1. Phases of Matter Part II
January 5, 2016

2. Goals:
Use graphical representation to understand how temperature changes in a substance undergoing phase change.
Able to explain Heat of Fusion and Heat of Vaporization.
Compare and Contrast Boiling and evaporation.

3. Q: What is a phase change diagram?
Shows the temperatures at which different changes of phase take place
Also shows how much energy is required to make certain changes in phase occur

4. Phase Change Diagram Gas Condensation Vaporization Freezing Liquid
Melting
Solid

5. Q: What do you need for a change of phase?
Energy
- Energy must be transferred in order for a phase change to occur!

6. Q: What do you need for a change of phase?
Heat of vaporization-
- the amount of energy needed to change something from l  g or g  l (amount of energy to turn something into a VAPOR)
Heat of fusion-
- the amount of energy needed to change something from s  l and l  s

7. Q: Compare and Contrast evaporation and boiling.
- Both are change from liquid to gas
- Both are COOLING processes (occur in order to cool something off)
*Think of when you sweat!*

8. Q: Compare and Contrast evaporation and boiling.
- Boiling occurs throughout the liquid AND at the surface; evaporation occurs only at the surface of a liquid
- Boiling can only happen when there is correct pressure from the surrounding atmosphere; evaporation isn’t affected by pressure

9. Homework
Parts 2 – 5 of pkt