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Homework Help: The work of compression

  1. Feb 11, 2008 #1
    One mole of a van der Waals gas is compressed quasi-satically and isothermally from volume V1 to V2. For a van der Waals gas, the pressure is:
    p= RT/(V-b)-a/V^2
    where a and b are material constants, V is the volume and RT is the gas constant x temperature.

    For the first part of the problem I was supposed to write an expression for the work done. According to the equation ∂w=-pdV (where w=work, p=pressure, and V=volume) we can solve the equation for work by integrating the pressure equation from V1 to V2. Doing this, we get:
    w=RTln((V_1-b)/(V_2-b))+a(1/V_1 -1/V_2 )

    The second part of the question asks: Is more or less work required than for an ideal gas in the low-density limit? What about the high-density limit? Why?
    Basically, I don't understand what the second part of the question is asking. Any help would be much appreciated! Thanks.

    (Sorry, I tired to format the equations in Microsoft equation editor first so they'd look normal, but it didn't work.. I don't know how to do that on here :-/ )
  2. jcsd
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