Question about Maxwell equation in thermal physics

AI Thread Summary
The discussion revolves around solving a problem related to Maxwell's equations in thermal physics. The user differentiates an equation involving enthalpy and pressure, leading to a complication with subscripts when substituting terms. They seek clarification on expressing entropy in terms of temperature and pressure, emphasizing a mathematical approach rather than relying on thermodynamic definitions. Ultimately, they derive a new expression for enthalpy that incorporates the relationships between volume, temperature, and pressure. The conversation highlights the importance of mathematical manipulation in thermodynamic equations.
Clara Chung
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Homework Statement


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Homework Equations

The Attempt at a Solution


How to do part ii)?
I differentiate part i with respect to p
(∂H/∂P)T = T (∂S/∂P)T + V ...(1)
Then I used the equation given in the question,
Applying maxwell equation I got
(∂T/∂V)S = -(∂P/∂S)V ...(2)
I planned to substitute (2) into (1), However the subscript of
-(∂P/∂S)V is V , but the subscript of (∂S/∂P)T is T which are not the same
What should I do?
 

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What is the expression for dS interns of dT and dP?
 
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Chestermiller said:
What is the expression for dS interns of dT and dP?
Do I need the expression according to the information given by the question or from dQrev/T?
 
Clara Chung said:
Do I need the expression according to the information given by the question or from dQrev/T?
Neither. Purely from mathematics.
 
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Chestermiller said:
Neither. Purely from mathematics.
If it is purely from mathematics.. I think I can do it like this
G=H-TS
dG=dH-TdS-SdT
dG=VdP-SdT
so
(∂V/∂T)P = - (∂S/∂P)T
Now I can put it into (∂H/∂P)T = T (∂S/∂P)T + V ...(1)
So
(∂H/∂P)T = -T(∂V/∂T)P + V
Thanks for helping!
 
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