1. Chapter 9: Classification of Matter
Mr. Skelton

2. 9-1: Composition of Matter
Matter is anything that has mass & takes up space.
Matter can be subdivided into two groups.
* substances
* mixtures

3. Substances can be either
Elements
Made of only one kind of atom
92 naturally occurring elements
26 synthetic ones
Cannot be broken down by physical means
Compounds
Two or more elements that are chemically combined in a specific ratio.
Examples: H2O = 2:1
NaCl= 1:1
Cannot be broken down by physical means.

4. characteristics of these
Mixtures
A combination of two or more substances that do not combine chemically, but remain the same individual substances
They can be separated by physical means
Two types:
Heterogeneous
Homogeneous
Based on the prefixes
“hetero” and “homo,”
what do you think are
characteristics of these
two types of mixtures?

5. Heterogeneous Mixture
“Hetero” means different
These mixtures have large particles that can be easily separated.
A suspension is a special type of heterogeneous mixture with even larger particles that eventually settle
Example:
Notice the
visibly
different
substances
Trail Mix

6. Other Examples of suspensions include: Salad Dressing
Other Examples of suspensions include: Salad Dressing. Muddy Water, Juice (that settles)

7. Heterogeneous Mixtures Colloids
Colloids – large particles that scatter light. This is called the Tyndall effect.
Examples: milk, fog, smog, dust, Jell-O, whipped cream

8. Homogeneous Mixture “Homo” means the same
These mixtures have very small particles that are evenly spread throughout the mixture giving it a uniform appearance
Commonly referred to as solutions
Example:
Salt Water
Stainless Steel
Soda
Coffee
Tea
Notice the
uniform
appearance

9. Composition of Matter Concept Map
classified as
Matter
classified as
Mixtures
Substances
which include
Which include
which include
Homogeneous
Heterogeneous
Elements
Compounds
which include
which include
are made up of
Solutions
Colloids
Suspensions
Atoms (Same)
Atoms
(Different)
examples
examples
examples

10. Solution
a mixture of two or more substances that is identical throughout
can be physically separated
composed of solutes and solvents
Salt water is considered a solution. How
can it be
physically separated?
the substance in the smallest
amount that gets dissolved in the solvent
the substance in the larger
amount that dissolves the solute
Iced Tea Mix
(solute)
Water
(solvent)
Iced Tea
(solution)

11. Solutes Change Solvents
The amount of solute in a solution determines how much the physical properties of the solvent are changed
Examples:
Lowering the Freezing Point
Raising the Boiling Point
The freezing point of a liquid solvent
decreases when a solute is dissolved in it.
Ex. Pure water freezes at 320F (00C), but when salt is
dissolved in it, the freezing point is lowered.
This is why people use salt to melt ice.
The boiling point of a solution is higher
than the boiling point of the solvent.
Therefore, a solution can remain a liquid at
a higher temperature than its pure solvent.
Ex. The boiling point of pure water is 2120F (1000C),
but when salt is dissolved in it, the boiling
point is higher. This is why it takes salt water
longer to boil than fresh water

12. Concentration
the amount of solute dissolved in a solvent at a given temperature
described as dilute if solvent has a low concentration of
solute
described as saturated if the solvent has a high concentration of solute
described as supersaturated if the solvent contains more dissolved solute than can be absorbed

13. Solubility
the amount of solute that dissolves in a certain amount of a solvent at a given temperature and pressure
influenced by:
What do we call things that are not soluble?
Temperature
Pressure
Solids increased temperature causes
them to be more soluble and vice versa
Gases increased temperature causes
them to be less soluble and vice versa
Ex. Iced Coffee
Solids increased pressure has no
effect on solubility
Gases increased pressure causes them
to be more soluble and vice versa
Ex. Soda, “The Bends”

14. 9-2 The Colloid Connection

15. The Colloid Connection
What is a colloid?
A heterogeneous mixture that never settles and scatters light because of large particles.
Examples:

16. Let’s look at the good first…
Aside from food products, are there any other colloids we encounter?
Yes – both good and bad.
Let’s look at the good first…

17. When you turn on the faucet, is the water clean or dirty?
Clean (we hope!) But why?

18. Colloids! But how?

19. Water is first taken from a stream,
river, or reservoir.

20. It then goes into a tank where
LIME and ALUM are added.
LIME
ALUM
LIME
ALUM

21. The LIME and the ALUM form a colloid that is a gel-like substance.
The gel-like substance traps microorganisms and other particles.

22. The “dirty” gel then passes through fine sand, where it is trapped.
Leaving…

23. Nice clean water.

24. Pollution Colloids aren’t always good though…
Unburned particles suspended in the air
Aka “soot”

25. Coagulation
In coagulation, small, suspended particles are attracted to each other. They clump together, forming a particle that is too big to remain suspended.

26. On to our favorite colloid – gelatin (Jell-o)
Gelatin is large strands weakly connected together.

27. When added to boiling water, the strands split apart.

28. Water molecules get trapped between the strands as the gelatin cools.
And the gelatin “hardens” into a semisolid colloid.

29. 9-3 Describing Matter

30. Two classifications of the properties of matter.
Physical Property
A characteristic of a substance that you can observe without changing the substance.
Examples include: size, shape, mass, temperature, density, volume, etc.

31. Chemical property
Characteristic of a substance that indicates how it will behave.
Examples include: rust, tarnish, flammable, photosensitive, etc.

32. When matter undergoes a change, the change can be classified as either a….

33. Physical Change
Any change in a physical property
Tearing a piece of paper, melting, freezing, boiling, etc.

34. Chemical change
A change in one substance to produce another new substance.
Examples include: rusting, tarnishing, cooking, burning, bubbling (like in alka-seltzer & water), reactions to light (like exposing film to light), etc.

35. Indications of chemical changes include a change in physical properties such as odor, color, bubbling, light, heat, sound, etc.
Plus the production of a new substance.

36. Law of Conservation of Mass
First developed by Antoine LaVoisier
States that mass cannot be created or destroyed.
This means that the total mass at the beginning of a chemical change will equal the mass at the end of the change.