Molar Enthalpy question

[Rote Learner]

The VP of Hg is given by the expression:

 

ln(P/torr)= 7060.7 K/T + 17.85

 

-At normal BP of Mercury, 629.88 K, the density of the liquid is 12.7 g/mL and the density of the vapor is 3.82 g/L. Find the molar enthalpy (kJ/mol) for vaporization at this temperature. State any "assumptions" made.

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I tried using Clausius-Clapeyron relation but I dont know what to do with the given relation. I also do not know what to do with the densities. I have been stuck on this problems for hours. Any pointers will be greatly appreciated.

 

Thank you

[hermanntrude]

if you review the work you must have done on gases fairly recently, you will find there is a relationship between a gases density and it's partial pressure (hint: try rearranging the ideal gas law). then you can use the C-C equation as you suggested.

[Rote Learner]

Now im stuck with the CC equation with a Delta H and a Delta V as well as two temperatures needed.

 

I graphed the expression by taking e^() of both sides and now have a slope which I believe is the phase separation between the liquid and solid phase.

 

I really have no idea what the question is fully asking and I see nothing online or in my book related to this. Any other pointers will be greatly appreciated.

 

Thank you

[hermanntrude]

there is no deltaV needed in this equation.

 

There is only one temperature required. you were given one. And the term "normal boiling point" refers to the temperature at which the vapor pressure is equal to 1atm.

 

any help yet?