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Freezing point of mercury

  1. Oct 10, 2009 #1
    1. The problem statement, all variables and given/known data
    The enthalpy of fusion of mercury is 2.292 kJ/mol, and its normal freezing point is 234.3 K with a change in molar volume of +0.517 cm/mol on melting. At what temperature will the bottom of a column of mercury (density 13.6 g /cm3) of height 10.0 m be expected to freeze?


    2. Relevant equations

    p = [tex]\rho[/tex]gh

    p = p* + [([tex]\Delta[/tex]fusH)[tex]/[/tex](T*[tex]\Delta[/tex]fusV)]/(T - T*)


    3. The attempt at a solution

    I calculated the pressure in the column of mercury using the first equation provided above. I then solved the second equation for T, plugged in the given values, with p*= 101 kPa and T* = 234.3 K (the normal pressure and boiling point).

    I get an answer of 234.2 K, which doesn't make sense, since when you raise the pressure, shouldn't you get a higher temperature freezing/melting point? I would expect it changes more than 0.1 K anyways.

    Am I using the correct equation?

    Thanks!
     
    Last edited: Oct 10, 2009
  2. jcsd
  3. Nov 26, 2016 #2

    Bystander

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    What's the slope of the m.p. line? Positive? Or, negative?
    Water changes 0.01 K/atm, and has which slope?
    Yes.
     
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