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Partial Pressure from Kp

  1. Feb 13, 2012 #1
    1. The problem statement, all variables and given/known data
    at 1000K, Kp=1.2*10^6 and Delta H = -101.7 kJ for the reaction H2(g)+ Br2(g) <-->2HBr.

    A 0.952 mol quantity of Br2 is added to a 1.00L reaction vessel that contains 1.25 mol of H2 gas at 1000K . What are the partial pressures of H2 ,Br2 ,HBr and at equilibrium?


    2. Relevant equations
    PV=nRT
    Kc=Kp(RT)^n
    Kc=products over reactants reased to power of stoichiometric coefficients

    3. The attempt at a solution
    P=nRT/v
    Pi(H2)=(1.25)(.08206)(1000)=78.121
    Pi(Br2)=(.952)(.08206)(1000)=102.575

    2.1*10^6=((2x)^2)/(78.121-x)(102.575-x))

    x=78.121

    Pf(H2)=102.575-x=25.45
    Pf(Br2)=78.121-x=0
    Pf(HBr2)=2x=156.24

    Mastering Chemistry rejected
     
  2. jcsd
  3. Feb 14, 2012 #2

    Borek

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    Staff: Mentor

    I just skimmed so it is possible I missed something, but at first sight nothing cries "wrong!", apart from the significant digits in the final answer.

    I wonder why they give delta H? It is not clear if the final temperature is still 1000K.
     
  4. Feb 14, 2012 #3
    It ends up they wanted
    Pf(H2) as 24.5
    Pf(Br2) as 4.75*10^-4
    Pf(HBr) as 156
     
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