1. The Classification of Matter
Chapter 15
The Classification of Matter

2. Section 1
Composition of Matter

3. Different Categories of Matter

4. Matter fits into 2 major categories…
Pure Substances
Mixtures
Matter with a fixed composition
Two types:
Elements
Compounds
Matter without a fixed composition
Two types:
Heterogeneous mixtures
Suspensions
Homogeneous mixtures
Solutions
Colloids

5. Elements When all the atoms in a substance have the same identity
Examples:
Pencil lead is graphite, which is just carbon in solid form
Oxygen tanks contain pure oxygen to help people with lung diseases breathe easier

6. Compounds When two or more elements are combined Examples:
Water is a combination of hydrogen and oxygen (H2O)
Air is a combination of multiple elements
Salt is a combination of sodium and chloride (NaCl)

7. Heterogeneous Mixtures
A mixture in which different materials can be easily distinguished
Things like pizza, salad, chicken noodle soup, granite, and concrete are all heterogeneous mixtures

8. Homogeneous Mixtures
A mixture of two or more gaseous, liquid, or solid substances blended evenly throughout
The air we breathe, Kool Aid, and sweet tea are all homogeneous mixtures

9. Solutions
A homogeneous mixture of particles so small they cannot be seen with a microscope and will never settle to the bottom of the container
Vinegar and soft drinks are examples of solutions because they remain mixed thoroughly

10. Colloids
A type of mixture with particles that are larger than those in solutions, but not heavy enough to settle to the bottom
Paint, Jell-o, fog, and smoke are all examples of colloids

11. The Tyndall Effect
To detect a colloid, shine a light through the substance
If there is a definite beam of light visible, it is a colloid

12. Suspensions
A heterogeneous mixture containing a liquid in which large particles settle out to the bottom because they are heavier.
Muddy water, oil and vinegar salad dressing, and snow globes are suspensions

13. Section 2
Physical & Chemical Properties
Physical & Chemical Changes

14. Physical Properties
Any characteristic of a material that you can observe without changing the identity of the substances that make up the material is a physical property.
Color
Shape
Size
Density
Melting point
Boiling point
Freezing point

15. Chemical Properties
Any characteristic of a substance that Indicates whether a material can undergo a chemical change is a chemical property
Flammability
Reaction to light
Solubility
Combustion
Reactivity

16. Physical Change A change in size, shape, or state of matter
The identity stays the same
Ice cube melting
Water boiling or freezing
Color changes
Cutting paper into smaller pieces
Stretching a rubber band
Grass growing

17. Chemical Change Change of one substance to another Eggs rotting
Cars rusting
Match burning
Leaves decomposing
Cooking anything
Chemical reactions

19. Weathering
Physical change: when rocks split after water seeps into cracks, freezes, then melts
The pieces of rock that break off still have the same identity, they’re just smaller
Chemical change: acid rain causes limestone to change its chemical makeup and dissolve
The White Cliffs of Dover have been shaped by this process over time

20. Weathering
Physical
Chemical

21. True or False: The Earth’s surface has stayed the same for thousands of years

22. The Earth’s surface is always changing!
True or False: The Earth’s surface has stayed the same for thousands of years
False
The Earth’s surface is always changing!

27. Weathering and Erosion
Wind
Water
Ice
Gravity

28. Chemical Change Evidence

29. The Law of Conservation of Mass
The mass of all substances present before a chemical change is equal to the mass of all substances that remain after the change
Suppose logs in a fireplace had a mass of 85 kg
After they burn, all you see is ashes. If you weigh the ashes, they may not have a mass of 85 kg. Where is the rest of the mass?