
laborator y.
7
and
Concentrated
sulfuric
acid
is
used
in
t he
et hanoic
acid
and
a
could
prepare
suitable
a
pure
sample
carbohydrate
name
et hanol
nclude
t he
an
most
equation
suitable
for
t he
in
t he
met hod
reaction
of
obtaining
of
et hanol
from
t he
fermentation
mixture.
as:
(5
A
a
reducing
B
an
C
a
catalyst
D
a
neutralising
Acid
oxidising
b
agent
Fats
oils
and
agent
hydrolysis
of
met hyl
et hanoate
will
and
are
oils
are
esters
A
met hanoic
acid
B
met hanoic
acid,
and
C
et hanoic
acid
D
et hanoic
acid,
of
sodium
t he
et hanol
B
propanoic
C
et hyl
D
olive
soaps.
long-chain
and
carbon
t he
str ucture
of
general
met hanol
following
will
and
a
fat
is
represented
by
not
C

react
wit h
aqueous
write
t he
ii)
acid
a
balanced
formation
Calculate
would
be
t he
carbon
question
soap
number
in
i)
in
of
t he
above
equation
from
t his
hydrogen
R
if
group
t hat
to
t he
information
soap.
is
a
The
given
in
t he
following
you
of
answer
t he
questions
which
(2
atoms
t he
group
fat
contains
(1
by-product
formula
of
in
t he
expect
glycerol
to
B
has
been
identied
for
is
be
C
H
(OH)
5
or
in
water?
Give
a
reason
for
your
H
12
O
Mg
A
(glucose)
6
B
(CH
3
COOH)
Describe
glycerol
E
+
H
what
reacts
would
wit h
expect
sodium.
to
Give
a
C
alkene)
D
(a
when
balanced
State
fat
or
to
T WO
oil
represent
ways
differs
in
t he
which
from
a
reaction.
a
soap
soapless
(3
prepared
marks)
from
a
detergent.
(2
(an
marks)
obser ve
(g)
equation
A
you
2
v)
+
answer.
you.
yeast
6
.
3
soluble
follow.
iv)
C
18
mark)
manufacture
glycerol
(2
Compound
marks)
t hat
reaction
insoluble
and
represent
fat.
atoms.
Glycerol
of
a
present
represented
oil
chemical
of
3
scheme
t he
formula,
water
Would
Study
and
acids
O
dioxide
iii)
7
Fats
fatty
met hanol
met hanoate
Structured
of
produce:
hydroxide?
A
manufacture
glycerol.
f
R
Which
to
consist
et hanol
et hanol
and
used
which
following
6
marks)
agent
i)
5
a
reaction
sample
between
you
from
3
O
2
4
how
2
to
2
oxidises
ion
7
ion
2
D
question
3
3
Cr
response
ion
7
2
B
Extended
2
ion
Cr
marks
et hanol:
3
A
15
of
Total
marks)
15
marks
sweet
smelling
compound)
271
B16
Polymers
Polymers
are
very
large
molecules
known
as
Objectives
By
the
be
able
end
of
this
topic
you
macromolecules.
will
They
can
be
natural
or
synthetic,
i.e.
to:
man-made.
●
dene
the
●
explain
term
the
polymer
process
of
of
natural
Proteins,
polymers,
starch
and
whereas
cellulose
are
polystyrene,
examples
PVC,
addition
terylene
and
nylon
are
examples
of
synthetic
polymers.
polymerisation
●
show
the
how
alkenes
structure
of
a
are
linked
in
Synthetic
polymers
Understanding
●
give
examples
●
state
of
uses
of
collectively
called
plastics.
the
chemistry
of
polymers
is
important
polyalkenes
as
the
are
polyalkene
it
allows
us
to
use
and
recycle
them
efficiently.
different
polyalkenes.
B16.1
Addition
The
carbon
can
form
atom
is
unique
long-chain
macromolecules
polymers
are
among
molecules
known
as
all
elements
known
as
polymers.
t hat
are
found
macromolecules.
Polymers
are
in
nature.
Some
made
of
from
It
t hese
small
molecules known as monomers which are linked toget her, usually in chains.
A
polymer
The
molecule
reaction
may
which
contain
produces
t housands
a
polymer
of
monomers.
from
monomers
is
known
as
polymerisation
Addition polymers are synthetic, i.e. man-made, polymers which are made by
addition polymerisation . Addition polymerisation occurs when monomers
containing
form
each
!
A
Key
fact
polymer
is
a
a
a
alkene
single
carbon–carbon
polymer.
For
this
molecule
covalent
bonds
to
double
occur,
breaks.
The
between
bond,
one
of
i.e.
molecules
adjoining
alkenes,
the
bonds
then
carbon
are
in
bond
atoms
linked
the
to
to
together
double
one
form
a
to
bond
another
of
by
polymer.
macromolecule
Polyalkenes
formed
more
by
linking
small
monomers,
together
molecules,
usually
in
50
known
chains.
or
as
Addition
known
only
The
polymers
as
have
single
bonds
carbon–carbon
toget her
derived
is
T
able
known
from
examples

produced
polyalkenes.
of
t he
between
single
as
an
name
Names
of
alkenes
t he
are
some
are
carbon
bond
alkane
of
polyalkenes
16.1.1
from
Polyalkenes
(–C–C–)
monomer
in
addition
polymerisation
compounds
t hey
t he
which
The
from
Table
links
specic
each
name
monomer
unit
which
it
of
was
a
polymer
formed.
polyalkenes
ethene
propene
monochloroethene
Polymer
polyethene
polypropene
polychloroethene
will
now
look
at
t he
is
Some
16.1.1.
Monomer
We
are
because
atoms.
linkage.
given
by
saturated
formation
of
polyet hene
and
polypropene
in
more
detail.
Formation
of
polyethene
Polyethene
is
and
it
formed
by
placing
et hene
(C
H
2
heating
et hene
272
wit h
molecule
a
catalyst.
breaks
and
One
t he
of
t he
saturated
)
in
a
pressurised
container
4
bonds
in
polymer,
t he
double
bond
polyet hene,
is
of
each
formed.
Polymers
The
Addition
addition
polymerisation
high
of
et hene
can
be
represented
by
t he
polymers
following:
pressure
et hene
polyet hene
catalyst,
heat
In t he formation of polyet hene, t housands of et hene molecules join toget her.
We
can
represent
t he
reaction
using
str uctural
formulae
as
in
Figure
16.1.1.
alkane
linkage
H
H
H


pressure,
 C  C  C  C 


heat

catalyst,
H




C  C
H
high

n
+

C  C
H


n
H

H

H

H
H
H
H
H
H
H
n
many
et hene
many
Figure
Formation
16.1.1
of
Polypropene
polyet hene
molecules
molecules

et hene
The
formation
of
polyethene
polypropene
is formed by placing propene (C
H
3
and
heating
toget her
In
order
we
to
to
must
two
wit h
form
in
B
a
catalyst.
Thousands
of
) in a pressurised container
6
propene
molecules
t hen
join
polypropene.
show
redraw
carbon
shown
it
t he
t he
atoms
polymerisation
propene
joined
by
of
molecule
t he
propene
shown
double
bond
using
in
are
A
str uctural
below
drawn
so
formulae,
t hat
only
horizontally.
t he
This
is
below.
H
CH
H
H
3
C
H
H
H
H
H
A
We
can
now
str uctural
show
C
how
B
propene
can
polymerise
to
form
polypropene
CH
H
CH
3
CH
CH
H
3
n
n
pressure
C
C
catalyst,
H
H
H
C
C
C
H
H
H
heat
H
H
propene
H
3
H
3
high
many
using
formulae:
many
n
propene
polypropene
molecules

Figure
molecules
16.1.2
The
formation
of
polypropene
If t he monomer contains ot her atoms, groups of atoms or functional groups,
e.g. chlorine, uorine or t he et hyl group, t hen t he monomer and t he resulting
polymer
can
represented
in
Figure
H


where
 C  C 
X
is
Cl,
F
,
C
H
2



H
16.1.3.
X


C  C
n
as
X

H
be
etc.
5
H
H
H
n
monomer

In
●
Figure
addition
t he
atoms
it
16.1.3
Formation
of
a
polyalkenes
polymerisation:
polymer
makes
polymer
is
t he
possible
from
only
for
between
product
t he
–
t he
monomers
breaking
to
link
of
t he
toget her
double
wit hout
bond
losing
any
t hem
273
Addition
polymers
Polymers
●
t he
monomers
●
t he
empirical
formed
it
ratio
atoms
of
Examples
Table

T
able
16.1.2
Examples
Monomer
of
monomers
H
H
their
addition
no
in
of
t he
t he
t he
atoms
two
monomers
are
is
lost
t he
and
polymer
polymer
is
are
t he
during
its
all
t he
same
same
as
t he
formation,
monomer
t herefore,
t hat
t he
same.
t heir
addition
polymers
are
given
in
t he
polymers
Cl
H
F
F
H
H
CH
H
C
H
H
5
H
propene
tetrafluoroethene
H
6
3
H
F
F
chloroethene
ethene
make
16.1.2.
H
H
H
and
since
of
which
formula
styrene
Polymer
H
H
H
Cl
F
F
H
CH
H
C
3
C
C
H
H
C
C
H
H
n
?
know?
polystyrene,
C
H
6
structure
shown
of
six
is
a
C
H
H
addition
polymers
C
C
H
H
5
n
are
polychloroet hene
polytetrauoroet hene
n
polypropene
more
is
is
polystyrene
commonly
commonly
known
known
commonly
by
ot her
as
polyvinyl
as
PTFE
knowºn
and
names,
for
chloride
or
polystyrene
ringed
5
carbon
F
polytetrafluoroethene
example,
PVC,
In
F
C
n
polychloroethene
Some
you
C
n
polyethene
Did
C
H
6
is
atoms
of ten
called
styrofoam.
as
below.
Uses
of
polyalkenes
H
Because
polyalkenes
can
be
moulded
easily
into
different
shapes,
are
light
in
C
weight, are coloured easily, can be made to be exible or rigid, are good thermal
C
C
C
C
and electrical insulators and are durable, i.e. they do not corrode or decay, they
have a great many uses. Table 16.1.3 summarises some of these uses.

T
able
16.1.3
Uses
of
some
polyalkenes
C
Name
This
can
also
be
represented
as:
of
polymer
Uses
Polyethene
T
o
make
wrap,
plastic
bags,
packaging
plastic
materials
bottles,
and
sandwich
moisture
bags,
barriers
cling
used
in
construction.
or
Polychloroethene
(PVC)
T
o
make
and
Polytetrafluoroethene
(PTFE)
As
a
T
o
fittings,
for
non-stick
make
Polypropene
pipe
insulation
coating
low-friction
make
water
electrical
ropes,
on
pipes,
wires
guttering,
and
kitchen
plastic
windows
cables.
and
garden
utensils
and
to
bearings.
plastic
toys,
carpets
and
plastic
food
containers.
Polystyrene
(styrofoam)
T
o
As
in

Figure
used
274
16.1.4
to
make
Polyvinyl
guttering
chloride
is
make
a
fast
food
protective
walls
and
containers
packaging
and
vending
material
and
an
cups
for
drinks.
insulation
material
roofs.

Figure
make
16.1.5
ropes
Polypropene
is
used
to
Polymers
Condensation
Summary
1
What
2
Explain
3
For
is
a
questions
polymer?
what
each
polymers
of
happens
the
during
following
formed
addition
polymers,
monomer
that
the
a
H
Cl
H
Cl
H
Cl
C
C
C
C
C
C
H
H
H
H
H
H
polymerisation.
draw
the
structural
formula
of
the
polymer:
b
H
H
4
Give
of
H
C
C
C
C
C
C
H
H
H
H
H
H
three
examples
of
addition
polymers
and
give
two
uses
of
each
them.
B16.2
Condensation
Condensation
Condensation
polymers
are
polymerisation
polymers
made
by
involves
Objectives
condensation
linking
By
the
be
able
monomers
toget her
in
by
eliminating
a
small
molecule
from
between
of
this
adjacent
The
molecule
is
of ten
water
(H
O),
where
one
you
will
explain
the
process
of
monomer
condensation
units.
topic
to:
long
●
chains
end
polymerisation .
hydrogen
atom
polymerisation
(H)
2
●
comes
from
one
monomer
unit
and
an
oxygen
and
a
hydrogen
atom
show
how
linked
come
from
t he
adjacent
monomer.
Instead
of
water,
ot her
small
in
the
also
be
eliminated
such
as
hydrogen
chloride
(HCl)
or
structure
are
of
a
molecules
polyester,
can
monomers
(OH)
ammonia
(NH
a
polyamide
and
a
).
3
polysaccharide
The
elimination
link
up
of
a
small
molecule
makes
it
possible
for
t he
monomers
to
●
in
give
examples
polyesters,
In
contrast
to
addition
polymerisation,
during
condensation
natural
polymerisation:
t he
polymer
synthetic
polyamides
is
not
t he
only
product
made
–
state
the
uses
polymerisation
always
forms
two
products,
t he
polymer
and
of
small
discuss
t he
polymer
is
of ten
the
harmful
effects
molecules
of
●
different
polymers
anot her
●
made
of
condensation
condensation
compound
and
and
polysaccharides
●
●
of
chains.
made
from
more
t han
one
different
type
of
synthetic
polymers
on
the
environment.
monomer
●
t he
empirical
since
In
atoms
order
fo r
molecules
(–OH)
lost
types
h ave
c a r b ox yl
of
of
t he
during
monomer s
m u st
and/or
d i f fe r e n t
formula
are
to
polymer
t he
fo r m
t wo
is
different
formation
condensation
t he
condensation
functional
g roups
of
p o ly m e r s ,
t he
p o ly m e r s ,
g roups,
(–COOH).
from
We
monomer
polymer.
e.g.
will
t he
monomer
hy d r ox yl
be
p o lye st e r s ,
g roups
st u d y i n g
t hree
p o lya m i d e s
and
p o ly s a c c h a r i d e s .
275
Condensation
polymers
Polymers
Polyesters
O

O
Polyesters

C 
are
synthetic
condensation
polymers
that
are
formed
from
the
 C

X

H O
condensation reaction between an alkanoic acid and an alcohol. The acid and
OH
the
a
alcohol
acid
H O 
 O H
Y
The
is,
therefore,
number
represent
a

Figure
diacid
16.2.1
and
a
must
both
have
two
functional
groups
in
their
molecules.
The
diacid
dialcohol
Structural
of
t he
known
carbon
carbon
as
a
diacid
atoms
chain
in
to
and
t he
the
acid
which
alcohol
and
t he
t he
is
known
alcohol
functional
can
groups
as
a
dialcohol.
var y,
are
so
we
can
attached
by
X or Y. The str uctural formulae in Figure 16.2.1 show t he two monomers t hat
formulae
of
are
a
involved
in
t he
formation
of
a
polyester.
dialcohol
When
t hese
eliminated
two
from
molecules
between
react
t hem
wit h
and
each
an
ot her,
ester
a
water
functional
molecule
group
is
(–COO–
O

or
–OOC–)
forms
which
links
t he
two
toget her.
The
str ucture
of
t he
ester
 C  O 
functional

Figure
16.2.2
The
ester
or
ester
is
shown
in
Figure
16.2.2.
functional
A
group
group
polyester
forms
by
linking
t housands
of
t hese
monomers
toget her
linkage
alternately
in
chains,
wit h
an
ester
functional
group
between
adjacent
monomers. Therefore, we say t hat polyesters are polymers where t he linkages
between
monomers
are
ester
linkages
Figure 16.2.3 uses a diacid molecule and a dialcohol molecule to give a simple
representation
of
how
t hey
can
be
condensed
to
form
a
polyester
ester
functional
group
O
C
H

Figure
X
C
Y
1
O
O
molecule.
(linkage)
O
X
C
C
O
Y
O
H
16.2.3
H
O
lost
2
A
section
of
a
polyester
molecule
An
or
is
example
by
brand
formed
of
a
polyester
names
from
a
such
diacid
is
as
in
polyet hylene
Ter ylene
which
X
or
has
terepht halate,
Dacron.
t he
formula
C
H
6
which
Y
has
t he
formula
C
also
known
Polyet hylene
and
as
PET,
terepht halate
a
dialcohol
in
4
H
2
4
O

 C  N 

Polyamides
H

Figure
group
16.2.4
or
The
amide
amide
Polyamides all contain the amide functional group
functional
The
linkage
str ucture
Some
of
the
polyamides
looking
at
bot h
amide
are
types
functional
synt hetic
in
t his
group
while
is
(–CONH– or –NHCO–).
shown
ot hers
in
occur
Figure
16.2.4.
naturally.
We
will
be
section.

H
 N
 NH

or
2
Synthetic
polyamides
H
The
amino
Synthetic polyamides
functional
two
The
amino
functional
str uctural
involved
in
are made from a diacid and a diamine. A diamine has
groups
formulae
t he
in
formation
shown
Figure
of
a
in
16.2.6
synt hetic
Figure
show
O

 C
formulae
of
a
diacid
and
a
diamine
monomers
a
diacid
 N
H
H
276
Structural
Y

OH
16.2.6
two
H
N 

X

HO
Figure
t he
polyamide.

C 

16.2.5.

O
as

16.2.5
group

Figure
H

diamine
t hat
are
Polymers
When
Condensation
t hese
eliminated
which
t hese
two
links
t he
between
two
monomers
group
between
polymers
Figure
molecules
from
16.2.7
toget her.
toget her
adjacent
where
t he
uses
a
react
t hem
A
wit h
and
monomers.
diacid
a
by
water
we
say
are
diamine
an
molecule
group
linking
wit h
monomers
and
a
functional
forms
chains,
Therefore,
between
molecule
in
ot her,
amide
polyamide
alternately
linkages
each
an
t hat
amide
molecule
is
forms
t housands
amide
polymers
of
functional
polyamides
are
linkages
to
give
a
simple
representation of how t hey can be condensed to form a synt hetic polyamide
molecule.
O
X
C
H
C
1
O
O
Y
N
N
X
C
H
H
O
C
Y
N
H
H
H
O
lost
amide
2
functional
group

Figure
An
16.2.7
example
diacid
in
A
of
section
a
which
of
a
polyamide
synt hetic
X
has
t he
polyamide
formula
C
C
is
an
a
6,6,
which
dialcohol
is
in
formed
which
Y
from
has
a
t he
12
are
natural
acids
functional
of
and
8
polyamides
Proteins
amino
nylon
H
H
6
Natural
(linkage)
molecule
4
formula
N
H
group
amino
polyamides
toget her.
acid
and
is
Amino
one
given
formed
acids
carboxyl
in
Figure
are
by
linking
molecules
functional
monomers
which
group.
The
have
known
one
str uctural
as
amino
formula
16.2.8.
H


O
 C

H

N  C


H

In
t he
which
amino
may
acid
molecule,
contain
ot her
R
atoms
amino
represents
such
Figure
16.2.8
Structural
formula
of
an
O  H
R
as
a
variable
nitrogen,
hydrocarbon
oxygen
and
sulfur,
acid
molecule
group
as
well
as carbon and hydrogen. There are 20 different groups, t herefore t here are 20
different
Figure
of
t he
amino
16.2.9
acids
uses
which
two
condensation
make
amino
of
acid
amino
up
molecules
acid
H
protein
molecules.
to
molecules
give
to
a
simple
form
a
molecule.
H
O
N
C
C
H
R
H
H
representation
protein
H
O
C
C
H
N
C
C
1
H
O
N
C
C
H
H
O
R
R9
H
O
N
H
H
R9
lost
2
amide
functional
group

Figure
Like
16.2.9
synt hetic
amide
Formation
of
a
protein
polyamides,
linkage.
In
proteins,
molecule
proteins
t his
(linkage)
contain
amide
t he
linkage
is
amide
also
functional
known
as
group
t he
or
peptide
linkage
Examples
collagen
such
as
many
of
proteins
which
is
ligaments
hormones
include
found
and
are
in
keratin
t he
tendons.
also
made
which
connective
of
is
found
tissue
Haemoglobin,
in
t hat
hair
makes
enzymes,
and
up
nails
and
str uctures
antibodies
and
proteins.
277
Condensation
polymers
Polymers
Polysaccharides
Polysaccharides
as
are
natural
monosaccharides
glucose,
fr uctose
formula
C
H
6
Starch
is
as
galactose.
These
are
by
of
all
linking
monomers
monosaccharides
isomers
wit h
t he
known
include
molecular
6
polysaccharide
polymerisation.
written
and
formed
Examples
O
12
a
polymers
toget her.
The
follows,
formed
simplied
where
n
is
when
glucose
chemical
t he
undergoes
equation
number
of
for
t his
repeating
condensation
reaction
glucose
can
units
in
be
t he
polysaccharide:
nC
H
6
O
12
(C
6
H
5
glucose
The
O
10
)
5

nH
n
O
2
starch
str uctural
formula
of
a
glucose
molecule
is
given
in
Figure
16.2.10.
If we t hink of two of t he –OH groups of a glucose molecule as being functional
H

groups,
H  C  O  H


t hen
we
can
represent
t he
glucose
molecule
X represents t he rest of t he glucose molecule, i.e. C
as
H
6
H–O–X–O–H,
O
10
where
. Figure 16.2.1
1 uses
4
two glucose molecules to give a simple representation of t he condensation of
glucose
O
H
C
molecules
to
form
a
starch
molecule.
H
H


ether
functional
C

H


OH

C
HO
(linkage)

C

C
group
OH
H
X
O
H
O
X
H
H
OH
O
O
X
O
H
X
O
lost
2

Figure
16.2.10
glucose
Structural
formula
of
a

Figure
16.2.11
Formation
of
a
starch
molecule
molecule
Polysaccharides
Ot her
which
is
Uses
Like
contain
polysaccharides
found
of
in
plant
bres.
t hem
molecules
These
ver y
ether
cell
bres
useful
summarises
synt hetic
are
some
are
condensation
of
long
strong,
t he
t he
(–
O
or
–)
between
animal
t he
starch
monomers.
and
cellulose
polymers
extremely
in
linkage
glycogen
walls.
condensation
polyalkenes,
Their
t he
include
and
light
in
production
uses
of
bot h
polymers
one
of
weight
of
a
have
t heir
and
variety
synt hetic
a
variety
main
uses
durable,
of
and
of
to
which
fabrics.
natural
is
Table
uses.
make
makes
16.2.1
condensation
polymers.

T
able
T
ype
of
16.2.1
Uses
polymer
Polyester
of
some
Name
polymer
Polyethylene
(PET
,
Polyamide
of
condensation
terephthalate
T
erylene
Nylon
or
Dacron)
polymers
Uses
T
o
make
bed
make
PET
T
o
make
fishing
e.g.
Protein
T
o
✔
Exam
Starch
Used
in
is
very
important
that
you
uses
of
and
hair
antibodies
drinks.
carpets
stretch
activity
and
and
is
wear.
nails.
some
and
required,
T
o
make
hormones.
the
different
to
living
produce
energy
organisms
during
after
first
as
food
respiration
being
types
glucose.
Stored
a
digested
reserve
of
organisms.
polymers.
Polysaccharide
278
clothing,
carpets.
know
to
the
soft
and
seatbelts,
where
cells,
outdoor
sails
tip
Polysaccharide
It
for
lines,
stockings
body
enzymes,
boat
bottles
especially
nylon
build
especially
towels,
T
o
clothing,
Polyamide
clothing,
sheets,
Cellulose
Used
to
build
cell
walls
of
plant
cells.
in
living
Polymers
Condensation
Environmental
Synt hetic
harmful
given
●
polymers,
effects
on
t he
released
from
t he
Many
Most
t he
synthetic
known
systems
plastic
of
items
t hese
plastics
and
as
polymers
plastics,
t he
are
aquatic
organisms,
can
can
(a)
have
environment.
a
Some
variety
of
t hese
of
are
to
air
Plastics
Their
water
of ten
for
during
use
persistent,
a
great
pollution.
leading
to
of
t hese
and
i.e.
many
They
They
t heir
toxic
chemicals
continue
when
t hey
to
be
are
released
disposed
remain
in
t he
years.
build
are
up
in
t he
par ticularly
deat h
by
being
environment
harmful
ingested
to
or
by
dense
smoke
and
damage,
and
poisonous
serious
cancer
healt h
and
gases
when
problems,
damage
to
t he
burnt.
such
as
ner vous
These
ast hma,
and
systems.
plastics
are
(b)
pollution
system
reproductive
●
and
produce
immune
Many
are
variety
of
suffocation.
lead
●
t hemselves
damage
a
Some
non-biodegradable.
to
Plastics
plastics,
chemicals
doing
land
of
environment.
leading
causing
●
ot her wise
living
manufacture
into
environment
●
of
below.
During
of.
impact
polymers
are
made
ammable.
from
manufacture
is
As
a
petroleum
result
t hey
which
contributing
to
t he
is
a
pose
re
hazards.
non-renewable
world
wide
resource.
depletion
of
petroleum.

Summary
questions
Figure
(a)
1
Explain
2
Give
what
two
happens
differences
16.2.12
terephthalate
during
condensation
between
addition
boat
sails
is
Polyethylene
used
and
(b)
to
make
PET
bottles
polymerisation.
polymerisation
and
condensation
polymerisation.
3
Draw
the
partial
monomer
4
Draw
the
structure
of
a
polyester
which
is
made
from
four
units.
structural
formulae
of
the
two
monomer
units
in
the
following
polymer:
O
O
O
C
N
H
5
Give
two
example
polymer
examples
of
a
of
natural
synthetic
O
C
N
H
H
condensation
condensation
polymer.
H
polymers
Give
two
and
uses
one
of
each
named.
279
Condensation
polymers
Polymers
Key
●
A
concepts
polymer
small
●
a
Polymers
can
polymers
are
●
The
●
Add ition
reaction
form
of
by
are
alkene
monomer
molecule
form
identical
are
t he
Polyalkenes
contain
●
Polyet hene,
polypropene,
examples
polyalkenes.
Polyalkenes
have
●
Condensation
Condensation
chains
●
In
of
necessarily
monomer
Polyesters
●
Polyet hylene
Synthetic
is
Proteins
●
All
or
more
Synt hetic
The
as
polymerisation
polymerisation .
t he
molecules
adjoining
product
is
Alkenes
carbon–carbon
t he
t hen
carbon
polymer,
formulae
of
double
bond
t he
to
one
atoms.
all
t he
polymer
and
polyalkenes
linkage
(–C–C–)
between
(PVC)
and
monomers.
polystyrene
are
uses.
are
a
and
formed
by
involves
small
a
condensation
linking
molecule
t he
a
polymerisation .
monomers
from
toget her
between
in
adjacent
t he
polymer
produced,
empirical
and
t he
anot her
compound
monomers
formulae
of
t he
are
not
polymer
and
t he
and
ester
of
a
of
are
diacid
example
of
a
are
amino
natural
polyamides
a
polymers
formed
by
t he
dialcohol.
linkage
(PET),
(–COO–)
also
between
known
as
monomers.
Ter ylene
or
Dacron,
is
polyester.
polyamides
are
are
condensation
diacid
polyamides
an
t he
terepht halate
condensation
●
of
molecules
synt hetic
of
of
condensation
Natural
in
empirical
polymerisation
contain
example
Nylon
50
different.
are
●
●
add ition
polychloroet hene
eliminating
identical
are
Polyesters
●
natural.
known
between
as
alkane
variety
small
condensation
●
t he
polymers
condensation
an
known
polymerisation
by
is
bond
only
t he
toget her
chains.
plastics
breaks.
t he
or
in
units.
composed
●
a
linking
usually
same.
polymers
●
by
one
bonds
and
●
of
as
polymer
when
Alkenes
monomer
a
covalent
by
man-made,
formed
●
long
i.e.
polymerisation
are
formed
monomers,
known
forms
polymers
single
addition
as
synt hetic,
polymers
monomers
t he
be
known
which
each
anot her
In
macromolecule
collectively
addition
bond
●
is
molecules,
condensation
and
a
polymers
formed
by
t he
diamine.
synt hetic
polyamide.
condensation
polymers
formed
by
t he
acids.
polyamides.
contain
t he
amide
linkage
(–CONH–)
between
monomers.
●
Polysaccharides
condensation
●
Polysaccharides
●
Starch,
●
Condensation
●
Synt hetic
are
contain
and
t he
condensation
t he
ether
cellulose
polymers
polymers
and
natural
polymers
formed
by
t he
monosaccharides.
glycogen
systems
280
of
can
have
have
are
a
a
environment.
linkage
(–O–)
examples
variety
variety
of
of
of
between
monomers.
polysaccharides.
uses.
harmful
effects
on
living
Polymers
Practice
Use
Practice
exam-style
t he
information
to
answer
exam-style
t he
questions
following
questions
questions.
i)
Multiple-choice
What
type
formation
1
Which
of
t he
following
is
not
an
addition
ii)
polymer?
Draw
unit
A
polystyrene
B
ter ylene
C
polyet hene
D
polypropene
t he
of
A
Amide
linkages
polymerisation
Name
t he
iv)
Name
ONE
be
found
EACH
is
involved
polymer?
str uctural
iii)
could
are
of
and
of
formula
of
EACH
I
proteins
ter ylene
III
nylon
A
I
B
II
C
I
D
I,
and
(2
unit
naturally
by C
makes
and
up
polymer
name
t he
b
The
two
compounds, E
t he
polymer
you
and
F,
illustrated
below,
O
O
C
X
C
HO
O
only
Y
3
Amino
A
and
OH
O
E
II
have
marks)
polymerisation.
only
III
mark)
t hat
(2
only
and
marks)
(1
occurring
represented
which
of B.
in:
undergo
II
t he
marks)
monomer
named.
II
in
(3
B.
monomer
monomer
2
of
questions
F
III
acids
contain
are
t he
so
called
because
i)
t hey:
Using
of
group
NH
F,
T WO
show
molecules
how
t he
of E
and
T WO
compounds
are
molecules
linked
2
B
contain
C
turn
D
contain
t he
blue
COOH
litmus
t he
toget her
group
red
NH
ii)
group
and
t he
COOH
group
Name
in
In
a
condensation
polymerisation
par t
i)
form
type
monomers
2
4
to
t he
in
a
of
t he
above
polymer.
linkage
polymer
and
(2
formed
name
you
t he
between
have
type
t he
polymer
has
a
different
t he
drawn
of
reaction,
polymer.
A
marks)
empirical
formula
to
(2
marks)
t he
iii)
Give
a
named
example
of
t he
type
of
polymer
monomer
drawn
B
one
C
t he
product
is
formed
polymer
is
always
in
i)
above
and
state
T WO
of
its
uses.
(3
monomer
D
water
is
formed
from
one
type
Total
only
always
The
monomer
of
starch
fr uctose
B
sucrose
C
galactose
D
glucose
Which
of
t he
following
response
Polymers
is
not
tr ue
about
are
are
What
They
are
question
b
Polymers
can
polymers
and
in
ever y
aspect
of
our
daily
named
be
(1
classied
into
condensation
addition
two
groups,
polymers.
polymer
and
Briey
ONE
discuss
named
condensation
polymer.
You
should
include
ammable.
B
They
are
easily
C
They
are
good
D
They
are
easily
your
answer:
biodegraded.
i)
The
str ucture
of
t he
monomer
units
of
EACH
insulators.
polymer.
(2
Appropriate
monomers
str uctures
are
linked
to
show
how
to
form
EACH
of
linkage
t he
polymer.
question
(4
a
The
marks)
moulded.
ii)
7
mark)
addition
plastics?
in
Structured
lives.
polymers?
synt hetic
A
found
a
ONE
6
marks
is:
8
A
15
produced
Extended
5
marks)
of
str uctures
A,
B
and
C
represent
t hree
types
marks)
of
iii)
The
name
of
t he
type
formed
between
polymers.
t he
H
H
H
H
H
iv)
A
C
C
H
CH
C
C
H
CH
monomer
C
C
H
CH
c
T WO
Addition
addition
3
3
of
EACH
polymers
in
EACH
polymer.
are
polymer.
formed
polymerisation
formed
Give
O
uses
and
by
a
process
H
O
H
T WO
by
condensation
N
C
C
N
CH
C
H
C
CH
3
marks)
called
condensation
polymers
differences
between
t he
two
types
N
H
3
of
O
C
C
d
Give
T WO
synt hetic
H
marks)
(2
polymerisation.
polymerisation.
B
(2
3
are
H
units
H
(2
disadvantages
polymers
of
t he
(plastics)
in
extensive
today ’s
use
of
world.
CH
3
(2
C
O
marks)
X
Total
marks)
15
marks
281
Section
C
Characteristics
of
metals
C17
Most
elements
in
the
periodic
table
are
metals.
In
fact,
Objectives
By
the
be
able
end
of
this
topic
you
will
metals
table.
●
describe
the
properties
physical
of
relate
of
for
about
80%
of
all
the
elements
in
the
the
metals
metal
physical
to
atoms
Metallurgy,
oldest
applied
the
study
sciences,
of
dating
metals,
back
to
is
one
6000 BC
of
the
with
the
way
are
discovery
of
gold.
Metals
have
a
variety
of
physical
properties
in
which
bonded
in
and
chemical
properties
which
enable
them
to
play
an
the
extremely
metallic
i.e.
metals
the
●
account
to:
important
part
in
our
daily
lives.
lattice.
C17.1
Metals
usually
table
Physical
are
1,
and
elements
2
or
3.
whose
Most
between
properties
atoms
metals
Groups

are
have
found
and

as
a
of
metals
small
in
number
Groups
t he
,

transition
of
valence
and

of
electrons,
t he
periodic
metals.
n Unit 5.4 you learnt t hat t he type of bonding between metal atoms in a metal
is
known
as
proper ties
of
metal
t hat
t he
t he
The
a
result
cations
lattice
between
as
metallic
as
t he
way
in
t his
held
positive
and
t hat
bonding.
surrounded
is
metallic
bond ing
of
by
toget her
cations
a
‘sea’
by
and
t he
t he
metals
Recall
of
have
t hat
a
ver y
metal
delocalised,
strong
mobile
electrostatic
delocalised,
distinct
lattice
physical
composed
electrons
force
negative
is
of
and
attraction
electrons
known
bond
which
t he
metal
atoms
are
bonded
in
metal
lattices
helps
us
to
understand t he physical proper ties of metals. We will consider some of t hese
in
detail
Metals
The
below.
have
high
melting
electrostatic
forces
points
of
and
boiling
attraction
between
negative, delocalised electrons are relatively
of
heat
metals.
energy
All
exception
Metals
The
Figure
good
used
17.1.1
Because
conductors
to
make
of
frying
metals
heat
pans
they
heat
required
good
and
an
are
are
separate
in
which
is
electrons
free
to
current
t he
to
atoms
state
electricity
metal
These
heat
t he
solid
t he
positive
and
at
in
order
room
to
melt
or
temperature,
boil
t he
wit h
t he
be
to
and
lattice
moving
carried
be
heat
are
not
electrons
t hrough
carried
t he
t hrough
held
act
as
metal.
t he
in
any
charge
They
metal
xed
carriers
also
act
when,
for
are
are
example,
a
ame,
Metals
one
t he
end
ot her
have
a
of
a
end
shiny
piece
of
of
t he
metal
metal
is
placed
quickly
in
a
heats
hot
environment,
up.
lustre
Lustre is t he shininess of a metal. Metals generally have a ver y
shiny,
metallic
lustre.
This
is
because
t he
mobile
electrons
reect t he photons of light back from t he metal surface before
t hey

282
cations
strong. As a result, large amounts
liquid
of
in
move.
allowing
t he
a
conductors
electric
carriers
to
found
mercur y
delocalised
allowing

of
are
position
as
are
metals
points
are
Figure
allowed
17.1.2
to
This
penetrate
silver
cup
far
has
a
into
shiny
t he
surface.
metallic
lustre
such
as
Characteristics
Metals
are
Metals
are
a
is
force
can
be
of
metals
hard,
bent
meaning
malleable
considered
applied
to
and
t hat
Chemical
to
be
t hem.
and
hammered
t hey
can
be
and
reactions
of
metals
ductile
hard
They
properties
because
are,
into
drawn
t hey
however,
different
out
into
are
not
easily
malleable
shapes.
wires.
They
This
is
damaged
meaning
are
also
because
when
t hat
t he
t hey
ductile,
atoms
in
t he metal are all of t he same type, t herefore t hey are all t he same size. f force
is applied to t he metal, t he atoms can roll over each ot her into new positions
wit hout
breaking

Metals
The
Figure
have
of
by
This
bond.
gold
ring
demonstrates
the
malleability
of
metals
densities
any
its
metallic
17.1.3
high
density
substance
t he
substance
volume.
is
Metals
calculated
have
high
by
dividing
densities
t he
because
mass
t heir
of
t he
atoms
are
packed ver y closely toget her. This means t hat t here are as many metal atoms
as
possible
in
a
given
Summary
1
Explain
2
Why
3
Explain
why
are
the
4
Why
do
C17.2
Because
by
losing
metals
have
good
terms
and
metal.
high
melting
conductors
‘malleable’
and
of
points
and
electricity
‘ductile’.
boiling
and
Explain
points.
heat?
why
metals
are
ductile.
metals
have
a
high
density?
Chemical properties and reactions of metals
metals
electrons,
of
questions
metals
malleable
volume
are
usually
t hese
elements
1,
2
or
valence
3,
whose
t hey
atoms
form
electrons.
This
have
positive
can
be
a
small
cations
in
number
of
chemical
summarised
as
Objectives
By
the
be
able
As
a
M
●
result,
metals
form
ionic
compounds
when
t hey
react
and
t he
causes
reducing agent
t he
ot her
the
water
and
name
the
reactant
to
gain
electrons
write
metal
water
We
will
dilute
now
an
metal’s
look
at
indication
position
t he
dilute
acids
products
balanced
various
gives
of
oxygen,
formed
by
(RG).
ot her substances, e.g. oxygen, water and acids. The way in which a par ticular
t he
with
reactions
equations
to
will
since it gives electrons to t he ot her reactant, i.e.
●
reacts
you
reactions
metals
Some metals are relatively stable while ot hers react violently when exposed to
related
topic
metal
the
it
this
ne
●
behaves as a
describe
various

of
to:
reactions
follows:
n
M
end
valence
in
of
its
t he
reactions
of
reactivity.
periodic
cer tain
The
reactivity
of
a
metal
is
for
metals
and
chemical
the
reactions
with
dilute
of
oxygen,
acids.
table.
metals
wit h
oxygen,
water
and
acids.
283
Chemical
properties
and
reactions
of
metals
Characteristics
The
reactions
Some
metals
t he
oxygen
and
see
be
to
stored
barrier,
be
t he
around
exposure
to
can
in
air
of
exposed
air.
us.
t he
with
air
of
metals
e.g.
metals
ot her
so
t he
to
metals
and
coming
any
ones
wit h
sodium.
into
great
t hat
we
oxid ises
vigorously
potassium
from
reacting
include
react
metals
oxygen
wit hout
metals
surface
some
parafn,
preventing
to
These
The
and
under
metals
of
t hey
parafn
wit h
t he
This
metal

Figure
stored
17.2.1
under
Sodium
parafn
has
to
to
be
prevent
Table
it
acts
with
oxygen
in
the
of
17
.2.1
summarised
oxygen
shows
what
happens
exposed
Reacts
very
potassium
following
the
reaction
T
able
17.2.1
Description
of
Reactions
the
of
metals
cer tain
to
readily
dry
air
when
forming
Burns
oxide
very
sodium
metals
heated
in
Reacts
wit h
oxygen
in
reaction
vigorously
formed
when
heated
and
equation
with
a
lilac
Forms
a
white
powdery
solid,
potassium
oxide:
flame
readily
forming
Burns
oxide

O
(g)
2K
vigorously
with
an
orange
Forms
a
4Na(s)

Forms
a
2Ca(s)

O(s)
2
white
powdery
solid,
sodium
oxide:
flame
readily
calcium
react
air
O
(g)
2Na
2
Calcium
metal
equation:
oxygen
2
Reacts
word
oxide
when
with
4K(s)
Sodium
general
air.
Products
when
t he
metal
Metal
Potassium
by
a
air

Description

be
as
from
t he
reacting
can
on
have
air.
When metals react wit h oxygen, t hey form ionic compounds known as
oxides.
wit h
regularly
immediately
oxygen
The
contact
extent
use
to
form
coating
of
oxide
Burns
very
easily
with
a
brick
red
O(s)
2
white
powdery
solid
called
calcium
oxide:
flame
O
(g)
2CaO(s)
2
Magnesium
Reacts
of
slowly
to
magnesium
form
a
coating
oxide
Burns
easily
with
a
bright
white
Forms
a
white
powdery
solid,
magnesium
oxide:
flame
2Mg(s)

O
(g)
2MgO(s)
2
Aluminium
Reacts
coating
slowly
of
to
form
aluminium
a
thin
Burns
oxide
when
especially
if
heated
strongly,
Forms
a
white
powdery
solid,
aluminium
4Al(s)

3O
(g)
2Al
2
Zinc
Reacts
coating
very
of
slowly
zinc
to
form
oxide
a
thin
Burns
when
especially
oxide:
powdered
if
heated
strongly,
Forms
a
2Zn(s)

O
2
white
powdery
solid,
(s)
3
zinc
oxide,
which
is
yellow
when
hot:
powdered
O
(g)
2ZnO(s)
2
Iron
Does
not
react
with
dry
air
Burns
when
especially
if
heated
strongly,
Forms
a
black
powdery
solid,
3Fe(s)

2O
(g)
Fe
2
Copper
Does
not
react
with
dry
air
Does
does
not
burn
form
iron(II,
III)
oxide:
powdered
an
when
oxide
heated,
coating
but
Forms
a
2Cu(s)

O
3
black
solid,
copper(II)
(s)
4
oxide:
if
O
(g)
2CuO(s)
2
heated
Silver
Does
not
react
with
dry
air
Does
heated
f
very
not
t he
very
water
to
form
form
oxides
form
at
potassium,
and
hydroxide,
hydroxide
which
calcium
reactions
example,
is
and
sodium
calcium
slightly
hydroxide
can
284
t he
reacts
reacts
All
t he
water,
reacts
wit h
wit h
Potassium
alkalis.
t he
reactions
are
of
calcium
found
in
metals
and
Groups
wit h
oxygen
magnesium

and

of
are
t he
periodic
table.
in
t he
t he
most
periodic
lef t of t he table. n general, t he reactivity of metals
across
in
oxide
oxide
oxide
soluble.
are
dissolve
potassium
t he
wit h
water
water
to
hydroxide,
ot her
oxides
in
insoluble.
sodium,
metals
t hese
For
potassium
hydroxide
are
in
alkaline.
sodium
hydroxide
Looking
produced
is
soluble
soluble
17
.2.1
These
when
solution
calcium
sodium
Table
even
strongly
metal
resulting
to
strongly
react,
air
we
see
reactive
table,
i.e.
t hat
metals.
to
t he
far
decreases from lef t to right
Characteristics
The
metals
reactions
Metals
can
metals
t hat
to
of
also
are
be
of
Chemical
metals
added
ver y
to
with
water
reactive
wit h
to
properties
and
reactions
of
metals
water
determine
oxygen
are
t heir
highly
reactivity.
reactive
n
general,
when
exposed
water.
When
a
metal
produced.
The
reacts
wit h
reaction
water,
can
be
t he
metal
summarised
hydroxide
by
t he
and
hydrogen
following
general
are
word
equation:
metal

water
metal
hydroxide

hydrogen
When a metal reacts wit h steam, t he metal oxide and hydrogen are produced.
The
reaction
metal
Table
into


17
.2.2
be
wit h
17.2.2
summarised
steam
shows
contact
T
able
can
t he
metal
what
water
Reactions
Description
Potassium
Reacts
very
happens
or
of
Metal
water
by
the
when
a
with
water
reaction
vigorously
producing
oxide

general
word
equation:
hydrogen
cer tain
metals
are
allowed
to
lilac
with
or
steam
Products
cold
formed
Potassium
and
hydroxide
equation
and
hydrogen:
flame
2K(s)

2H
O(l)
2KOH(aq)

H
2
Sodium
Reacts
water,
vigorously
producing
come
steam.
metals
of
following
with
an
cold
orange
Sodium
(g)
2
hydroxide
and
hydrogen:
flame
2Na(s)

2H
O(l)
2NaOH(aq)

H
2
Calcium
Reacts
moderately
with
cold
Slightly
(g)
2
soluble
calcium
hydroxide
and
hydrogen:
water
Ca(s)

2H
O(l)
Ca(OH)
2
Magnesium
Reacts
water
very
and
slowly
slowly
with
with
cold
hot
W ith
water
water:
hydroxide
Mg(s)

(aq)
very
and
2H
slightly
soluble
vigorously
with
steam
W ith

H
Mg(OH)
(aq)

Does
not
water.
react
Reacts
with
with
cold
or
hot
Aluminium
magnesium
oxide
O(g)
and
MgO(s)
hydrogen:

2H
not
water.
react
Reacts
with
with
cold
or
hot
Zinc

oxide
3H
oxide
and
hydrogen:
O(g)
Al
O
2
and
(s)

Does
not
react
Reacts
with
with

H
O(g)
ZnO(s)

H
cold
or
hot
Iron(II
III)
oxide

4H
and
hydrogen:
O(g)
Fe
2
Does
not
(g)
2
steam
3Fe(s)
Copper
(g)
2
2
water.
3H
3
hydrogen:
steam
Zn(s)
Iron
(g)
2
2
Does
(g)
2
steam
2Al(s)
Zinc
H
2
2
Aluminium
(g)
2
hydrogen:
O(l)
steam:
Mg(s)
H
magnesium
2
Reacts

2
react
with
water
or
react
with
water
or
O
3
(s)

4H
4
(g)
2
steam
Silver
Does
not
steam
t
can
water.
to
be
react
water.
most
seen
They
from
do,
means
Once
Table
however,
t hat
again,
vigorously
t hey
17
.2.2
react
are
less
potassium,
wit h
t hat
wit h
some
steam.
reactive
sodium
of
t he
The
t han
and
metals
fact
t he
t hat
ones
calcium
do
not
t hey
t hat
are
react
require
react
metals
wit h
steam
wit h
t hat
cold
react
water.
When potassium and sodium react wit h cold water, t hey bot h roll into a ball
and
move
rapidly
around
on
t he
surface
of
t he
water
as
t hey
decrease
in
size.
As t hey move, a lilac ame forms around t he ball of potassium and an orange

ame forms around t he ball of sodium. The lilac ame around t he potassium
is
shown
in
Figure
17
.2.2.
Figure
around
cold
17.2.2
A
lilac
potassium
ame
when
it
forms
reacts
with
water
285
Chemical
properties
and
reactions
of
metals
Characteristics
Investigating
(T
eacher
Your
●
teacher
teacher
Great
of
metals
with
metals
water
demonstration)
may
observation,
Y
our
reactions
of
care
use
this
recording
will
perform
must
be
activity
and
the
taken
to
assess:
reporting.
following
when
experiment.
reacting
potassium
and
sodium
with
water.
Method
3
1
Place
about
clean
2
2 cm
of
magnesium
Look
for
signs
of
distilled
ribbon.
water
Leave
effervescence
into
a
test
undisturbed
and
dip
a
tube
for
piece
and
one
of
add
a
piece
of
hour.
red
litmus
into
the
solution.
3
3
4
Place
about
piece
of
Look
by
5
Half
for
a
a
Look
for
surface
7
a
of
into
Repeat
around
the
8
the
9
The
n
Table
t hat
17
.2.3
is
a
with
the
the
water
surface
Note
the
of
the
gas
for
mouth
and
the
test
tube
and
add
a
of
the
the
presence
tube.
Dip
of
a
hydrogen
piece
of
red
place
a
very
small
piece
of
water.
as
the
colour
potassium
a
a
small
sodium,
potassium
of
the
ame
disappears,
the
piece
test
burning
reacted
We
and
by
is
chemical
of
dip
moves
that
a
around
forms
piece
of
on
the
around
the
red
litmus
of
for
sodium.
the
If
a
presence
ame
of
does
not
hydrogen
form
by
touching
splint.
most
vigorously
can
react
again
are

with
ver y
what
water
t he
and
which
reacted
word
metal
t he
reacts
acids
nitric
metals
wit h
acid,
which
acids.
are
The
to
form
ver y
a
salt
reactive
reaction
can
be
equation:

hydrogen
metal
when
reactions.
except
reactive
on
four
dilute
salt
happens
a
the
acids,
t hat
general
depends
When
chloride.
wit h
acid
produced
for
with
see
also
following
metal
acid.
equations
metals
metals
water
t he
shows
hydrochloric
formed
of
with
reactive
oxygen
test
at
effervescence
with
reactions
salt
another
vigorously?
reactive
286
6
metal
summarised
The
into
solution.
ball
hydrogen.
wit h
of
balanced
general,
and
step
least
Write
water
solution.
water.
When
the
the
the
the
and
splint
trough
trail
the
sodium
Which
into
onto
potassium.
paper
burning
large
potassium
6
distilled
effervescence
paper
ll
of
calcium.
placing
litmus
2 cm
used
cer tain
wit h
and
t he
metals
acid.
react
hydrochloric
wit h
acid
dilute
t he
salt
Characteristics

T
able
17.2.3
of
metals
Reactions
Chemical
of
Metal
Description
Potassium
An
extremely
metals
of
the
violent
with
hydrochloric
reaction
reaction
and
reactions
of
metals
acid
Products
occurs
properties
Potassium
formed
chloride
and
and
equation
hydrogen:
2K(s)

2HCl(aq)
2KCl(aq)

H
(g)
2
Sodium
A
violent
reaction
occurs
Sodium
chloride
and
hydrogen:
2Na(s)

2HCl(aq)
2NaCl(aq)

H
(g)
2
Calcium
A
fairly
violent
reaction
occurs
Calcium
chloride
and
hydrogen:
Ca(s)

2HCl(aq)
CaCl
(aq)

H
2
Magnesium
A
very
vigorous
reaction
occurs
Magnesium
chloride
and
hydrogen:
Mg(s)

2HCl(aq)
(g)
2
MgCl
(aq)

H
2
Aluminium
A
vigorous
Zinc
A
fairly
reaction
occurs
Aluminium
chloride
and
hydrogen:
2Al(s)

6HCl(aq)
2AlCl
(g)
2
(aq)

3H
3
vigorous
reaction
occurs
Zinc
chloride
and
hydrogen:
Zn(s)

2HCl(aq)
ZnCl
(aq)

H
2
Iron
A
very
slow
reaction
occurs
Iron(II)
chloride
and
hydrogen:
Fe(s)

2HCl(aq)
FeCl
Does
not
react
with
dilute
acids
–
Silver
Does
not
react
with
dilute
acids
–
Looking
t hat
at
t he
reactions
potassium,
of
sodium,
metals
wit h
calcium
hydrochloric
and
magnesium
acid
are
we
t he
can
again
most
(g)
2
(aq)

H
2
Copper
(g)
2
(g)
2
see
reactive
Did
?
you
know?
metals.
It
The
reactions
between
t he
metals
and
dilute
sulfuric
acid
are
ver y
similar
is
unadvisable
reactions
t he
reactions
which
occur
wit h
dilute
hydrochloric
acid.
However,
when
reacts
wit h
sulfuric
acid,
t he
salt
formed
is
a
the
Your
teacher
reactions
may
use
this
of
activity
●
observation,
recording
●
analysis
interpretation.
Y
ou
will
zinc,
be
iron
tubes
and
supplied
and
and
a
with
copper,
wooden
metals
and
the
sodium
with
an
acid
because
and
these
dilute
metals
react
reactions
are
so
violently
that
dangerous.
acids
assess:
reporting
samples
dilute
to
with
perform
potassium,
sulfate.
three
Investigating
of
a
calcium
metal
to
to
of
the
metals
hydrochloric
acid,
magnesium,
dilute
sulfuric
aluminium,
acid,
ve
test
splint.
Method
3
1
Carefully
ve
2
test
Label
place
about
2 cm
of
dilute
hydrochloric
acid
into
each
of
the
tubes.
each
tube
with
the
symbol
of
the
particular
metal
that
will
be
added.
hydrogen
3
Add
a
small
piece
of
metal
to
each
tube
so
that
each
tube
contains
lighted
4
different
metal
Observe
each
test
the
gas
as
indicated
tube
for
the
for
by
signs
its
of
presence
of
the
mouth
of
the
tube
and
effervescence.
hydrogen
feel
splint
label.
by
If
effervescence
placing
a
lighted
is
seen,
splint

at
the
bottom
of
the
tube
to
see
if
Figure
17.2.3
If
no
effervescence
is
seen,
heat
the
tube
gently.
the
presence
If
effervescence
is
holding
mouth
pop’
seen
on
gas
production
can
be
of
conrmed
warm.
by
5
The
it
hydrogen
becomes
gas
a
heating,
test
the
gas
for
of
hydrogen.
Make
of
a
the
sound
lighted
test
will
splint
tube.
identify
A
near
the
‘squeaky
the
gas
as
sure
hydrogen.
that
acid
you
do
boils.
source
of
not
confuse
effervescence
Effervescence
heat,
boiling
continues
does
with
after
bubbling
the
tube
is
that
occurs
removed
if
the
from
the
not.
287
Reactions
of
metal
compounds
Summary
1
Write
a
Characteristics
questions
balanced
6
Repeat
for
method
using
dilute
acid.
Record
observations
sulfuric
acid
in
place
of
metals
dilute
chemical
7
equation
the
hydrochloric
of
each
of
your
in
a
table,
noting
if
the
reaction
needed
the
heating.
following
reactions:
a
calcium
b
zinc
c
reacting
reacting
with
Did
acid
iron
with
the
metal
with
hydrochloric
reacting
8
oxygen
even
sulfuric
9
In
metals
reacted
when
what
differ
the
in
their
most
reactivity
vigorously
with
and
the
which
acids?
If
showed
they
no
did,
which
reaction
at
all,
heated?
ways
were
the
reactions
between
the
metals
and
the
two
acids
acid.
similar?
2
How
do
the
products
of
10
reactions
differ
when
Aluminium
with
water
and
reacts
with
steam?
were
Write
each
chemical
Write
equation
Which
seems
reactive,
balanced
sulfuric
to
be
iron
or
seem
reactive,
metals
to
be
the
Group
or
the
I
metals,
transition
Group
II
metals?
t he
react
from
t he
end
of
this
topic
you
chemical
metal
reactions
oxides,
17.2.3
until
the
test
equations
for
the
reactions
of
the
metals
with
describe
reactions
of
carbonates
possibly
t he
test
discovered
tubes
were
t hat
aluminium
heated.
This
is
did
because
wit h
These
wit h
a
t hin
acids
 lm
oxide
salts
when
of
for ming
dissolve
cold.
aluminium
soluble
and
t he
When
oxide
heated,
aluminium
aluminium
t he
whic h
acids
prevents
c hlor ide
is
t hen
or
able
react
wit h
aluminium
to
react
wit h
Reactions
of
metal
compounds
have
will
already
review
come
t hese
across
and
some
look
at
of
t he
some
reactions
new
of
metal
reactions
in
compounds.
t his
unit.
The
of
hydroxides
with
the
you
until
acids.
we
will
be
looking
at
include
metal
oxides,
metal
hydroxides,
and
metal
carbonates
acids
coated
aluminium
You
the
is
compounds
●
T
able
will
to:
describe
t he
reacting
sulfate.
We
●
in
why?
acid.
exper iment,
wit h
C17.3
Objectives
able
suggest
least
t he
be
described
you
copper?
it
the
as
Can
more
aluminium
Which
By
heated.
for
not
4
differences?
reaction.
Dur ing
3
any
react
a
dilute
balanced
not
when
11
it
there
did
magnesium
tubes
reacts
Were
the
carbonates
and
metal
nitrates.
acids
decomposition
metal
and
Reactions
nitrates,
of
metal
oxides
hydroxides.
Metal
oxides
summarised
metal
This
a
reacts
t hat
wit h
is
wit h
t he
oxide
reaction
base
react
by

known
acid
to
form
general
acid
neutralises
an
acids
following
as
a
t he
t he
a
salt
word
salt

to
reaction
form
a
reaction
salt
becomes
water.
The
reaction
can
be
water
neutralisation
acid
and
equation:
and
since
water.
warmer
t he
When
because
it
is
metal
a
oxide
metal
exot hermic.
Examples
1
Copper(II)
sulfate
oxide
and
reacts

H
SO
2
During
Figure
17.3.1
Black
powdery
slowly
disappears
in
acid
to
produce
soluble
copper(II)
t he
(aq)
CuSO
4
reaction,
(aq)

H
4
t he
black,
powder y
O(l)
2
copper(II)
oxide
disappears
copper( II)
slowly
oxide
sulfuric
water:
CuO(s)

wit h
and
a
blue
solution
forms.
This
is
because
soluble
copper(II)
sulfuric
2
sulfate
acid
as
it
copper( II)
288
reacts
sulfate
to
form
soluble,
is
produced
which
blue
speeded
up
by
heating
it.
contains
blue
Cu
ions.
The
reaction
is
oxide
can
be
Characteristics
2
of
metals
Magnesium
oxide
magnesium
chloride
MgO(s)
Reactions
reacts
wit h
and
hydrochloric
acid
to

O(l)
white,
acid
to
2HCl(aq)
powder y
form
Reactions
Metal
can
MgCl
is
a
of
metal
also
summarised
metal
(aq)
t he
and
exot hermic,
is
it
also
a
of
H
soluble
2
disappears
magnesium
wit h
acids
following

to
acid
t he
form
general
acid
becomes
to
a
as
it
reacts
wit h
t he
chloride.
salt
word
salt
neutralisation
it
compounds
hydroxides
neutralises
t herefore
oxide
solution
react
by
hydroxide
reaction
base
magnesium
colourless
hydroxides
be
This
a
metal
water:
2
The
produce
of

a
water.
The
reaction
water
reaction
form
and
equation:
since
salt
and
t he
metal
water.
hydroxide
The
reaction
is
warmer.
Examples
1
Copper(II)
nitrate
hydroxide
and
reacts
Cu(OH)
(s)

2HNO
2
During
t he
solution
wit h
nitric
acid
to
produce
soluble
copper(II)
water:
(aq)
Cu(NO
3
reaction,
forms
due
t he
to
blue
t he
)
3
copper(II)
production
(aq)
2H
soluble
O(l)
2
hydroxide
of

2
disappears
copper(II)
and
nitrate
a
blue
which
2
contains
2
Zinc
blue
Cu
hydroxide
chloride
and
ions.
reacts
wit h
hydrochloric
acid
Zn(OH)
(s)

2HCl(aq)
ZnCl
2
The
to
white,
form
a
Metal
The
powder y
of
metal
When
carbon
a
can
zinc
react
be
metal
soluble
zinc
(aq)

2H
disappears
zinc
O(l)
2
at
it
reacts
wit h
t he
acid
chloride.
carbonates
wit h

carbonate
is
of
acids
summarised
carbonate
dioxide
hydroxide
solution
metal
carbonates
reaction
produce
2
colourless
Reactions
to
water:
to
by
form
t he
acid
reacts
a
salt,
salt
wit h
carbon
following
an

acid,
dioxide
general
carbon
word
and
d ioxide
effer vescence
water.
equation:
is

water
seen
as
t he
evolved.
Examples
1
Calcium
nitrate,
carbonate
carbon
CaCO
(s)
reacts
dioxide

2HNO
3
During
t he
calcium
colourless
solution
nitric
acid
to
(aq)
fairly
quickly
of
produce
soluble
calcium
water:
Ca(NO
3
reaction,
carbonate
wit h
and
)
3
vigorous
as
it

CO
reacts
(g)

H
2
effer vescence
disappears
calcium
(aq)
2
occurs,
wit h
t he
O(l)
2
and
t he
acid
to
white
form
a
nitrate.
289
Reactions
of
metal
compounds
Characteristics
2
ron(II)
carbonate
carbon
dioxide
FeCO
(s)
reacts
and

H
3
Fairly
SO
a
acid
(aq)
FeSO
4
to
produce
green
(aq)

CO
4
effer vescence
and
sulfuric
iron(II)
metals
sulfate,
water:
2
vigorous
disappears
wit h
of
occurs.
solution
The
forms

H
2
green
due
to
iron(II)
t he
O(l)
2
carbonate
production
of
quickly
soluble
2
iron(II)
sulfate
which
Decomposition
Many
metal
contains
of
green
metal
compounds
Fe
ions.
compounds
decompose
when
t hey
are
heated.
Table
17
.3.1
summarises t he effects of heat on metal nitrates, metal carbonates and metal
hydroxides.

T
able
17.3.1
The
effect
Metal
of
heat
on
metal
nitrates,
metal
carbonates
and
metal
hydroxides
compound
Metal
Nitrates
Carbonates
Potassium
Decompose
Sodium
2NaNO
to
form
the
metal
nitrite
and
Do
oxygen:
not
The
(s)
2NaNO
3
Decompose
Calcium
dioxide
(s)

O
2
and
to
form
the
metal
Hydroxides
decompose.
carbonates
are
Do
stable.
not
The
decompose.
hydroxides
are
stable.
(g)
2
oxide,
nitrogen
Decompose
oxygen:
and
carbon
to
form
the
metal
oxide
Decompose
dioxide:
water
(as
to
form
the
metal
oxide
and
steam):
Magnesium
2Mg(NO
)
3
Aluminium
2Cu(NO
(s)
2MgO(s)

4NO
2
)
3
Zinc
(g)

O
2
(s)
2CuO(s)

4NO
2
(g)
MgCO
2
(g)

O
2
(s)
MgO(s)

CO
3
(g)
CuCO
2
(g)
Mg(OH)
2
(s)
CuO(s)

CO
3
(s)
MgO(s)

H
2
(g)
Cu(OH)
2
O(g)
2
(s)
CuO(s)

H
2
O(g)
2
Iron
Lead
Copper
Sliver
Decomposes
dioxide
and
2AgNO
to
form
the
metal,
silver,
nitrogen
oxygen:
(s)
2Ag(s)

2NO
3
(g)

O
2
Silver
carbonate
is
unstable.
too
does
not
exist
since
it
Silver
too
hydroxide
does
not
exist
since
it
is
unstable
(g)
2
When some metal compounds are heated and they decompose,
are
obser ved.
For
example,
when
the
compounds
of
copper
colour changes
are
heated
they
change colour from blue or blue-green to black because black copper(II) oxide
is formed in each reaction. When compounds of lead are heated, they change
colour
from
white
to
yellow
because
yellow
lead(II)
oxide
is
produced.
Tests
given in Table 22.3.1 on page 354 can be used to identify the oxygen, nitrogen
dioxide,
carbon
dioxide
and
water
vapour
produced
when
metal
compounds
decompose.
Looking at t he decomposition of metal compounds we can see t hat potassium
and
in
Investigating
Your
●
teacher
will
be
and
dry
test
this
recording
with
hydroxide,
tubes,
one
activity
and
water,
tted
form
of
stable
t he
which
decomposes
ver y
to
of
metal
compounds
nitrates,
are
too
easily
only
unstable
and
which
do
decompose
to
completely
exist
not
decompose
slightly.
or,
when
in
on
However,
t he
case
of
heating
silver
silver
nitrate,
heated.
compounds
assess:
with
of
sodium
nitrate,
a
wooden
splint,
a
cork
which
has
calcium
nitrate,
a
piece
of
a
delivery
blue
tube
sodium
litmus
carbonate,
paper,
running
a
copper(
piece
through
it.
of
II)
cobalt
carbonate,
chloride
or,
forms
reporting.
samples
lime
case
compounds
decomposition
use
supplied
magnesium
290
may
observation,
Y
ou
the
sodium
t he
paper
Characteristics
of
metals
Reactions
of
metal
compounds
Method
1
Place
still
2
3
a
spatula
heating
Repeat
to
fumes.
If
Place
end
a
of
Repeat
5
Place
you
and
7
Which
8
Explain
9
Write
2
of
using
of
the
you
the
colour
balanced
a
sodium
saw
did
of
not
into
a
the
each
you
saw
in
test
tube
nitrate.
litmus
should
tube.
strongly
glowing
do
Place
until
the
lime
in
test
the
the
cork
water
see
slowly
time
into
this
you
splint
This
paper
containing
place
in
a
of
test
copper( II)
tube
for
was
Explain
when
equations
chemical
equation
you
the
for
magnesium
b
the
reaction
between
copper( II)
c
the
reaction
between
zinc
and
explain
into
balanced
following
you
compound
between
Write
sodium
blue
a
for
brown
fume
into
(see
vigorous
into
the
oxygen
gas.
effervescence.
While
tube.
when
T
ake
a
care
brown
not
to
gas
inhale
the
cupboard.
the
mouth
Figure
of
the
8.1.2).
tube
Heat
the
with
test
the
other
tube
and
carbonate.
heat
strongly.
Place
a
piece
of
dry
cobalt
chloride
heated.
why.
heated
copper( II)
decomposition
carbonate.
reactions.
questions
balanced
put
a
heat
tube.
reaction
is
into
hydroxide
the
Describe
of
moist
test
and
inserting
available,
decompose?
change
chemical
place
carbonate
when
tube
by
water.
magnesium
mouth
compound
lime
test
of
carbonate
leading
the
in
piece
cupboard
copper( II)
tube
a
a
oxygen
nitrate
Place
fume
into
of
a
oxide
3
3
what
Summary
Write
a
nitrate
presence
calcium
observe
across
Describe
1
have
spatula
6
the
using
delivery
step
a
sodium
for
produced.
spatula
strongly
paper
be
the
4
1
step
begins
of
test
metal
a
calcium
b
potassium
c
zinc
d
lead( II)
the
sulfuric
chemical
and
change
and
to
the
and
which
following:
and
sulfuric
heated
equations
of
carbonate
oxide
colour
acid
each
hydroxide
nitric
acid
hydrochloric
acid
acid.
occurs
when
copper( II)
gently.
show
the
effect
of
heat
on
the
compounds:
carbonate
nitrate
hydroxide
nitrate.
291
Reactions
of
metal
compounds
Characteristics
Key
●
Metals
are
reactions
A
metal
elements
usually
by
The
is
whose
2
or
3,
t hese
atoms
and
valence
composed
of
have
t hey
a
small
form
number
positive
of
valence
cations
in
chemical
electrons.
metal
cations
surrounded
by
a
‘sea’
of
electrons.
electrostatic
negative
1,
losing
lattice
delocalised
●
metals
concepts
electrons,
●
of
attraction
electrons,
known
between
as
t he
positive
metallic
cations
bond,
and
holds
delocalised
t he
metal
lattice
toget her.
●
●
n
general,
have
densities.
The
high
Metals
of
form
a
behave
●
Metals
react
●
f
●
Potassium,
metal
Ot her
and
●
●
as
and
Metal
●
and
boiling
malleable
by
relating
points,
and
conduct
ductile
t hem
to
and
t he
to
form
in
and
in
and
by
losing
valence
reactions.
metal
water
reactions
compounds
oxides.
t hey
form
magnesium
alkaline
react
solutions.
wit h
water
to
form
hydrogen.
copper,
react
wit h
steam
to
form
t he
metal
oxide
metals
react
react
Metal
a
hydrochloric
acid
and
sulfuric
acid
to
form
a
wit h
acids
to
form
a
salt
and
water.
The
reaction
is
a
reaction.
hydroxides
also
wit h
hydrogen.
oxides
Metal
is
are
chemical
ionic
agents
calcium
except
points
lustre,
explained
in
form
dissolve
sodium,
be
cations
t hey
hydroxide
neutralisation
●
can
oxygen
can
melting
shiny
lattice.
reducing
wit h
metals,
a
hydrogen.
Reactive
salt
metals
metallic
result
oxides
high
have
positive
As
Metals
metal
of
t he
●
t he
heat,
proper ties
electrons.
●
have
and
str ucture
●
metals
electricity
react
neutralisation
carbonates
react
wit h
acids
to
form
a
salt
and
water.
The
reaction
reaction.
wit h
acids
to
form
a
salt,
carbon
dioxide
and
water.
●
The
t he
●
nitrates
metal
The
nitrates
form
●
●
t he
Silver
of
of
nitrate
oxygen.
The
carbonates
to
carbonates
form
t he
metals,
oxide,
and
when
of
metal
and
sodium
decompose
when
heated
to
form
oxygen.
except
nitrogen
decomposes
and
The
and
ot her
metal
decomposed
●
potassium
nitrite
silver,
dioxide
when
hydroxides
heated
of
decompose
and
to
when
heated
to
oxygen.
form
potassium
silver,
and
nitrogen
sodium
are
dioxide
not
heated.
ot her
oxide
metals,
and
except
carbon
silver,
dioxide.
decompose
Silver
when
carbonate
heated
does
not
exist.
●
The
t he
292
hydroxides
metal
oxide
of
metals,
and
water
except
as
silver,
steam.
decompose
Silver
when
hydroxide
does
heated
not
to
exist.
form
Characteristics
of
metals
Practice
i)
Practice
exam-style
Complete
t he
table
by
exam-style
writing
in
t he
ii)
Using
All



solid
lose
at
room
electrons
form
symbols
A
and
B,
as
shown
temperature
when
t hey
react
above,
write
balanced
–
t he
reaction
between
A
–
t he
reaction
between
B
–
t he
equations
A

B

and

C

and

between
A
D

and
hydrochloric
reaction
and
oxygen.
only
and
i)
When
following
may
be
statements
are
all
tr ue
metals
are
heated,
one
or
two
given
off.
calcium
hydroxide
and
reacts
reacts
wit h
cold
calcium,
From
t he
sodium,
nitrates
zinc
and
of
copper,
except:
select
ron
nitrates
only
t he
B
most
only

When
marks)
only
gases
A
t he
steam
and
(5
The
t he
for
acid
soluble basic oxides when they react with oxygen
b
2
marks)
in
following:
metals:
are
t he
(3
questions
table
1
missing
questions
information.
Multiple-choice
questions
water
it
forms
ONE
nitrate
t hat:
calcium
–
gives
off
–
gives
off
ONE
gas
hydrogen.
more
vigorously
t han
zinc
wit h
T WO
gases.
(2
marks)
hydrochloric
ii)
Write
t he
equation
for
t he
reaction
which
acid.
gives
C
Magnesium
burns
readily
in
c
D
3
When
silver
Metals
can
A
t he
atoms
B
t he
cations
C
t here
nitrate
conduct
an
decomposes
electric
it
forms
current
An
t he
metal
t he
gases
metal,
Z,
above.
was
(2
found
to
react
marks)
in
a
ver y
silver.
similar
way
of
on
heat
to
t he
magnesium.
carbonate
How
of
Z
would
differ
t he
from
action
t he
because:
of
heat
on
sodium
carbonate?
vibrate
Give
in
T WO
unknown
action
in
off
air.
metal
lattice
are
t he
relevant
equation(s)
given
t hat
Z
forms
mobile
2
t he
are
lattice
D
some
small
which
of
t he
spaces
allow
between
electricity
electrons
in
t he
t he
to
atoms
pass
metal
in
t he
Which
of
t he
A
Metals
B
All
C
react
metal
wit h
and
Copper
is
a
lattice
are
Total
reacts
in
t he
air
readily
to
when
wit h
form
when
decomposes
dioxide
Zinc
acidic
oxides.
8
a
response
Metals
heated.
into
magnesium
t hey
heated.
high
hydrochloric
have
common.
acid.
in
liberates
hydrogen
gas
cold
are
are
malleable
melting
metals,
physical
good
and
points.
explain
ductile
By
t he
proper ties
conductors
and
reference
reason
for
of
in
electricity,
t hey
to
have
t he
EACH
bonding
of
listed.
Zinc
carbonate,
copper(II)
oxide
and
sulfuric
acid
are
A

B

and

each
C
,
D


t hree
treated
wit h
separate
excess
dilute
experiments.
reaction
using
t he
following

and
obser vations
on
adding
dilute
nitric
acid
only
explanation
of
t he
obser vations

iii)
equation
for
t he
reaction.
(9
Total
sodium
nitrate
but
t hey
melt
B
t hey
form
a
brown,
C
t hey
form
a
gas
D
t hey
evolve
a
Structured
The
do
cr ystals
A
not
a
table
A
below
and
Charge
on
Metal
causes
squeaky
B,
gives
and
some
t heir
a
glowing
lighted
splint
splint
to
be
pop
information
about
two
reactions.
of
water
on
the
Does
not
does
react
react
with
with
cold
Action
of
on
metal
dilute
metal
ion
but

a
the
Action
metal
B
marks
question
metals,
2
15
heated:
gas
relights
which
wit h
are
decompose
acidic
which
gas
extinguished
A
marks)
only
When
a
Discuss
sub-titles:
only
i)
and
in
acid
ii)
7
marks)
magnesium
steam
EACH
6
t he
(6
water
nitric

cer tain
They
hydroxide

question
from:
b

marks
mobile
proper ties
5
marks)
15
statement?
decompose
carbonate
carbon
tr ue
oxygen
hydroxides
Magnesium
oxide
D
following
(3
t hrough
Extended
4
ion.
Z
metal
or
hot
hydrochloric
acid
Action
the
water
Burns
steam
if
Reacts
of
air
when
on
the
heated
metal
strongly,
especially
powdered
violently
293
Reactivity,
extraction
and
C18
uses
Metals
of
vary
metals
considerably
in
their
reactivity.
Some
are
Objectives
By
the
be
able
end
of
this
topic
you
will
so
reactive
with
●
discuss
●
describe
the
reactivity
of
metals
oxygen
metal
between
metals
must
be
stored
out
of
contact
unreactive.
the
basis
series
the
reactivity
of
of
order
moisture
The
in
reactive
the
air.
metals
Others
occur
in
are
the
extremely
Earth’s
ionic
compounds
from
which
they
are
extracted.
compounds
are
known
as
ores.
The
unreactive
the
occur
in
the
Earth’s
crust
in
their
elemental
state.
metals
Metals
of
metals
experimental
in
These
of
ones
deduce
or
and
compounds
explain
reactivity
●
they
displacement
crust
reactions
●
that
to:
based
on
of
the
are
used
things
we
extensively
by
man
see
us
and
around
to
make
this
many
makes
their
results.
extraction
C18.1
t
is
The
possible
reactions.
from
●
t he
t he
extremely
to
The
determine
reactive
strengt h
of
hydrochloric
how
●
displacement
will
now
Strength
dilute
t heir
t he
of
each
metals
least
dilute
series
is
reactive
wit h
are
a
of
list
metals
of
based
oxygen,
sulfuric
by
metals
on
t he
water
looking
arranged
at
in
t heir
order
following:
and
dilute
acid
decomposed
between
of
metals
reactivity
compounds
at
of
reactions
reactions
look
of
or
t he
series
to
t heir
acid
●
We
easily
reactivity
reactivity
most
important.
t he
metals
when
and
heated
metal
compounds.
t hese.
reaction
with
oxygen,
water
and
acids
You studied t he reactions of a variety of metals wit h oxygen, water and dilute
acids
●
in
Unit
reactive
●
metals
acid.
Copper
is
from
oxygen,
potassium,
nally
n
Unit
easily
4
its
ionises,
wit h
least
or
at
t hese
calcium
oxygen,
reactive
dilute
and
acid.
we
water
metal
Silver
can
see
cer tain
magnesium
and
wit h
does
trends.
appear
to
hydrochloric
oxygen
not
react
and
it
wit h
be
t he
most
not
react
and
does
oxygen,
water
or
acids.
Star ting
wit h
t he
steam
dilute
Looking
sodium,
sulfuric
wit h
●
17
.2.
Potassium,
potassium,
water
sodium,
and
t he
strengt h
dilute
calcium,
acid
of
t he
decreases
magnesium,
reaction
in
t he
zinc,
of
t he
metals
following
iron,
copper
order:
and
silver.
you
atoms
t he
learnt
t hat
ionise,
more
t he
known
reactive
it
reactivity
as
is.
ease
Of
t he
of
of
a
metal
ionisation .
metals
is
determined
The
studied,
more
by
easily
potassium
is
a
how
metal
t he
most
reactive metal because it ionises t he most easily and silver is t he least reactive
because
294
it
ionises
t he
least
easily.
Reactivity,
extraction
and
Decomposition
uses
of
of
metals
metal
The
reactivity
of
metals
compounds
We studied t he decomposition of metal compounds in Unit 17
.3. Looking at
t hese
●
reactions
The
ver y
we
reactive
compounds.
not
The
and
decomposes
from
t he
of
and
trends.
and
sodium,
hydroxides
and
of
easily
t he
t heir
iron,
it
can
be
of
seen
form
are
nitrates
so
are
fairly
stable
stable
t hat
t hey
decomposed
are
only
t he
t hat
unstable
unstable
decompose
t he
ease
following
nally
t he
less
too
such
to
t hat
exist
silver
and
silver
nitrate
heated.
metals
and
The
are
calcium,
in
lead
compounds.
extremely
when
ot her
compounds
aluminium,
t his
are
hydroxide
increases
its
potassium
heated
silver
silver
compounds
are
cer tain
carbonates
when
ver y
Compounds
From
see
slightly.
compounds
carbonate
●
again
metals,
Their
decomposed
ver y
●
can
of
order:
when
heated.
Star ting
decomposition
calcium,
of
t he
magnesium,
zinc,
copper.
more
reactive
reactive
t he
t he
metal
metal
is,
is,
t he
t he
less
more
stable
stable
are
its
compounds and t he more easily t hey decompose. This is because t he reactive
metals
ionise
compounds
t he
ions
easily
ver y
t hey
and
t he
stable.
form
are
ions
The
t hey
less
unstable.
form
reactive
This
are
ver y
metals
means
t hat
stable.
do
not
t heir
This
makes
ionise
t heir
easily
compounds
are
and
also
unstable.
Displacement
A
d isplacement
reactions
reaction
occurs
when
a
metal
in
its
free
state
(chemically
uncombined) takes t he place of (displaces) anot her metal from a compound.
A
more
reactive
metal
will
always
displace
a
less
reactive
metal
from
its
compounds.
f
a
more
reactive
reactive
metal,
reactive
metal
t he
less
This
will
reactive
of ten
metal
t he
more
be
off
placed
d ischarged
metal
drops
is
reactive
will
into
form
t he
in
a
solution
metal
to
on
will
form
t he
solution
atoms.
surface
when
containing
ionise
As
of
and
a
more
and
ions
ions
result,
t he
disturbed
t he
a
of
of
less
less
precipitate
reactive
t he
a
t he
more
of
metal.
reactive
metal gradually decreases in size. Depending on t he nature of t he solution, it
may
also
undergo
Displacement
difference
t he
A
in
a
colour
reactions
t he
change
are
reactivity
of
as
t he
reaction
exothermic
t he
two
proceeds.
reactions .
metals,
t he
more
The
heat
is
greater
t he
produced
in
reaction.
displacement
reaction
can
be
summarised
by
t he
following
general
equation:
A
BX

more
less
reactive
reactive
t han
B
t han
AX
B

A
n
●
A
is
more
reactive
t han
B.
A
ionises
to
form
A
ions:
n
A
A

ne
n
●
B
is
less
reactive
t han
A.
The
B
ions
are
discharged
to
form
B
atoms:
n
B

ne
B
295
The
reactivity
of
metals
Reactivity,
Displacement
Did
?
you
acts
know?
as
a
reactive
It
is
by
a
possible
placing
solution
a
of
to
make
coil
of
silver
a
‘silver
copper
nitrate.
tree’
wire
reactions
reducing
metal.
reducing
are
agent
The
also
redox
because
more
it
reactive
reactions .
gives
t he
extraction
The
electrons
metal
is,
t he
and
more
to
t he
more
uses
of
metals
reactive
ions
of
powerful
metal
t he
it
less
is
as
a
agent.
into
Copper
is
Example
more
it
reactive
displaces
silver
than
the
nitrate
silver,
silver
and
therefore,
from
after
a
The
the
while
reaction
between
magnesium
and
copper(II)
Mg(s)

CuSO
(aq)
MgSO
4
is
deposited
forming
a
on
the
beautiful
copper
sulfate
solution:
silver
(aq)

Cu(s)
4
wire
‘tree’.
Magnesium
is
more
reactive
t han
copper,
t herefore,
t he
magnesium
ionises
2
and
t he
Mg
ions
enter
t he
solution.
2
Mg(s)
Mg
(aq)

2e
2
The
Cu
copper
ions
in
t he
copper(II)
sulfate
solution
are
discharged
forming
atoms:
2
Cu
A
pink
t he
(aq)

2e
precipitate
solution
Cu(s)
of
when
copper
builds
disturbed.
The
up
on
t he
magnesium
magnesium
becomes
and
drops
smaller
and
off
t he
into
blue
2
colour
The
of
t he
overall
solution
ionic
gradually
equation
for
fades
t he

Figure
into
a
18.1.1
solution
When
copper
containing
is

Cu
is
deposited
on
the
blue
Cu
ions
are
discharged.
is:
2
(aq)
Mg
(aq)

Cu(s)
placed
silver
ions,
Investigating
silver
t he
reaction
2
Mg(s)
as
displacement
reactions
copper
Your
teacher
may
use
this
activity
●
observation,
recording
●
analysis
interpretation.
Y
ou
will
and
be
supplied
approximately
sulfate
the
solution,
with
same
zinc
and
sulfate
assess:
reporting
clean
size:
to
samples
of
magnesium,
solution,
the
following
zinc
copper( II)
and
metals
copper,
sulfate
of
magnesium
solution
and
six
test
tubes.
Method
3
1
Place
about
5 cm
magnesium
sulfate
solution
into
each
of
two
test
tubes
and
5 cm
3
tubes,
of
2
Add
a
each.
shake
If
a
After
10
If
sulfate
off
of
zinc
and
a
into
the
into
last
another
two
two
tubes.
Measure
and
record
solution.
magnesium
to
to
the
the
piece
of
zinc
sulfate
magnesium
copper
to
and
the
sulfate
the
copper( II)
and
the
magnesium
sulfate
copper( II)
sulfate
and
solutions.
each
tube
metal
from
minutes,
the
solution
solution
each
displacement
displaced
tube.
296
of
of
piece
sulfate
dropping
4
a
solutions
zinc
Gently
the
sulfate
piece
sulfate
the
zinc
temperature
solutions,
3
of
copper( II)
the
3
5 cm
periodically
reaction
deposited
the
metal
measure
temperature
of
on
into
the
any
and
occurs,
the
the
observe
it
should
metal
solution
temperature
tube
you
what
be
added
when
of
the
increases,
occurs
possible
and
in
to
see
possibly
shaken.
contents
calculate
of
the
each
increase.
Reactivity,
5
extraction
Observe
about
6
Record
similar
was
the
30
uses
colour
of
of
the
metals
The
copper( II)
sulfate
solution
in
each
tube
reactivity
of
metals
after
minutes.
your
to
not
and
observations
the
one
carried
appropriate
outlined
out.
If
no
and
any
below.
temperature
The
reaction
increases
indicates
occurred,
place
a
in
that
a
the
cross
in
table
reaction
the
place.
Observations
on
adding
Magnesium
Magnesium
dash
Zinc
Copper
sulfate
solution
Zinc
sulfate
Copper(II)
7
Using
so
the
that
metal
8
9
10
Why
solution
sulfate
most
appears
the
at
in
sulfate
solution?
a
the
why
the
copper( II)
balanced
Explain
a
from
reactive
the
table,
metal
draw
occurs
at
up
the
a
list
top
of
and
the
the
three
least
metals
reactive
bottom.
temperature
placed
Write
–
information
the
was
–
solution
increase
sulfate
chemical
greater
solution
than
equations
for
when
when
each
it
magnesium
was
placed
reaction
that
was
in
zinc
occurred.
following:
reaction
occurred
between
magnesium
and
copper( II)
sulfate
solution
b
why
no
c
why
the
zinc
and
reaction
blue
occurred
colour
copper( II)
of
between
the
sulfate
solution
copper
faded
and
in
the
zinc
sulfate
reaction
solution
between
solution.
most
reactive
potassium
zinc
magnesium
sulfate
sulfate
solution
copper(II)
solution
sulfate
sodium
solution
calcium
magnesium
aluminium
zinc
iron
lead
(hydrogen)

Figure
18.1.2
The
displacement
reactions
of
various
metals
with
metal
copper
salts
mercury
silver
The
reactivity
series
of
metals
gold
The
reactivity
strengt h
t he
of
ease
t he
of
series
of
reactions
some
of
of
t he
decomposition
of
t he
common
metals
t he
wit h
metal
metals,
oxygen,
drawn
water
compounds
and
and
up
from
dilute
t he
acids,
least

reactions,
is
given
in
Figure
18.1.3.
reactive
displacement
Figure
18.1.3
The
reactivity
series
of
metals
297
The
reactivity
of
metals
Reactivity,
Potassium, at t he top, is t he
extraction
and
uses
of
metals
most reactive. t ionises t he most easily and forms
t he most stable ions which are ver y hard to discharge. Gold, at t he bottom, is
✔
Exam
tip
t he
It
is
the
really
order
important
that
of
reactivity
the
reactivity
you
of
learn
in
reactive. t ionises wit h great difculty and forms ver y unstable ions
are
ver y
easy
to
discharge.
the
We
metals
least
which
can
use
t he
reactivity
series
of
metals
to
make
cer tain
predictions
series.
●
We
can
series
predict
is
known.
magnesium
water
will
how
and
also
it
For
will
dilute
not
any
metal
example,
react
acids
displace
less
but
will
if
a
react
metal
vigorously
more
calcium
if
its
occurs
t han
vigorously
but
will
position
in
between
calcium
t han
displace
t he
reactivity
calcium
wit h
and
oxygen,
magnesium.
magnesium
The
from
metal
t heir
compounds.
●
We
can
t he
way
predict
it
vigorously
wit h
to
zinc
displace
magnesium
below
position
what
reacts
is
known.
dilute
from
sulfate
a
For
metal
hydrochloric
zinc
sulfate
solution,
will
example,
occupy
if
acid
t he
in
metal
t han
solution
t hen
a
but
metal
t he
is
zinc
not
must
reactivity
found
and
is
to
series
react
also
if
more
found
magnesium
from
occur
zinc
above
but
magnesium.
f two metals are ver y similar in t he way t hey react, t hen it is easy to determine
which is higher in t he series by carr ying out displacement reactions between
t he
two
t he
lower
metals
Hydrogen
We
can
and
metal
is
use
t heir
from
its
included
t he
compounds.
The
higher
metal
will
always
displace
compounds.
in
t he
position
of
reactivity
hydrogen
series
to
even
predict
t hough
how
it
is
metals
a
non-metal.
will
react
wit h

acids
●
✔
Exam
if
since
a
metal
is
important
that
you
know
how
●
to
of
deduce
metals
the
order
based
on
of
or
above
t he
hydrogen
hydrogen
in
t he
ion,
H
:
data
if
a
t he
acid
metal
is
because
below
it
displaces
reactivity
hydrogen
in
t he
series,
t he
hydrogen
reactivity
in
t hen
t he
it
will
react
series,
it
acid
will
not
react
wit h
reactivity
t he
acid
because
t he
higher
it
will
not
displace
t he
hydrogen
in
t he
acid
experimental
●
results
is
contain
tip
wit h
It
acids
up
t he
metal
is
in
t he
series,
i.e.
t he
fur t her
it
is
away
from
supplied.
hydrogen,
t he
Summary
1
Why
is
2
Why
don’t
when
3
a
If
a
a
t he
reaction
will
be
wit h
an
acid.
questions
sodium
more
reactive
potassium
a
reaction
piece
sulfate
b
vigorous
than
carbonate
copper?
and
sodium
carbonate
decompose
heated?
Would
a
more
clean
of
occur
clean
if:
magnesium
ribbon
was
copper
placed
placed
into
copper(
II)
solution
piece
reaction
of
occurs,
was
explain
why
and
into
give
sodium
a
sulfate
balanced
solution?
equation
for
the
reaction.
4
Explain
metals
5
Metal
react
C
in
the
A
will
with
their
reactive.
298
benet
even
a
of
though
react
with
solution
correct
including
it
is
a
a
solution
containing
order
hydrogen
of
in
the
reactivity
series
of
non-metal.
containing
ions
reactivity
of
ions
metal
from
the
C.
of
metal
Write
most
B
but
metals
reactive
to
A,
will
B
the
not
and
least
Reactivity,
extraction
C18.2
The
ver y
state,
The
silver
uses
of
metals
extraction
unreactive
e.g.
and
metals
and
gold,
occur
and
of
in
The
metals
t he
can,
Ear t h’s
of
metals
Objectives
cr ust
t herefore,
extraction
be
in
t heir
mined
free
elemental
directly
from
By
the
be
able
end
of
this
topic
you
will
to:
t he
●
explain
how
the
position
of
a
Ear t h. Most metals, however, occur combined wit h ot her elements in impure
metal
in
the
reactivity
series
ionic compounds and t hey t hen have to be extracted from t hese compounds.
determines
Compounds
from
which
metals
can
be
extracted
are
known
as
ores.
its
extraction
The
method
most
impor tant
ores
are
metal
oxides,
suldes
and
carbonates.
●
The
extraction
positive
of
metal
a
metal
cations
from
have
its
to
ore
be
is
a
reduction
discharged
to
process
form
because
atoms
by
t he
describe
the
extraction
of
extraction
of
aluminium
gaining
●
describe
the
iron.
electrons:
n
M

ne
M
The actual met hod used depends on t he position of t he metal in t he reactivity
series.
●
Metals
high
in
magnesium
reduce.
They
met hod
energy
●
Metals
stable
They
the
is
reactivity
need
is
lower
ions
a
a
less
a
of
in
are
the
i.e.
potassium,
ver y
met hod
molten
stable
of
sodium,
ions
which
reduction.
ore .
This
The
met hod
calcium,
are
difcult
most
uses
to
powerful
t he
most
expensive.
t he
reactivity
easier
powerful
reducing
This
form
powerful
most
down
with
hydrogen.
t he
which
need
series,
aluminium,
electrolysis
and
ore
t he
and
met hod
to
met hod
agent
uses
series,
reduce
of
zinc
t hose
reduction
such
less
i.e.
t han
as
t han
below,
in
which
carbon,
energy
and
high
t he
form
involves
carbon
heating
monoxide
electrolysis
less
series.
and
is
or
less
expensive.
Extraction
Aluminium
silicon,
is
is
and
Al
is
O
2
Guyana.
t he
t he
extracted
oxide,
of
t hird
most
O.
most
abundant
abundant
known
xH
3
as
metal.
bauxite.
There
are
in
t he
The
Bauxite
large
Ear t h’s
main
is
bauxite
ore
cr ust
from
impure,
reser ves
af ter
bot h
t hen
t he
bauxite
aluminium
expor ted,
extracted
The
by
aluminium
Jamaica
has
oxide,
been
also
mined,
known
as
it
is
puried
mainly
to
Canada
and
t he
alumina,
USA ,
Al
where
to
O
.
form
and
The
pure,
alumina
3
t he
aluminium
is
electrolysis
electrolysis
(graphite),
and
aluminium
hydrated
in
2
is
oxygen
which
2
Af ter
anhydrous
aluminium
of
which
alumina
forms
takes
an
place
in
electrolytic
a
large
cell.
steel
The
tank
carbon
lined
with
lining
carbon
acts
as
the
negative cathode in the electrolysis process. n the middle of the tank there are
huge
An
blocks
of
carbon,
electrolytic
Figure
cell
hung
used
from
for
above,
t he
which
extraction
act
of
as
the
positive
aluminium
is
anode.
shown
in
18.2.1.
carbon
blocks
(positive
anode)
steel
bubbles
oxygen
carbon
of
alumina
+
gas
lining
molten
(negative
cell
in
dissolved
molten
cryolite
molten
aluminium
can
tapped
aluminium
cathode)
–
be
off

Figure
18.2.1
Extracting
aluminium
by
electrolysis
299
The
extraction
of
metals
Reactivity,
The
1
extraction
The
at
pure
about
process
alumina
950 °C.
involves
t he
(aluminium
Cr yolite
is
following
oxide)
sodium
is
extraction
and
uses
is
dissolved
extremely
poor
much
t he
high,
conductor.
reduced
2
is
molten
i.e.
By
meaning
better
in
t he
dissolved
aluminium
cr yolite
2050 °C,
dissolving
less
energy
conductor
cr yolite,
its
of
and
it
is
in
because
t he
in
molten
uoride,
ions
required
are
free
melting
formed
cr yolite,
and
Once
to
t he
liquid
molten
electricity.
metals
steps:
cryolite
Na
AlF
3
alumina
of
t he
t he
when
its
it
of
solution
The
alumina
melts
melting
alumina
.
6
point
is
point
produced
has
a
is
is
dissolved
a
in
move.
The molten cryolite/alumina solution is electrolysed in the electrolytic cell:
●
The
aluminium
reduced
to
ions
form
move
towards
aluminium
t he
cat hode
where
t hey
are
atoms:
3
Al
Did
?
you
extraction
of
molten
and
is
The
oxide
aluminium
since
it
is
an
requires
3e
Al(l)
aluminium
t hat
expensive
energy
to
tapped
off.
ions
t
is
move
t hen
forms
made
collects
towards
into
at
t he
sheets
t he
anode
or
bottom
of
t he
cell
where
blocks.
t hey
are
oxidised
to
by
form
electrolysis

know?
●
The
(l)
The
oxygen
gas:
process
melt
2
the
2O
(l)
O
(g)

4e
2
cryolite,
it
uses
huge
amounts
of
The
electricity
is
and
replacing
the
oxygen
gas
t hat
forms
is
released
as
bubbles.
t
forms
carbon
anodes
dioxide
by
reacting
need
be
replaced
wit h
t he
carbon
anodes,
and
over
time
t he
anodes
costly.
to
Extraction
of
The
from
main
ores
Haematite
is
since
t hey
disintegrate
oxide
which
impure
Fe
O
3
ores
A
using
blast
.
t he
iron
iron(III)
The
is
extracted
oxide,
extraction
reducing
for
shaped
hot
result
Fe
O
of
iron
are
and
from
agent,
t he
tower
carbon
haematite
magnetite
its
ores
extraction
t hat
can
be
of
up
monoxide ,
iron
to
is
and
is
reaction.
magnetite.
impure
involves
hot
waste
iron(II,
reducing
a
blast
t he
in
furnace.
Figure
18.2.2.
t
is
tall.
iron
ore,
and
coke
waste
they
air
in
shown
30 m
released
are
that
limestone
gases
used
enters
to
carbon
released;
heat
the
iron(III) oxide
air
t he
3
gases
hot
of
4
furnace
chimney
a
iron
2
III)
as
the
furnace
meets
monoxide
is
hot
blasted
into
air
is
blasted
the
into
the
furnace
furnace
molten
slag
can
slag
from
and
molten
drained
300
reaction
calcium
iron
off
iron

the
be
Figure
18.2.2
A
blast
furnace
used
for
is
tapped
extracting
off
iron
oxide
of
silicon
dioxide
a
Reactivity,
The
The
1
extraction
extraction
following
A
mixture
t he
to
mixture
2
Hot
3
At
steps
of
air
t he
a
is
iron
The
of
metals
involved
ore,
blown
in
of
t hat
as
‘t he
is
t he
is
extraction
and
coke
calcium
made
t he
furnace,
is
of
from
coal
iron
added
carbonate
bottom
t he

O
(g)
CO
2
t he
extraction
of
metals
its
t hrough
and
which
from
is
coke
ores.
t he
is
t he
mainly
top
of
name
carbon.
The
coke
of
t he
burns
furnace.
in
t he
hot
air
forming
dioxide:
C(s)
The
The
charge’.
t hrough
t he
in
limestone
limestone
known
bottom
carbon
are
substance
is
uses
process
furnace.
given
and
reaction
furnace
is
at
(g)
ΔH
ve
2
exot hermic
about
and
1900 °C.
keeps
The
t he
carbon
temperature
at
dioxide
fur t her
rises
t he
bottom
up
of
t he
furnace.
4
n
t he
form
middle
carbon
CO
(g)
of
t he
furnace,
t he
carbon
dioxide
reacts
wit h
more
coke
to
monoxide:

C(s)
2CO(g)
2
The
5
n
carbon
t he
monoxide
upper
part
of
t hen
t he
rises
furnace,
fur t her
t he
up
carbon
t he
furnace.
monoxide
t hen
reduces
t he
Did
?
iron
ores
to
The
Fe
O
2
(s)

3CO(g)
2Fe(l)

3CO
3
iron
the
series
from
O
(s)

4CO(g)
3Fe(l)

4CO
4
blast
of
molten
iron
r uns
to
t he
bottom
of
t he
This
as
furnace
where
it
is
iron
contains
a
fairly
high
percentage
of
carbon
(about
4%),
to
ot her
impurities
such
as
silicon
and
phosphor us,
and
is
iron’.

alloy
Most
Figure
These
The
ron
of
bottom
of
t he
pig
iron
is
t hen
main
into
branch
channel.
a
off
puried
and
conver ted
the
way
a
These
litter
that
of
the
suckling
piglets
into
each
other
when
they
lie
are
from
a
sow.
This
is
why
the
as
that
is
tapped
off
from
the
blast
steel,
is
known
as
‘pig
iron’.
iron.
18.2.3
‘Pig
moulds
function
ore
the
as
known
furnace
an
of
flows
tapped
iron
‘pig
out
that
resemble
in
feeding
well
moulds
the
moulds
next
off.
runs
furnace
(g)
2
piglets
The
that
(g)
or
3
know?
2
of
Fe
you
iron:
iron’
gets
resemble
of
the
contains
a
a
its
litter
name
of
from
suckling
the
moulds
in
which
liquid
iron
collects.
piglets.
limestone
lot
of
impurities,
mainly
silicon
dioxide
(sand),
which
would eventually build up and ‘clog up’ t he blast furnace. Limestone is added
to
●
remove
The
t he
heat
silicon
in
carbonate
t he
to
CaCO
upper
part
decompose
(s)
3
dioxide.
The
of
steps
t he
blast
forming
CaO(s)

involved
furnace
calcium
CO
are
as
causes
oxide
and
follows:
t he
calcium
carbon
dioxide:
(g)
2
301
Uses
of
metals
and
their
alloys
Reactivity,
The
●
to
calcium
form
oxide,
calcium
being
silicate,
basic,
then
CaSiO
.
reacts
Calcium
extraction
with
the
silicate
is
and
acidic
also
uses
of
silicon
known
metals
dioxide
as
slag:
3
CaO(s)

SiO
CaSiO
(s)
(l)
3
2
slag
The
slag
forms
used
n
t he
in
it
steel
1
2
Why
are
from
their
a
Name
Outline
a
the
methods
ore
the
in
diagram
What
it
can
is
be
Por t
Lisas,
associated
to
use
to
Trinidad,
as
a
is
t he
and
carbon
uses
use
into
the
reduce
product
gases
of
tapped
ground
agent
wit h
waste
bottom
and
nely
possible
vapour
ot her
the
iron
reducing
water
and
to
furnace
separately.
mixed
or
t he
no
coke,
with
ore,
where
t
is
in
for
place
such
atmosphere,
is
harmful
as
t he
are
of
example,
Hydrogen
ot her
it
then
cement.
hydrogen
iron
hydrogen.
and
of
t he
blast
off
ideal
gases.
release
avoided
of
wit h
hydrogen.
used
to
extract
aluminium
and
iron
ores?
b
The
of
or
t he
in
down
molten
questions
different
named
3
t he
the
iron
as
problems
dioxide
use
of
plant
carbon
r uns
building
produces
Pollution
Summary
road
and
above
monoxide
spat
since
melts
layer
extraction
carbon
t he
a
are
from
which
process
a
by
aluminium
which
is
extracted.
aluminium
is
A
extracted
from
the
ore
above.
shows
the
a
blast
three
furnace:
materials
that
are
added
to
the
top
of
the
blast
iron
ore
reduced
furnace
at
A
in
the
What
removed
extraction
of
iron?
to
b
is
c
Explain
d
The
e
Why
why
air
at
is
B
and
blown
iron
C?
into
the
blast
furnace.
molten
the
4
Write
carbon
iron( III)
is
the
it
monoxide
oxide.
easy
What
to
balanced
acts
as
does
remove
the
chemical
a
reducing
this
agent
when
it
reacts
iron
with
mean?
slag?
equation
hot
to
show
air
hot
air
how
C
iron(III)
oxide
is
converted
to
iron
in
the
blast
furnace.
B
Objectives
C18.3
By
the
be
able
end
of
this
topic
you
Metals
●
describe
the
uses
of
lead
and
are
metals
and
uses
of
iron
to
their
extensively
proper ties,
by
man.
especially
●
explain
what
●
explain
why
t hey
an
are
and
strong
ductile,
and
have
last
a
high
alloy
metal
●
used
and
relate
in
the
lead
the
and
All
of
t hese
place
uses
of
of
the
metal
is
directly
linked
Metals
are
to
used
relatively
of
properties.
long
and
time.
can
They
conduct
are
also
shiny,
electricity
proper ties
make
metals
par ticularly
useful.
Metals
can
and
also
of
t he
alloys. This is done to improve or modify
metals.
metals
aluminium,
Uses
alloys
uses
lead
proper ties
of
metals
aluminium,
alloys
to
t his
unit
their
and
302
a
proper ties.
are
n
iron
of
is
alloys
t he
describe
use
physical
densities
be mixed wit h ot her metals to make
often
The
its
properties
heat.
iron
alloys
aluminium,
malleable
●
their
iron
the
and
used
par ticular
because
relate
lead
of
aluminium,
its
●
Uses
will
to:
iron.
we
will
look
at
t he
uses
of
t hree
metals,
aluminium,
lead
Reactivity,
extraction
and
uses
of
metals
Uses
of
metals
and
their
alloys
Aluminium
Aluminium
aluminium
it
ver y
is
resistant
produce
a
par ticularly
oxide
on
to
louvred
its
useful
surface.
corrosion
windows
This
(Unit
and
metal
layer
19).
because
adheres
Because
window
of
frames,
it
to
has
t he
t his,
a
t hin
metal
aluminium
which
can
layer
and
resist
is
of
makes
used
to
corrosion
when t hey are exposed to oxygen and moisture in t he air. Anot her major use
of
aluminium
and
is
to
make
aluminium
cans
used
as
containers
to
store
food
drink.

Figure
make
18.3.1
louvred
Aluminium
is
in
power
overhead
a
Aluminium
is
used

to
Figure
are
windows
good
conductor
cables.
These
of
electricity
cables
have
a
18.3.2
used
to
which
steel
Aluminium
store
enables
core
cans

Figure
drinks
to
it
down
to
t he
be
it
useful
t hem.
to
protected
make
by
Aluminium
saucepans.
t he
t hin,
is
also
a
good
Aluminium
unreactive
layer
conductor
foil
of
is
used
of
heat
for
aluminium
which
cooking
oxide
to
Did
it
it
is
has
a
There
was
reective
surface
t hat
allows
it
to
reect
heat
back
into
t he
food,
it
warm
for
a
longer
period
of
has
t he
disadvantage
t hat
it
is
not
t he
strongest
of
metals.
For
t his reason it is usually alloyed wit h ot her metals to make it stronger. We will
be
discussing
some
of
t he
uses
of
used
know?
was
a
time
Napoleon
when
more
III
was
aluminium
precious
than
believed
have
held
a
banquet
where
time.
the
Aluminium
be
t hus
to
keeping
you
considered
gold.
highly
can
makes
since
and
Aluminium
saucepans
used
centre
?
strengt hen
18.3.3
make
aluminium
alloys
in
t he
next
honoured
aluminium
the
other
gold
section.
guests
utensils
guests
to
were
eat
were
given
with
only
while
given
utensils.
Lead
As
one
of
t he
rst
metals
to
be
discovered,
lead
has
been
used
for
several
t housand years. The largest use of lead today is in lead–acid batteries because
it
is
highly
batter y
made
resistant
used
of
lead(IV)
in
lead
to
motor
alloyed
oxide
(PbO
corrosion
vehicles
wit h
)
and
a
and
small
an
conducts
consists
of
six
quantity
electrolyte
of
of
electricity.
cells.
Each
antimony,
sulfuric
acid.
A
typical
cell
a
has
12-volt
an
cat hode
Chemical
anode
made
of
reactions
2
occurring
t he
in
batter y
each
can
be
cell
produce
electricity.
Since
t he
reactions
are
reversible,
recharged.
Anot her impor tant use of lead is as a radiation shield around X-ray equipment
and
nuclear
reactors
because
X-rays
and
nuclear
radiation
do
not
penetrate

t hrough
wear
it.
Whenever
which
shields
you
you
have
from
an
t he
X-ray
taken
harmful
you
effects
of
are
t he
given
a
lead
apron
Figure
18.3.4
A
lead–acid
battery
to
X-rays.
Iron
Today,
iron
is
t he
most
widely
used
of
all
met als
because
of
its
high
abundance, low cost and high strengt h. However, because pure iron is quite
303
Uses
of
metals
and
their
alloys
Reactivity,
sof t
Did
?
you
to
The
word
from
the
lead.
Latin
was
civilisations
Greek
as
was
plumbum,
Plumbing
ancient
and
plumbing
they
derived
meaning
originated
such
as
and
baths,
historians
the
was
due
getting
causing
✔
to
into
of
lead
the
Roman
from
water
widespread
Exam
tip
is
important
that
the
uses
of
metals
actually
their
physical
of
and
made
t han
wrought
t hese
items
wrought
or nament al
railings.
of
mild
it
wrought
Most
steel
wit h
iron,
str uctures,
items
because
carbon
has
suc h
descr ibed
it
is
easier
as
as
for m
used
steel .
for
fur niture,
wrought
and
lighting
iron
c heaper
Pure
centur ies
today
to
produce
iron.
have
The
t he
descr iption
bent
and
wrought
shaped
iron
appearance
is
of
still
items
used
because
for merly
made
that
water
pipes
supply
lead
you
and
iron.
Empire
and
poisoning.
can
Figure
18.3.5
Wrought
iron
gates
relate
their
alloys
uses
of
metals
and
t he
proper ties
t hat
make
t hem
par ticularly
suitable
properties
for

each
T
able
use
are
18.3.1
summarised
Properties
Metal
Use
Aluminium
•
to
•
to
and
in
uses
Table
of
18.3.1.
metals
Properties
make
cables
overhead
(with
make
a
electrical
steel
•
core)
good
conductor
corrosion,
saucepans
•
good
light
attractive
•
to
make
food
aluminium
and
cans
to
store
•
drink
weight,
•
to
make
window
•
to
make
foil
for
resistant
frames
cooking
manufacture
•
to
make
car
•
as
of
aluminium
lead–acid
alloys
batteries,
e.g.
resistant
•
unreactive
easily
•
good
batteries
a
to
to
make
shield
Wrought
weights,
keel
•
manufacture
•
to
produce
•
e.g.
weights
of
lead
fishing
for
alloys
ornamental
to
the
therefore
highly
alloyed
high
density
•
high
iron
work
•
easily
•
malleable
used)
non-toxic,
light
in
aluminium
oxide
does
not
react
with
food,
reflective
with
other
of
metals
electricity,
resistant
to
of
steel
prevents
radiation
from
through
density,
malleable
alloyed
resistant
manufacture
to
weight,
corrosion
conductor
shaped,
•
in
sailboats
iron
(rarely
to
corrosion
radiation
weights,
resistant
light
corrosion,
(due
penetrating
•
heat,
resistant
ductile
appearance
•
•
of
non-toxic,
to
non-toxic,
•
electricity,
weight,
malleable
coating),
Lead
of
in
conductor
corrosion,
304
to
been
water
The
to
var iety
alloying
as
metals
by

It
a
gates
by
known
of
Some
speculated
the
make
are
hardened
uses
Roman
drinking
systems.
have
decline
usually
and
developed
piped
drainage
is
commercially
 xtures,
of
public
it
iron,
know?
extraction
•
easily
with
and
easily
to
other
ductile,
metals
therefore
welded,
strong
easily
therefore
stress
alloyed
with
carbon
and
other
metals
Reactivity,
Alloys
extraction
and
and
their
uses
of
metals
Uses
of
metals
and
their
alloys
uses
There are many situations where metals are not used in t heir pure form. More
atoms
t han
one
an
alloy.
To
make
metal
may
be
Sometimes
a
combined
non-metal
to
produce
may
also
a
be
mixture
of
metals
known
as
of
original
added.
atoms
t hat
an
t hey
making
alloy,
solidify
an
alloy
t he
metals
again.
is
to
are
Alloys
improve
heated,
are
t he
solid
mixed
t horoughly
metallic
proper ties
the
metal
of
solutions.
t he
metals
and
The
or
to
cooled
pur pose
modify
of
of
alloying
so

Figure
18.3.6
Structure
of
an
the
element
alloy
t heir
proper ties. Alloys are usually harder, stronger and more resistant to corrosion
t han
The
t he
original
atoms
of
metals.
t he
Did
?
metals
t hat
are
mixed
are
usually
of
different
sizes.
t hey
are
changed
when
a
metals
only
and
it
force
is
slightly
makes
it
different
more
applied.
This
in
size,
difcult
is
why
for
t he
t he
alloys
regular
atoms
are
to
harder
packing
slide
and
of
over
atoms
each
stronger
is
ot her
t han
t he
of
is
zinc.
It
now
look
at
t he
alloys
of
aluminium,
lead
and
is
electrical
pins
is
and
produce
to
aluminium
of ten
of
mixed
wit h
different
duralumin
are
duralumin
18.3.2
and
and
copper,
alloys.
magnesium,
Two
of
t he
magnalium.
magnalium
are
The
given
manganese,
most
common
Composition,
alloy
Duralumin
uses
and
properties
Composition
Uses
About
In
4%
94%
copper
amounts
composition,
in
Table
uses
and
and
Magnalium
of
aluminium
of
aluminium,
with
small
having
very
being
good
Did
?
you
the
construction
and
precision
to
95%
was
by
a
of
make
tools
Stronger
than
so
withstand
it
can
greater
weight
aluminium
stress,
as
Alfred
Originally
as
German
it
aluminium
Construction
magnesium
and
of
automobile
aircraft
Stronger,
parts,
and
and
metallic
scientific
more
mirrors
to
W ilm
instruments
a
lightweight
and
is
used
aluminium,
to
name
by
a
Dürener
of
duralumin
‘Dürener’
In
1917
during
and
World
I,
Hugo
Junkers,
lighter
than
construct
designer,
a
German
pioneered
the
use
than
of
in
duralumin
the
aluminium
J 7
in
fighter
Did
can
the
to
construction
know?
alloyed
form
specialist
of
plane.
you
be
metals
as
and
The
called
resistant
of
strong
made
company
contraction
Iron
is
1909.
harder
?
Duralumin
in
only
aluminium
corrosion
weight
18.3.7
and
metallurgist
in
aircraft
make
developed
German
was
Metallwerke.
light
War
5%
know?
18.3.2.
Properties
aircraft
magnesium
to
with
what
steels.
a
variety
are
For
known
example,
aircraft
titanium
steel
titanium,
is
an
alloy
manganese
of
steel
iron
is
and
an
alloys
alloy
of
cobalt
The
is
alloys
manganese
About
and
Iron
to
it
make
properties.
‘Aluminium’.
Figure
due
to
of
and
is

since
and
silicon
alloys
called
Aluminium
plugs
copper
instruments
patented
T
able
30%
manufacture
iron.
Duralumin

consisting
and
alloys
Aluminium
proper ties
to
for
than
acoustic
zinc
alloy
copper
used
malleable
Aluminium
copper
70%
stronger
alone.
will
a
about
musical
We
know?
Even
Brass
if
you
building
industr y
makes
extensive
use
of
iron,
usually
in
t he
form
Steel
is
an
alloy
of
iron
wit h
carbon
or
various
ot her
metals.
There
and
is
manganese
an
alloy
of
and
iron
and
of
cobalt.
steel.
iron
steel
Each
steel
has
specialist
are
uses;
titanium
steel
can
withstand
quite a few different types of steel. Steels formed by alloying iron wit h carbon
very
are known as
between
0.1%
and
1.5%.
As
t he
carbon
content
increases,
t he
harder
but
less
malleable
and
ductile
and
t herefore
becomes
make
and
harder
to
spacecrafts,
is
cobalt
used
steel
magnetised
easily
so
is
used
to
more
make
brittle
so
steel
is
becomes
temperatures
carbon steels. Generally t he amount of carbon in carbon steels
to
varies
high
magnets.
weld.
305
Uses
of
metals
and
their
alloys
Reactivity,
The
are

composition,
given
T
able
Iron
Mild
in
Table
18.3.3
alloy
uses
and
proper ties
some
Composition,
uses
and
properties
Contains
less
0.25%
In
the
other
are
in
common
between
1.5%
iron
of
alloys
metals
of
iron
alloys
to
a
0.25%
T
o
carbon
thin
ships
of
layer
of
so
‘tin
and
stronger
malleable
easily
and
shaped,
than
ductile
easy
to
weld
and
‘tin
steel
iron,
T
o
and
food
i.e.
Harder
cans’
coated
tin
to
corrosion.
make
bits,
nails
store
made
of
vehicles.
items,
prevent
Contains
some
bridges,
wire,
cans’
and
uses
Properties
motor
make
carbon
of
construction
buildings,
and
steel
t he
Uses
than
carbon
High
of
and
18.3.3.
Composition
steel
of
extraction
cutting
knives
and
tools,
drill
Harder
masonry
more
than
mild
steel,
but
brittle
nails
Stainless
steel
T
ypical
70%
and

Figure
18.3.8
Steel
is
widely
used
values
iron,
10%
are
20%
about
T
o
chromium
make
utensils,
nickel
cutlery,
kitchen
cooking
Hard,
sinks,
hospital
equipment,
catering
equipment
more
strong
(rusting)
steels.
than
Has
construction
a
to
much
corrosion
carbon
shiny,
in
attractive
the
and
resistant
industry
but
to
is
appearance,
more
expensive
produce
than
carbon
steels.
Cast
iron
Contains
about
4%
T
o
carbon
make
e.g.
small
manhole
railings,
blocks
castings,
grates,
in
Inexpensive
covers,
cast
cylinder
engines
into
Hard,
and
steel,
saucepans
Lead
Lead
is
of ten
and
solder
t he
is
40%
of
lead
so
lead
and
2
What
used
it
tin,
to
join
into
be
rather
to
brittle
it
than
tends
than
to
bend
hit.
of
b
making
saucepans?
3
What
is
4
What
are
5
Discuss
and
the
is
an
joint
copper
solder
is
items
to
t hat
of
toget her.
The
t he
produced
t han
make
composed
between
toget her.
t han
stronger
aluminium
overhead
than
or
solder
metallic
t he
items
lead
and
Lead
t he
To
has
a
about
do
items.
melting
lead
alloys.
of
One
60%
t his,
On
making
make
electrical
alloys,
suitable
points
of
t he
solder.
lower
melting
point
lead.
for
give
the
use
it
useful
for:
cables
two
uses
of
lead
and
in
each
case
explain
given.
alloy?
the
two
t he
cooling
questions
properties
lead
t he
higher
t he
harder
making
Other
antimony
solder.
ows
joining
must
also
tin,
lead
a
why
306
is
wit h
is
is
t hat
joined
Summary
1
t
solidies,
being
wit h
lead
tin.
melted
alloying
t han
mixed
alloy
solder
metals
By
more
easy
shapes.
alloys
common
lead
but
therefore
shatter
when
and
exact
advantages
named
uses
of
of
alloys
each.
using
of
an
alloy
aluminium
rather
by
than
referring
a
to
pure
the
metal?
composition
Reactivity,
Key
●
t
extraction
and
uses
of
metals
Uses
of
metals
and
their
alloys
concepts
is
possible
t heir
to
reactions
decomposed
determine
wit h
when
t he
oxygen,
heated,
reactivity
water
and
and
series
dilute
of
metals
acids,
displacement
how
reactions
by
looking
easily
t heir
between
at
t he
strengt h
compounds
t he
metals
and
of
are
metal
compounds.
●
The
more
●
n
d isplacement
a
reactive
t he
metal,
t he
reaction ,
a
more
more
stable
its
reactive
compounds.
metal
displaces
a
less
reactive
metal
from
its
compounds.
●
The
is:
reactivity
potassium,
copper,
●
The
●
The
e.g.
●
mercur y,
position
metals
will
ver y
and
metals
are
●
The
●
Metals
occur
high
aluminium,
Metals
are
of
with
a
down
●
Aluminium
●
Bauxite
is
in
reduce.
reducing
is
to
be
metals
metal
t he
They
t he
cr ust
can
During
●
ron
is
extracted
impure,
extracted
●
its
ions
need
a
Ear t h’s
be
is
t he
lead
least
reactive
(hydrogen),
to
compare
how
cer tain
from
in
t heir
wit h
t hese
are
free
from
ot her
elemental
t he
state,
Ear t h.
elements
in
impure
ionic
compounds.
known
as
ores.
The
most
impor tant
is
i.e.
a
reduction
potassium,
which
of
are
difcult
the
series,
process.
sodium,
molten
i.e.
less
powerful
ore,
bauxite,
zinc
to
calcium,
reduce.
magnesium
They
need
a
and
powerful
ore .
and
met hod
below,
of
form
less
reduction,
stable
i.e.
ions
heating
which
the
ore
from
its
aluminium
by
oxide,
electrolysis.
Al
aluminium
as
impure
its
t he
ores,
forms
t he
haematite
reducing
iron( III)
at
O
agent
oxide,
Fe
and
in
O
a
xH
3
cat hode
O.
2
and
magnetite
blast
and
oxygen
by
forms
reducing
at
t he
t he
anode.
ores
using
furnace.
magnetite
is
impure
iron(II,
III)
oxide
3
O
3
●
used
directly
extracted
2
Fe
be
cr ust
mined
combined
be
ore
series,
reactivity
hydrated
from
monoxide
Haematite
to
iron,
agent
electrolysis,
carbon
reactive
zinc,
carbonates.
electrolysis
t he
can
2
●
most
aluminium,
series
extracted
and
from
stable
i.e.
in
t herefore,
reactivity
ver y
reactivity
occur
suldes
reduction,
to
t he
Ear t h’s
have
which
a
form
lower
easier
of
t he
from
acids.
can,
t he
oxides,
in
in
metals
and
in
metals
magnesium,
gold.
dilute
t hey
from
extraction
met hod
wit h
common
calcium,
silver,
gold,
metal
t he
hydrogen
and
Compounds
ores
●
of
react
compounds
●
of
unreactive
silver
Most
series
sodium,
4
Molten
iron
and
molten
slag,
calcium
silicate
(CaSiO
),
are
produced
in
t he
blast
furnace.
3
●
The
physical
●
The
main
frames,
●
The
●
The
●
An
●
Alloys
●
use
and
main
alloy
more
use
is
are
a
●
is
an
lead
of
iron
of ten
more
to
are
cans
make
to
t hem
make
and
foil
is
to
make
is
to
manufacture
and
of
alloy
of
metals
useful
corrosion
for
lead–acid
ver y
useful
overhead
to
man.
electrical
cables,
saucepans,
window
cooking.
batteries.
t
is
also
used
to
make
radiation
t han
t han
magnalium
steel.
alt hough
t he
t he
are
sometimes
pure
pure
alloys
metal
a
non-metal
because
t hey
can
are
be
added.
harder,
stronger
and
metal
of
aluminium.
Their
main
use
is
in
t he
aircraf t.
of
iron
different
proper ties
Solder
an
is
metals
storage
mixture
resistant
Duralumin
Steel
of
of
aluminium
weights.
constr uction
●
of
aluminium
main
shields
proper ties
uses
alloy
of
wit h
and
carbon
or
ot her
elements.
Different
types
of
steel
have
uses.
lead
and
tin.
t
is
used
to
join
metal
items.
307
Practice
exam-style
questions
Reactivity,
iii)
Practice
exam-style
Explain
your
What
would
precipitate
Which
most
A
of
t he
following
reactions
is
likely
to
take
v)
place

B
Mg(s)

Pb(NO
C
Mg(s)

Cu(NO
(aq)
Mg(NO
D
Mg(s)

Zn(NO
)
3
)
3
(aq)
3
)
3
(aq)
(aq)
)
3
(aq)

vi)
2Ag(s)
used
Mg(NO
2
to

(aq)
if
Pb(s)

t he
t he
point
t he
position
C
t he
solubility
of
electrical
(aq)

vii)
Zn(s)
a
metal
from
zinc
Explain
its
ore
of
t he
t he
of
Anot her
in
conductivity
is
extracted
from
molten
t he
of
reactivity
t he
molten
reduction
of
alumina
alumina
alumina
rod
reaction
rate
was
of
your
order
iron
of
occurring
in
molten
D
electrolysis
of
alumina
of
t he
reaction
be
in
t he
following
extraction
of
cr yolite
t he
using
replaced
t he
same
wit h
a
piece
of
dimensions?
answer
to a
(1
vi)
(2
haematite,
B
limestone,
C
haematite,
carried
to
out
determine
and
an
1:
A
experiments
t he
unknown
piece
dissolved
in
a
list
of
t he
molten
raw
lead(II)
of
of
relative
metal
metal
nitrate.
materials
A
appearance
Use
t he
most
cr yolite
2:
piece
iron(II)
of
of
X
X,
was
Metal
X
in
metal
sulfate.
metal
1
and
D
coke,
which
X
placed
became
has
into
carbon
air,
carbon
dioxide,
limestone,
haematite,
t he
constr uction
order
of
X
was
placed
There
was
no
given
to
place
reactivity,
lead,
star ting
an
metal
X
(2
ionic
stainless
equation
for
t he
reaction
magnetite,
How
marks)
between
and
t he
lead(II)
nitrate
solution.
would
you
expect
metal
X
to
react
following
silicon
is
coke
acid?
(1
mark)
15
marks
dioxide
most
widely
used
in
t he
Extended
response
question
industr y?
a
Chemical
and
electrolytic
reduction
are
t he
two
steel
B
mild
C
duralumin
met hods
used
to
extract
metals
from
t heir
ores.
steel
should
ONE
be
factor
t hat
employed
in
determines
t he
t he
extraction
of
met hod
metals
t hat
from
solder
t heir
ores.
met hod
Structured
A
student
places
copper(II)
hours,
The
t he
a
sulfate
gently
of
zinc
below
t he
rod
solution
shaking
diagrams
star t
several
Explain
to
be
how
t his
factor
determines
used.
t he
(3
marks)
question
b
a
marks)
wit h
coke
dentify
6
and
t he
monoxide
main
D
a
in
iron
wit h
reactive.
Write
into
change
used
7
A
a
iron?
limestone,
air,
a
coated
Total
air,
of
2
reactivity
X.
information
hydrochloric
Which
mark)
marks)
lead.
metal
alumina
is
of
solution
carbon
iii)
5
mark)
affected
(2
A
mark)
t he
2.
Experiment
i)
of
of
t he
(1
ore
by:
using
dissolved
electrolysis
t he
of
series
monoxide
C
in
bottom
ore
of
Which
of
t he
student
in
lead,
ii)
4
t he
metal
metal
t he
reduction
carbon
in
hours?
is
wit h
Aluminium
B
mark)
solid
2
solution
A
seen
t he
(1
Experiment
3
(1
of
by:
melting
B
t he
colour
was
several
type
would
t he
valency
D
t hat
af ter
magnesium
Cu(s)
of
A
t he
2
)
3
extract
How
below
determined
be
2
Mg(NO
2
)
(aq)
b
met hod
ii).
metals
2
Mg(NO
2
)
3
The
of
beaker.
2AgNO
3
2
Name
readily?
Mg(s)
to a
uses
questions
beaker
1
answer
and
questions
iv)
Multiple-choice
extraction
t he
show
in
a
and
beaker
leaves
solution
what
experiment
and
containing
it
for
iron
several
t he
student
again
saw
t he
from
include
occasionally.
t hen
Outline
involved
iron(III)
relevant
silicon
oxide.
in
Your
equations.
dioxide,
is
t he
extraction
answer
Details
removed
are
of
not
Stainless
ii)
steel,
how
alloy
of
iron,
is
used
to
is
Suggest
an
alloy?
T WO
make
(1
reasons
cooking
why
utensils
stainless
instead
of
steel
is
solid
mark)
used
iron.
rod
d
solution
sulfate
marks)
make
(2
copper(II)
t he
required.
utensils.
What
to
an
of
must
(7
c
i)
zinc
ore,
steps
at
af ter
cooking
rod
its
THREE
impurity,
hours.
zinc
main
precipitate
Aluminium
Name
ONE
is
anot her
alloy
of
metal
used
aluminium
to
and
make
give
marks)
alloys.
its
main
use.
solution
start
of
the
experiment
experiment
several
(2
after
hours
Total
i)
Explain
during
why
t he
equation
ii)
What
zinc
rod
experiment.
to
suppor t
change
solution?
308
t he
would
decreased
Give
your
you
marks)
a
in
size
relevant
answer.
expect
to
ionic
(3
marks)
obser ve
(1
in
t he
mark)
15
marks
Metals
in
living
systems
and
C19
the
Some
metals
are
extremely
environment
important
in
the
lives
of
Objectives
plants
and
poisoning
animals,
if
while
consumed
others
and
can
can
cause
have
severe
harmful
By
the
be
able
●
on
the
environment.
Conversely,
the
end
environment
can
explain
metals
have
devastating
effects
on
metals
and
can
of
lead
to
●
give
for
●
●
corrosion
of
what
the
Metals,
especially
to
its
occurs
reaction
t hose
when
wit h
used
t he
c hemicals
in
will
when
explain
explain
to
what
necessary
corrode
happens
when
corrodes
what
happens
when
metals
outdoors,
surface
happens
conditions
metals
iron
Cor rosion
you
corrode
aluminium
The
topic
their
corrosion.
C19.1
this
to:
effects
of
t he
t he
tend
metal
to
undergo
g radually
environment,
cor rosion .
wears
mainly
rusts.
away
due
oxygen
and
moisture, and it is speeded up by t he presence of cer tain pollutants. n some
cases
it
may
cor rode,
e.g.
rate
at
general,
close
aluminium
will
The
On
of
now
for med
t he
of
iron
at
exposure
to
aluminium
a
off
from
and
fur t her
aluminium
reactivity
f
a
in
of
to
shiny
t he
air
wit h
linked
t he
to
faster
cor rode
sodium
wit h
quite
while
of
metal
carbon
to
it
bot h
t he
will
at
an
c hlor ide
different
t he
metal’s
t he
of
t he
Al
piece
O
corrosion.
less
aluminium
see
t he
section
again
process
ar ticially
shiny
to
and
faster
t he
iron
in
t hese
by
to
dyes,
added
making
Met als
rate
n
t hat
t han
corrosion
is
of
detrimental.
more
detail.
.
of
This
aluminium
layer
adheres
immediately
to
t he
metal
forms
below,
a
layer
does
not
3
unreactive.
t
is
As
because
reactive
is
a
of
t han
scratched
metal
become
renews
which
thickened
advantages
absorbs
salts,
atmosphere.
result,
t his
is
it
protects
aluminium
predicted
by
t he
aluminium
oxide
its
layer
position
its
and
t he
underneat h.
dull
as
oxide
t he
oxide
t
layer
does
aluminium
not
is
t hat
in
t he
so
by
t he
t he
reacts
aluminium;
anodised
advantages,
cookware
such
it
objects
anodised
as
pots
of
t he
(Unit
can
oxide
10.5).
makes
t he
be
pans
layer
The
to
has
on
oxide
surface
coloured
aluminium
and
ver y
wit h
it
long
t he
is
for
oxygen
lm.
t hickness
electrolysis
removed,
take
Aluminium can be made even more resistant to corrosion by
is
metals
for m
reactivity.
cor rode.
results;
metals
When
also
dioxide.
even
in
corrosion
t hese
object.
sometimes
aluminium
relatively
appears
of
is
t he
They
series.
piece
possible
t hat
is
tend
corrosion
fresh
oxide ,
reaction
metal,
will
of
oxides.
cor rode
t he
2
peel
t he
benecial
of
air,
by
presence
t he
corrosion
t heir
corrode
mostly
look
sea
t he
destr uction
to
met als
reactive
to
and
is
tot al
most
more
Aluminium
We
are
because
t he
oxid ised
whic h
t he
used
nor mal
to
are
carbonates
The
are
lead
t hey
anod ising. This
t he
aluminium
layer
harder
gives
and
attractively.
a
great
protecting
many
satellites
it
is
added
readily
Because
uses,
from
of
from
space
debris.
309
The
corrosion
of
metals
Metals
The
On
corrosion
exposure
to
immediately
Fe
O
2
xH
3
O,
t
order
does
Figure
19.1.1
Rust
formation
on
a
forms
known
for
iron
not
damaging

which
systems
and
the
environment
iron
oxygen
begin
living
to
and
moisture
corrode
has
an
to
in
form
t he
air
mainly
orange-brown
iron
and
hydrated
colour.
steel
objects
iron(III)
Hydrated
iron(III)
oxide ,
oxide
is
2
commonly
n
of
in
on
to
occur
and
t he
as
rust.
r ust,
if
bot h
only
costly.
surface
Corrosion
Unlike
of
oxygen
one
is
t he
of
iron
and
water
present.
The
adherent
aluminium,
and
r ust
steel
or
known
moisture
r usting
coating
does
is
not
of
of
as
must
iron
be
can
aluminium
adhere
to
rusting
t he
present.
be
bot h
oxide
iron
t hat
below.
padlock
Rust
akes
exposed
t he
T
o
investigate
Your
teacher
may
observation,
●
Y
ou
will
be
what
use
conditions
this
recording
supplied
with
activity
and
and
t hen
exposes
r usts
fresh
and
t he
iron
to
process
oxygen
and
continues
and
moisture.
gradually
The
newly
wears
away
iron.
are
to
off
iron
needed
for
rusting
to
occur
assess:
reporting.
three
steel
nails,
some
calcium
chloride,
some
oil
and
three
test
tubes
with
corks.
Method
1
Place
one
2
Place
the
The
3
some
test
tube
the
Leave
5
Record
6
What
7
Which
8
Did
9
What
the
water
nail
any
to
nails
in
into
nails
it
three
the
a
signs
you
could
on
of
Add
the
oxygen
of
for
a
the
few
layer
conditions
rusting?
whether
a
to
water
small
the
half
in
the
allow
it
completely
water.
days
cover
amount
air
and
to
Cork
and
of
the
nail
calcium
and
cork
chloride
If
the
so,
to
the
were
what
third
to
cool
cover
the
quickly.
the
nail.
Place
Gently
nail
in
rusts
this
was
necessary
more
dry
observe
any
absent
for
quickly
in
each
in
sea
water
or
air
of
oil
water
calcium
chloride
310
in
19.1.2
tube
Investigating
2
the
oil
the
case?
nail
T
est
tube.
nail
some
changes
water
Figure
third
rusting?
boiled

the
pour
case?
layer
1
the
into
T
est
conditions
tube
3
needed
for
rusting
tap
water.
another
down
tube.
air
tube
cork
tube?
condition
air
T
est
and
tube.
tube.
carefully
present
conditions
steel
steel
the
table.
oil
about
a
from
water
top
tubes
What
draw
test
tube.
suitable
adding
enough
moisture
boiled
layer
a
add
dissolved
this
test
in
test
any
the
most?
no
can
of
tube,
dry
of
forms
the
show
you
a
remove
purpose
rusted
test
absorbs
observations
the
how
rst
enough
that
conclusion
Explain
nail
add
so
your
was
the
chloride
and
tube
4
into
second
calcium
Boil
of
10
nail
nails.
the
side
Metals
in
living
systems
Summary
1
What
2
Y
ou
a
given
Which
Which
3
What
4
Explain
5
Suggest
a
metal
deep
C19.2
metal
to
be
of
for
the
the
iron
on
the
present
impact
of
metals
on
zinc
reactive
Why
is
and
than
systems
on
position
in
the
iron
for
rusting
corrode
to
occur?
differently.
iron
tend
to
rust
more
at
the
bottom
of
the
shipwrecks
surface
and
the
of
tend
the
of
to
rust
very
slowly
when
found
water.
metals
on
living
systems
Objectives
environment
t heir
compounds
are
extremely
impor tant
to
By
the
be
able
However,
cer tain
metals
and
t heir
compounds
can
have
end
same
living
organisms
and
also
on
t he
of
metals
and
their
ions
play
a
vital
role
in
the
functioning
e.g.
calcium,
referred to as
for
good
potassium,
sodium
and
you
will
explain
the
and
importance
their
of
compounds
in
environment.
organisms
discuss
the
harmful
effects
of
compounds
of
living
organisms.
Some
of
these ions are required by the human body in amounts in excess of 100 mg per
day,
topic
living
metals
Metal
this
harmful
●
importance
of
to:
living
The
environment
top.
impact
t he
the
this?
metals
effects
and
aluminium.
its
●
organisms.
living
following.
of
The
and
iron,
less
suggest?
and
made
at
below
copper,
appear
would
aluminium
than
metals
The
corrodes?
metals
must
railings
Pieces
environment
rusts?
reasons
railing
Many
series
why
a
four
tends
conditions
Metal
b
when
the
metal
reactivity
b
the
questions
happens
are
and
magnesium.
These
are
on
and
living
their
compounds
organisms
and
the
environment.
sometimes
macro-minerals. Others are recommended in smaller amounts
health,
molybdenum,
these
include
selenium
and
manganese,
chromium.
iron,
These
zinc,
are
cobalt,
referred
to
copper,
as
micro-
minerals or trace minerals. Plants also require cer tain metal ions for healthy
growth.
Some
of
organometallic
Table
19.2.1
the
ions
required
compounds ,
summarises
t he
for
by
plants
example,
impor tance
and
animals
chlorophyll
of
cer tain
are
and
used
to
make
haemoglobin.
metal
ions
in
living
organisms.

T
able
Metal
19.2.1
ion
Magnesium
The
importance
Importance
Magnesium
Chlorophyll
plant
so
parts
that
in
the
are
the
their
green
can
is
and
for
pigment
the
Chlorophyll
is
its
(g)

6H
2
shortage
known
as
play
and
a
own
of
chlorophyll
chloroplasts
food
in
plants
by
organisms
of
to
in
green
plant
trap
cells.
the
plants.
It
gives
sunlight
photosynthesis.
The
green
energy
equation
for
energy
O(l)
C
H
6
magnesium
ions
body
vital
teeth,
living
causes
by
the
chlorophyll
leaves
of
O
12
(aq)

6O
6
(g)
2
glucose
plants
to
become
yellow,
a
condition
chlorosis
Magnesium
human
the
2
of
in
below:
absorbed
A
in
essential
sunlight
6CO
compounds
formation
found
manufacture
given
their
organisms
necessary
colour.
plant
photosynthesis
metals
living
ions
is
of
role
in
are
since
in
the
also
they
the
required
are
for
essential
production
transmission
of
of
more
for
energy
nerve
than
the
300
biochemical
functioning
in
cells,
impulses
in
and
of
the
in
many
reactions
enzymes.
formation
the
of
in
strong
contraction
of
the
The
ions
bones
muscles.
311
The

impact
T
able
of
metals
19.2.1
on
living
systems
and
the
environment
Metals
in
living
systems
and
the
environment
(continued)
Metal
ion
Importance
Iron
Iron
the
ions
red
body.
with
are
in
living
necessary
pigment
The
C
found
oxygen
energy.
The
H
6
organisms
O
12
is
for
in
then

for
6O
6
formation
red
used
equation
(aq)
the
the
blood
by
the
of
haemoglobin
cells.
body
respiration
(g)
is
It
is
cells
in
given
6CO
2
in
essential
animals.
to
carry
respiration
to
Haemoglobin
oxygen
provide
around
the
is
the
body
below:
(g)

6H
2
O(l)

energy
2
glucose
A
shortage
tiredness
Calcium
Zinc
fact
the
is
natural
release
of
the
contamination
environment
unpleasant
by
and
of
and
ions
The
of
know?
too
phrase
‘mad
as
a
the
an
in
the
to
in
the
at
ions
a
in
and
play
contraction
of
number
known
strong
of
as
of
red
calcium
bones
blood
cells
in
the
body,
anaemia
and
phosphate
teeth.
in
the
Calcium
body.
ions
are
also
cut.
bones
part
the
production
build
which
cell
in
condition
to
clot
important
and
a
for
leads
potassium
and
to
condition
of
of
metals
toxic
Other
Many
effects
same
become
high.
them.
The
a
reduction
needed
blood
wounds,
and
is
calcium
play
of
impulses
harmful
health
you
ions
a
necessary
the
rickets,
to
energy,
and
the
the
becoming
become
functioning
tissue
an
teeth
legs
growth
important
of
the
and
role
soft
and
weak.
It
may
also
bowed.
immune
system,
in
the
repair.
in
the
transmission
of
nerve
muscles.
the
Some
Did
Zinc
of
of
harmful
substances.
?
to
are
for
shortage
lead
Sodium
potassium
leads
lack
phosphate
healing
Sodium
Pollution
a
Calcium
A
Key
iron
Calcium
necessary
!
of
and
to
metals,
these
required
the
not
are
metals
same
by
a
living
living
required
in
by
group
and
their
organisms
organisms
living
known
compounds
when
organisms,
as
heav y
to
maintain
their
can
levels
also
metals,
their
become
be
toxic
which
to
mainly
hatter’
includes the transition metals and some of the metalloids. All of these metals
was
coined
during
the
1800s
occur naturally in ionic compounds, however, their concentrations within the
when
mercury
was
used
in
the
environment
production
used
by
felters
levels
of
felt,
felters
were
of
to
which
make
exposed
mercury.
was
hats.
daily
This
to
The
trace
Heavy
metal
compounds
in
of
them
their
dementia
to
to
pollution
T
able
effects
19.2.2
ion
Lead
become
par ticularly
combining
Table
on
t he
Harmful
wit h
19.2.2
human
effects
Sources
toxic
organic
when
summarises
some
the
Disused
in
car
the
of
disease
in
the
1956.
release
industrial
was
environment
batteries,
car
T
oxic
using
leaded
exhaust
petrol,
lead
fumes
based
city
It
of
was
Lead
damages
and
kidneys,
of
methyl
wastewater
from
into
mercury
with
local
shellfish
when
population,
mercury
the
and
fish
eaten
by
resulted
poisoning
the
and
of
body
to
particular
the
brain.
normal
leading
in
It
nervous
also
formation
anaemia.
the
system,
interferes
of
It
red
is
blood
especially
to
young
IQ
and
children
causing
potentially
learning
disorders.
permanent
Disused
and
thermometers
from
hospitals
Mercury
damages
the
central
nervous
gradually
in
the
in
1700
industry,
extraction
gold,
severe
over
laboratories,
lights,
the
Cadmium
and
refining
Arsenic
e.g.
smoke,
of
of
fossil
of
and
metals
sodium
fuels,
e.g.
metals,
fuels,
coal,
such
as
impairing
hearing,
touch
sight,
known
muscular
speech
as
and
coordination,
the
Minamata
sense
of
disease.
hydroxide.
Cadmium
e.g.
causes
respiratory
extraction
of
and
paint
can
also
bones
damage
system,
cause
become
to
kidneys
osteoporosis
weakened
the
and
liver.
where
and
It
the
fragile.
PVC.
especially
purification
fossil
of
system
batteries,
manufacture
plastics,
certain
extraction
burning
of
of
industry,
metals,
certain
Mining
of
fluorescent
combustion
refining
nickel–cadmium
combustion
and
disused
manufacture
Disused
cigarette
deaths.
312
variety
Minamata
and
in
and
have
a
Mercury
up
lead
can
mercury
methyl
which,
a
organs,
bones
especially
Minamata,
factory
bay,
t hat
caused
Bay.
built
ions
effects
tissues
first
chemical
This
organometallic
tetraet hyl
metals
reduced
in
form
e.g.
metal
harmful
by
activities.
body.
cells
in
t hey
compounds,
paints.
Japan,
man’s
know?
when
discovered
by
(madness).
you
Minamata
caused
symptoms
Metal
Did
due
bodies
develop

?
ions
by
mercur y.
harmful
causing
increasing
gradually
met hyl
accumulated
are
then
of
gold,
metals,
especially
coal.
Arsenic
can
problems.
system,
It
cause
also
heart
cancer
and
damages
and
blood
the
skin
nervous
vessels.
Metals
in
living
systems
Heav y metal ions
are
persistent,
organic
and
the
environment
The
impact
of
metals
on
t hey
pollutants.
living
remain
They
also
in
t he
have
environment
t he
potential
to
and
do
build
not
up
in
decay
t he
like
Did
?
organisms,
especially
fatty
tissue,
and
t hey
concentrate
harming
mercury
sh
eat
in
t he
of
general
top
consumers
such
as
sh,
humans
plankton.
mercur y
than
especially
due
f
to
t his
large
mercur y
sh,
is
t he
major
concentrating
plankton
gradually
builds
up
in
contains
t he
Larger
sh
t hen
eat
t he
up
small
bodies
smaller
food
in
chain
t heir
to
t he
bodies
ver y
t hroughout
large,
sh,
t heir
long-lived
of
source
t he
food
of
ingested
chain.
amounts
t he
sh
of
need
since
more
they
such
as
This
building
continues
sharks,
bodies
Also
women
they
get
each
lose
iron
during
must
month
in
menstruation.
ensure
that
Small
adequate
supplies
of
mercur y,
t hroughout
constantly
lifespan.
sh
know?
women
haemoglobin
during
marlin,
pregnancy
since
it
is
t heir
up
up
tuna
for
growth
of
the
cells
and
t he
tissues
mercur y
you
men
their
essential
lifetime.
environment
humans.
zinc
t his
the
food
from
Consumption
and
tissues
up
iron
chains,
systems
are par ticularly harmful in t he environment because t hey
i.e.
In
of
living
of
the
foetus.
t he
and
swordsh.
Disposal
of
solid
since
t hese
waste
includes:
●
lead–acid
●
t hermometers
●
compact
mercur y
waste
metals
batteries
not
from
be
motor
containing
uorescent
light
heavy
metals
allowed
to
poses
enter
t he
a
serious
problem
environment.
This
vehicles
mercur y
bulbs
from
and
hospitals
ot her
and
uorescent
laboratories
bulbs
containing
vapour
nickel–cadmium
●
containing
should
batteries.
These items should not be disposed of in landll sites because of t he possibility
of
contaminating
incinerated
t he
metal
groundwater
because
ions
into
of
t he
t he
and
nearby
possibility
air.
The
of
soil.
releasing
problem
of
t heir
They
should
harmful
disposal
also
gases
can
be
not
be
containing
solved
to
a

Figure
light
large
extent
by
recycling
Summary
all
What
is
haemoglobin?
2
What
is
chlorophyll?
3
Why
4
a
zinc
Name
b
5
why
swordsh
heavy
19.2.1
bulbs
Compact
contain
uorescent
mercury
vapour
metals.
Why
Why
is
calcium
different
is
it
it
important
important
important
metals
to
whose
in
to
our
bodies?
plants?
humans?
ions
have
negative
effects
on
the
body.
Describe
Explain
and
three
human
containing
questions
1
are
items
or
some
it
may
of
the
be
negative
dangerous
effects
to
of
each
consume
metal
large
sh
named
such
in
a
as
marlin.
313
The
impact
of
metals
on
living
systems
and
the
environment
Key
Metals,
●
Corrosion
due
to
and
its
When
occurs
metals
living
systems
and
the
environment
The
●
When
wit h
it
is
corrode,
t he
outdoors,
surface
chemicals
of
in
tend
t he
t he
speeded
up
t hey
oxidised
are
by
to
undergo
metal
gradually
environment,
t he
presence
to
corrosion.
t heir
of
wears
mainly
cer tain
oxides
and
away
oxygen
pollutants.
sometimes
tend
to
corrode
much
faster
t han
t hose
t hat
are
lower
in
series.
aluminium
fur t her
●
when
and
metals
relatively
used
salts.
reactivity
When
t hose
reaction
form
Reactive
t he
●
especially
moisture,
t hey
●
in
concepts
●
●
Metals
corrodes
unreactive
and
it
forms
adheres
a
to
layer
the
of
aluminium
metal
below,
oxide
which
protecting
it
is
from
corrosion.
layer
of
iron
aluminium
corrodes
it
oxide
forms
can
be
t hickened
hydrated
iron (III)
by
anod ising
oxide,
also
known
as
rust
●
n
order
for
iron
to
r ust,
bot h
oxygen
and
water
or
moisture
must
be
present.
●
Rust
The
akes
gradually
●
Metal
of
off
newly
wears
ions
t hese
over
time
exposed
play
are
away
a
exposing
iron
t hen
t he
vital
iron
and
t he
to
oxygen
process
and
moisture.
continues
and
iron.
role
combined
fresh
r usts
in
wit h
t he
functioning
organic
of
compounds
living
to
organisms.
form
Some
organometallic
compounds
●
Macro-minerals
of
100 mg
per
macro-minerals
●
healt h.
needed
Calcium,
by
t he
human
potassium,
body
sodium
in
amounts
and
in
excess
magnesium
are
t he
needed.
Micro-minerals
good
are
day.
are
Two
of
required
t he
in
most
small
amounts
impor tant
by
t he
human
micro-minerals
are
body
iron
for
and
zinc.
●
One
●
Metals
are
impor tant
in
can
a
group
transition
●
The
The
●
Heavy
most
decay
such
in
Disposal
of
t hese
heav y
some
t hese
metals
are
of
by
on
to
include
in
up
is
magnesium.
organisms.
which
mainly
Many
of
includes
t hese
t he
metalloids.
harmful
harmful
plants
living
metals,
t he
due
concentrate
of
sh,
humans
solid
heavy
metals
pollution
lead,
t he
food
especially
due
waste
metals
includes
bulbs
Waste
of
effect
wit hin
caused
mercur y,
t he
man’s
cadmium
environment
chains,
by
because
harming
t he
activities.
and
arsenic.
t hey
top
do
not
consumers
humans.
mercur y
light
required
increasing
ions
t hey
Consumption
waste
314
metal
as
and
harmful
and
as
since
●
known
is
ion
negative
concentration
●
●
a
metals
environment
●
metal
have
large
mercur y
containing
should
lead–acid
and
to
not
be
heavy
metals
heavy
allowed
batteries,
nickel–cadmium
containing
sh,
is
t he
major
concentrating
metals
to
mercur y
up
poses
enter
t he
be
a
recycled.
of
food
serious
ingested
chain.
problem
environment.
t hermometers,
batteries.
should
source
t he
This
uorescent
Metals
in
living
systems
and
the
environment
Practice
Extended
Practice
exam-style
a
questions
Most
Which
of
t he
following
must
be
present
for
iron
to
t he

case
undergo
t his
of
can
iron
it
corrosion.
be
n
benecial
can
be
t he
to
harmful
case
t he
of
metal
and
while
costly.
What
happens
when
a
metal
corrodes?
(1
carbon
Explain
why
t he
corrosion
of
aluminium
is
dioxide
benecial
while
t he
corrosion
of
iron
is
not.
A

only
B

and
of

C

D
,
and

‘Metal
corrosion
ions
and
include
and
t heir
reference
to
t he
proper ties.
products
are
extremely
impor tant
(6
to
By
reference
to
magnesium,
iron
and

calcium,
provide
evidence
to
suppor t
t his
statement.
(6
Which
of
t he
following
is
not
a
benet
to
be
gained
corrosion
t
causes
of
Cer tain
metals
in
Explain
why
t he
to
be
reactivity
less
reactive
series
t
forms
be
C
D
oxide
coloured
The
t
an
oxide
forms
a
harmful
to
living
organisms.
t han
layer
on
t he
aluminium,
which
are
released
formed
relatively
metals
into
t he
are
so
harmful
environment
when
by
human
(2
Total
akes
off
unreactive
marks)
can
attractively.
layer
t hese
its
predicts.
activities.
B
are
aluminium?
aluminium
t hey
position
marks)
from
c
t he
marks)
living
only
organisms.’

should
only
b
A
Your
moisture
answer
2
mark)
oxygen
ii)

question
r ust?
i)

metals
aluminium
in
1
questions
questions
7
Multiple-choice
response
exam-style
15
marks
easily.
oxide
layer
on
t he
aluminium.
3
Which
of
t he
following
metals
is
a
constituent
of
chlorophyll?
4
A
magnesium
B
zinc
C
calcium
D
iron
Which
human
5
t he
body
following
for
A
calcium
B
potassium
C
zinc
D
magnesium
Which
are
6
of
of
t he
harmful
good
following
to
t he
arsenic,
iron,
B
arsenic,
cadmium,
C
cadmium,
D
arsenic,
rickets
B
anaemia
C
cancer
D
Minamata
a
large
trace
mineral
needed
by
t he
list
of
heavy
ions
t hat
lead
mercur y
mercur y,
lead
magnesium,
sh
metal
body?
lead,
calcium,
of
is
mercur y,
cadmium,
A
a
human
A
Consumption
is
healt h?
is
most
mercur y
likely
to
cause:
disease
315
C20
Non-metals
Most
elements
in
the
periodic
table
are
metals,
the
Objectives
By
the
be
able
end
of
this
topic
you
will
rest
make
metals.
give
●
the
general
properties
of
physical
the
specic
properties
oxygen,
side
group
of
elements
known
as
the
non-
of
state
where
nitrogen,
sulfur
the
non-metals
table.
Many
are
found
on
non-metals
the
are
right-hand
found
naturally
their
elemental
state,
mostly
as
gases
or
solids.
are
also
found
combined
with
other
non-metals
chlorine,
covalent
compounds
and
combined
with
metals
in
sulfur
hydrogen,
chlorine,
occur
of
They
hydrogen,
nitrogen,
and
The
physical
in
carbon
●
a
non-metals
in
give
●
up
to:
oxygen,
carbon
and
ionic
compounds.
man.
However,
Non-metals
because
the
are
used
properties
extensively
of
the
by
different
naturally.
non-metals
vary
significantly,
their
uses
also
vary
quite
considerably.
C20.1
Physical
Non-metals
valence
,
,
The
you
are
and
bonding
learnt
and
elements
electrons,

0
of
usually
t he
graphite.
t he
6,
7
of
t he
diatomic
of
atoms
or
8.
non-metals
usually
Most
have
non-metals
a
large
are
number
found
in
of
Groups
table.
non-metal
bonding
Several
Each
whose
5,
periodic
between
about
molecules.
properties
in
atoms
t he
ot her
in
two
a
non-metal
allotropes
non-metals
molecule
is
made
of
are
up
varies.
carbon,
composed
of
two
n
i.e.
of
atoms
Unit
5.5
diamond
d i atomic
of
t he
non-
metal bonded covalently. Weak intermolecular forces t hen exist between t he
diatomic
molecules.
hydrogen
(H
),
Non-metals
oxygen
(O
2
in
Group

),
composed
nitrogen
(N
2
of
t he
)
of
diatomic
and
all
t he
molecules
halogens,
include
i.e.
t hose
2
periodic
table
including
uorine
(F
),
chlorine
(Cl
2
bromine (Br
) and iodine (
2
exist
as
individual
between
t he
Because
t he
physical
✔
It
is
the
important
way
of
in
due
ot her
which
of
non-metals
t he
have
to
having
full
non-metals
t he
non-metal
different
t he
valence
electron
shells.
Bonding
varies.
atoms
non-metals
following
general
are
also
bonded
var y
physical
to
differs,
some
t he
extent.
proper ties:
tip
that
differences
physical
atoms
atoms
proper ties
However,
Exam
),
2
). The non-metals in Group 0, i.e. t he noble gases,
2
you
can
between
properties
of
●
t hey
have
●
t hey
are
poor
low
●
t hey
are
dull
●
t hey
are
weak
●
t hey
have
melting
points
conductors
of
and
heat
boiling
and
points
electricity
give
the
metals
in
appearance
when
in
t he
solid
state
and
and
brittle
when
in
t he
solid
at
room
state
non-metals.
Many
of
t he
low
densities.
non-metals
are
gases
temperature
because
of
t he
weak
forces of attraction between t he diatomic molecules or atoms, e.g. hydrogen,
oxygen,
nitrogen,
found
a
The
liquid
specic
given
316
as
in
at
uorine,
room
proper ties
Table
20.1.1.
chlorine
temperature
and
and
and
all
t he
characteristics
t he
noble
ot her
of
gases.
non-metals
some
of
t he
Bromine
are
is
solids
non-metals
are
Non-metals

T
able
Physical
20.1.1
Properties
Non-metal
Hydrogen
and
Properties
(H
)
A
characteristics
and
colourless,
of
some
odourless
of
non-metals
non-metals
characteristics
tasteless,
properties
Occurrence
gas
Occurs
in
the
compound
water
(H
2
O),
in
hydrocarbons
and
in
most
other
organic
2
compounds
The
lightest
Acts
Oxygen
(O
)
A
as
a
of
all
elements
reducing
colourless,
agent
tasteless,
odourless
gas
Occurs
in
the
Occurs
in
water,
elemental
state
as
O
2
Nitrogen
(N
)
A
as
an
oxidising
colourless,
agent
tasteless,
odourless
gas
and
carbon
and
in
very
in
oxides
dioxide,
many
in
other
Occurs
in
the
Occurs
in
proteins,
Occurs
combined
Occurs
in
the
Occurs
in
all
of
metals
metal
in
the
air.
non-metals,
It
carbonates
and
metal
e.g.
makes
metal
up
about
sulfates,
in
ores,
21%
many
silicon
of
the
dioxide
air.
organic
(sand)
compounds
elemental
state
as
N
molecules
in
the
air.
It
makes
up
about
78%
of
the
air.
2
One
it
(Cl
and
compounds
2
Chlorine
molecules
2
Acts
)
is
A
of
the
least
considered
yellow
reactive
non-metals;
relatively
green
metal
nitrates
and
ammonium
compounds
inert
gas
in
metal
chlorides,
e.g.
sodium
chloride
(table
salt)
2
Has
Carbon
a
strong
Poisonous
to
Acts
oxidising
Has
as
an
two
graphite
(Unit
a
very
A
Y
ou
will
copper,
bulb,
a
be
and
as
light
the
soft,
has
a
flaky,
very
conducts
reducing
yellow
use
supplied
of
this
with
two
in
elemental
state
as
diamond
compounds,
in
and
metal
graphite
carbonates
and
metal
hydrogencarbonates
and
dioxide
solid.
opaque,
high
dark
melting
electricity.
agent
of
two
activity
and
to
Occurs
in
the
Occurs
in
metal
metals
and
elemental
sulfides
two
state,
and
e.g.
metal
near
hot
springs
and
in
volcanic
regions
sulfates
non-metals
assess:
reporting.
samples
of
non-metals,
conducting
carbon
organic
point.
solid
recording
samples
switch,
a
a
It
and
hard,
sparkling
melting
properties
may
observation,
is
solid.
Acts
●
extremely
high
point
teacher
an
colourless,
has
diamond
5.5)
It
grey
Your
is
agent
allotropes,
transparent,
Graphite
Comparing
humans
main
Diamond
Sulfur
odour
wire
and
two
e.g.
two
metals,
e.g.
graphite
aluminium
and
crocodile
roll
foil
sulfur,
a
and
cell,
a
clips.
Summary
questions
Method
1
Set
up
a
circuit
crocodile
clips
non-metal
In
2
each
in
as
turn
case,
Classify
using
each
the
shown
cell,
in
between
does
metal
the
bulb,
Figure
the
bulb
switch,
20.1.1.
crocodile
light
connecting
Attach
clips
following
to
metal
close
the
1
2
or
Is
it
properties
of
Name
seven
diatomic
non-metal
3
be
Where
would
you
nd
oxygen
tested
the
in
nature?
criteria:
4
●
ve
hydrogen.
and
switch.
List
elements.
metal
and
according
and
up?
to
non-metal
each
and
wire
shiny
or
Compare
graphite,
●
Is
it
malleable
●
Is
it
a
or
conductor
diamond
and
bulb
dull?
brittle?
or
and
a
the
giving
the
differences
similarities
between
them.
non-conductor?
cell
3
Record
your
ndings
in

table.
switch
a
Figure
20.1.1
conductivity
A
circuit
to
test
electrical
5
By
the
means
of
a
properties
those
of
table,
of
compare
metals
with
non-metals.
317
Chemical
properties
and
reactions
of
non-metals
C20.2
Objectives
By
the
be
able
end
of
Non-metals
this
topic
you
will
the
reactions
of
reactions
of
metals
with
oxygen
and
non-metals
valence
the
products
formed
of
elements
usually
whose
5,
6,
7
atoms
or
8,
usually
t hey
have
for m
a
large
negative
number
anions
reactions
wit h
metals
by
gaining
electrons
into
t heir
in
valence
by
electron
reactions
electrons,
metals
chemical
state
are
non-
of
the
and
non-metals
Because
●
properties
to:
describe
●
Chemical
shell.
non-metals
n
with
oxygen
explain
●
the
and
metals
oxidising
N
As
reducing
properties

ne
N
and
of
a
result
t hey
form
ionic
compounds
when
t hey
react
wit h
metals.
The
non-
non-metal
behaves
as
an
oxidising
agent
since
it
gains
electrons
from
t he
metals.
metal,
i.e.
it
causes
Non-metals
can
t he
also
metal
react
to
lose
wit h
electrons
each
ot her.
(OL).
n
t hese
reactions
t hey
share
valence electrons forming covalent compounds and may behave as oxidising
and
We
reducing
will
metals,
agents.
now
and
look
at
t he
Reactions
Non-metals
oxides.
is
in
contrast
Most
of
t he
reactions
wit h
oxygen
non-metal
wit h
non-metal
and
of
metal
oxides
oxides
are
with
to
oxides
cer tain
reducing
non-metals
react
These
at
oxidising
form
are
acidic,
compounds
are
e.g.
of
wit h
oxygen
and
non-metals.
oxygen
usually
which
non-metals
proper ties
gases
solids
carbon
at
at
known
room
room
dioxide
as
non-metal
temperature.
This
temperature.
(CO
),
sulfur
dioxide
2
(SO
),
sulfur
trioxide
(SO
)
2
and
nitrogen
dioxide
(NO
3
known
acidic
as
acid
anhydrides
solutions.
A
few
).
These
oxides
are
also
2
(Unit
non-metal
8.1)
since
oxides
are
t hey
react
neutral,
e.g.
wit h
water
water
(H
to
O),
form
carbon
2
monoxide
or
Did
?
you
and
nitrogen
(NO).
They
don’t
react
20.2.1
T
able
summarises
20.2.1
Reactions
Non-metal
Reaction
Hydrogen
Hydrogen
t he
of
reactions
some
with
acids
of
non-metals
cer tain
with
non-metals
wit h
oxygen.
oxygen
oxygen
burns
with
a
very
pale
blue,
almost
colourless,
flame
forming
water
as
know?
2H
destruction
airship
an
killing
of
35
infamous
the
example
of
combustion
of
hydrogen.
Hindenburg
was
a
(g)

O
2
Hindenburg
A
passengers
mixture
The
luxurious
Nitrogen
feet
long
feet
decks
and
tall.
for
Inside
were
passengers
sixteen
hydrogen
to
gas
cells
make
it
and
air
or
oxygen
explodes
when
lit.
with
oxygen
if
the
temperature
is
high
enough,
forming
airship
(g)

O
(g)
2NO(g)
2
reaction
occurs
during
lightning
storms
and
in
the
engines
of
motor
two
and
filled
Carbon
crew
with
lighter
than
Carbon
If
the
burns
oxygen
forming
supply
is
either
carbon
limited,
monoxide
carbon
or
monoxide
carbon
is
dioxide.
produced:
air.
2C(s)

(g)
O
2CO(g)
2
As
it
was
coming
to
land
in
New
If
Jersey
on
6
May
1937,
a
the
oxygen
supply
is
plentiful,
carbon

O
(g)
CO
2
and
ship
at
within
was
the
34
rear
of
seconds
consumed
in
dioxide
is
produced:
flame
C(s)
appeared
nitrogen
oxide):
and
This
135
O(g)
2
(nitrogen(II)
2
804
2H
hydrogen
reacts
monoxide
N
measuring
(g)
2
of
the
Nitrogen
the
the
(g)
2
ship
entire
Sulfur
Sulfur
burns
with
a
blue
flame
forming
flames.
S(s)

O
2
318
wit h
steam:
The
is
monoxide
alkalis.
Table

(CO)
(g)
SO
2
(g)
sulfur
dioxide
(sulfur(IV)
oxide):
vehicles.
Non-metals
Chemical
Investigating
(T
eacher
Your
●
of
non-metals
with
and
reactions
of
non-metals
oxygen
demonstration)
teacher
may
observation,
Y
our
reactions
properties
teacher
use
this
recording
will
activity
and
to
assess:
reporting.
perform
the
following
piece
carbon
experiment.
Method
1
Place
2
Carefully
a
begins
small
observe
Repeat
4
Compare
5
1
the
of
react
a
a
metal
and
2
and
Which
Non-met als
in
a
to
a
Bunsen
burning,
using
violence
products
Reactions
spoon
Once
on
place
deagrating
burner
it
into
a
spoon.
ame
gas
until
jar
full
the
of
carbon
oxygen
and
happens.
steps
oxygen.
What
the
burn.
what
3
with
heat
to
of
of
the
seems
were
sulfur
in
wit h
metals
is
a
to
of
carbon.
carbon
with
oxygen
and
sulfur
reaction?
with
for m
redox
of
reactive?
each
non-metals
non-met al
place
reaction
more
formed
in
metals
ionic
reaction
compound s .
because
t he
A
reaction
metal
loses
between
electrons,
i.e. it is oxidised, and t he non-met al gains t hese electrons, i.e. it is reduced. The
non-met al
●
acts
Hydrogen
e.g.
as
an
reacts
Ca(s)
oxid ising
wit h

H
agent
metals
to
(g)
in
form
CaH
2
Oxygen
reacts
e.g.
wit h
2Mg(s)

of
metal
t hese
reactions.
hydrides,
(s)
2
calcium
●
all
metals
O
to
hydride
form
(g)
metal
oxides,
2MgO(s)
2
magnesium
●
Nitrogen
e.g.
reacts
wit h
3Mg(s)

metals
N
to
form
(g)
metal
Mg
2
N
3
magnesium
●
Chlorine
e.g.
reacts
wit h
2Al(s)

metals
3Cl
to
form
(s)
reacts
e.g.
wit h
Fe(s)

metals
Non-metals
can
as
to
form
S(s)
(s)
chloride
metal
suldes,
FeS(s)
oxidising
behave
chlorides,
3
iron(II)
Non-metals
(s)
2
2AlCl
aluminium
Sulfur
nitrides,
nitride
metal
2
●
oxide
as
bot h
sulde
and
reducing
oxidising
agents
agents
and
reducing
agents.
They
generally behave as oxidising agents, however, some non-metals can also behave
as
reducing
agents,
for
example,
hydrogen,
carbon
and
sulfur.
319
Chemical
properties
and
reactions
of
non-metals
Non-metals
Non-metals
●
All
to
as
oxidising
non-metals
form
ionic
e.g.
behave
agents
as
oxid ising
compounds.
2Zn(s)

O
They
agents
remove
(g)
when
t hey
electrons
react
from
t he
wit h
metals
metal
atoms,
2ZnO(s)
2
2Fe(s)

3Cl
(s)
2FeCl
2
Mg(s)
●
Chlorine
and
Whenever
oxidising

S(s)
oxygen
t hey
react
(s)
3
MgS(s)
are
par ticularly
wit h
anot her
powerful
element
or
oxid ising
compound
S(s)O
(g)
SO
2
2KBr(aq)
caused
rst
their

oxidation
as
Hydrogen ,
wit h
the
reaction.
Non-metals
●
Cl
(g)
(g)
2KCl(aq)

Br
oxidation
number
reducing
a
2H
ver y
(g)
to
increase
O

O
S(s)

O
sulfur
act
as
(g)
2H
each
●
oxygen
Hydrogen
metal
and
oxides.
e.g.
in
CO
(g)
SO
2
(s)
the
to
second
4
in
causing
reaction.
agents
when
t hey
react
agent,
(g)
(g)
t he
non-metal
oxygen
also
act
t he

H

3C(s)
to
as
caused
decrease
reducing
metal
ions
(g)
to
Cu(s)
t he
from
oxidation
0
agents
to
number
of
2.
when
t hey
react
wit h
atoms,

H
2
O
in
0
ions
2
t he
reduce
CuO(s)
2Fe
0
from
Br
2
carbon
They
to
the
O(g)
(g)
reactions,
atom
1
increase
from
2
2
t hese
to
reducing
oxidising
2
each
sulfur
from
2
C(s)
of
electrons
agents
and

number
removed
powerful
2
(aq)
2
Chlorine
carbon
oxygen,
e.g.
n
as
2
2
the
act
agents,
e.g.
Oxygen
agents.
t hey
O(l)
2
4Fe(s)

3CO
3
(g)
2
2
Hydrogen
oxide
to
caused
t he
decrease
oxidation
from
2
to
number
0
in
t he
of
t he
rst
Cu
ion
reaction.
in
t he
Carbon
copper(II)
caused
t he
3
oxidation
number
3
t he
to
0
in
Summary
1
What
2
When
is
4
What
determines
b
Write
balanced
the
b
the
When
different
balanced
a
ion
in
a
with
non-metal
oxygen
which
it
oxide
chemical
is
oxide
to
decrease
from
chemical
equations
equations
for
reaction
between
sodium
non-metal
agent.
reacts
Explain
non-metals
Name
reacts
with
form
oxygen?
one
of
two
different
oxides.
to
show
the
formation
of
the
oxides.
aluminium
Certain
iron(III)
produced?
between
a
t he
can
reaction
agents.
320
Fe
reaction.
when
reacts
a
Write
each
questions
produced
oxidising
5
second
carbon
two
3
of
one
answer
by
Include
balanced
can
with
the
act
to
two
equations
and
as
both
that
for
the
reactions:
the
non-metal
always
acts
as
an
this.
oxidising
can
different
for
following
chlorine
hydrogen.
metal,
reason
non-metal
reference
a
the
and
agents
behave
reactions
reactions.
as
of
and
both
the
reducing
and
support
named
your
non-metal.
Non-metals
Laboratory
C20.3
Laboratory
preparation
and
uses
of
gases
Oxygen, carbon dioxide and ammonia are all gases which, if required, can be
made
ver y
wit h
relative
impor tant
ease
uses
in
in
t he
laborator y.
today ’s
These
same
gases
also
have
t he
considering
following
t he
proper ties
of
t he
to
be
gas
used
need
to
to
prepare
be
a
gas
in
t he
By
the
be
able
The
solubility
of
t he
gas
in
water
to
if
t he
gas
can
be
bubbling
it
t hrough
The
reactivity
of
●
The
agents
t he
density
met hod
of
used
Laboratory
Oxygen
is
peroxide
can
gas
t he
to
be
gas
wit h
relative
collect
prepared
topic
you
will
how
and
relate
in
the
oxygen,
ammonia
the
carbon
can
be
laboratory
methods
collecting
the
of
drying
gases
to
different
dr ying
agents
to
determine
properties
which
explain
the
carbon
dioxide
uses
of
oxygen
and
used.
t he
to
dr y
preparation
solution
this
water.
●
dr ying
gases
collected
their
●
of
describe
and
by
of
to:
prepared
considered:
determine
end
dioxide
laborator y,
●
●
uses
some
world.
met hod
and
Objectives
●
When
preparation
in
t he
using
a
t he
density
of
air
to
determine
t he
based
on
their
properties.
gas.
of
oxygen
laborator y
catalyst
of
by
t he
decomposition
manganese(IV)
oxide.
of
hydrogen
The
hydrogen
oxyge
peroxide
decomposes
according
to
t he
following
equation:
MnO
2
2H
O
2
(aq)
2H
2
O(l)

O
2
(g)
hydrogen
2
peroxide
The
oxygen
which
●
f
t hat
depends
dr y
Figure
lls
on
oxygen
bubbling
it
is
produced
whet her
not
gas
since
jar,
t he
can
dr y
water
water
t hen
into
oxygen
t hen
oxygen
required,
t hrough
20.3.1,
t he
is
is
an
not
level
in
be
is
t he
collected
required
gas
upside
ver y
t he
can
be
down
soluble
jar
or
one
of
two
solution
ways
water
not.
collected
gas
in
drops.
in
jar,
as
water.
This
is
by
shown
As
t he
known
in
oxygen
as
manganese(IV)
downward
full.
The
having
●
f
dr y
d isplacement
oxygen
been
it
as
shown
in
in
t he
t he
it
Figure
Laboratory
Carbon
usual
in
wash
20.3.2.
The
dr y
is
following
CaCO
(s)
be
of
t he
is
can
to
be
react
it
can
wit h
whet her
●
f
dr y

since
when
of
soluble
water
dried
it
in
when
vapour
it
is
t he
absorb
directly
t he
due
jar
to
is
reacting
t hrough
t he
into
denser
problem
jar
it
calcium
oxide,
concentrated
slightly
The
passing
or
compounds
carbon
by
by
chloride
carbonate
2HCl(aq)
carbon
carbon
see
oxide
is
it

catalyst
Figure
20.3.1
a
water
t han
wit h
jar
air
t his
The
laboratory
oxygen
a
or
sulfuric
gas
of
by
acid,
vapour
by
and
sinks
met hod
is
an
The
full.
dioxide
a
carbonate
wit h
wit h
hydrochloric
acid
acid.
as
shown
equation:
preparation
dr y
to
water
CaCl
(aq)

CO
2
t he
bubbling
be
collected
3
As
easy
containing
t hese
prepared
calcium
is
preparation
upwards.
determined
it
contains
calcium
t hen
air
air
way
bottle
All
gas
and
water.
t hen
preparation
d ioxide
met hod
t he
a
displacing
cannot
t his
anhydrous
d isplacement
jar,
in
water
t hrough
required,
t hrough
oxygen.
upward
t hat
is
containing
bubbling
in
bubbled
oxygen
U-tube
collected
of
dioxide
t hrough
water.
of
dioxide
is
oxygen,
is
not
water
However,
t he
required
required,
into
t he
an
met hod
or

H
of
O(l)
2
collection
depends
on
not.
t hen
upside
carbon
(g)
2
t he
gas
down
dioxide
can
gas
be
jar
collected
since
collected
will
it
is
by
not
ver y
contain
vapour.
321
Laboratory
preparation
and
uses
of
gases
Non-metals
f
●
✔
Exam
it
It
is
can
very
important
draw
line
apparatus
carbon
that
drawings
used
dioxide
dr y
carbon
t hrough
tip
to
and
of
the
prepare
wit h
oxygen,
ammonia
in
dioxide
U-tube
t hrough
oxide
you
a
a
wash
cannot
it.
The
be
dr y
d isplacement
is
bottle
used
gas
of
required,
containing
to
is
air
t hen
containing
dr y
t hen
since
t he
gas
can
is
be
dried
calcium
t han
passing
into
or
sulfuric
carbon
directly
denser
by
chloride
concentrated
because
collected
it
it
anhydrous
a
acid.
dioxide
gas
jar
by
it
bubbling
Calcium
reacts
by
upward
air.
the
laboratory.
hydrochloric
acid
carbon
dioxide
concentrated
sulfuric
calcium

t
is
be
Figure
20.3.2
impor tant
used
to
calcium
acid
carbonate
The
to
note
produce
sulfate.
laboratory
t hat
carbon
This
forms
preparation
calcium
dioxide
a
layer
of
dry
carbon
carbonate
since
t he
around
dioxide
and
sulfuric
reaction
t he
calcium
acid
produces
cannot
insoluble
carbonate
cr ystals,
which prevents t hem from continuing to react wit h t he acid and t he reaction
quickly
stops.
Laboratory
ammonium
Ammoni a
and
preparation
of
ammonia
chloride
calcium
can
be
prepared
in
t he
laborator y
by
reacting
an
alkali
wit h
an
hydroxide
ammonium
salt,
for
example,
calcium
hydroxide
and
ammonium
chloride
ammonia
as
shown
in
t he
Ca(OH)
following
(s)

2NH
2
equation:
Cl(s)
CaCl
4
(s)

2NH
2
(g)

2H
3
O(g)
2
The solid calcium hydroxide and ammonium chloride are mixed toget her in
heat
a
calcium
boiling
tube
tube.
placed
They
are
t hen
horizontally,
as
heated
shown
using
in
a
Bunsen
Figure
burner
20.3.3.
Since
wit h
t he
boiling
ammonia
is
ver y
oxide
soluble in water, it cannot be collected over water. The gas is dried by passing
it
t hrough
calcium

Figure
20.3.3
The
of
dry
U-tube
or
nor
up
a
dr ying
tower
concentrated
containing
sulfuric
acid
can
calcium
be
used
oxide.
to
Neit her
dr y
t he
gas
laboratory
since
preparation
a
chloride
ammonia
reacts
wit h
bot h
of
t hem.
ammonia
The
ammonia
since
it
less
is
collected
dense
t han
air
in
a
and
gas
jar
rises
to
by
downward
t he
top
of
t he
d isplacement
jar,
displacing
of
t he
air
air
downwards. t is possible to determine when t he gas jar is full of ammonia by
placing a piece of moist red litmus paper at t he mout h of t he jar. f t he litmus
turns
blue,
t he
jar
is
full.
Table 20.3.1 summarises t he met hods used to prepare oxygen, carbon dioxide
and
322
ammonia
in
t he
laborator y.
Non-metals

T
able
Laboratory
20.3.1
Summary
Gas
Usual
Oxygen
Hydrogen
and
a
of
the
methods
reagents
Solubility
peroxide
catalyst
used
Slightly
of
to
of
prepare
gas
soluble.
in
Can
gases
in
the
Drying
collected
over
agent(s)
Anhydrous
calcium
Calcium
dioxide
hydrochloric
and
Slightly
acid
soluble.
Can
be
collected
over
Anhydrous
The
of
gases
of
collecting
displacement
denser
gases
than
the
of
dry
gas
air.
Oxygen
air.
Carbon
is
air.
calcium
acid
chloride
Upward
dioxide
and
Very
chloride
to
soluble.
form
cannot
Uses
sulfuric
water.
hydroxide
ammonium
of
oxide
carbonate
Calcium
Upward
slightly
Concentrated
Ammonia
uses
oxide
Concentrated
Carbon
Method
chloride
water.
Calcium
manganese(VI)
and
laboratory
water
be
preparation
Ammonia
ammonium
be
reacts
hydroxide,
collected
over
with
water
Calcium
sulfuric
displacement
is
slightly
of
denser
than
air.
acid
oxide
Downward
therefore,
Ammonia
displacement
is
less
dense
of
air.
than
air.
water.
gases
which
we
can
make
in
t he
laborator y
also
have
many
impor tant
uses. We will look at some of t he uses of oxygen and carbon dioxide based on
t heir
Uses
proper ties.
of
oxygen
Oxygen is essential for all living organisms to make energy during t he process
of
aerobic
breat he.
respiration .
Oxygen
is
also
Humans
essential
obtain
for
t his
oxygen
combustion
to
from
t he
occur.
air
when
Because
of
we
t hese

two
proper ties,
which
●
are
given
Oxygen
and
humans
is
also
found
a
variety
of
uses
for
oxygen,
some
Figure
in
ease
hospitals
cer tain
for
patients
medical
who
disorders,
have
e.g.
difculty
breat hing
bronchitis
and
hear t
Oxygen
is
re
extinguisher
emphysema,
carried
on
questions
ast hma,
Describe
how
you
could
disease.
prepare
●
A
Summary
1
chronic
20.3.4
of
below.
used
to
have
aeroplanes
and
submarines
for
breat hing
dry
oxygen
in
the
pur poses
laboratory.
in
emergencies.
2
●
Nearly
pure
oxygen
is
used
in
spacesuits
for
astronauts
to
Ammonia
the
●
Oxygen
is
used
in
oxyacetylene
and
oxyhydrogen
can
be
prepared
laboratory
by
heating
torches
to
burn
or
hydrogen
and
produce
extremely
high-temperature
are
used
to
weld
and
cut
ammonium
Write
hydroxide
a
chloride.
balanced
equation
Liquid oxygen is used to burn the fuel that generates the lift in spaceships.
for
b
Uses
of
carbon
the
Name
Carbon
d ioxide
has
cer tain
proper ties
liquid
carbon
dioxide
t hat
make
it
useful
to
c
humans.
What
used
Pressurised
is
used
in
re
extinguishers.
When
a
is
suitable
reduced
by
opening
t he
valve
of
t he
extinguisher,
t he
for
the
drying
gas.
method
to
would
collect
the
be
dry
gas
t he
and
pressure
reaction.
dioxide
agent
●
calcium
metals.
a
●
of
ames
and
t hat
a
t he
mixture
acetylene
in
breat he.
why
is
this
method
carbon
used?
dioxide
t han
is
air,
released.
so
it
The
smot hers
carbon
t he
dioxide
ames,
is
non-ammable
keeping
out
t he
and
oxygen
in
denser
t he
d
air.
Why
is
ammonia
collected
●
Solid
carbon
industr y.
items
t
dioxide
sublimes
extremely
cold
(‘dr y
at
ice’)
is
78.5 °C,
and
leaves
used
as
a
refrigerant
t herefore,
no
liquid
it
can
when
it
be
in
t he
used
to
sublimes
not
water?
food
keep
to
a
food
3
a
What
method
collect
gas.
in
●
over
the
dry
is
used
carbon
to
dioxide
laboratory?
Carbon dioxide is used to make carbonated soft drinks. The solubility of
b
the gas increases as the pressure increases. The carbon dioxide is dissolved
in the drink under pressure. When the pressure is released by opening the
4
Why
Explain
is
this
why
method
oxygen
is
used?
used:
bottle or can, its solubility decreases and bubbles form causing the drink
a
in
hospitals
b
in
welding.
to ‘zz’. The carbon dioxide also adds a pleasant taste to the drink.
5
●
Carbon
cer tain
dioxide
is
used
foodstuffs,
as
such
an
as
aerosol
whipped
propellant
cream,
in
cans
because
it
is
Explain
why
used
re
carbon
dioxide
is
containing
relatively
in
extinguishers.
iner t.
323
The
uses
of
non-metals
Non-metals
C20.4
Objectives
By
the
be
able
end
of
this
topic
you
The
non-metals
only
a
small
number
of
elements
in
t he
periodic
table
are
non-
to:
metals,
list
of
will
Alt hough
●
uses
the
uses
metals
and
of
various
their
non-
t hem
compounds.
play
metals

t hese
a
and
T
able
elements
are
par ticularly
t heir
20.4.1
used
impor tant
compounds
The
uses
of
are
carbon
Non-metal/compound
Uses
Carbon
•
in
•
to
•
in
•
diamond
(diamond)
Carbon
(graphite)
Sodium
carbonate
(Na
)
CO
2
3
Sodium
in
a
wide
role
given
and
its
in
in
range
of
industr y.
Tables
applications.
The
uses
of
Some
some
of
non-
20.4.1–20.4.6.
compounds
jewellery
cut
the
and
tips
•
as
•
to
the
•
as
•
to
make
•
to
soften
•
in
•
as
a
•
as
an
•
in
powder
the
in
is
and
other
diamonds
used
as
an
abrasive
for
polishing
and
fine
grinding
pencils
electrodes
solid
glass
drills
‘lead’
make
a
engrave
of
for
use
in
industry
lubricant
carbon
hard
fibres
manufacture
raising
to
strengthen
plastics
water
agent
of
in
glass
baking
powder
hydrogencarbonate
(NaHCO
antacid
)
3

Figure
been
20.4.1
Did
?
This
reinforced
you
Vulcanisation
hardening
is
heated
is
racquet
carbon
the
process
The
sulfur
has
make

Figure

T
able
20.4.2
20.4.2
Carbon
The
in
uses
the
of
form
sulfur
Non-metal/compound
Uses
Sulfur
•
to
•
in
of
and
diamond
its
is
used
to
make
jewellery
compounds
of
rubber
to
extinguishers
bre
know?
rubber.
with
tennis
with
fire
it
vulcanise
the
(harden)
manufacture
rubber,
e.g.
of
medicinal
of
fungicides
for
car
drugs
tyres
and
ointments
to
treat
fungal
infections
stronger,
resistant
more
to
elastic
chemical
and
more
attack.
•
This
in
the
manufacture
garden
is
achieved
cross-links
chains
of
is
discovery
history
of
the
sulfur
between
the
Goodyear
its
by
the
rubber.
in
1839,
stabilising
credited
with
however,
the
rubber
Sulfur
dioxide
(SO
324
1600
attacks
•
to
make
•
to
manufacture
the
heads
•
as
a
food
•
as
a
bleaching
of
matches
)
sulfur
dioxide
preservative,
e.g.
and
in
sulfuric
jams
and
acid
fruit
agent
in
the
manufacture
of
juices
paper
dates
acid
(H
2
to
fungal
2
Sulfuric
back
prevent
polymer
Charles
generally
to
plants
forming
SO
)
•
in
the
•
in
lead–acid
manufacture
of
fertilisers,
e.g.
ammonium
4
BC
batteries,
e.g.
car
batteries
sulfate
on
crops
and
Non-metals

T
able
The
20.4.3
The
uses
Non-metal/compound
of
phosphorus
and
its
Did
?
•
to
make
the
•
to
make
flares,
striking
surface
of
safety
you
to
•
in
•
to
make
the
fireworks
and
of
phosphoric
acid
to
supply
of
the
for
acid
(H
PO
3
)
manufacture
)
4
•
e.g.
P
fertilisers,
e.g.
ammonium
to
the
that
growth.
elements
one
soil
they
or
require
Three
needed
more
of
by
the
plants
phosphate
sulfides,
as
•
to
a
PO
3
are
]
nitrogen
(N),
phosphorus
(P)
4
rust
make
and
remover
the
heads
of
potassium
supply
mainly
known
as
(K).
Fertilisers
these
which
elements
are
matches
NPK
fertilisers.
3

T
able
Figure
20.4.4
20.4.3
The
The
uses
of
heads
of
chlorine
these
and
its
matches
contain
a
phosphorus
sulde
compounds
Non-metal/compound
Uses
Chlorine
•
to
treat
•
to
make
solvents
•
to
make
pesticides,
•
to
make
antiseptics,
•
to
make
monochloroethene,

drinking
water
and
to
destroy
dry-cleaning
window
•
to
frames
manufacture
e.g.
fluids,
and
e.g.
tetrachloroethene
(C
Cl
chlorate( )
(NaClO)
and
chlorate( )
•
as
•
to
[Ca(ClO)
used
to
)
TCP
and
Dettol
which
is
used
Did
?
to
make
PVC
for
Chlorine
guttering
chlorate(I)
and
calcium
you
know?
pipes,
poison
chlorate(I)
gas
gas
was
during
trenches
in
used
as
World
a
War
I
in
Europe.
20.4.5
releases
The
uses
Non-metal/compound
Nitrogen
sterilise
agents
as
of
‘free
)
water
chlorine’
and
which
swimming
is
toxic
to
pool
water
–
the
compound
bacteria
disinfectants
nitrogen
and
its
compounds
Uses
•
liquid
•
to
•
in
fill
nitrogen
light
food
aerobic
(NH
drinking
]
•
Ammonia
is
bleaches
calcium
2
T
able
bleaching
Chlorine
chlorine
4
the
Sodium
20.4.4
DDT
e.g.
sodium
Figure
manufacture
bacteria
2

elements
with
S
4

added
4
[(NH
Phosphorus
phosphate
are
plants
healthy
major
Phosphoric
know?
explosives
pesticides
manufacture
non-metals
matches
Fertilisers
•
of
compounds
Uses
Phosphorus
uses
is
bulbs
used
to
quick
together
packaging
to
with
provide
freeze
foods
argon
an
inert
atmosphere
which
prevents
decay
•
in
the
•
in
household
manufacture
•
to
of
ammonia
cleaners,
e.g.
oven
and
window
cleaners
3
manufacture
fertilisers,
e.g.
ammonium
nitrate
(NH
4
ammonium
sulfate
[(NH
4
[(NH
)
4
•
Nitric
acid
(HNO
)
in
the
PO
3
)
SO
2
]
and
ammonium
NO
),
3
phosphate
4
]
4
manufacture
of
nitric
•
to
manufacture
fertilisers,
•
to
manufacture
explosives
acid
e.g.
ammonium
3
nitrate
(NH
4
NO
)
3

and
Figure
20.4.5
Ammonia
is
often
used
dyes
in
cleaning
agents
325
Harmful
effects
of
non-metals
and
their
compounds

Non-metals
T
able
20.4.6
The
uses
of
silicon
Non-metal/compound
Uses
Silicon
•
in
the
(SiO
dioxide
(quartz)
its
compounds
manufacture
pocket
Silicon
and
calculators
•
to
make
silicone
•
to
make
a
•
in
jewellery,
•
in
the
silicon
chips
used
in
electronic
devices
from
computers
implants
silicon
e.g.
of
to
steel
for
alloy
amethyst
plastic
in
is
the
and
steel
purple
reconstructive
surgery
industry
quartz
)
2
manufacture
of
glass
–
silicon
manufacture
of
cement
dioxide
is
the
main
ingredient
of
glass
Metal
silicates
•
in
•
mixed
the
•
to
make
roof
Summary
1
Which
2
What
used
of
3
four
is
cement
ceramic
tiles,
floor
and
aggregate
products,
tiles,
building
such
to
as
bricks
make
concrete
pottery
and
and
sewer
porcelain
products,
pipes
questions
compounds
mean
to
with
by
of
non-metals
‘vulcanisation
vulcanise
rubber
and
of
are
used
rubber’?
explain
what
to
Name
make
the
happens
fertilisers?
non-metal
during
the
that
is
process
vulcanisation.
Discuss
some
of
the
uses
of
the
following
non-metals
and
their
compounds:
a
C20.5
Objectives
By
the
be
able
end
of
this
topic
you
Harmful
will
c
chlorine
effects
of
silicon.
non-metals
and
their
compounds
to:
While
discuss
●
b
carbon
the
harmful
non-metals
and
t heir
compounds
are
extremely
useful
to
humans,
effects
some compounds of t he same non-metals can have harmful effects on living
of
non-metals
and
their
systems
compounds
on
living
t hese
and
the
and
t he
environment.
Like
cer tain
metals,
t he
concentrations
of
systems
non-metal
compounds
wit hin
t he
environment
are
increasing
due
environment.
to
pollution
caused
by
man’s
activities.
These
harmful
substances
are
called
pollutants
We
will
t hese
now
environment
will
look
pollutants
also
be
T
able
20.5.1
Non-metal
Harmful
effects
of
some
compounds
of
some
in
Table
discussed


at
and
of
t heir
t he
20.5.1.
in
more
Figure
sources
negative
Some
detail
20.5.1
of
some
effects
of
t hese
af ter
Pollution
on
t he
harms
of
t he
effects
table.
the
environment
non-metals
compound/
Sources
in
the
environment
Harmful
effects
pollutant
Sulfur
dioxide
(SO
)
Combustion
of
fossil
fuels,
especially
coal
and
Sulfur
dioxide
causes
respiratory
problems
in
humans,
2
heavy
oils,
e.g.
in
industry
and
power
stations
e.g.
bronchitis.
dissolves
as
Carbon
monoxide
(CO)
Incomplete
in
motor
combustion
vehicles
of
fossil
fuels,
mainly
acid
Carbon
readily
(see
reaching
mental
in
binds
oxygen
the
growth
forming
later
monoxide
dizziness,
326
reduces
rainwater
rain
than
oxygen
and
in
It
this
body
and
solution
haemoglobin
a
reduction
tissues.
awareness,
headaches,
acidic
plants
known
unit).
with
causing
an
of
causes
This
in
much
the
reduces
visual
more
amount
of
respiration
impairment,
unconsciousness
and
even
death.
Non-metals

T
able
Harmful
20.5.1
Non-metal
effects
of
non-metals
and
their
compounds
(continued)
compound/
Sources
in
the
environment
Harmful
effects
pollutant
Carbon
dioxide
(CO
)
Complete
combustion
of
fossil
fuels,
e.g.
in
Carbon
dioxide,
together
with
other
gases,
builds
up
in
2
motor
vehicles,
industry,
power
stations
and
the
aeroplanes
upper
effect
and
About
25%
by
the
shellfish
in
(H
S)
Decay
of
organic
matter
in
garbage
dumps,
of
Hydrogen
carbon
leading
acidity
and
contributing
warming
the
such
produce
sulfide
global
oceans
increase
Hydrogen
atmosphere
as
is
to
expected
maintain
is
sea
their
the
later
dioxide
ocean
oysters,
sulfide
(see
to
in
greenhouse
this
released
unit).
is
absorbed
acidification.
to
affect
urchins
the
and
This
ability
corals
of
to
shells.
extremely
toxic.
Like
carbon
2
landfills
and
petroleum
farmyards.
Released
from
monoxide,
refineries.
reduces
it
combines
cellular
headaches,
of
nitrogen
(NO
and
NO
)
Combustion
at
high
temperatures
in
motor
Oxides
of
respiration
with
and
unconsciousness
concentrations
Oxides
readily
irritate
nitrogen
the
are
haemoglobin,
causes
and
eyes
even
and
extremely
death.
Low
respiratory
toxic
which
dizziness,
causing
system.
lung
2
vehicle
engines
nitrogen
and
and
power
oxygen
in
the
stations
air
to
causing
damage.
react
respiratory
the
of
(CFCs)
Used
as
a
refrigerant
refrigerators
aerosol
Carbon
particles
(C)
and
in
a
air-conditioners
propellant
in
and
fires
rain
fossil
fuels,
e.g.
in
industry.
blacken
and
sulfur
)
(NO
and
phosphate
Fertilisers
ions
used
in
agriculture,
especially
in
These
drivers
e.g.
ions
role
layer
trees
in
in
in
to
the
eyes
die,
and
reduce
development
rainwater
the
forming
upper
light
to
reach
the
unit).
reducing
combine
smog,
aircraft
bronchitis,
cause
skin,
leaves
dissolve
this
They
form
and
the
ultraviolet
in
blacken
cause
major
ozone
buildings.
irritate
unit).
more
later
to
a
and
this
the
(see
dioxide
for
in
allowing
particles
and
problems,
ions
down
also
play
smog
later
surface
Carbon
cigarettes.
They
plants,
(see
break
visibility
Nitrate
of
atmosphere
Earth’
s
of
and
system.
growth
CFCs
some
sprays
Combustion
Bush
as
concentrations
photochemical
acid
Chlorofluorocarbons
Low
which
pilots
asthma
(see
water
causes
and
and
eutrophication
photosynthesis
with
vapour
poor
respiratory
lung
disease.
later
in
this
unit).
3
3
intensive
)
(PO
farming.
Synthetic
detergents.
4
Pesticides,
e.g.
insecticides,
fungicides
and
Used
herbicides
in
control
agriculture
and
vectors
of
control
disease,
for
of
pest
control,
weeds.
e.g.
Used
disease
Pesticides
to
consumers
control
mosquitoes.
useful
as
which
are
concentrate
(see
well
as
later
up
in
harmful
essential
for
food
this
chains
unit).
They
organisms,
pollination
harming
top
can
harm
for
are
also
example,
being
killed
bees
by
insecticides.
Acid
Acid
of
rain
rain
is
nitrogen
when
t hey
SO
formed
are
react
(g)

wit h
H
2
when
released
pollutant
into
the
rainwater
O(l)
H
2
t hey
SO
2
(g)

H
2
O(l)
such
form
as
sulfur
These
acidic
dioxide
oxides
solutions,
are
for
and
oxides
acidic
and
example:
(aq)
3
sulfurous
2NO
gases
atmosphere.
acid
HNO
2
(aq)

HNO
2
nitrous
(aq)
3
acid
nitric
acid
These acidic solutions t hen fall to Ear t h as acid rain which can have a serious
effect
t he
on
soil,
corrodes
causes
plants,
animals,
damages
crops,
buildings,
lakes,
organisms,
streams
such
as
cars,
and
sh.
t he
trees
soil
and
and
machiner y
rivers
to
water.
ot her
Acid
plants
and
become
rain
and
historical
acidic
decreases
harms
and
t he
animals.
monuments
unsuitable
for
pH
t
of
also
and
it
aquatic

Figure
20.5.2
corroded
by
A
limestone
acid
statue
rain
327
Harmful
effects
of
non-metals
and
their
compounds
The
greenhouse
When
t he
Non-metals
fossil
fuels
are
atmosphere,
greenhouse
monoxide
burnt
a
including
gas.
(N
effect
O)
Ot her
and
and
number
carbon
passes
The
Ear t h’s
gases
form
t his
by
t he
a
layer,
surface
radiation.
absorbed
warming
are
produced
Carbon
include
and
dioxide
water
released
is
into
known
vapour,
as
a
dinitrogen
).
4
t hrough
infrared
gases
gases
(CH
2
Greenhouse
of
dioxide.
greenhouse
met hane
global
layer
t hen
Some
around
reaches
t he
radiates
of
t his
greenhouse
t he
t his
heat
radiation
gases
Ear t h.
Ear t h’s
back
goes
around
Radiation
surface
t he
and
into
back
t he
into
Ear t h.
from
warms
Sun
Ear t h.
atmosphere
space
The
t he
t he
and
some
greenhouse
as
is
gases
t hen re-emit t his radiation. Some of it is re-emitted into space, however, most
of
it
is
re-emitted
known
as
the
back
towards
greenhouse
the

Figure
on
20.5.3
The
effects
of
acid
t he
Ear t h
as
heat.
The
heat
causes
a
warming
effect
Earth
heat
rain
radiates
back
into
space
trees
some
is
radiation
absorbed
radiated
into
radiation
space
from
CH
the
Sun
the
Earth
H
warms
4
O
2
CO
2
absorb
CO
some
radiation
2
H
O
O
H
2
2
400
CO
CH
space
2
4
CO
O
noillim
2
is
radiated
back
towards
Earth
atmosphere
380
H
O
CO
2
2
CH
4
rep
360
straP

Figure
20.5.4
The
greenhouse
effect
340
An
increase
warming
1960
1970
1980
1990
2000
of
greenhouse
warming
Figure
levels
20.5.5
in
the
Average
carbon
atmosphere
from
to
ooding
weat her
is
of
t he
gases,
fuels,
Ear t h’s
is
especially
resulting
surface
as
a
in
result
carbon
t he
of
dioxide
Ear t h
caused
getting
increasing
by
warmer.
t he
The
gases
in
causing
t he
atmosphere
polar
ice
caps
is
called
and
global
concentrations
glaciers
to
warming.
melt,
sea
This
of
levels
global
low-lying
coastal
areas,
global
climate
changes
and
to
more
rise,
severe
patterns.
Ozone
you
fossil
dioxide
1960
2012
Did
greenhouse
of
2010
Year
?
in
combustion
320

H
2
layer
depletion
know?
Ozone (O
) is a gas found in the upper atmosphere which shields the Ear th from
3
In
1800
the
average
concentration
was
about
(ppm)
was
or
in
280
the
In
316 ppm
dioxide
atmosphere
parts
0.028%.
about
carbon
per
and
by
million
1960
the
in
in
figure
2012
dangerous
risen
to
about
394 ppm.
aerosol
is
currently
sprays,
about
2 ppm
per
This
which,
refrigerators and
ozone
until
layer
recently,
air-conditioners.
is
becoming
were
These
used
CFCs
depleted
extensively
are
iner t
and
it
damaging
light
is
the
ozone
reaching
the
layer.
Depletion
Ear th
and
this
of
is
the
ozone
leading
to
layer
more
means
and
that
more
more
people
increasing
developing
at
radiation.
(CFCs)
The
U
concentration
(U)
insoluble in water causing them to accumulate in the atmosphere where they
are
had
ultraviolet
chlorouorocarbons
skin
cancer,
cataracts
and
depressed
immune
systems.
year.
Eutrophication
Eutrophication
is
the
rapid
growth
of
green
plants
and
algae
in
waterways
such as lakes, ponds and rivers caused by nitrates and phosphates entering the
water. Nitrate and phosphate ions are needed by green plants to make proteins
so they can grow. When their concentrations increase, it promotes the growth
of
328
plant
life,
especially
algae.
This
rapid
growth
causes
the
water
to
turn
Non-metals
green.
and
Harmful
Underwater
the
algae
decomposed
plants
start
by
to
die
aerobic
then
due
begin
to
to
die
due
overcrowding.
bacteria
which
to
reduced
The
multiply
dead
and
light
plants
use
up
all
effects
of
non-metals
and
their
compounds
penetration
and
the
algae
are
dissolved
oxygen. This leads to the death of other aquatic organisms such as sh.
Effects
of
Pesticides
pesticides
are
chemicals
used
to
destroy
pests.
They
are
used
especially
in
agriculture and in t he control of vectors of disease such as mosquitoes. There
are different types of pesticides: herbicides are used to kill weeds, insecticides

are
used
to
kill
insects
and
fungicides
are
used
to
destroy
Figure
when
Some
are
pesticides
persistent,
have
t he
absorb
are
i.e.
par ticularly
t hey
potential
toxic
do
for
substances
not
harmful
break
in
down
bioaccumulation
at
a
faster
rate
t he
in
environment
t he
which
t han
t hey
because
environment.
occurs
excrete
20.5.6
Eutrophication
occurs
fungi.
when
t hem.
t hey
They
green
there
algae
is
uncontrolled
in
growth
of
water
also
organisms
For
example,
if fat soluble pesticides such as DDT are absorbed by living organisms t hey are
stored in fatty tissues of t he organisms where t hey gradually accumulate. The
concentration
moving
up
are
of ten
ver y
Disposal
Plastics
of
food
pesticides
harmed,
of
are
t he
chains.
a
in
t he
result,
especially
solid
organic
As
fatty
tissues
consumers
birds
of
of
at
animals
t he
top
of
t hen
t he
increases
food
chain
prey.
waste
compounds
composed
of
t hey are organic compounds, most plastics are
non-metals.
Even
t hough
non-biodegrad able , i.e. t hey
cannot be broken down by microorganisms and t herefore t hey remain in t he
environment
waste
●
Plastics
t hat
to
●
for
ver y
containing
make
more
accept
Some
up
and
all
danger
●
Plastics
and
●
of
When
and
of ten
The
not
where
leading
problem
recycling
all
of
1
Explain
to
how
of
all
being
time.
solid
used
chemicals
plastics
This
waste
up
gases
of
to
are
if
of
burnt
t hey
are
makes
going
t he
to
extend
by
of
being
are
of
in
disposal
landlls,
and
build
groundwater
which
can
ver y
of
solid
meaning
landlls
can
be
to
or
in
wit hin
t here
and
lead
of
of ten
harmful
ingested
plastics
persistent
landlls
disposed
plastics
par ticularly
deat h
disposal
which
disposed
when
properly,
t hey
made
are
contaminating
problems
t heir
t he
items
Summary
toxic
toxic
healt h
disposed
oceans
is
chemicals
produce
serious
25%
of
problem.
plastics.
When
t hese
periods
serious
land
release
environment.
a
about
more
t hese
plastics
long
plastics
to
land
nearby
air
up
soil.
pollution
in
to
a
water ways
organisms,
causing
solved
t he
t he
incinerators.
aquatic
by
is
suffocation.
large
extent
by
plastic.
questions
carbon
dioxide
contributes
to
global
warming
and
suggest
some
of
the
consequences
of
global
warming.
2
Name
3
What
4
5
two
are
a
What
b
Why
What
which
pesticides
is
is
are
gases
can
and
why
eutrophication
eutrophication
some
of
the
form
are
and
a
acid
they
what
is
problem
problems
of
rain
and
harmful
it
in
discuss
to
caused
aquatic
disposing
of
some
organisms
of
at
the
the
effects
top
of
of
food
acid
rain.
chains?
by?
environments?
plastics?
329
Green
chemistry
Non-metals
C20.6
Objectives
By
the
be
able
end
of
this
topic
you
Green
chemistry
will
Green
chemistry
is
also
known
as
sustainable
chemistry .
Green
chemistr y
to:
involves designing chemical products and processes t hat reduce or eliminate
●
dene
●
outline
green
chemistry
t he
the
principles
of
use
or
generation
of
substances
t hat
are
hazardous
to
living
organisms
green
and
t he
environment.
chemistry.
The
principles
when
The
for
t hey
principles
economic
and
t he
Key
!
fact
a
chemistry
of
a
or
eliminates
set
of
is
the
principles
the
use
utilisation
that
or
reduces
They
hazardous
the
design,
application
and
substances
manufacture
of
chemical
processes.
on
new
t he
provide
materials,
development
at
t he
a
of
same
framework
products,
sustainable
time
as
for
chemists
processes
and
designs
protecting
to
use
systems.
which
human
allow
healt h
of
costs
processes
reagents,
and
pressures
create
yields
associated
usually
including
and
purication
below
wit h
raw
take
solvents.
100%,
place
They
has
to
generate
materials,
energy
in
several
of ten
take
place
at
substantial
usage
steps
require
and
and
elevated
each
waste,
waste
step.
incur
disposal
generation
and
of
focus
chemical
usually
heavy
chemistr y
development
variety
temperatures
Green
green
designing
environment.
Trad itional
use
of
are
have
a
negative
impact
on
t he
environment.
in
and
products
Green
chemistr y
is
doing
chemistr y
t he
way
nature
does
chemistr y;
using
renewable, biodegradable materials which do not persist in t he environment
or
harm
Using
t he
t he
environment.
technologies
of
green
chemistr y
provides
a
number
of
benets
including:
●
reduced
wastage
●
reduced
pollution
●
safer
●
reduced
●
improved
The
are
and,
to
toget her
at
‘It’s
term
t he
wit h
principles
Prevent
and
principles
follow
The
working
twelve
energy
natural
of
principles
twelve
systems.
while
of
competitiveness
chemists
and
1
use
twelve
There
for
products
‘green
United
John
are
chemical
of
of
when
green
chemistry
chemistr y,
new
chemistr y’
States
below
manufacturers.
green
designing
Warner,
stated
resources
was
which
coined
Environmental
he
developed
wit h
a
provide
materials,
shor t
by
Paul
twelve
road
in
Agency
principles.
explanation
of
map
processes
Anastas
Protection
t he
a
products,
1991
(EPA)
These
each.
waste
better
to
prevent
waste
than
to
treat
or
clean
up
waste
af ter
it
has
been
created.’
Chemical
waste
2
as
Maximise
‘Synthetic
mater ials
materials
in
few,
if
atom
should
be
designed
to
produce
as
little
hazardous
economy
methods
used
Chemical
330
processes
possible.
in
should
the
processes
into
any,
t he
be
process
which
nal
wasted
designed
into
the
to
maximise
nal
incor porate
products
atoms.
the
incorporation
of
all
product.’
most
should
be
or
all
used.
of
t he
This
star ting
would
t hen
result
Non-metals
3
Green
Design
less
‘Wherever
generate
hazardous
practicable,
substances
chemical
synthetic
that
possess
chemistry
syntheses
methods
little
or
should
no
be
toxicit y
designed
to
which
human
use
health
and
and
the
environment.’
Chemical
least
risk
harmless
4
Design
processes
to
All
safer
5
be
Use
they
products
use
designed
t he
using
reactants
environment
and
which
which
pose
t he
produce
of
t heir
auxiliar y
be
made
chemical
agents.
waste.
use
The
of
and
be
perform
their
desired
functions
Many
to
uses,
be
but
safer.
have
These
products
minimum
should
toxicity.
auxiliaries
substances
or
which
designed
innocuous
t hese
totally
designed
specic
processes
separating
eliminated
be
products
toxicity.’
should
for
solvents
should
Many
be
and
and
should
their
products
effective
safer
‘The
chemicals
minimising
new
still
healt h
by-products.
‘Chemical
while
should
human
use
of
should
when
auxiliar y
t hese
are
substances
t hey
be
should
minimised
wherever
possible
and
used.’
substances
hazardous
should
be
be
such
and
reduced
replaced
wit h
as
lead
to
less
solvents
to
a
and
considerable
minimum,
hazardous
alternatives.
6
Increase
‘The
energy
synthetic
if
energy
efficiency
requirements
methods
of
should
chemical
be
processes
conducted
at
should
ambient
be
minimised
temperature
and
and
pressure
possible.’
Chemical
processes
of
f
energy.
(surrounding)
amounts
of
should
possible,
temperature
energy
be
designed
processes
and
associated
should
to
be
pressure
wit h
use
to
using
t he
carried
avoid
higher
minimum
out
at
t he
t he
need
amounts
ambient
for
temperatures
large
and
pressures.
7
Use
renewable
‘Raw
mater ials
whenever
The
as
waste
feedstocks
feedstock
Whenever
materials
such
or
should
be
rene wable
rather
than
depleting
practicable.’
term
process.
feedstocks
which
refers
are
ot her
any
raw
material
chemical
renewable.
pur pose-grown
from
to
possible,
crops,
These
wood
used
processes
include
chips,
in
an
should
industrial
use
agricultural
processed
solid
raw
products
waste
and
processes.
The use of non-renewable raw materials should be reduced to a minimum
since t hey are rapidly r unning out. Non-renewable raw materials include
t hose
and
obtained
t hose
from
which
are
fossil
fuels,
mined
such
from
t he
as
petroleum,
Ear t h,
such
as
natural
gas
and
coal,
ores.
331
Green
chemistry
Non-metals
8
Reduce
derivatives
‘Unnecessar y
derivatisation
Derivatisation
processes.
waste,
9
Use
involves
Since
t his
be
minimised
temporarily
requires
derivatisation
should
modifying
additional
be
or
avoided
physical
reagents
avoided
or
if
and
possible.’
and
can
chemical
generate
minimised.
catalysts
‘Catalytic
reagents
Catalysts
are
reaction
are
should
not
itself.
used
up
are
super ior
used
up
in
to
reactions
Stoichiometric
and
t he
stoichiometr ic
reaction
since
reagents
of ten
t hey
take
forms
reagents.’
do
par t
in
not
t he
unwanted
or
take
par t
reaction
in
so
hazardous
t he
t hey
by-
products.
Catalysts
reaction
t he
10
should
occurs
reaction
products
of
by-products.
for
‘Chemical
products
persist
in
Analyse
in
‘Choose
the
any
our
to
improves
reagents
designed
the
for
t he
and
several
reasons.
temperature
it
conversion
reduces
The
needed
t he
of
for
reactants
production
be
so
they
break
down
into
innocuous
environment.’
designed
down
into
prevent
potential
to
be
so
t hat
harmless
at
t he
end
products
of
t heir
which
do
not
be
chemical
is
pollution
developed
minimise
chemical
hazardous
should
to
a
the
process
complete
to
allow
for
formation
should
and
to
of
real-time,
in-process
hazardous
always
detect
be
t he
substances.’
monitored
formation
to
of
any
by-products.
for
used
accidents
in
chemical
accidents,
processes
including
which
explosions,
minimise
res
and
the
toxic
releases
always
to
The
show
by
in
chosen
to
reduce
t he
risk
of
chemical
action
understand
year,
awards
be
minimum.
way
Each
chemistr y
to
reaction
The
which
332
of
chemistry
Awards.
break
should
Green
various
it
t he
atmosphere.’
accidents
best
in
should
control
t he
the
for
Reagents
action.
of
processes
reduces
environment.
and
or
be
persist
t hey
reagents
potential
wastage
real-time
when
Minimise
chemical
catalyst
energy,
should
not
methods
unwanted
into
life
progress
know
12
do
t he
monitor ing
The
saves
products
‘Analytical
in
t he
degradation
products
functional
used
reducing
that
Chemical
11
which
to
Design
be
faster,
t he
US
including
following
how
small
environmental
t he
t he
potential
Environmental
are
The
a
Presidential
few
effective
businesses
examples
green
larger
chemistr y
Green
of
application
and
challenges.
of
Protection
Agency
Chemistr y
award-wining
of
is
t he
cor porations
to
(EPA)
it
in
Challenge
innovations
principles
is
see
sponsors
of
beginning
to
green
solve
Non-metals
●
irent
Green
Energy
gasoline,
plants.
Systems
diesel
The
process
economically
resource
●
so
Eastman
esters
uses
use
and
Battelle
and
in
to
and
carbohydrates
paper
than
star ting
also
place
from
traditional
lower
have
from
allowing
considerable
toner
which
the
of
a
new
are
made
to
than
be
energy
for
protein
much
a
to
Their
of
renewable
of
make
method
avoids
using
to
strong
undesirable
traditional
laser
from
easily
are
by-
methods.
printers
together
easier
and
make
compete
method
energy,
toner
can
Plants
production
and
is
paper
amounts
a
to
cellulose
petroleum.
products.
saves
developed
This
toners
care
the
oil
and
on
temperatures
soya
and
petroleum.
which
minimises
at
energy
developed
personal
esters
corn.
from
method
starch
dependence
has
and
catalytic
sugar,
external
reduce
the
made
materials,
saves
little
Company
par tners
the
produced
helps
solvents,
takes
its
fuels
water-based,
from
requires
make
photocopiers
a
fuel
cosmetics
organic
and
use
jet
use
Chemical
for
products
●
with
their
enzymes
acids
and
chemistry
with
remove
from
petroleum-based
recycled.
reduces
ts
the
production
use
of
petroleum.
●
Buckman
derived
order
to
and
means
recycled
saves
natural
make
stronger
This
nternational
from
paper.
of
paper,
Paper
higher
that
the
thus
signicant
has
carefully
sources,
to
made
quality
paper
can
amounts
of
using
than
be
conser ving
selected
modify
the
these
paper
made
energy
and
designed
bres
modied
made
using
natural
and
cellulose
by
less
reduces
bres
wood
is
traditional
wood
resources.
enzymes,
in
The
the
bre
use
of
methods.
and
process
in
much
more
also
additional
chemicals.
●
Seventh
Generation
products,
diapers,
such
body
as
washes
phosphate-
and
materials
its
in
produces
laundr y
and
and
green
cleaning,
dishwasher
lotions.
chlorine-free
The
paper
and
detergents,
company
ingredients
in
uses
its
personal
paper
care
towels,
baby
biodegradable
products
and
and
recycled
packaging.

Figure
20.6.1
Seventh
biodegradable
and
Generation
phosphate-
products
and
use
chlorine-free
ingredients
Summary
1
Dene
2
Suggest
3
Outline
questions
‘green
chemistry’.
some
six
benets
principles
of
of
using
green
the
technologies
of
green
chemistry.
chemistry.
333
Green
chemistry
Non-metals
Key
●
concepts
Non-metals
valence
●
n
general,
not
a
●
and
Many
few
●
Carbon
●
Diamond
●
Graphite
●
Non-metals
●
and
has
is
is
two
is
a
a
are
low
at
green
allotropes,
have
points
dull,
weak
and
and
temperature.
sof t,
aky,
colourless,
and
diamond
opaque,
negative
into
are
gas
dark
anions
t heir
in
valence
sulfur
and
colourless,
a
large
number
of
boiling
brittle
points,
in
t he
do
solid
Bromine
is
a
liquid
and
tasteless
is
a
and
yellow
odourless
solid.
graphite.
sparkling
grey
solid.
solid.
chemical
electron
reactions
shell.
As
a
wit h
metals
result
t hey
by
form
compounds
share
valence
covalent
electrons
react
wit h
oxygen
●
Non-metals
react
wit h
metals
●
All
●
Oxygen
non-metals
and
ot her
Hydrogen,
when
t hey
react
wit h
each
ot her
compounds .
Non-metals
●
are
room
●
wit h
usually
8.
melting
nitrogen
yellow
transparent,
electrons
forming
●
atoms
or
heat,
gases
and
a
form
Non-metals
wit h
7
densities.
oxygen
chlorine
gaining
6,
solids.
Hydrogen,
ionic
low
5,
have
electricity
have
whose
usually
non-metals
are
gases,
elements
non-metals
conduct
state
●
are
electrons,
behave
chlorine
as
to
form
form
oxid ising
always
non-metals
or
carbon
sulfur
and
to
act
as
non-metal
ionic
agents
oxides
compounds
when
oxidising
t hey
agents
react
when
wit h
t hey
metals.
react
compounds.
act
as
reducing
agents
when
t hey
react
oxygen.
Hydrogen
and
carbon
act
as
reducing
agents
when
t hey
react
wit h
metal
oxides.
●
Oxygen
can
hydrogen
●
Carbon
with
●
acid,
Ammonia
Calcium
used
●
Dr y
air,
●
to
Two
impor tant
Carbon
in
dioxide
in
carbon
is
in
of
t he
a
the
by
laborator y
and
decomposition
by
oxide
reacting
hydrochloric
laborator y
and
t he
manganese(IV)
hydroxide
oxide
t he
by
and
reacting
concentrated
a
carbonate
acid.
an
ammonium
of
catalyst.
alkali
wit h
an
chloride.
sulfuric
acid
may
be
laborator y.
dioxide
collected
by
oxygen
used
drinks
and
bres
are
collected
downward
are
in
by
upward
displacement
displacement
hospitals
and
for
of
of
air.
welding
and
to
and
t heir
in
re
and
as
an
aerosol
compounds
strengt hen
to
extinguishers,
make
have
plastics,
to
insecticides,
as
a
refrigerant,
to
make
propellant.
a
great
many
strengt hen
matches,
uses
r ubber
fer tilisers,
including
used
in
tyres,
bleaches,
glass
ceramics.
Non-metals
organisms
334
sof t
jeweller y
and
calcium
in
of
carbonate
calcium
made
uses
laborator y
prepared
calcium
prepared
is
t he
presence
metals.
Non-metals
making
●
and
in
t he
be
e.g.
gases
carbonated
●
be
salt,
ammonia
cutting
●
can
chloride,
dr y
in
usually
can
oxygen
dr y
prepared
dioxide
an
ammonium
●
be
peroxide
and
and
t heir
t he
compounds
environment.
can
have
a
negative
effect
on
living
Non-metals
●
The
Green
concentration
wit hin
t he
of
t hese
environment
is
harmful
non-metals
increasing
due
to
and
t heir
pollution
chemistry
compounds
caused
by
man’s
activities.
●
The
most
carbon
harmful
non-metal
monoxide,
carbon
chlorouorocarbons,
compounds
●
Acid
rain
in
compounds
dioxide,
carbon
include
hydrogen
par ticles,
sulfur
sulde,
nitrate
and
dioxide,
oxides
of
phosphate
nitrogen,
ions
and
pesticides.
forms
when
sulfur
dioxide
and
oxides
of
nitrogen
react
wit h
rainwater.
●
Carbon
dioxide
is
contributing
to
the
greenhouse
effect
and
global
warming
●
Chlorouorocarbons
are
atmosphere
more
●
Nitrate
●
Pesticides
●
Disposal
Waste
●
and
allowing
phosphate
of
solid
Green
t he
manufacture
Using
t he
●
of
and
t he
or
energy
and
of
wastage,
natural
chemical
manufacturers.
There
twelve
are
of
green
principles
of
poses
a
set
of
chemical
green
t he
a
in
t he
Ear t h’s
top
upper
surface.
consumers.
serious
principles
problem.
and
provides
pollution,
and
t hat
substances
products
chemistr y
resources
t he
eutrophication
hazardous
reduced
layer
reach
recycled
of
of
ozone
to
harming
plastics
be
utilisation
application
reduced
chains,
should
t he
light
causing
generation
technologies
including
use
is
use
are
food
containing
plastics
chemistry
eliminates
●
waste
up
down
ultraviolet
ions
concentrate
containing
breaking
safer
improved
a
in
reduces
t he
or
design,
processes.
number
products,
of
benets
reduced
competitiveness
of
chemistr y.
335
Practice
exam-style
questions
Non-metals
9
Practice
exam-style
Acid

1
Which
of
t he
questions
following
A
Most
have
B
They
are
high
all
C
They
are
D
Most
have
is
tr ue
of
nitrogen

carbon
Which
of
metals
A
at
usually
t he
solid
at
melting
following
room
chlorine,
A

only
B

and
C

D
,
hydrogen,
C
uorine,
D
oxygen,
of

room
is
Most
list
bromine,
oxygen,
oxygen,
of

and
A
4
of
neon,
10
The
gaseous
diatomic
increase
A
depletion
B
changes
C
melting
amphoteric
D
neutral
n
which
behaving
D
ooding
Zn(s)
B
2K(aq)

a
following
reducing

are:
11
reactions
is
2Mg(s)
(g)
t he
2KCl(aq) 
t he
atmosphere
except:
t he
ozone
global
layer
weat her
of
polar
ice
patterns
caps
of
low-lying
coastal
areas
a
The
question
diagram
used
to
below
prepare
shows
a
dr y
t he
apparatus
sample
of
t hat
oxygen
in
could
t he
X
non-metal

(aq)
2
(g)
H

in
following
ZnS(s)
Cl
Pb(s)

H
2
D
levels
t he
helium
2
PbO(s)
of
agent?
S(s)

dioxide
all
laborator y.
t he
as
A
C
of
in
liquid
of
cause
chlorine
be
basic
carbon
to
non-
acidic
C
in
predicted
nitrogen
hydrogen,
non-metals
B
only

nitrogen
hydrogen,
nitrogen,
oxides
only

temperature.
points.
a
and
electricity.
Structured
3
dioxide
monoxide
temperature?
oxygen,
B
by:
non-metals?
are
2
caused
dioxide
densities.
non-conductors
low
is
sulfur

Multiple-choice
rain
questions
O(l)
2
O
(g)
2MgO(s)
2
5
Oxygen
can
be
prepared
in
t he
laborator y
by
t he
dry
decomposition
of
hydrogen
peroxide.
Manganese(IV)
oxygen
oxide
is
also
usually
A
a
source
B
a
catalyst
of
C
an
t he
used
in
t he
preparation
solid
as:
solid
oxygen
i)
oxidising
a
reducing
Y
dentify
t he
State
t he
role
Write
an
of
t he
following
is
used
as
t he
dr ying
agent
in
of
dr y
ammonia
in
t he
Name
A
calcium
oxide
B
calcium
chloride
v)
C
calcium
D
concentrated
sulfuric
t he
t he
suitable
following
to
prepare
pairs
a
of
reactants
sample
of
would
carbon
be
dioxide
Give
A
calcium
B
magnesium
C
copper(II)
D
calcium
form
ONE
re
ii)
carbonate
and
carbonate
carbonate
carbonate
dioxide
is
dilute
and
and
and
used
can
nitric
dilute
dilute
dilute
in
all
of
t he
a
to
acid
react
zinc
how
oxygen
Y.
for
and
wit h
could
be Z
marks)
and
collecting
name
t he
t he
state
marks)
oxygen
met hod.
(2
bot h
metals
and
by
t he
marks)
non-metals
is
by
added
reacts
to
wit h
Give
for
t he
reaction
oxygen.
a
a
few
t he
(2
drops
oxide
sulfur,
reason
blue
formed
what
for
of
would
your
when
you
(2
following
non-metal
hydrogen
can
behave
expect
answer.
acid
The
marks)
litmus
as
bot h
marks)
an
except:
agent
and
a
reducing
agent.
Write
T WO
extinguishers
sof t
one
to
show
hydrogen
behaving
as
an
drinks
agent
and
one
to
show
it
behaving
as
a
hospitals
aerosol
agent.
(2
marks)
sprays
Total
336
mark)
is
(2
t hat
equation
and
followed
obser ve?
reducing
D
reason
balanced
water,
oxygen
acid
hydrochloric
sulfuric
f
oxidising
C
and
show
compound
shown
solution,
acid
sulfuric
Write
equations,
B
X
to
oxides.
oxidising
A
marks)
(1
(2
between
in
laborator y?
Carbon
(2
role.
Oxygen
i)
t he
c
8
Y.
acid
to
of
solid
carbonate
b
least
by
ONE
met hod
Which
t he
laborator y?
its
7
and
solid Y.
t he
iv)
preparation
t he
equation
produced
Which
of
agent
iii)
6
liquid X
agent
ii)
D
Z
15
marks
Non-metals
Practice
Extended
12
a
The
response
Four t h
Annual
Assessment
ntergovernmental
Change
published
t he
next
par tially
gases
i)
ii)
in
is
likely
two
in
to
t he
2007
be
decades.
attributed
Name
to
This
on
predicts
about
t he
Repor t
Panel
t hat
0.2 °C
global
of
t he
per
overall
decade
warming
increase
in
United
Climate
has
Explain
t he
b
main
how
greenhouse
t he
gas.
greenhouse
(1
effect
Over
t he
a
This
t he
possible
years
studies
signicant
Your
of
has
been
c
some
answer
t he
of
global
linked
ozone
‘Non-metals
extensively
shown
t he
wit h
for
of
t he
t he
t here
extensive
many
and
man.’
provide
has
layer.
use
of
of
reference
t his
to
depletion.
t he
function
(3
t heir
compounds
By
reference
evidence
on
marks)
years.
consequences
include
t hat
ozone
layer.
by
non-metals,
statement.
of
must
have
marks)
warming
(3
depletion
chlorouorocarbons
Discuss
effects
mark)
works.
environment.
been
been
atmosphere.
t he
Discuss
global
for
greenhouse
(4
iii)
questions
question
Nations
warming
exam-style
to
are
to
marks)
used
T WO
suppor t
different
t his
(4
Total
marks)
15
marks
337
C21
Water
Water
makes
up
between
60%
and
70%
of
the
human
Objectives
By
the
be
able
●
end
of
this
topic
you
will
body
describe
some
properties
of
of
the
unique
a
liquid
explain
of
it
covers
71%
of
the
Earth’s
surface.
Water
is
why
water
and
the
can
harmful
at
it
exists
room
on
temperature
Earth
in
all
three
and
pressure,
states,
solid
however,
(ice),
liquid
water
and
●
and
to:
gas
(water
vapour
or
steam).
Water
has
certain
properties
have
unique
useful
effects
on
properties
that
make
it
essential
for
life
on
Earth.
living
These
properties
help
us
to
understand
such
things
as
systems
●
discuss
the
●
the
consequences
solvent
distinguish
types
of
properties
between
water
of
the
of
water
how
the
water
becomes
bottom
of
lakes
polluted
when
and
the
why
top
is
life
can
exist
at
frozen.
two
hardness.
C21.1
Pure
water,
tasteless
a
side
shown
unique
water
t hat
charges
Figure
a
The
and
properties
does
liquid
Water
has
charge.
in
t hat
odourless
pressure.
negative
positive
i.e.
and
standard
has
The
molecules
par tial
two
t he
not
contain
t hat
boils
are
positive
hydrogen
oxygen
of
any
at
charge
atom
has
and
meaning
and
in
a
impurities,
100 °C
polar,
atoms
water
a
par tial
t hat
side
each
is
a
colourless,
freezes
at
each
t hat
has
molecule
negative
0 °C
at
molecule
a
par tial
have
par tial
charge.
This
is
21.1.1.
oxygen
partially
hydrogen
negative
partially

side
 +
of
positive
molecule
side
of
hydrogen
molecule
 +

Figure
The
21.1.1
par tial
A
polar
positive
water
molecule
hydrogen
atoms
and
par tial
negative
oxygen
atoms
of

O
H
 +
t he
water
molecules
are
attracted
to
each
ot her.
This
attraction
forms
what
H

is
 +
known
as
t he
hydrogen
bond.
Hydrogen
bonds
are
usually
stronger
hydrogen
O
H
t han
ot her
intermolecular
gives
water
several
forces
which
exist
between
molecules
and
t his
bonds

H
 +

O
 +
unique
properties .
We
will
now
look
at
some
of
t hese
t he
mass
H
proper ties
 +
H
O
and
at
t heir
signicance
to
living
organisms.
H

 +
H
 +
The
 +
maximum
density
of
water
occurs
at
4 °C

O
Density
H
is
a
measure
of
how
compact
a
substance
is.
t
is
dened
as
 +
of
H
a
substance
divided
by
its
volume,
i.e.
 +
mass
________
density

Figure
21.1.2
Hydrogen
bonding

in
.
volume
water
f
f
t he
its
of
a
xed
increases,
When
most
liquids
of
solid
is
t he
solid
is,
liquid
338
volume
volume
it
less
t herefore,
sinks.
mass
its
are
cooled
t han
of
density
t he
denser
a
substance
and
become
volume
t han
decreases,
its
density
increases.
decreases
t he
of
solids
t he
liquid
t hey
liquid
and
if
contract.
from
it
is
which
placed
The
it
in
volume
forms.
more
of
The
t he
Water
The
Somet hing
cooled
However,
until
it
of
t he
forms.
if
to
it
is
freezes
volume
t han
slightly
down
is
below
This
from
water
why
ice
happens
contracts
0 °C.
water
liquid
This
it
cooled
at
t he
different
4 °C
and
4 °C
it
means
which
from
oat
star ts
t hat
it
which
cubes
in
to
t he
forms.
it
in
t he
case
becomes
expand
cold
water.
Solid
of
ice
and
just
and
volume
formed
a
of
denser,
it
When
like
continues
ice
is,
is
to
greater
t herefore,
oats
on
water
ot her
t he
unique
properties
of
water
is
liquids.
expand
t han
less
t he
dense
liquid
as
it
drink.
1.0000
m c g(
3
)
0.9995
ytisneD
0.9990
0.9985
0.9980
0
2
4
6
8
10
12
14
T
emperature

When
a
Figure
pond
or
21.1.3
lake
The
freezes,
maximum
ice
density
forms
at
t he
16
18
20
(°C)
of
water
surface
occurs
and
at
t he

4 °C
denser,
Figure
21.1.4
Ice
oats
in
water
warmer
water remains below t he ice. This enables aquatic organisms to sur vive under
t he
ice.
ice
summer

Figure
Water
n
Unit
t he
has
12.2
amount
substance,
requires
t hat
ver y
a
water
changes,
The
or,
t he
t heir
As
of
body
sur vive
●
in
by
1 °C.
a
lot
ot her
living
of
of
of
of
of
in
heat
t he
heat
water
for
does
capacity
a
high
of
and
not
of
a
in
its
by
a
winter
substance
unit
specic
temperature
main
mass
heat
1 °C.
change
t he
ver y
is
t he
capacity,
This
temperature
of
of
it
means
changing
surroundings
much.
This
is
of
reasons.
between
absorb
ver y
summer
temperature
contain
can
in
wit hout
t he
two
heat
has
its
energy
when
lake
temperature
water
increase
a
capacity
specic
changing
large
not
change
much.
not
water
a
much.
60%
lot
of
This
and
heat
70%
water.
energy
means
t hey
wit hout
can
temperature.
of
do
4 °C
temperatures
temperature
environments
3 °C
4 °C
organisms
t he
ver y
to
organisms
temperature
extremes
2 °C
5 °C
raise
words,
living
environmental
t he
to
organisms
living
t his,
1 °C
6 °C
Because
energy
absorb
in
t hat
needed
heat
0 °C
7 °C
specific
temperature
to
bodies
Because
1 g,
8 °C
temperature
learnt
heat
of
can
The
high
you
e.g.
signicance
●
a
of
lot
much
21.1.5
winter
bodies
This
change,
of
water
means
experience
t hat
e.g.
from
such
as
winter
lakes
organisms
extreme
to
and
living
uctuations
in
summer,
seas
in
does
aquatic
temperature.
339
The
unique
properties
of
water
Water
Water
The
a
heat
liquid
gas
has
due
t hat
of
to
to
water
when
large
a
a
gas.
amount
has
ot her
ver y
of
of
is
ice
of
a
is
t he
t he
met hods
high
and
t he
a
a
cooling
boiling
due
high
heat
of
change
water
This
to
a
means
vaporisation,
organism
This
to
liquid
molecules.
makes
it
removes
sweating
a
and
organisms.
point
point
to
required
change
living
organism.
of
size
energy