1. CHM 108 SUROVIEC SPRING 2014 Chapter 11 1

2. I. Solids, Liquids and Gasses 2

3. A. Changes between phases Using temperature, pressure or both you can convert from one phase to another 3

4. II. Intermolecular Forces Originate from interactions between charges, partial charges and temporary charges 4

5. II. Intermolecular Forces Looking at the difference between an O-H bond and 2 H 2 O molecules 5

6. A. Dispersion Forces One intermolecular force present in all molecules and atoms s the dispersion force 6

7. A. Dispersion Forces Magnitude of dispersion force depends on how easily the atom/molecule can polarize 7

8. B. Dipole – Dipole Forces Exists in all molecules that are polar – that have permanent dipoles. 8

9. B. Dipole – Dipole Forces Polarity is important in determining miscibility 9

10. C. H – Bonding hydrogen bond = a special dipole-dipole interaction between they hydrogen atom in a polar N-H, O-H, or F-H bond and an electronegative O, N, or F atom. 10

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12. D. Ion – Dipole Forces Occurs when an ionic compound is mixed with a polar compound 12

13. IV. Vaporization and Vapor Pressure Phase is a homogeneous part of the system in contact with other parts of the system but separated from them by a well – defined boundary. 13

14. A. Vapor Pressure Equilibrium is reached between liquid and vapor, the net number of molecules exchanging does not change. 14

15. Molar heat of vaporization (  H vap ) is the energy required to vaporize 1 mole of a liquid at its boiling point. ln P = -  H vap RT + C Clausius-Clapeyron Equation Vapor Pressure Versus Temperature B. Vapor Pressure and Temperature 15

16. Example 16 Glacier National Park in Montana is a great vacation spot. It is about 4100 ft above sea level with an atmospheric pressure of 681 mm Hg. At what temperature does water (  H vap = 40.7 kJ/mol) boil in the park?

17. C. Boiling Point 17 The boiling point is the temperature at which the (equilibrium) vapor pressure of a liquid is equal to the external pressure. The normal boiling point is the temperature at which a liquid boils when the external pressure is 1 atm.

18. D. Critical Temperature and Pressure 18 There are temperatures and pressures for gasses and liquids that when reached the molecule exhibit unique properties The critical temperature (T c ) is the temperature above which the gas cannot be made to liquefy, no matter how great the applied pressure. The critical pressure (P c ) is the minimum pressure that must be applied to bring about liquefaction at the critical temperature.

19. V. Phase Diagrams 19 The melting point of a solid or the freezing point of a liquid is the temperature at which the solid and liquid phases coexist in equilibrium. The sublimation of a solid or the deposition of a gas is the temperature at which the solid and gas phases coexist in equilibrium. The vaporization of a liquid or the condensation of a gas is the temperature at which the solid and gas phases coexist in equilibrium.

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