Chem Ch11.txt

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Chem Ch11.txt
2011-01-27 22:22:38
chem ch11

Chapter 11 material
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  1. What is the two-point Clausius-Clapeyron equation?
    ln P2/P1 = ΔHvap/R (1/T2 –1/T1)
  2. What is the Clausius-Clapeyron equation? How does it relate to a linear equation?
    ln Pvap = ΔHvap/R (1/T) + ln β

    • y = ln Pvap
    • m = ΔHvap/R
    • x = (1/T)
    • b = ln β
  3. What is the equation to determine the heat required to change phase?
    q = n ΔH
  4. What is the equation to determine energy needed/given off when heating/cooling within a phase?
    q = m Cs ΔT
  5. What is polarizabilty?
    How easily a molecule's electron cloud can be distorted. More polarizable = easier to distort = higher dispersion forces.
  6. What is polarity?
    A permanent separation of charges in a molecule - the molecule has a permanent dipole moment, and will display dipole-dipole forces.
  7. What is dynamic equilibrium?
    When the rate of evaporation = the rate of condensation in a closed system at a stable temperature.
  8. What is vapor pressure?
    Pressure of a gas that is in dynamic equilibrium with its liquid.
  9. What are dispersion forces?
    Intermolecular forces that are the result of fluctuations in the electron cloud of an atom or molecule.
  10. What are dipole-dipole forces?
    Intermolecular forces found in polar molecules.
  11. What is hydrogen bonding?
    Intermolecular forces found in polar molecules that contain hydrogen atoms directly bonded to N, O, or F.
  12. What is an ion-dipole force?
    Intermolecular force found when an ionic compound is mixed with a polar compound, esp. in aqueous solutions.
  13. List the intermolecular forces weakest to strongest.
    • London dispersion
    • dipole-dipole bonding
    • hydrogen bonding
    • ion-dipole bonding
  14. What is the relationship between surface tension and intermolecular force?
    Surface tension decreased with decreasing intermolecular forces.
  15. How does viscosity relate to intermolecular forces?
    Viscosity is greater in substances with stronger intermolecular forces. Viscosity also depends on molecule shape and temperature, increasing in longer molecules and in lower temps.
  16. What forces result in capillary action?
    Adhesive (attraction between molecules in a liquid and the sides of the tube) and cohesive (attraction between molecules in a liquid) forces.
  17. How does vapor pressure relate to intermolecular forces?
    Weak forces result in a high vapor pressure.
  18. Define boiling point.
    The temperature at which vapor pressure = external pressure. "Normal" boiling point is at 1 atm.
  19. What are the terms for:
    a gas changing phase to a solid
    a solid changing phase to a gas
    • gas --> solid: deposition
    • solid --> gas: sublimation
  20. What is an alternate term for melting?
  21. What is the triple point?
    The point in a phase diagram where all three phases of a substance are equally stable and can exist in equilibrium.
  22. What is the critical point?
    The point in a phase diagram that represents the temperature and pressure above which a supercritical fluid exists.