Heat of vaporization and BP

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Heat of vaporization and BP
2011-04-22 21:21:39
Heat Vaporization BP

/\HVap and BP
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  1. molar heat of vaporization (Delta Hvap)
    the energy (usually in KJ) required to vaporize 1 mole of liquid. Directly related to the strength of the intermolecular forces that exist in the liquid

    the clauses claperon equation measures Hvap

    ln P1/P2= Delta Hvap/ R (T1-T2/T1T2)
  2. equilibrium vapor (vapor pressure)
    the rate of evaporation is constant at any given temperature. the vapor pressure measured when a dynamic equilibrium exists between condensation and evaporation. It is the maximum vapor pressure at a given temperature
  3. Clasius Claperon Equation
    P1/P2= Delta Hvap/R(T1-T2/T1T2)
  4. boiling point
    the temperature at which the vapor pressure of a liquid is equal to the external pressure
  5. Liquid - Solid Equilibrium:
    melting point or freezing point
    melting point of a solid or the freezing point of a liquid is the point at which solid and liquid phases coexist in equilibrium.

    water and ice at 0 degrees celcius and 1atm
  6. sublimation
    the process where molecules go directly from a solid into the vapor phase.
  7. molar heat of fusion (Delta Hfus)
    is the energy ( usually in KJ) required to melt one mole of a solid. Delta Hfus is smaller than Delta Hvap
  8. Deposition
    the opposite of sublimation- molecules make the transition from vapor to solid directly
  9. Molar heat of sublimation (Delta H sub)
    the energy (usually in KJ) required to sublime 1 mole of a solid. It is equal to the sum of of the molar heats of fusion and vaporization

    Delta Hsub= Delta H fus + Delta H vap