Unit 1. Matter and Change

advertisement
Unit 1.
Matter and
Change
Chapter 1 and 3
Do Now:
 What
is matter as described in Chemistry?
Chapter 1 & 3
Objective
 Distinguish



between:
intensive and extensive properties
Physical & chemical changes/properties
Classify matter
Matter and its Properties
 It’s
 But
Classified!
first what is Scientific Method and
what does it involve?
Properties & Changes in Matter
 Extensive
 Physical
vs. Intensive
vs. Chemical
A. Extensive vs. Intensive
 Extensive
Property

depends on the amount of matter present

ex,.-
 Intensive
Property

depends on the identity of substance, not
the amount

Ex.-
A. Extensive vs. Intensive



Extensive Property

depends on the amount of matter present

ex,.- Volume, mass, Energy
Intensive Property

depends on the identity of substance, not the
amount

Ex.- melting point, boiling point, conduct
electricity or heat
WHAT ABOUT DENSITY??
A. Extensive vs. Intensive
 Examples:

boiling point

volume

mass

density

conductivity
A. Extensive vs. Intensive
 Examples:

boiling point…… intensive

Volume …. extensive

Mass ….. extensive

Density ….. intensive

Conductivity ….. intensive
PROPERTY
B. Physical vs. Chemical
 Physical

Property
can be observed without changing the
identity of the substance
 Chemical

Property
describes the ability of a substance to
undergo changes in identity
B. Physical vs. Chemical
Examples:
melting
point
physical
flammable
chemical
density
physical
magnetic
physical
tarnishes
chemical
in air
CHANGE
C. Physical vs. Chemical
 Physical
Change

changes the form of a substance without
changing its identity

properties remain the same
 Chemical
Change

changes the identity of a substance

products have different properties
B. Physical vs. Chemical
 Signs
of a Chemical Change
 change
in color or odor
 formation
of a gas
 formation
of a precipitate (solid)
 change
in light or heat
B. Physical vs. Chemical
 Examples:
rusting
iron
dissolving
in water
burning
a log
melting
ice
grinding
spices
B. Physical vs. Chemical
 Examples:
rusting
iron
dissolving
burning
in water
a log or
charcoal
melting
ice
grinding
spices?
chemical
physical
chemical
physical
physical
Properties and Changes in
Matter
In the example of burning of charcoal, carbon
and oxygen are the reactants in the combustion
reaction. Carbon dioxide is the product.
carbon + oxygen
C
+
O2
(reactants)
carbon dioxide
CO2
(product)
Homework
 Review
Scientific Method:
Read page 12 – 16 Q 17
Complete - Work sheet
STATE OF MATTER
Chapter 3
Do Now
 Name
 How
the State of Matter
do they differ?
States of Matter
 There
are Four state of matter
 A. Solid
 B. Liquid
 C. Gas
 D. Plasma
 State
of matter depends on Kinetic
Energy between the particles
A. Kinetic Molecular Theory
 KMT
 Particles
 The
of matter are always in motion.
kinetic energy (speed) of these
particles increases as temperature
increases.
Four States of Matter
 A.
Solids
 very
low KE - particles vibrate
but can’t move around
 fixed
shape
 fixed
volume
Four States of Matter
 B.
Liquids
 low
KE - particles can move
around but are still close
together
 variable
 fixed
shape
volume
Four States of Matter
 C.
Gases
 high
KE - particles can
separate and move
throughout container
 variable
shape
 variable
volume
Four States of Matter
 D.
Plasma
 very
high KE - particles collide
with enough energy to break
into charged particles (+/-)
 gas-like,
variable
shape & volume
 stars,
fluorescent
light bulbs, CRTs
SOLUTIONS
AND
MIXTURES
Objective:
 Classification
 DO


of Matter
NOW:
What is a solution?
Describe the difference between a
heterogeneous and homogenous mixture
A. Pure Substances
 Element


composed of identical atoms
EX: copper wire, aluminum foil
A. Pure Substances
 Compound

composed of 2 or more elements in
a fixed ratio

properties differ from those of
individual elements

EX: table salt (NaCl)
A. Pure Substances
 Law

A given compound always contains the same, fixed
ratio of elements.
 Law

of Definite Composition
of Multiple Proportions
Elements can combine in different ratios to form
different compounds.
A. Pure Substances
 For
example…
Two different compounds,
each has a definite composition.
Pure Substances
(constant composition)
 Elements



Listed on the Periodic
Table
Cannot be broken down
into unique components
Na, Cl, Al, O2, S8
 Compounds



Made of elements that
are chemically joined
Can be broken down
NaCl, H2O, AlCl3, H2SO4
B. Mixtures
 Variable
combination of 2 or more pure substances.
Heterogeneous
Homogeneous
B. Mixtures
(variable composition)
 Homogeneous
Solutions

–
evenly distributed
 Heterogeneous

not evenly distributed
B. Mixtures

Solution
homogeneous
very small particles
no Tyndall effect
Tyndall Effect
B. Mixtures
Colloid
heterogeneous
medium-sized
Tyndall
particles
effect
particles don’t settle
EX: milk
B. Mixtures
 Suspension
 heterogeneous
 large
particles
 Tyndall effect
 particles settle
 EX: fresh-squeezed
lemonade
C. Mixtures
 Examples:
mayonnaise
muddy
water
fog
saltwater
Italian
salad
dressing
C. Mixtures
 Examples:
mayonnaise
colloid
muddy
suspension
water
fog
colloid
saltwater
solution
Italian
suspension
salad
dressing
A. Matter Flowchart
MATTER
yes
MIXTURE
yes
Is the composition
uniform?
Homogeneous
Mixture
(solution)
PURE SUBSTANCE
no
Heterogeneous
Mixture
Colloids
no
Can it be physically
separated?
yes
Can it be chemically
decomposed?
Compound
Suspensions
no
Element
A. Matter Flowchart
 Examples:
graphite
pepper
sugar
paint
soda
(sucrose)
A. Matter Flowchart
 Examples:
graphite
element
pepper
hetero. mixture
sugar
compound
(sucrose)
paint
hetero. mixture
soda
solution
Tea – Homogeneous Mixture
Air – Homogeneous Mixture
Alloys – Homogeneous
Mixtures
Cereal – Heterogeneous
Mixture
Sand – Heterogeneous Mixture
Separating Mixtures
Only a physical change- no new matter
 Filtration - separate solids from liquids with
a barrier (filter paper)
 Distillation
- separate liquids because of
different boiling points


Heat mixture
Catch vapor in cooled area
 Chromatography
- different substances
are attracted to paper or gel, so move at
different speeds
Separating Mixtures cont….
 Crystallization
- results in formation of solid
particles of a substance from a solution
containing the dissolved substance
 Sublimation
– separation when a solid
changes to a vapor without melting or
going through a liquid phase
Filtration
Distillation
Chromatography
 d.
Crystallization
Ex: rock candy
e. Sublimation
Ex: Dry Ice
Homework
 Pg
83 – Q 15, 17
 Pg
94 & 95 – Q 42, 43, 48, 58, 63
The Periodic
Table
A. Mendeleev
 Dmitri



Mendeleev (1869, Russian)
Organized elements
by increasing
atomic mass.
Elements with
similar properties
were grouped
together.
There were some
discrepancies.
C. Johannesson
A. Mendeleev
 Dmitri

Mendeleev (1869, Russian)
Predicted properties of undiscovered elements.
C. Johannesson
B. Moseley
 Henry
Moseley (1913, British)

Organized elements by increasing atomic
number.

Resolved discrepancies in Mendeleev’s
arrangement.
C. Johannesson
II. Organization of the
Elements
A. Metallic Character
 Metals
 Nonmetals
 Metalloids
C. Johannesson
B. Blocks
 Main Group Elements
 Transition Metals
 Inner Transition Metals
C. Johannesson
Do Now:
 Classify
the following as either a
METAL, NON-METAL or METALLOID:
a. Au
b. Si
c. Br
Periods and Families
 Periods:


horizontal rows on the periodic table
physical and chemical properties change
somewhat regularly across a row.
Elements closer to each other in the same
period tend to be similar properties than those
that are farther apart.
 Families:
groups

vertical rows of elements, aka
Each group contains similar chemical properties
Types of Elements
METALS:
 Shiny
 Conductors
of heat and electricity
 Most
metals are malleable (can be pounded
into thin sheets; a sugar cube sized chunk of
gold can be pounded into a thin sheet which
will cover a football field),
 Most
metals are ductile (can be drawn out
into a thin wire).
Metals cont…..
 All
are solids at room temp (except
Mercury, which is a liquid)
 Metals tend to have low ionization
energies, and typically lose electrons (i.e.
are oxidized) when they undergo
chemical reactions
 Alkali metals are always 1+ (lose the
electron in s subshell)
 Alkaline earth metals are always 2+ (lose
both electrons in s subshell)
 Compounds of metals with non-metals
tend to be ionic in nature.
Types of Elements
NON- METALS:
 Vary
greatly in appearance
 Non-lustrous
 Poor conductors of heat and electricity
 The melting points of non-metals are generally
lower than metals
 Seven non-metals exist under standard
conditions as diatomic molecules:
H2(g) N2(g) O2(g) F2(g) Cl2(g) Br2(l) I2(l)
(volatile liquid - evaporates readily)
Non-Metals cont……..
 Nonmetals,
when reacting with metals,
tend to gain electrons (typically attaining
noble gas electron configuration) and
become anions: Nonmetal + Metal -> Salt
 Compounds
composed entirely of
nonmetals are molecular substances (not
ionic)
Types of Elements
 Metalloids:
 Elements
may share properties of metals and
non-metals.
A
stair-step line separates the metals from the
nonmetals on the periodic table.
Metalloids


Properties:
All metalloids are solids at room temperature.

Less malleable than metals but not as brittle as
nonmetals.

Metalloids tend to be semiconductors of
electricity. (intermediate between metals and
nonmetals).
Metalloids

Properties:

Metalloids are used in semiconducting
materials found in computers, calculators,
televisions and radios.

Elements include: boron, silicon, germanium,
antimony
Noble Gases
Noble Gases - the elements in Group
18 of the periodic table.
 They are considered nonmetals.
 These elements are generally
unreactive.
 All are gases at room temperature.
 Examples: neon, argon, krypton,
xenon (all used in lighting) and
helium.

DO NOW:
Name an element that is:
a. An
element that is brittle and conducts
electricity
b. An element that is malleable
c. An element that has tendency to
become an anion
Group Practice
 Look
at Page 95 – Insert Questions
Law of Conservation of
Matter:
 Matter
 Since
is neither created nor destroyed.
chemical reactions cannot create
or destroy atoms, chemical equations
representing the reactions must always be
BALANCED.
 Mass reactants = Mass products
% by Mass of Substance
Mass of Element
 Percent
by mass =
X 100
Mass of Compound
Download