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Homework Help: Thermodynamics problem Help!

  1. Jun 20, 2009 #1
    1. The problem statement, all variables and given/known data
    Five moles of an ideal monotomic gas initially occupies a volume of 100 x 10-3m3 at a temperature of 280 K. (state 1)
    The gas is then subject to the following processes in sequence:
    * heated at constant volume to a temperature of 600K (state 2)
    * allowed to expand isothermally to its initial pressure (state 3)
    * compressed isobarically to its original volume (state 1)

    (a) Find the pressure and volume of the gas in state 3
    (b) Calculate the work done on the gas in going from state2 to state 3.
    (c) Calculate the heat exchanged between the gas and its environment during each of the 3 processes of the cycle 1->2, 2->3, 3->1.
    In each case, indicate whether the heat enters or leaves the gas.
    (d) Calculate the net work done on the gas in one cycle

    2. Relevant equations

    pVr=constant, r=Cp/Cv

    3. The attempt at a solution
    I'm stuck on question (a).
    I calculated the pressure using PV=nRT where the initial volume, temperature and number of moles of gas is provided. P=(5*8.314*280)/(100x10-3)
    Now, I dont know how to calculate the volume in state 3. Do I use T=600K and P=the above I calculated, to obtain the volume?
    Last edited: Jun 20, 2009
  2. jcsd
  3. Jun 20, 2009 #2


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    Gold Member

    You got it.
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