1. Phase Changes

2. Names Evaporation / Condensation Melting / Freezing
Sublimation / Deposition
Endothermic / Exothermic

3. Heat of Vaporization
The energy required to vaporize 1 mol of liquid at 1 atm pressure
Same as enthalpy of vaporization
Varies according to intermolecular forces

4. Vapor Pressure The pressure of the vapor present at equilibrium
Varies with temperature
Varies with intermolecular attraction

5. Figure 10.38: Behavior of a liquid in a closed container.

6. Figure 10.40: The three liquids have quite different vapor pressures.

7. As temperature increases, more molecules have enough kinetic energy to become a gas.

8. Heating Curves
Show the temperature changes as heat is added at a constant rate
Levels off at places where phase changes because heat is being used to change phase and not to change temperature

9. Heat of Fusion
Heat released when a substance changes from a liquid to a solid
Same thing as enthalpy of fusion

10. Heating Curves Heat of vaporization keeps temp. constant
Heat of fusion keeps temp. constant

11. Figure 10.49: The phase diagram for water.

12. Figure 10.52: The phase diagram for carbon dioxide.