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1st law of thermodynamics, work/heat

  1. Oct 3, 2008 #1
    1. The problem statement, all variables and given/known data
    http://img404.imageshack.us/img404/1913/captureop6.jpg [Broken]

    2. Relevant equations
    adiabatic expansion: q = 0
    deltaU = w = Cv (T2-T1)
    reversible (ideal gas): P1V1 = P2V2
    gamma = Cp/Cv
    Cp - Cv = R

    3. The attempt at a solution
    V1 = nRT/P1
    V2 = nRT/P2
    Combine into w = -P2 (V2 - V1)

    This is where I got stuck.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Oct 3, 2008 #2
    Use the ideal gas law equation to find the temperatures first. Did you do this? What are the temperatures at states 1,2, and 3?
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