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CHAPTER 2
Matter and Change
What is Matter?
 Matter is anything that has mass and takes up space

Mass = the amount of matter an object contains
 How do mass

and weight differ?
Space = volume
Describing Matter…Physical Properties
 Qualities of matter that can be observed
or measured
without changing the substance’s composition
 Include color, solubility, odor, hardness, density, melting
point and boiling point
 Help chemists identify substances
READ ONLY
For example
 Look at the table on page 29 of your textbook for the
physical properties of some common substances
 Two clear liquids


Liquid A boils at 100oC and melts at 0oC
Liquid B boils at 78oC and melts at -117oC
 Using the table on page 29, which of these liquids is
water?
A
B
States of Matter
1. Solid

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
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Shape: Definite
Volume: Definite
Compressibility: None
Particle Spacing: close together
Particle Movement: very little (low energy)
States of Matter
2. Liquid





Shape: Indefinite
Volume: Definite
Compressibility: slight
Particle Spacing: not as close as a solid
Particle movement: more movement that solid
States of Matter
3. Gas

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

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Shape: Indefinite
Volume: Indefinite
Compressibility: Great
Particle Spacing: far apart
Particle Movement: Fast (lot of energy)
Is a gas the same thing as a vapor?
 Gas = a substance that exists as a gas at room temperature

Ex: air is a mixture of gases including oxygen and nitrogen
gas
 Vapor = gaseous state of substance that is normally a solid
or liquid at room temperature


Ex: steam = gaseous form of water
Ex: moist air contains water vapor
Describing Matter…Physical Changes
 Changes in matter without a change in the chemical
composition
 Ex: boil, freeze, dissolve, melt, condense, break, split,
crack, grind, crush…
Classification of Matter
1.
2.
Pure Substance = contains only one kind of matter;
chemical composition is uniform
Mixture = a physical blend of two or more substances;
chemical composition can vary
Classification of Matter
I.
Pure Substance
Element (think periodic table)
B. Compound (chemical combination of elements)
A.
Classification of Matter
II.
Mixture
A. Homogenous (uniform composition)
1. Solution
2. EX:
B.
salt water
Heterogenous (not uniform in composition)
1. Suspension
2. Colloid
3. EX:
tossed salad
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Classification of Matter…mixtures
 Homogeneous mixtures (uniform in composition)
 Also known as solutions
 Very important
in chemistry
 May be any combination of solids, liquids or gases

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Carbon dioxide and oxygen (air) gas-gas
Water vapor in air (moist air) liquid-gas
Carbon dioxide in water (soda water) gas-liquid
Acetic acid in water (vinegar) liquid-liquid
Sodium chloride in water (salt water) solid-liquid
Copper in silver (sterling silver) solid-solid
Classification of Matter…mixtures
 Heterogeneous mixtures (not uniform in composition)
So where does Shaving Cream Belong?
What kind of matter is it?
 Shaving cream is a colloid, a heterogenous mixture of a
liquid and gas
Review:
 Identify each of the following as
1.
2.
3.
4.
Lemonade
Pure water
CO2
dirt
substance or mixture
Mixtures can be separated by
physical methods
1.
Distillation

2.
A solution is boiled to
produce a vapor that
is then condensed
again to a liquid
Chromatography

A solution is
separated as is passes
over a solid
Paper Chromatography
Classifying
matter
activity
 Describe the matter pictured below…
LAB REPORT TO BE COLLECTED MOMETARILY
Chemical Reactions
 One or more substances combine to form new and
different substances


Reactants = starting substances
Products = substances formed
 The
ability of a substance to undergo a chemical reaction
and to form new substances is called a chemical property

Chemical properties are only observed when a substance
undergoes a chemical change
How to tell whether a chemical reaction
has taken place?
 Energy is always absorbed or given off

in a chemical reaction
Energy change by itself does not indicate chemical change
 Change in color
 Change in odor
 Production of a
gas
 NEW SUBSTANCE FORMED
 Clue words: burn, rust, rot,
decompose, ferment, explode, corrode
Symbols and Formulas
 Every element has a chemical symbol




One or two letters
First letter is always capitalized
Second letter, if present is always lowercase
can be derived from common names or Latin names
 Every compound has a chemical formula


Tells the types and amounts of elements in the compound
Ex: H2O is the chemical formula for water
Law of Conservation of Mass
 Mass is neither created or destroyed but is conserved
(changed into another form)


During any chemical reaction, the quantity of matter is unchanged
The mass of products ALWAYS equals the mass of the reactants
“change into”
Chemical Equations
4 Fe (s) + 3 O2 (g)  2 Fe2O3 (s)
iron
+ oxygen 
Coefficients
rust
- # of atoms or molecules
Subscripts - # of elements in a
compound
Chapter 2 EOC Questions
 Page 46-49 # 24, 25, 28, 30, 32-36, 44, 48
CHEM-LOG
 List three physical properties of shaving cream.
Shaving
Cream
Inquiry