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Homework Help: Total derivative

  1. Jul 31, 2011 #1
    Hi everyone
    1. The problem statement, all variables and given/known data

    Let's say I want to do the totale drivative of the Gibbs free energy in dependent of: volume, temperature, amount of substance and surface. And let's say afterwards we have a closed system where the temperature is constant. How does the total derivative change?

    2. Relevant equations

    3. The attempt at a solution

    I guess I know that the amount of substance doesn't change in a closed system, so my dn=0 and this part gets lost, also dT=0. But I'm not sure about the surface, does that change aswell? I think the Volume can't be disregarded.

    Thanks for your help
  2. jcsd
  3. Aug 1, 2011 #2


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    Science Advisor

    If all you are given is that the temperature is constant, I would see no reason to assume that volume or "surface" are constant.

    (What, exactly, do you mean by "surface"? All other variables you mention are numbers.)
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