1. Section 2 – pg 96 Changes of State
Chapter 3
Section 2 – pg 96
Changes of State

2. Pg 97
Changes of State
Change from liquid to gas involves addition of thermal energy
Change from liquid to solid involves a decrease in thermal energy

3. Melting The change in state from a solid to a liquid
Pg 97
Melting
The change in state from a solid to a liquid
In pure substances, the substance melts at a specific point – Melting Point

5. Pg 97
When a substance melts, the particles in the solid vibrate so fast that they break from their fixed positions.

6. Freezing Pg 98 The change from a liquid to a solid Reverse of melting
When a substance freezes, the particles in the liquid move more slowly that they begin to take on fixed positions

7. Liquid -> Gas Vaporization: the change from liquid to a gas
Pg 98
Liquid -> Gas
Vaporization: the change from liquid to a gas
Takes place when the particles in a liquid gain enough energy to move independently, forming a gas
Evaporation and Boiling

8. Pg 99
Evaporation
Vaporization that takes place only on the surface of a liquid

9. Pg 99
Boiling occurs when a liquid changes to a gas below its surface as well as at the surface
-Boiling Point: the temperature at which a liquid boils
-Boiling point depends on the air pressure above it

11. Pg 100
Gas -> Liquid
Condensation: the change in state from a gas to a liquid
The reverse of vaporization
The particles in a gas lose enough thermal energy to form a liquid

12. Pg 100
These are not gases, they are water droplets suspended in air

13. Pg 101
Solid <-> Gas
Sublimation: the surface particles of a solid gain enough energy that they form a gas
During sublimation, particles of a solid do not pass through the liquid state as they form a gas

14. Chapter 3 Section 2 Homework pg 101

15. 1A. What happens to the particles of a solid as it becomes a liquid?

16. 1B. How does the thermal energy of solid water change as it melts?

17. 1C. You are stranded in a blizzard
1C. You are stranded in a blizzard. You need water to drink and you’re trying to stay warm. Should you melt snow then drink it or just eat snow?

18. 2A. What is vaporization?

19. 2B. Name the two types of vaporization
2B. Name the two types of vaporization. Tell how they are similar and how they differ.

20. 2C. Why does the evaporation of sweat cool your body on a warm day?

21. 3A. What process occurs as pieces of dry ice gradually gets smaller?

22. 3B. SKIP!