1. Physical and Chemical Changes
Unit II—Part 2

2. Concept of Change
Change: the act of altering a substance

3. Physical Change
Physical change: a change that occurs that does not change the identity of the substance
Melting ice
Freezing Kool-aid
Tearing paper
Dissolving sugar in water

4. Chemical Changes
Chemical change: a change that occurs causing the identity of the substance to change
Burning
Digesting food
Rusting
A chemical change is called a chemical reaction

5. Chemical Changes Cont’d
Indicators of a chemical change:
Production of light
Production of heat
Production of a gas
Color change
Formation of a precipitate

6. Is it Physical or Chemical?
Glass breaking

7. Is it Physical or Chemical?
Burning leaves 7

8. Is it Physical or Chemical?
Butter melting 8

9. Is it Physical or Chemical?
Fireworks exploding 9

10. Is it Physical or Chemical?
Pouring milk on cereal 10

11. Is it Physical or Chemical?
Mowing a lawn 11

12. Is it Physical or Chemical?
Separating sand and gravel 12

13. Is it Physical or Chemical?
Bleaching hair 13

14. Is it Physical or Chemical?
Frying an egg 14

15. Is it Physical or Chemical?
Hammering nails into wood to frame a house 15

16. Is it Physical or Chemical?
Burning toast 16

17. Is it Physical or Chemical?
Mixing powdered Kool-Aid with water 17

18. Is it Physical or Chemical?
Adding salt to water to gargle 18

19. Is it Physical or Chemical?
Food spoiling 19

20. Is it Physical or Chemical?
Rusting bicycle 20

21. Is it Physical or Chemical?
Melting ice cream 21

22. Changes
Physical Chemical

23. Describing Matter

24. What is Matter? What is a Substance?

25. Properties of Matter
Substance: Single kind of pure matter with a specific makeup and set of properties.
1. Physical Property:
Characteristic of a pure substance that can be OBSERVED without changing it into another substance.
Helps you identify/classify/describe matter
ie: Density, hardness, texture & color

26. What are some Physical Properties?

27. 2. Chemical Properties
Characteristic of a pure substance that describes its ability to change into different substances because of its composition.
CAN’T be observed by looking or touching
ie:
a. IRON reacts with oxygen to form RUST… a completely different/new substance.
b. SILVER reacts with sulfur in the air to form TARNISH.

28. What was the substance before and what did it become?
Burning produces new products…heat, gas and ashes

29. Properties
Physical Chemical