Classification
of Matter
Chapter 3
Mixtures
Section 3.3
A combination of 2 or more pure substances.
Each substance retains its chemical properties.
Categories of Mixtures
Homogeneous mixture
1. Constant composition
2. Always a single phase (or
state of matter)
3. Composition will be the
same no matter where you
sample
Heterogeneous mixture
1. Does not blend smoothly
2. May have more than one
phase (or state of matter).
3. Composition may be
different when you take a
sample.
Suspension
Particles settle out
Homogeneous or heterogeneous?
Heterogeneous
Colloid
• A mixture that scatters light.
Hetero or homogeneous?
Heterogeneous
Solution
• The two parts: Solvent and Solute
• Solute is the substance that is dissolved
• Solvent is the substance that the solute is
dissolved in
Homo or heterogeneous?
Homogeneous
Solution Systems
All are homogeneous
Solid in solid
Gas in liquid
Solid in liquid
Elements and Compounds
Section 3.4
Elements
Compounds
1. Pure substance
1.
Pure substance
2.
Made of 2 or more different
elements chemically combined.
3.
Symbols on the periodic table
are used to write formulas for
compounds.
4.
The compound has different
properties than the elements
that make it.
2. Cannot be separated into any
smaller substance with the
same properties.
3. Found on the periodic table.
4. All of the same element have
the same properties.
Relationship Laws
Law of Definite Proportions:
A compound is always made of
the same elements in the
same proportion, by mass.
C6H12O6 –> glucose = 180 g
CH4 –> methane = 16 g
C=12 amu
H= 1
0=16
Percent by mass – need the
periodic table
Mass of element
Mass of compound
X
100
Carbon in glucose
C6H12O6 –> glucose = 180 g
C=12 amu
6gx12g=72g
72 g / 180 g x 100 = 40% C
Law of Multiple Proportions:
When different compounds
are formed by the same
elements, the relative mass is
in small ratios of whole
Numbers.
Example
H2O
and H2O2
The ratio of oxygen in
hydrogen peroxide compared
to water is 2:1
What is the ratio of O?
FeO and Fe2O3
1:3