Partial derivatives of enthelpy and Maxwell relations

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SUMMARY

This discussion focuses on the application of Maxwell relations in thermodynamics to derive partial derivatives of enthalpy (H) with respect to volume (V) while holding internal energy (U) constant. The key equations referenced include the definitions of enthalpy (H = U + PV) and the differential form of internal energy (dU = TdS - PdV). The conclusion reached is that the partial derivative of enthalpy with respect to volume at constant internal energy is given by the equation: ∂H/∂V|_U = P + V ∂P/∂V|_U. Further manipulation using Maxwell relations allows for the expression of pressure as a function of entropy (S) and volume (V).

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Homework Statement
Write the following partial derivatives in terms of heat capacity (##c##), compressibility (##\kappa##) and coefficient of thermal expansion (##\alpha##).

##(\frac{\partial H}{\partial V})_U##
##(\frac{\partial H}{\partial V})_S##

With ##H##: enthalpy, ##U##: internal energy, ##V##: volume, ##S##: entropy and the subscript denotes a magnitud held constant in differentiation.
Relevant Equations
##dH=dU+Pdv+vdP##
##dU=TdS-PdV##
I've attached images showing my progress. I have used Maxwell relations and the definitions of ##\alpha##, ##\kappa## and ##c##, but I don't know how to continue. Can you help me?
 

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You have that ##H = U + PV##. And you also have that ##dU = T dS - P dV##. So when ##U## is constant, you have: ##dH = d(PV) = PdV + V dP##. And you also have when ##U## is constant, ##TdS - PdV = 0##. So we conclude:

##\frac{\partial H}{\partial V}|_U = P + V \frac{\partial P}{\partial V}|_U##

Now, if you think of ##P## as a function of ##S## and ##V##, then

##\frac{\partial P}{\partial V}|_U = \frac{\partial P}{\partial V}|_S + \frac{\partial P}{\partial S}|_V \frac{\partial S}{\partial V}|_U##

At this point, you can use ##TdS - PdV = 0## (when ##dU = 0##) to rewrite ##\frac{\partial S}{\partial V}|_U##, and you can use one of the Maxwell relations to rewrite ##\frac{\partial P}{\partial S}|_V##.
 
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