Physical and Chemical Changes Notes Pages 78-87

1. Define physical change. Give an example of a physical change. A change in which the form or appearance of matter changes, but not its composition. Examples: water changes to ice.

2. Generally, how can you cause a physical change? Cut, tear, grind, bend matter

3. Why is dissolving a physical change? Give an example to support your answer. The dissolved substance does not have its composition changed. Sugar dissolving in tea.

4. Why is a change of state a physical change? Give an example to support your answer. The substance does not change its composition. Ice changes to water.

5. Define a chemical change. Give an example of a chemical change. A change in which the composition of a substance changes. Example: Rust

6. Page 80, answer the reading check. A chemical change alters the composition of the matter, while a physical change alters appearance but not composition.

7. A change in color is a chemical change. Give an example to support this statement. A half eaten apple exposed to air turns brown.

8. How can you tell if an energy chemical change has occurred? There will be a change in temperature (change in thermal energy)

9. What chemical change can occur with spoiled foods? A change in odor will occur.

10. The formation of a gas is a clue to a chemical change.

11. The formation of a solid out of a solution is a chemical change.

12. The substances produced during a chemical change cannot be changed back into the original substances by physical means.

13. What six signs indicate a chemical change? 1.Change in color 2.Change in energy 3.Change in odor 4.The formation of a gas 5.The formation of a solid 6.The substance cannot change back to its original composition.

14. Do not do.

15. Define the law of conservation of mass. The total mass of the matter is the same before and after a physical or a chemical change.