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
Colloids
Suspensions
Homogeneous mixtures
Solutions

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. Homogeneous Mixtures
Contain two or more substances blended evenly throughout
The air we breathe, Kool Aid, and sweet tea are all homogeneous mixtures

8. Solutions
Specific type of homogeneous mixture in which particles are 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

9. Heterogeneous Mixtures
Different materials can be easily distinguished
Things like pizza, salad, chicken noodle soup, granite, and concrete are all heterogeneous mixtures

10. Colloids
Particles are larger than those in solutions, but they are 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
Heterogeneous mixtures in which particles will settle 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
Characteristics that can be observed without changing anything about the material
Color
Shape
Size
Density
Melting point
Boiling point
Freezing point

15. Chemical Properties
Indication of whether a material can undergo a chemical change
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. The Law of Conservation of Mass
The mass of all substances present before a chemical change is equal to the mass of all substances present after a chemical 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?