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Temperature & Pressure. Beginner Physics.

  1. Feb 22, 2009 #1
    1. The problem statement, all variables and given/known data
    A rigid, perfectly insulated container has a membrane dividing its volume in half. One side contains a gas at an absolute temperature To and pressure Po, while the other half is completely empty. Suddenly a small hole develops in the membrane, allowing the gas to leak out into the other half until it eventually occupies twice its original volume. In terms of To and Po, what will be the new temperature and pressure of the gas when it is distributed equally in both halves of the container?

    2. Relevant equations

    3. The attempt at a solution
    I have no idea how to explain this answer. I don't know how to approach this. Please help.
  2. jcsd
  3. Feb 22, 2009 #2
    The box has a definite volume of V and a definite amount of mass inside (n). If the gas starts off with a volume of V, Pressure of Po, Temp of To, and mass of n, use the Ideal Gas Law to solve for a change in volume and respective pressure/temperature changes.

    PV=nRT where R is the ideal gas constant.

    Case 1, Po*V=n*R*To
    Case 2 P2*V2=n*R*T2


    Since V2=2*V then P2/T2=0.5(nR)/V or the ratio of the pressure to the temperature of the final volume of gas will be half that of the original. P2/T2=.5*Po/To
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