Monday, January 12, 2009

HW2, problem 6 hint

By definition, the constant-pressure heat capacity is given by

Cp = d(U + PV)/dT

However, for liquids the molar volume V changes very little upon heating. Therefore, at constant pressure, we can neglect the second term to good approximation in liquids:

Cp ~ dU/dT

Rearranging, we arrive at an equation we can integrate to get a relation between U and T:

Cp dT = dU

-MSS

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