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Homework Help: Thermodynamics, system of 2 gases

  1. Mar 26, 2012 #1


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    1. The problem statement, all variables and given/known data
    Two particular systems separated by a diathermic wall have the following equations of state:
    [itex]\frac{1}{T^{(1)}}=\frac{3}{2}R \frac{N^{(1)}}{U^{(1)}}[/itex]
    [itex]\frac{1}{T^{(2)}}=\frac{5}{2}R \frac{N^{(1)}}{U^{(2)}}[/itex] where R=1.986 cal/mol K, [itex]N^{(1)}=2[/itex] and [itex]N^{(1)}=3[/itex].

    2. Relevant equations
    Euler relation in entropy representation: [itex]S=\sum _j F_j X_j[/itex]. In energy representation: [itex]U=TS+\sum _j P_j X_j[/itex].
    Gibbs-Duhem relation under the entropy and energy form respectively: [itex]\sum _j X_j dF_j=0[/itex], [itex]SdT+\sum _j X_j dP_j =0[/itex].

    3. The attempt at a solution
    I simply don't know what formula to use and how exactly. Here they don't give the pressure so this seems really hard to use any formula. I don't know if I can use the ideal gas relations [itex]PV=nRT[/itex] and [itex]U=KT+U_0[/itex], they don't say anything about the gases.
    I realize that V is constant.
    Any help on getting me started will be appreciated!
  2. jcsd
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