1. Water phase changes constant Temperature remains __________
during a phase change.
constant
Water phase changes

2. Latent Heat of Phase Change
Molar Heat of Fusion
The energy that must be absorbed in order to convert one mole of solid to liquid at its melting point.
Molar Heat of Solidification
The energy that must be removed in order to convert one mole of liquid to solid at its freezing point.

3. Latent Heat of Phase Change #2
Molar Heat of Vaporization
The energy that must be absorbed in order to convert one mole of liquid to gas at its boiling point.
Molar Heat of Condensation
The energy that must be removed in order to convert one mole of gas to liquid at its condensation point.

4. Latent Heat Fusion kJ/kg Melting Point °C
Substance
Latent Heat Fusion kJ/kg
Melting Point °C
Latent Heat Vaporization kJ/kg
Boiling Point °C
Alcohol, ethyl
108
-114
855
78.3
Ammonia
339
-75
1369
-33.34
Carbon dioxide
184
-78
574
-57
Helium 21
Hydrogen(2) 58
-259
455
-253
Lead[3]
24.5
372.3
871
1750
Nitrogen
25.7
-210
200
-196
Oxygen
13.9
-219
213
-183
R134a
-101
215.9
-26.6
Toluene
-93
351
110.6
Turpentine
293
Water
334
2260 (at 100oC)
100

5. Latent Heat – Sample Problem
Problem: The molar heat of fusion of water is
6.009 kJ/mol. How much energy is needed to convert 60 grams of ice at 0C to liquid water at0C?
Mass
of ice
Molar
Mass of
water
Heat of
fusion