Unit 2 - Classification and Properties of
Matter and Energy
Classification of Matter
Pure
Substances
Definition (Book)
Mixtures
Substances
Characteristics
Element-
Elements exist in all three states:
-Each element has a unique set of
properties, although certain elements have
similar chemical and physical properties.
No element exists naturally in more than one
state.
-Organized by
Elements
Examples
Non-examples
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•  Allotrope –
Definition
Substances
Characteristics
- A compound has different physical and
chemical properties than the elements
that comprise it.
Compounds –
- Law of Constant Composition
Compounds can be broken down into their
- Law of Multiple Proportions
Compounds have the same
composition throughout!
component elements!
Compounds
Examples
Non-examples
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•  Law of Constant Composition -
•  Law of Multiple Proportions -
Liquid water and salt are pure substances.
•  Ionic –
•  Covalent –
• Organic – A covalent molecule that contains carbon and
hydrogen
• Inorganic – A compound that does not contain carbon and
hydrogen
Definition
Mixtures
Heterogeneous Mixture- A mixture where
the components are not spread evenly
throughout
Characteristics
More than one PHASE – distinct layer with a
uniform composition. Phases can be
distinctly identified.
Colloid –
.
Suspension – Suspended
particles in this mixture will
settle out.
Examples
Suspensions
Colloids
Heterogeneous
Separation
Filtration – separates a
solid from a liquid by collecting the
solid in a funnel and allowing the
liquid (filtrate) to drain through the
funnel into a flask. (Suspensions)
Centrifugation – Separates particles
in a mixture by particle size and
density differences. (Colloids)
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Types of Colloids
Dispersing
Medium
Dispersed Type
Phase
Example
Gas
Liquid
Aerosol
fog, clouds
Gas
Solid
Aerosol
smoke, airborne virus, car
exhaust
Liquid
Gas
Foam
whipped cream
Liquid
Liquid
Emulsion mayonnaise, milk, face cream
Liquid
Solid
Sol
milk of magnesia, mud
Solid
Gas
Foam
styrofoam, marshmallow
Solid
Liquid
Gel
jelly, jello, butter
Solid
Solid
Solid Sol
steel, gemstones
Centrifugation – Blood is a Heterogeneous
Mixture
Mixtures
Definition
Characteristics
Homogeneous Mixture- A mixture where the
components are spread evenly throughout.
Components:
Another name for a homogeneous mixture =
Examples
Homogeneous
Separation
Distillation- boiling a
solution to produce a vapor that is
then condensed into a liquid.
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Gold as an alloy
Alloy – a homogeneous mixture of metal
- Properties of alloys vary based on the composition of the component
elements.
What about air?
•  How would you classify air as matter?
•  What type of mixture is air? –
Heterogeneous or Homogenous?
Percent of Gas
Molecules
78.08%
20.95
[~1-3%]
0.93
0.033
0.002
0.0005
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Important!
•  Mixtures can be separated by physical
means…
•  Make use of physical properties
•  Make use of physical changes
Modeling Matter
a.
b.
c.
d.
e.
1.  Is an element or compound shown in a?
2.  Two kinds of atoms are shown in b; is this a compound?
3.  Which diagrams show only molecules? Compare them.
4.  Which diagrams show mixtures? Compare them.
Physical Properties
Qualities or characteristics of
matter that can be described or
measured!
Property
Depends on the
of matter
Property
Depends on the
of matter
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What about density?...
Mass
Density = Volume
10 g of
gasoline
Volume
14 cm3 = 14 mL
Density
0.7
g/cm3
(g/cm3 or g/mL)
10 g of
water
10 cm3
1.0
g/cm3
10 g of
lead
0.88 cm3
11.4 g/cm3
Physical Changes
•  A physical change involves a change in one or more
physical properties, but no change in the fundamental
components that make up the substance.
•  Examples:
Water and Its Phase Changes
Heating Curve
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Separation of sand-salt water
mixture
Separating Mixtures by Distillation
Filtration separates a solid from a liquid
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Definition
Evidence of Chemical
Changes
Chemical Change –
Chemical changes are called reactions.
- Reactants
- Products
Chemical
Changes
Examples
Non-examples
Electrolysis is a chemical change
-Compounds can
be separated by
chemical means
Questions…
• 
You have two beakers, one filled to the 100-mL mark with
180.0 g sugar and the other filled to the 100-mL mark with
100.0 g water. You pour it all together into a bigger beaker
and stir until the sugar is completely dissolved.
1. 
Which of the following is true about the mass of the solution?
a)  It is much greater than 280.0 g
b)  It is somewhat greater than 280.0 g
c)  It is exactly 280.0 g
d)  It is somewhat less than 280.0 g
e)  It is much less than 280.0 g
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Questions…
• 
You have two beakers, one filled to the 100-mL mark
with 180.0 g sugar and the other filled to the 100-mL
mark with 100.0 g water. You pour it all together into a
bigger beaker and stir until the sugar is completely
dissolved.
2.  Which of the following is true about the volume of the solution?
a)  It is much greater than 200.0 mL
b)  It is somewhat greater than 200.0 mL
c)  It is exactly 200.0 mL
d)  It is somewhat less than 200.0 mL
e)  It is much less than 200.0 mL
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