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Homework Help: How to determine exact differentials

  1. Feb 18, 2013 #1
    1. The problem statement, all variables and given/known data

    See thumbnail

    2. Relevant equations

    3. The attempt at a solution

    I'm not having trouble with the first part, just having trouble understanding why dQ is not exact but dS=dQ/T is. At first I was thinking that it had to do with the V in the dT part of the dQ equation because the single V does not account for changes in V, but this part still exists in the entropy equation. Please help me conceptualize what it means to be an exact differential.

    Attached Files:

  2. jcsd
  3. Feb 19, 2013 #2


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    Homework Helper

    hi relativespeak! :smile:
    the book is a little misleading :frown:

    it means that, as a function of V and T, dQ is not an exact differential, but dQ/T is

    of course, if we ignore V ant T, dQ is an exact differential … of Q !! :biggrin:
  4. Feb 19, 2013 #3
    What is the differential of a two-variable function?
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