Advanced Subsidiary (AS)
CHEMISTRY
excellearninginc.com/.../_uimages/chemistry2.jpg
Course Handbook 2010-11
Student Name: _____________________
Student ID No.:_____________________
Contents
Welcome
3
Some useful names
4
Course Structure & Qualification
5
Assessment
6
Specification structure and ‘How Science Works’ 7
What you can expect from us
9
What we expect from you
10
Resources
11
Progression
13
Your Notes
14
Health & Safety
15
A note on equality
16
Some useful information for your studies
17
Welcome to the
Chemistry Department
The Chemistry Laboratories are situated on the first floor of
the Middlehaven building. This subject is part of the A level
department which falls within the Directorate of Academic and
Professional Studies.
You will have 5 hours of lessons per week broken up into
three sessions: one 2 hour session and two 1.5 hour sessions.
In addition to this you should allow at least 2 hours for self
directed study each week. This will include weekly homework
and revision for regular topic tests.
It is important to try to organise your time effectively. Most of
you will be studying 4 AS levels, so try to balance your
workload. You will also be attending Tutorial sessions every
week.
You will all have access to the College Virtual Learning
software known as Blackboard that you can access through
College or your home computer via the College Website
www.mbro.ac.uk. You will be able to access all your subject
areas, and will find a wealth of course information, topicspecific questions and power point presentations. Check the
site regularly for announcements.
You will be offered enrichment opportunities such as visiting
speakers and visits such as Revision Conferences and Field
Trips as appropriate and available. You will also be kept
informed about University Open Days and ‘Discovery Days’ in
relevant subject areas as well as national conferences such as
“Medsix” for those intending to study Medicine.
Merit Awards are given to students who show outstanding
attendance and performance in this subject.
Meet the Team
Here are some names you may need to know: The Principal
Mike Hopkins
Assistant Principal for Teaching and Learning: Marion Fitt
Director of Academic & Professional Studies:
Richard Ronksley
Deputy Director of A & P Studies:
Sue Brown
Course Co-ordinator:
Emma Griffiths
Course Lecturers
Emma Griffiths
Laboratory Technicians
Mike Ford
Victoria Harper
Michael Connelly
COURSE STRUCTURE & QUALIFICATION
Your course is AQA Chemistry. You will normally
study towards the AS level in the first year and if
successful, you can progress onto the full A2 level.
The exam board's address is
Assessment and Qualifications Alliance (AQA)
Stag Hill House
Guildford
GU2 5XJ
Website: www.aqa.org.uk
Qualification Code Numbers:
AS
A2
Chemistry
1421
2421
The full 'A' level consists of six units as shown below.
Unit
number
1
2
3
4
5
6
Unit name
Foundation Chemistry
Chemistry In Action
Investigative and practical
skills in AS Chemistry
Kinetics, Equilibria and
Organic Chemistry
Energetics, Redox and
Inorganic Chemistry
Investigative and practical
skills in A2 Chemistry
Raw
marks
70
100
50
UMS
marks
100
140
60
100
120
100
120
50
60
AS + A2 = A level
Important: Please be aware that progression to the A2 course is
dependant upon a satisfactory pass grade at AS level (at least an E
grade).
As
units
A2
Units
ASSESSMENT
You will be assessed by written exams and internally assessed
coursework.
Written Exams (80%)
There will be two written exams in the first year; one in January
(Unit 1; foundation chemistry) and one in May/June (Unit 2;
Chemistry in action). The first exam lasts for 1 hour and 15
minutes and consists of 4-6 short answer questions (this exam is
worth 33% of total AS marks and 16% of the full A level). The
second exam lasts for 1 hour and 45 minutes and consists of 6 - 8
short answer questions plus two longer questions (this exam is
worth 46% of the total AS mark and 23% of the total A level).
In the second year there are two more written exams; one in
January (Unit 4; Kinetics, Equilibria and Organic Chemistry)
and one in June (Unit 5; Energetics, Redox and Inorganic
Chemistry). Both of these exams last one hour and 45 minutes
and will have some synoptic content which will test your knowledge
and understanding of AS material as well as A2 material. Each A2
written exam is worth 20% of the total marks for the final A level.
Dates for these exams are published by AQA and details can be
obtained from the AQA website: www.aqa.org.uk. At the time of
printing this document the exam dates for year 1 are as follows:
Unit 1, Thursday 14th January (am)
Unit 2, Monday 7th June (am)
Note these are provisional dates
Coursework (20%)
Your investigative and practical skills will be assessed once at AS
(Unit 3) and once again at A2 (Unit 6). These skills are marked by
your teachers and moderated by the exam board. Each year there
will two parts:
PSA (Practical Skills Assessment) – maximum 12 marks
Practical skills are assessed throughout the course on the basis of
your abilities during practical work. There are three strands to
consider: Ability to follow instructions, Selecting and using
equipment and organisation and safety.
ISA (Investigative Skills Assignment) – maximum 38 marks
You will be given an Investigative Skills Assignment to carry out.
This is set by the exam board and will include carrying out practical
work, collecting and analysing data and completing a short written
test on the investigation.
The coursework in year one contributes 20% to your AS result
(10% of the full A level), so it is essential that you spend time
and take care in producing a good quality piece of work. Make
sure you read all the guidance notes and mark schemes.
Specification Structure
The specification, which you will be issued with (and you can
download from the AQA website), sets out exactly the knowledge
and understanding that you will need in order to be successful in
your exams. In addition to the theoretical chemistry, the
specification contains twelve key aspects of ‘how science works.’
How Science Works
How Science Works is an underpinning set of concepts and is the
means whereby students come to understand how scientists
investigate scientific phenomena in their attempts to explain the
world about us. Moreover, How Science Works recognises the
contribution scientists have made to their own disciplines and to
the wider world.
Further, it recognises that scientists may be influenced by their
own beliefs and that these can affect the way in which they
approach their work.
Also, it acknowledges that scientists can and must contribute to
debates about the uses to which their work is put and how their
work influences decision making in society.
In general terms, it can be used to promote students’ skills in
solving scientific problems by developing an understanding of:
 The concepts, principles and theories that form the subject
content
 The procedures associated with the valid testing of ideas
and, in particular, the collection, interpretation and validation
of evidence
 The role of the scientific community in validating evidence
and also in resolving conflicting evidence.
What you can expect from us
Lessons
You will have five hours of timetabled lessons. You will be taught
using a variety of teaching and learning methods to meet the
varied Learning Preferences of the students in the class. This will
include lectures, worksheets, practical work, presentations, videos,
models, posters, etc.
Homework
Homework will be set and marked on a weekly basis. Much of the
work set will be in the form of past exam paper questions to help
you improve exam technique. There may also be electronic tests
set on Blackboard and occasionally you will be asked to research
a topic.
Monitoring Progress
Homework and test marks will be recorded along with attendance.
Your lecturer will review your progress regularly and will discuss
this with you to set realistic targets. This will initially be based on
your Value Added score (based on your GCSE grades) to give a
baseline for achievement.
In addition to this you will receive a written report on your
performance twice during the year.
Textbooks
The LRC has a well-stocked Chemistry section with up to date
textbooks, CD ROMS, videos and journals such as ‘New Scientist’.
Documents
You will receive a copy of the Specification. Keep this with your
chemistry notes for constant reference when researching and
revising.
Support
Your lecturers are there to help and support you in your learning and
understanding of the chemistry topics. Please do not be afraid to
ask for help if something is not clear.
Always remember:
If you don’t understand - ask for help.
What we expect from you
Entry Requirements
To join the AS course you need to have at least 4 GCSE’s at
grade C or above to include Maths and English as well as a grade
B in Additional Science/Science Double Award.
Attendance and Punctuality
You are expected to attend 100% of timetabled lessons and to
arrive on time. If you are genuinely unable to attend, or will be
unavoidably late, please telephone or e mail your lecturer to let
them know BEFORE the lesson. This is important because if
you are absent from the lesson the college will telephone you to
find out why, and if your attendance falls below 85% you will be
charged a fee of approximately £15 per written exam.
Stationery
You are expected to have Ring binder, paper, pens, pencils
and rulers at all lessons. You will occasionally need a simple
calculator in the lessons and will definitely need one for the exams
– you are advised to buy one at the start of the course (approx £2).
Homework
It is essential that you complete homework and hand it in on time
so that we can continually monitor your performance. Late
homework may not be marked and may be recorded as a zero in
the mark books and you Personal Tutor will be informed.
Blackboard (Bb)
Check the Chemistry site regularly as there may be important
announcements there. Browse the site to find useful extra notes,
animations, power points and questions, as well as the AQA exam
board mark schemes to correct answers to your homework.
Revision
You will be provided with summary ‘revision’ sheets at the end of
each topic to aid your own revision but you are also advised to
look through your notes at the end of each week and make sure
you have understood the topic. This will make final revision for
exams much easier. We will encourage this by setting regular
topic tests.
RESOURCES
At A level you are expected to carry out extra study outside lesson
time and you will develop your skills of independent learning. This
will help to prepare you for University, where you are often left to
your own devices and must rely on self motivation and a mature,
organised approach to study.
There is a wealth of information in chemistry to help you carry out
the necessary research of all topics from a wide range of sources.
Scientific Journals
You can access a variety of journals such as New Scientist on the
LRC site of Blackboard.
Websites
You will be provided with a comprehensive list of Chemistry
Websites, but here are a few of the main sites.
www.mbro.ac.uk to access Blackboard (Bb)
www.bbc.co.uk/asguru
www.s-cool.co.uk
www.learn.co.uk
www.schoolscience.co.uk
www.abpischools.org.uk
http://www.chemcool.com/index.htm
http://www.wwnorton.com/college/chemistry/gilbert/home.htm
http://neon.chem.ox.ac.uk/vrchemistry/
www.creative-chemistry.org.uk/alevel
www.knockhardy.org.uk/sci.htm
www.chemguide.co.uk
Other Useful Media
Radio
Try to keep up to date with current issues in science/chemistry
through the media:
There are many useful programmes on Radio 4 that discuss
Science, Food and Health issues.
Newspapers
You can read the Science pages of a broadsheet newspaper such
as the Guardian, Times, Independent or Telegraph which are
available in the LRC, and look out for relevant television
programmes such as Horizon.
PROGRESSION
Chemistry and the chemical sciences offer access to a varied
range of careers. For those who study chemical science to a
higher level, the challenges and rewards are significant.
Research scientist
Medicine
Nursing
Forensic Science
Chemical engineering
Teaching
Dentistry
Pharmacy
Environmental scientist
Food Science
Agriculture
Radiography
Laboratory Technician
Check University prospectuses for grades and preferred subject
combinations necessary for these University Degrees. Better still,
telephone universities and speak to the Admissions Tutors.
UCAS Points
Grade
A
B
C
D
E
AS
60
50
40
30
20
A2
120
100
80
60
40
NB These are not the same as UMS points awarded by AQA, but
are used by Universities to make you an offer.
YOUR NOTES
Make a note here of: Your lecturer’s name: ___Angela Waldock_____________
Your lecturer’s e mail address: ae.waldock@mbro.ac.uk .
Course Co-ordinator’s Name: _ Angela Waldock__
.
Science Department phone number ________________
Record your Examination Dates and Results here:
Module Title
Date
Grade and
UMS mark
Total UMS to
date
Final June session
What marks do I need to achieve in the summer exam to reach my
final target grade?
To achieve a
grade:
A
B
C
D
E
I need this many more UMS marks from units 2
and 3
HEALTH AND SAFETY
Rules for students during science lessons in laboratories
1.
You must not enter a laboratory unless instructed to do so by
a teacher.
2. You must not do anything with equipment or materials unless
told to do so by a teacher. Follow instructions carefully.
3. You must wear eye protection when told to do so and keep it
on until told to take it off when all practical work including
clearing away is finished.
4. When instructed to use a Bunsen burner, make sure that hair,
scarves, ties etc. are tied back or tucked in to keep them well
away from the flame.
5. When working with liquids, always stand up, never sit. Then
you can move out of the way quickly if there is a spill.
6. Never taste anything or put anything in your mouth when in
the laboratory. This includes sweets, fingers and pencils,
which might have picked up poisonous chemicals from the
bench.
7. If any chemicals get on your hands or any other part of the
body, wash them off. Wash your hands after work with
chemicals or with animal or vegetable matter.
8. Put waste solids in the right bin, never in the sink.
9. Reports any accident to the teacher. This includes chemicals
in the mouth, the eyes or on the skin. Also any burns or cuts.
10. Keep your bench clean and tidy, with bags pushed out of the
way underneath. Wipe up small splashes with a damp cloth
and report bigger ones to the teacher.
11. Always walk slowly and watch where you are going and what
your neighbours are doing.
12. You must wear laboratory coats for all practical work.
A note on Equality
Middlesbrough College is committed to race and gender equality
and to providing opportunity and support for students with
disabilities. Students are expected to adopt the same ethos and
encouraged to welcome contact and friendship with those whose
life experiences differ from their own.
All the staff at Middlesbrough College, wish you success in your
studies and an enjoyable time at our new state of the art facility.
Some Useful information
1.
Measurements and units you will meet in chemistry
The following table identifies some of the more common SI units
and their symbols
Physical quantity
Length
Mass
Time
Temperature*
Amount of
substance
Energy
Pressure
Name of SI Unit
Metre
Kilogram
Second
Kelvin
Mole
Symbol of SI Unit
m
kg
s
K
mole or mol
Joule
Pascal
J
Pa
* Although we still quote temperatures in degrees Celsius (°C), you will find modern
reference books giving temperatures in Kelvin, K. We do not say degrees Kelvin but
simply Kelvin. To convert from degrees centigrade to kelvin, use the simple formula:
degrees Celsius + 273 = Kelvin
This allows all temperatures to be given as positive figures since 0 Kelvin is absolute
zero, the lowest temperature we ever need to refer to.
2. SI prefixes
Prefixes allow us to use larger and smaller quantities of the base
units without having to use very large and very small numbers.
Some prefixes used in chemistry are given below.
Multiple
10-2
10-3
10-6
10-9
103
106
SI prefix
centi
milli
micro
nano
kilo
mega
Symbol
c
m

n
k
M
Example
Centimetre (cm)
Millilitre (ml)
Micrometer (m)
Nanometer (nm)
Kilogram (kg)
Megabyte (Mbyte)
Essential underpinning mathematical requirements
The AS and A2 Chemistry courses will require you to use your mathematical
skills. Don’t worry if you’re a bit ‘rusty’; you will be given the opportunity to
practice as the course progresses. The information here brings together the
mathematical requirements of the AS course.
Information is included that will help you carry out specific types of calculation
when they are met in the main course of study. You may prefer to refer to this
section only when you need to apply/use each particular mathematical
concept.
Decimal and standard form
You will be expected to express numbers in both decimal and standard form
and interconvert between them.
You are probably used to expressing figures in decimal form, for example:
£5.25, 0.5 of an hour. However, in chemistry, figures can be much smaller
than this, for example, 0.000005. It is more appropriate to quote figures like
this in standard form (the number multiplied by a factor of ten):
0.000005
can be expressed as 5 x 10-6
0.000125
can be expressed as 1.25 x 10-4
Figures which are very large can also be better expressed in standard form,
for example the Avogadro constant is written as 6.02 x 10 23 rather than 602
followed by 21 zeros!
So in standard form we have a number x 10n, where n is the number of places
the decimal point moves. When we use standard form the number in front of
the x 10n should he between 1 and 10. So we write 0.00095 as 9.5 x 10-4, not
0.95 x 10-3, and 0.00101 would be written as 1.01 x 10-3, not 10.1 x 10-4
To put 3 x 104 in your calculator, put in 3 then press the EXP key, then press
4. To put 3 x 10-4 in your calculator put in 3, then press the EXP key, then
press the +/- key, then press 4. (This will vary with different calculators).
Significant figures
As a general rule you are advised to quote answers to numerical calculations
to the same number of significant figures as given in the question. This means
that if values in a question are given to three significant figures, for example,
1.25 g or 3.50 mol dm-3, you should not quote an answer to any greater
number of figures. This is because you are unable to be confident of the
accuracy beyond this number of figures.
For example, using these figures to calculate the volume of water in which
1.25 g of sodium hydroxide should be dissolved to give a solution of
concentration 3.50 mol dm-3 gives an answer 8.9285714 cm3. This answer is
quoted to eight significant figures but needs to be rounded off to just three
figures. The correct expression of the answer would be 8.93 cm3.
(The fourth significant figure here is ‘8’, so we add on one to the third
significant figure to get 8.93. We would add one on when the fourth significant
figure is 5 or greater than 5. If the fourth significant figure was 4 or less, say if
we had 8.923517, then to 3 significant figures this would be 8.92).
When calculations involve several stages it is good practice to give one more
significant figure in your answer at each stage than the number of significant
figures in the data. Then at the final stage, the answer is rounded off to the
appropriate number of significant figures.
Estimating answers
Estimating is a useful skill. You should be able to estimate answers without
the use of a calculator. This just means rounding everything off to nice
convenient numbers. It’s a good habit to get into since it enables you to check
that your answers are roughly correct.
As an example, estimate:
117.5  41.9
3 .2
Choosing easy numbers, we get:
120  40
3
So that’s  4800 ÷ 3 = 1600
So the answer is roughly equal to 1600.
The real answer is 1641.1, but the estimated answer is good enough to show
us that the real answer is of the right order.
If in a calculation we had 0.275 x 12.2 we could estimate this by saying 0.3 x
12 = 3.6. The real answer is 3.355, but the estimate confirms that the real
answer is of the right order.
Arithmetic means
You will frequently need to calculate a mathematical average, especially
during practical work involving experimental repeats.
For example, the following titre values may he obtained: 14.85cm 3, 14.80cm3
and 14.75cm3. The average (mean) titre value can be calculated and is equal
to:
14.85  14.80  14.75
 14.80 cm3
3
Changing the subject of an equation
You will frequently need to do this in calculations when you have been asked
to find an unknown value. For example:
a. Concentration =
moles
and so changing the subject of the equation:
volume
b. Moles = concentration  volume
And changing the subject of the equation once more
c. Volume =
moles
concentration
When you are changing the subject of the equation that value should appear
on its own on one side of the equals sign. This can be achieved by multiplying
or dividing both sides by the quantity which you wish to remove.
For example in equation (a) above, both sides are multiplied by volume to
arrive at equation (b). In equation (b) both sides are divided by concentration
to arrive at equation (c).
Straight-line graphs
A straight-line graph can be expressed in the form y = mx + c. In this equation
m is the gradient of the line, c is called the intercept; this is where the graph
line crosses the y axis.
y
Gradient,
m
a
b
a
b
Intercept, c
x
The gradient shows us how much the y value is changing relative to the x
value. To find the gradient draw a large triangle, then read off the graph the
values to find a and b. In the graph above both m and c are positive values.
y
Here m has a positive
value, but c is negative
because it crosses the y
axis below y = 0.
x
c
y
Here we have a straight line
passing through: 0,0,
so c = 0
This graph line is
represented by y = mx + c
x
The gradient, m of this line
has a negative value; this
means that y values are
decreasing as x values
increase
a
b
3.
Glossary
The following is a collection of terms that you may come across
during your studies (in both AS and A2 parts of the ‘A’ level). This
is not to be learned by heart, rather it is to provide an accessible
reference when required. You are also encouraged to add to this
list as you come across new words and terminology.
Activation energy The minimum energy required for a reaction to occur
Acylation Substitution of a hydrogen atom by an acyl group
Addition reaction A reaction in which two substances react together to form
a single substance
Alkylation Substitution of a hydrogen atom by an alkyl group
Allotropes Two different forms of the same element
Anion A negatively charged ion
Anode A positively charged electrode
Atomic number The number of protons in an atom; this determines its
position in the Periodic Table
Avogadro constant The number of atoms in exactly 12 g of carbon-12
(equivalent to 6 x1O23 atoms)
Bond energy The enthalpy change when a covalent bond is broken to give
atoms in the gaseous state
Born-Haber cycle A special type of enthalpy cycle which enables Hess’s law
to be applied to the standard enthalpy changes which occur when an ionic
crystal is formed
Brominatlon Substitution of a hydrogen atom by a bromine atom
Bronsted-Lowry theory A Brønsted-Lowry acid is a substance which
donates a proton to another substance. A Brønsted-Lowry base is a
substance which accepts a proton from another substance
Buffer solution A solution which resists change of pH when a small amount
of acid or alkali is added
Carbonium ion or carbocation A species in which a carbon atom carries a
positive charge
Catalyst A substance which alters the rate of a chemical reaction
Cathode A negatively charged electrode
Cation A positively charged ion
Chemical shift The value of the applied field that will cause a proton in a
particular chemical environment to resonate
Chiral centre A central carbon atom which has four different groups attached
to it. The central carbon atom represents an asymmetric centre
Chromophore The structural feature responsible for the absorption of ultraviolet/visible radiation
Complex ion A central transition metal ion surrounded by ligands
Condensation reaction A reaction between two organic compounds to form
a larger compound and a small molecule, such as water or hydrogen chloride
Conjugate acid The resulting substance or ion when a base has accepted a
proton from another substance
Conjugate base The resulting substance or ion when an acid has donated a
proton to another substance
Covalent bond A shared electron pair
Datlve covalent bond A covalent bond where both electrons are provided by
one atom
Derivatives of carboxylic acids Acid chlorides, amides and esters, which
can be produced from carboxylic acids
Disproportlonatlon reaction A reaction in which a species is simultaneously
oxidised and reduced
Electrochemical series A list of elements placed in order of their standard
electrode potentials
Electrolysis Decomposition of a substance caused by electricity
Electrolyte A substance decomposed by electricity
Electronegativity Power of an atom to withdraw electron density from a
covalent bond
Electrophiles Electron pair acceptors
Elimination reaction A reaction involving the removal of small molecule from
a larger organic molecule
Empirical formula The simplest whole number ratio of atoms in a compound
Enantiomer One optical isomer
Enthalpy change Heat energy change at constant pressure in a reaction
Enthalpy change of atomisation The enthalpy change when one mole of
isolated gaseous atoms is formed from the element in its standard state
Enthalpy change of combustion The enthalpy change when one mole of a
substance is completely burned in oxygen
Enthalpy change of formation The enthalpy change when one mole of a
substance is formed from its elements in their standard states
Enthalpy change of hydration The enthalpy change when one mole of
gaseous ions are hydrated
Enthalpy change of neutralisation The enthalpy change when an acid and
a base react to form one mole of water
Enthalpy change of solution The enthalpy change when one mole of an
ionic solid dissolves in water to form an infinitely dilute solution
Esterification The reaction between carboxylic acids or acid chlorides with
alcohols to produce esters
First electron affinity The energy required to add 1 electron to I mole of
gaseous atoms to produce 1 mole of singly negative charged gaseous ions
First ionisation energy The energy required to remove 1 electron from each
atom in I mole of gaseous atoms, to produce 1 mole of gaseous uni-positive
ions
Free radicals Species which contain an unpaired electron
Full structural formula A formula showing the arrangement of atoms in a
molecule and the bonds between them
FunctionaI group The structural feature responsible for the reactions a
molecule undergoes
Geometric (cis-trans) isomerism A type of isomerism found in alkenes
which results from the restricted rotation about the carbon—carbon double
bond
HaIf-life The time taken for a reaction to go to half-completion; the time taken
for the concentration to fall to half its original value
Hess’s law If a reaction can proceed by more than more than one route the
enthalpy change is the same whichever route is followed
Heterogeneous equilibrium Equilibrium in which there is more than one
physical state Heterolytic fission Breakage of a covalent bond where both of
the two shared electrons go to one atom
Hofmann reaction The reaction of amides with bromine and sodium
hydroxide to produce primary amines with one less carbon atom than the
original amide
Homogeneous equilibrium Equilibrium in which there is only one physical
state
Homologous series Compounds which have the same general formula and
contain the same functional group
Homolytic fission The breakage of a covalent bond where one of the two
shared electrons goes to each atom
Hydrocarbons Molecules containing only carbon and hydrogen
Hydrogen bonds An attractive force between a hydrogen atom and a lone
pair of electrons on an electronegative atom
Hydrolysis A reaction involving water
Inductive effect An effect in organic molecules whereby neighbouring alkyl
groups slightly donate electrons through sigma bonds to adjacent carbonium
ions
Integration ratio The relative numbers of each type of proton in a nuclear
magnetic resonance (NMR) spectrum
Ionic bond An electrostatic force between oppositely charged ions
Ionic product of water, Kw The product of the hydrogen ion concentration
and the hydroxide ion concentration = 1.0 x 10-14 mol2 dm-6 at 25 °C
Isotopes Atoms with the same atomic number and different mass numbers
Lattice enthalpy The enthalpy change when one mole of a solid crystal is
formed from its component ions in the gaseous state
Ligand A molecule or negative ion which carries a lone pair of electrons
Mass number The number of protons + number of neutrons in an atom (also
sometimes called the nucleon number)
Mole The amount of substance which contains the same number of
elementary entities as there are atoms in exactly 12 g of carbon-12
Molecular formula The actual number of each type of atom in one molecule
of a compound
Nitration Substitution of a hydrogen atom by a nitro group
Nucleophiles Electron pair donors
Optical isomerism A type of isomerism which involves molecules existing in
two different forms, which have differing effects on the plane of polarised light
Optical isomers Two different forms of the same molecule: one form will
rotate the plane of polarised light to the right and the other form will rotate the
plane to the left
Optically active The ability of a molecule to rotate the plane of polarised light
Orbital The region which encloses most of an electron-charge cloud
Order of reaction With respect to a reagent this is the power to which the
concentration of that reactant is raised in the rate equation
Overall order of reaction The sum of the powers of the concentration terms
in the rate equation
Oxidation number The number assigned to an atom or ion to describe its
relative state of oxidation or reduction
Partial pressure In a mixture of gases the partial pressure of gas A is given
by the expression:
Number moles of A
 total pressure
Total number of moles
Periodicity Repeating patterns within the Periodic Table
Permanent dipole A permanent displacement of charge within a covalent
bond
pH The negative logarithm to the base ten of the hydrogen ion concentration:
pH = -log10[H+]
Polyamide A polymer formed by the linking together of diamine molecules
with either carboxylic acid or acid chloride molecules
Polyester A polymer formed by the linking together of carboxylic acid and
alcohol molecules
Quantum shell The energy level within an atom
Racemic mixture (racemate) A 50/50 mixture of two enantiomers
Rate-determining step The slowest reaction step which determines the
overall rate of a reaction
Reaction condition A necessary requirement for a reaction to occur
Redox reaction A reaction in which one substance is oxidised and another is
reduced
Relative atomic mass The average mass of one atom of an element divided
by 1/12 the mass of one atom of carbon-12
Relative Isotopic mass For a particular isotope: the mass of a single atom
compared with an atom of carbon-12
Relative molecular mass The mass of one molecule divided by 1/12 the
mass of one atom of carbon-12
Second electron affinIty The energy required to add one electron to one
mole of singly charged gaseous ions
Second lonlsation energy The energy required to remove 1 electron from
each unipositive ion in 1 mole of gaseous ions to produce 1 mole of gaseous
dipositive ions
Standard electrode potential The potential difference which develops when
a metal is placed in a solution of its ions of concentration 1.00 mol dm -3, at 25
°C and 1 atmosphere pressure
Strong acid / Strong alkali An acid or alkali which is totally ionised in water
Structural Isomers Compounds that have the same molecular formulae but
different structural formulae
Substitution reaction A reaction in which one atom, or group of atoms, is
replaced by another
Titration curves Graphs of pH against the volume of alkali added to a given
volume of acid
Titration A practical operation for reacting two solutions and determining the
volume of one which reacts with a fixed volume of the other
Transition metals D-block elements which form one or more stable ions
which have incompletely filled d orbitals
Transition state theory A way of explaining reaction rates in terms of what
happens when reactants are about to change into products
Van der Waals forces Weak induced dipole-induced dipole attractions
Weak acid / Weak alkali An acid or alkali which is only partially ionised in
water
Zwitterions Dipolar ions