1. Changes of State
10.4

2. Definitions
Phase – any part of a system with uniform composition and properties.
Condensation – gas changes to a liquid
Molecules of liquid can evaporate and then condense and re-enter the liquid phase

3. Equilibrium Condensation and evaporation can happen at the same rate…
Equilibrium – a dynamic condition in which 2 opposing changes occur at equal rates in a closed system
No net change in amt. of substance in either phase.

4. Equilibrium and Vapor Pressure
P is directly proportional to [ ]
Equilibrium vapor pressure – pressure exerted by vapor in equilibrium with its corresponding liquid at a given temp
Different for each liquid
The higher the bonding the _____the EVP
Think about the KMT

5. Definitions Volatile Liquids – liquids that evaporate readily
__________ forces of attraction.
Boiling – conversion of a liquid to a vapor within the liquid as well as at the surface
Boiling point – the temp at which the equilibrium vapor pressure of the liquid = atm pressure

6. Boiling The ________ the atm pressure, the lower the b.p.
Temp is constant while boiling
Normal atmospheric pressure = 1 atm, 760 torr, kPa
E needs to be + constantly to continue boiling

7. Molar Enthalpy of Vaporization
MEV – the amt of E as heat that is needed to vaporize 1 mol of liquid at the liquids b.p. at constant pressure.
ΔHv
Measure of attraction of particles

8. Freezing and Melting Freezing – physical change of liquid to solid
Loss of E
Freezing point – the temp at which solid and liquid are at equilibrium at 1 atm
At f. p. particles have same amt of ave K. E.

9. Melting At m.p. the solid and liquid have the same amt of k.e. also.
For pure crystalline solids, f.p. and m.p. are at the same temp.

10. Molar Enthalpy of fusion
Molar Enthalpy of fusion – the amount of energy as heat required to melt one mole of solid at the solids melting point.