Understanding Expansion, Compression and Entropy Coefficients

AI Thread Summary
The discussion focuses on deriving the temperature change with respect to volume at constant entropy, expressed as (DT/DV)s. The user starts with known thermodynamic relationships involving expansion and compression coefficients, and attempts to manipulate these to find the desired derivative. They propose that (DT/DV)s can be expressed as a*T/Cv*k, indicating a relationship between various thermodynamic properties. The conversation includes mathematical formulations and seeks confirmation on the correctness of the derived expression. Overall, the thread emphasizes the connection between thermodynamic coefficients and their implications for understanding entropy and temperature changes.
tsuwal
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So, until now I know:
(DV/DS)p=(DT/Dp)s=a*T/cp*(rho) (enthalpy)
(Dp/DT)v=(DS/DV)t=-a/k (helmoltz)
(DS/Dp)t=-(DV/DT)p=-Va (gibbs)

a=expansion coefficient
k=isothermal compression coefficent
cp=heat capacity at constante pressure

I want to deduce DT/DV at constant entropy=(DT/DV)s. BUT HOW?
Let me try to write S(T,V), then,
dS=Cv/T*dT-a/k*dV
putting S=0, i get,
a/k*dV=Cv/T*dT <=> (DT/DV)s=a*T/Cv*k

am I right?
 
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Is this the one you want?

\begin{array}{l}<br /> T = {\left( {\frac{{\partial U}}{{\partial S}}} \right)_V} \\ <br /> {\left( {\frac{{\partial T}}{{\partial V}}} \right)_S} = \left[ {\frac{\partial }{{\partial V}}{{\left( {\frac{{\partial U}}{{\partial S}}} \right)}_V}} \right] = \frac{{{\partial ^2}U}}{{\partial V\partial S}} \\ <br /> \end{array}

and

\begin{array}{l}<br /> P = - {\left( {\frac{{\partial U}}{{\partial V}}} \right)_S} \\ <br /> {\left( {\frac{{\partial P}}{{\partial S}}} \right)_V} = - \left[ {\frac{\partial }{{\partial S}}{{\left( {\frac{{\partial U}}{{\partial S}}} \right)}_V}} \right] = - \frac{{{\partial ^2}U}}{{\partial S\partial V}} \\ <br /> \end{array}

Therefore

{\left( {\frac{{\partial T}}{{\partial V}}} \right)_S} = - {\left( {\frac{{\partial P}}{{\partial S}}} \right)_V}
 


Hey, thanks for worring so much, but until there I knew...
I want to evaluate that derivative further and write in terms of a,k,Cv,Cp,T,p,... as I did
(∂T/∂p)s=a*T/cp*(rho)
 
It may be shown from the equations of electromagnetism, by James Clerk Maxwell in the 1860’s, that the speed of light in the vacuum of free space is related to electric permittivity (ϵ) and magnetic permeability (μ) by the equation: c=1/√( μ ϵ ) . This value is a constant for the vacuum of free space and is independent of the motion of the observer. It was this fact, in part, that led Albert Einstein to Special Relativity.
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