How Do You Derive U, T, P, C_v, and V for This Thermodynamic System?

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SUMMARY

The discussion focuses on deriving the thermodynamic variables U (internal energy), T (temperature), P (pressure), C_v (heat capacity at constant volume), and V (volume) for a system defined by the entropy equation S=A*(N*V*U)^{1/3}. Key equations include dS=1/T dU+P/T dV-(mu)/T dN and U=TS-PV+mu N. The final temperature of two identical bodies at initial temperatures T_1 and T_2 can be calculated using the principles of thermodynamics and the provided equations.

PREREQUISITES
  • Understanding of thermodynamic equations and variables
  • Familiarity with partial derivatives in thermodynamics
  • Knowledge of entropy and its relation to thermodynamic properties
  • Basic concepts of internal energy and heat capacity
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  • Study the derivation of thermodynamic identities, particularly U=TS-PV+mu N
  • Learn about the Maxwell relations in thermodynamics
  • Explore the concept of heat capacity and its calculation using C_V=T(dS/dT)_{V,N}
  • Investigate the relationship between enthalpy and pressure, specifically V=(dH/dP)_{S,N}
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This discussion is beneficial for students and professionals in thermodynamics, particularly those studying or working in fields related to physical chemistry, mechanical engineering, and materials science.

BurrowK
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Given S=A*(N*V*U)^{1/3} where A is a constant.
a) What is U, T, and P for the system?
b) what are C_v and V?
c) 2 identical bodies consisting of a material obeying the equations found in A. N and V are the same for both and they are initially at temps T_1 and T_2. The two bodies are brought together, what is the final temp?


I know that dS=1/T dU+P/T dV-(mu)/T dN, but I'm not sure how this helps.

I'm unsure where to start for this, my prof forgot to lecture on the subject before giving us this question. ANy help is appreciated.
 
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Hi BurrowK, welcome to PF. From your dS equation it looks like

\frac{1}{T}=\left(\frac{dS}{dU}\right)_{V,N}

which should help your figure out T (and P can be calculated similarly). It may also help that

U=TS-PV+\mu N

C_V=T\left(\frac{dS}{dT}\right)_{V,N}

V=\left(\frac{dH}{dP}\right)_{S,N}

where the enthalpy H=U+PV. Does this get you started?
 

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