Deriving the TdS Equation for Thermal Physics

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The discussion focuses on deriving the TdS equation in thermal physics, specifically the relationship TdS = C_{V} (∂T/∂P)_{V}dP + C_{P} (∂T/∂V)_{P}dV. The initial approach involves using the first law of thermodynamics and expressing heat transfer as TdS for a closed system. Participants suggest considering entropy S as a function of pressure P and volume V, leading to the expression for dS. The conversation emphasizes the importance of manipulating partial derivatives of S with respect to T, P, and V to progress in the derivation. The discussion highlights the complexity of the relationships involved in deriving the equation.
Elzair
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Homework Statement


Derive the following equation


Homework Equations


TdS = C_{V} \left( \frac{\partial T}{\partial P} \right)_{V}dP + C_{P} \left( \frac{\partial T}{\partial V} \right)_{P}dV


The Attempt at a Solution



dU = \delta Q - \delta W

\delta Q = TdS for a closed system

C_{P} = T \left( \frac{\partial S}{\partial T} \right)_{P}

C_{V} = T \left( \frac{\partial S}{\partial T} \right)_{V}

I am not sure where to go from here.
 
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I think the trick here is playing around with the relations.

If you consider S as a function of p and v as independent variables, then
dS = \left(\frac{\partial S}{\partial P}\right)_V dP + \left(\frac{\partial S}{\partial V}\right)_P dV

But, \frac{\partial S}{\partial P}_V = \left(\frac{\partial S}{\partial T}\right)_V \left(\frac{\partial T}{\partial P}\right)_V, and so on.
 

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