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Clausius-Clapeyron question

The temperature-dependence of the vapour pressure of solid and liquid benzene is
given below.

Solid:
T / K, p / kPa
265, 1.83
275, 3.88

Liquid:
280, 5.40
290, 9.05

Use the Clausius-Clapeyron equation for the vapour pressure above a liquid or
solid to estimate the enthalpies of sublimation and vaporization of benzene, identifying
any approximations that you use.

As a 7-mark question, is this really just, integrate the Clausius-Clapeyron equation (or go from the integrated form which everyone knows anyway), rearrange for the enthalpy change, and then plug in the numbers twice?
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Reply 2
Original post by Big-Daddy
The temperature-dependence of the vapour pressure of solid and liquid benzene is
given below.

Solid:
T / K, p / kPa
265, 1.83
275, 3.88

Liquid:
280, 5.40
290, 9.05

Use the Clausius-Clapeyron equation for the vapour pressure above a liquid or
solid to estimate the enthalpies of sublimation and vaporization of benzene, identifying
any approximations that you use.

As a 7-mark question, is this really just, integrate the Clausius-Clapeyron equation (or go from the integrated form which everyone knows anyway), rearrange for the enthalpy change, and then plug in the numbers twice?


Read through the Clausius-Clapeyron section. It might help.
http://www.christianhill.co.uk/media/teaching/td_crib.pdf
Reply 3
Original post by shengoc
Read through the Clausius-Clapeyron section. It might help.
http://www.christianhill.co.uk/media/teaching/td_crib.pdf


All that does is show the equation, which of course I have seen before. What I'm asking is, do I simply need to use the integrated form of the version from p0 to p and T1 to T2 and solve for the enthalpy change, in each case? This is simpler than I would have expected so I want to check that the method is correct.
Reply 4
Original post by Big-Daddy
All that does is show the equation, which of course I have seen before. What I'm asking is, do I simply need to use the integrated form of the version from p0 to p and T1 to T2 and solve for the enthalpy change, in each case? This is simpler than I would have expected so I want to check that the method is correct.


It is indeed that simple - solving differential equation. Moreover, Claucius-Clayperon eqn also takes into account other assumptions.

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