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Homework Help: Change in internal energy of a gas

  1. Nov 30, 2008 #1
    1. The problem statement, all variables and given/known data
    Two moles of carbon monoxide (CO) start at a pressure of 1.2 atm and a volume of 30 liters. The gas is then compressed adiabatically to 1/3 this volume. Assume that the gas may be treated as ideal.

    What is the change in the internal energy of the gas?

    n = 1.2 atm
    V2 = 10L
    V1 = 30L
    Cp = 29.16 J/(mol * K)

    2. Relevant equations
    Q = dU + W

    3. The attempt at a solution
    dU = dQ - dW
    dU = nCpdT - pdV

    dT is not known, and I can't go any further.
  2. jcsd
  3. Nov 30, 2008 #2
    You can find [tex]T_1[/tex] using PV = nRT. You can then use the adiabatic equation [tex]TV^{\gamma}= constant [/tex] to find [tex]T_2[/tex]
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