1. Liquids & Solids
Changes of State

2. Phase Changes

3. Phase Changes Evaporation
molecules at the surface gain enough energy to overcome IMF
Volatility
measure of evaporation rate
depends on temp & IMF

4. Phase Changes temp volatility IMF volatility Boltzmann Distribution
# of Particles
volatility
IMF
volatility
Kinetic Energy

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

6. Phase Changes temp v.p. IMF v.p. Vapor Pressure
pressure of vapor above a liquid at equilibrium
v.p.
depends on temp & IMF
directly related to volatility
temp
temp
v.p.
IMF
v.p.

7. 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.

9. 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

10. Phase Changes Sublimation solid  gas
v.p. of solid exceeds external pressure at or near room temperature
EX: dry ice, mothballs, solid air fresheners