1. Chapter 2 Notes
By: William Hunt

2. Mixtures, Elements, and
Compounds
• Mixtures – Two or more substances that are not
chemically combined, and can be separated by physical
means. The substances in a mixture retain their
properties of their individual substance.
• Elements – An element is a substance that cannot be
broken down into simpler substances. It has a fixed
compositions because it has one type of atom.
• Compounds – A compound is a substance that is made
of from two or more simpler substances and can be
broken down into those simpler substances (elements
or compounds). A compound always contains two or
more elements joined in a fixed proposition.
• Pure Substance – Matter that always has the exact
same compositions as a pure substance. Every sample
has the same properties because it has a fixed uniform
composition.

3. Homogeneous
Mixture
• A mixture that is the same throughout.
• “well mixed.”
• Particles that make up the mixture are very small and not
recognizable.
• Ex. Stainless steel spoon, which is a homogenous mixture because
of the mixture of iron, chromium, and nickel.

4. Heterogeneous
Mixture
• In a mixture the parts are noticeably different from one another.
• Comes from the Greek word hetero and genus meaning “different”
and “kind”
• Ex. Sand, which is a heterogeneous mixture and a stainless steel
spoon, which is a homogenous mixture.

5. Solutions
• When substances dissolve and form a homogenous mixture, the
mixture that form is called a solution.
• The substance that is dissolved is the solute and the substance that
does the dissolving is the solvent.
• Ex. Windshield wiper liquid

6. Suspensions
• A heterogeneous mixture that separates into layers over time.
• Ex: If you shake up a container of sand and water the sand mixes
with the water to form a solution.

7. Colloids
• In a colloid contains some particles that are intermediate in size
between the small particles in a solution and the larger particles in
a suspension.
• Colloids do not separate into layers.
• Ex. Fog is a colloid of water droplets in the air.

8. Physical Properties
• Viscosity - How liquid flows.
• Conductivity - Ability to allow heat to flows.
• Malleability - Ability to be hammered without shatter.
• Hardness - How hard an item can be hit.
• Melting Point - Ability to change from solid to liquid
• Boiling Point - Temperature at which a substance boils.
• Density - Can be tested to find the purity of the substance.

9. Separation
Techniques
Examples:
Decantation
Filtration
Centrifugation
Evaporation
Crystallization
Distillation
Using a Separating Funnel
Fractional Distillation
Sublimation
Chromatography
Melting Point
Boiling Point

10. Distillation
• A process that separates substances in a solution based on their
boiling points.
• Ex.
#1 B #2
U
F
F
100
E
Plateau
Temp (˚C)
R
50
Plateau
0
0
Time (Min)

11. Filtration
• A process that separates materials on the size of their particles
and/or solubility.
• Ex.

12. Evaporation
• A process used to isolate a solid dissolved in a liquid: Solubility
property
• Ex. NaCL (sodium chloride) (table salt) + water
• You will not be able to isolate pure substances of a mixture in a
liquid.

13. Chemical Properties
• A chemical property is any ability to produce a change in the
composition of matter.
• Chemical properties can only be observed when the substances
in a sample of matter are changing into different substances.
•

14. Evidence of
Chemical Change
• When matter undergoes a
chemical change, the
composition of matter changes.
When matter undergoes a
physical change, the
composition of matter will
retain the same.
• Four types of common chemical
change are...
• Color change.
• Temperature change.
• Production of gas.
• Formation of a precipitate.

15. Electrolysis
• Electrolysis is a chemical
separation technique
• Notes: 2H20(liquid) ->
Electricity 2H2(gas) +
O2(gas), React H:1, 2:1
• Hydrogen Oxygen
Explosive Allow flame
to ignite
Less dense More dense
than air than air
(rise) (sink)
“PAP”

16. Question Review...

17. Question #1
• At room temperature, a substance
with a melting point of 40˚C is
a________.

18. Question #2
• Formation of a precipitate is usually
evidence of________.

19. Question #3
• A material that can be hit hard
without shattering is an example of
what property?

20. Question #4,5
• List 1 physical change and 1
chemical change that occurs when a
candle burns.
• How does the composition of a
mixture of hydrogen and oxygen
differ from the composition
containing of a compound hydrogen

21. Question #6
• A solid, rectangular block of
material floats on water. Is it
possible that the block is pure gold?
Explain your answer.
• Suppose you mix two colorless
liquids together and a green solid
settles to the bottom of the
container. Explain why you might be

22. Question #7
(Bonus)
• RELATING CAUSE AND EFFECT-
Explain why painting an iron railing
can slow down the rate at which the
railing will rust.