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Homework Help: Thermodynamics problem

  1. Aug 17, 2008 #1
    1. The problem statement, all variables and given/known data
    An Open container of volume V contains an ideal gas having molar mass M. If the temperature of the container is raised from T1 to T2, what mass of the gas will leave the container ? Assume that the gas pressure in the container is maintained at P.

    2. Relevant equations

    3. The attempt at a solution

    I tried but failed. could anyone help me get the solution.
  2. jcsd
  3. Aug 17, 2008 #2


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    Homework Helper
    Gold Member

    You have to show your work in order to get help here. What have you tried? I can't find you mistake without seeing your work.
  4. Aug 17, 2008 #3
    I had this exact question on my thermal physics paper, not sure if I got it right though.

    As it is, I am currently redoing the paper so ive attempted this too.

    From PV = nRT

    n = m/M, where m is mass of substance, and M is molar mass.

    so PV = (m/M)RT

    rearrange: m = PVM/RT.
    That'll be the mass of the gas inside the container, I believe.

    Not sure about the rest of it though, im sure there's stuff to do with V1/T1 = V2/T2, and ive had a play around with them but im not sure about a final answer.
  5. Aug 28, 2008 #4
    Simply use the fact that because p,v are constant and pv=nrt,nt is constant,calculate initial moles from pv=nrt(p,v,t given,r is known).then calculate final no. of moles(again everything is given,(n1-n2)*M is the mass of the gas that left.
    If you dont get the answer by this,then the question is wrong or the answer given in the book is wrong.....
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