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Homework Help: Physics degrees of freedom problem

  1. May 27, 2005 #1
    A 1.12 mol sample of an ideal diatomic gas at a pressure of 1.00 atm and temperature of 491 K undergoes a process in which its pressure increases linearly with temperature. The final temperature and pressure are 735 K and 1.39 atm. Assume 5 active degrees of freedom.

    Neither pressure nor volume nor temp are constant, so I'm confused to how I'm supposed to find work or q.
  2. jcsd
  3. May 27, 2005 #2
    Have you seen this formula before?

    [tex]\Delta Q = \Delta U \pm W[/tex], the [tex]\pm[/tex] is there depending on how you define when is work positive. If I recall correctly [itex]U = \frac {q}{2} n R T[/itex] where [itex]q[/itex] is the numbers of degree of freedom.
  4. May 27, 2005 #3


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    A couple of things you need to key on. What is the connection between degrees of freedom and heat capacity? And what can you do with the fact that the P vs T curve is linear?
  5. May 27, 2005 #4
    I assume I could graph P vs V and find work, but that seems like more work then should be neccesary. I can find the change in U, or overall energy of the system, the only problem I'm having is with work, which should give me heat since I know U.
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