Chapter 10 Section 4 p

Experimental Heating Curve for Water

Definitions (p ) 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 H v 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 H 2 O Answer section review question #7

Chapter 10 Secion 5 p

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) = kJ/mol Mass of H 2 O given = 47.0 g Molar mass of H 2 O = 18 g/mol 47.0 g / 18 g = 2.6 mol H 2 O x kJ/mol = 15.7 kJ Molar enthalpy of vaporization (boils) = kJ/mol 2.6 mol H 2 O x kJ/mol = 106 kJ Complete practice #1 and 2 individually section review due by end of class (exit ticket)