Calculating the Freezing Point of Mercury Under Pressure

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winterwind
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Homework Statement


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?


Homework Equations



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

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


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!
 
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winterwind said:
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?
What's the slope of the m.p. line? Positive? Or, negative?
winterwind said:
I would expect it changes more than 0.1 K anyways.
Water changes 0.01 K/atm, and has which slope?
winterwind said:
Am I using the correct equation?
Yes.