Chapter 10
Section 4
p.342-348
Experimental
Heating Curve for Water
Temperature vs Time (Water)
140
120
Temperature oC
100
80
temp LMJK
temp NASS
60
temp ACHKK
40
20
0
0
1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00
Definitions (p.342-346)
 Define each of the following out of the book:
1. Phase
2. Condensation
3. Equilibrium
4. Equilibrium vapor pressure
5. Volatile liquids
6. Boiling point/boiling
7. Molar enthalpy of vaporization
8. Freezing point/freezing
9. Molar enthalpy of fusion
10. Sublimation
11. Deposition
Phase changes (changes of state)
 Copy Table 2 on page 342 into your notes. You will
need to know it for your test (including examples)
Equilibrium Vapor Pressure of a
Liquid
 At a constant temperature and pressure, the rate of
evaporation and condensation remains at equilibrium.
 Explanation:
 Increasing temperature increases energy of particles (K.M.
Theory #5).
 More particles gain energy and evaporate.
 This increases the pressure (more gas particles pushed into
the same space).
 Increasing the pressure further increases the temperature,
which increases energy, and so on.
 When temperature and pressure stay the same,
particles don’t gain or lose energy, so they stay in the
same phase, at equilibrium.
Molar Enthalpy
 Molar enthalpy is a measure of the attraction
between particles (assumption #4) of either the
liquid for vaporization or solid for fusion.
 Ex. Water has a very high Hv because of the hydrogen
bonding between H and O in the compound.
Phase diagrams (p.347)
 Define:
 Phase diagram
 Triple point
 Critical point
 Critical temperature
 Critical pressure
 Copy down the phase diagram for H2O
 Answer section review question #7
Chapter 10
Secion 5
p.349-351
Structure of Water
 What is the structure of water? Draw a molecule.
 What is special about the bonding in water molecules?
 Why does ice have such a low density?
 What happens to the structure of ice as it melts?
 Describe Figure 19 on page 350.
Physical Properties of Water
 At what temperature (Celsius) does water freeze?
 What is the molar enthalpy of fusion of ice?
 What is the density of ice? Water?
 Why is the density of ice important for organisms
living in lakes and ponds?
 At what temperature (Celsius) does water boil?
 What is the molar enthalpy of vaporization of water?
 Why are these values so high for water?
Practice p.351
 Example:
 Molar enthalpy of fusion (ice melts) = 6.009 kJ/mol
 Mass of H2O given = 47.0 g
 Molar mass of H2O = 18 g/mol

47.0 g / 18 g = 2.6 mol H2O x 6.009 kJ/mol = 15.7 kJ
 Molar enthalpy of vaporization (boils) = 40.79 kJ/mol

2.6 mol H2O x 40.79 kJ/mol = 106 kJ
 Complete practice #1 and 2 individually.
 10.5 section review due by end of class (exit ticket)