1. Ch. 13 – States of Matter
III. Phase Changes (p. 425 – 429)

2. A. Phase Changes

3. A. Phase Changes Vaporization Conversion of a liquid to a gas or vapor
When this occurs at the surface of a liquid that is not boiling, it is called evaporation
molecules at the
surface gain enough
energy to overcome IMF

4. A. Phase Changes Equilibrium
trapped molecules reach a balance between evaporation & condensation

5. A. Phase Changes Vapor Pressure
pressure of vapor above a liquid at equilibrium
depends on temp & IMF
temp
v.p.
IMF
v.p.

6. A. Phase Changes Patm b.p. IMF b.p. Boiling Point
temp at which v.p. of liquid equals external pressure
depends on Patm & IMF
Normal B.P. - b.p. at 1 atm
Patm
b.p.
IMF
b.p.

7. A. Phase Changes Liquids don’t always boil at same temp
B.P. varies with altitude

8. A. Phase Changes IMF m.p. Melting Point equal to freezing point
Which has a higher m.p.?
polar or nonpolar?
covalent or ionic?
polar
ionic

9. A. Phase Changes Sublimation solid  gas
v.p. of solid equals external pressure
EX: dry ice, mothballs, solid air fresheners

10. B. Phase Diagrams
Show the phases of a substance at different temps and pressures

11. Water vs. Carbon Dioxide
B. Phase Diagrams
Water vs. Carbon Dioxide