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Homework Help: Say there is a vessel with constant volume

  1. Nov 9, 2013 #1
    Say there is a vessel with constant volume. We know the EOS, moles and Cp of the vapor in it. How can we design an experiment to measure the (dS/dP) at constant V?

    I think the idea is to transform (dS/dP)v into something that consists of Cp, V,P,T only. Then we can measure the small difference in T or P to substitute into equation and get (dS/dP)v.

    But how? Anyone has an opinion?

    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Nov 9, 2013 #2

    Simon Bridge

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    Science Advisor
    Homework Helper

    Welcome to PF;
    Directly: dS/dP is the slope of the S vs P graph isn't it?

    Well, you could find a way to vary the pressure and measure the entropy - plot S vs P and take the slope.
    How you do that, and cope with the complications, determines the experiment.
  4. Nov 9, 2013 #3
    Start with the equation for dH expressed in terms of dT and dP, and set this equal to TdS + VdP. Then eliminate VdP from both sides, and you will see what to do next.
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