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Homework Help: What is the partial pressure of the NH3

  1. Apr 3, 2007 #1
    1. The problem statement, all variables and given/known data
    The combined pressure of 32.0 g of CH4, 64.2 g NH3, and 100 g of CO2 is 9.42 atm. What is the partial pressure of the NH3

    2. Relevant equations
    Dalton's Law of Partial Pressure = P=Pa +Pb + Pc ...
    The individual partial pressure follow the ideal gas law. For component A, (Pa)V=(nA)RT where nA is the number of oles in component A

    3. The attempt at a solution
    I have converted all the grams to moles by dividing the grams by the compounds molar mass. I have no idea what to do from there. Someone please help.
  2. jcsd
  3. Apr 3, 2007 #2
    Partial pressure of any gas is its molefraction * total pressure.
    so, for your problem it is

    [itex]\frac{n_{NH_3}}{n_{total}}.(9.42) [/itex]
  4. Apr 3, 2007 #3
    So, I would take the moles of NH3 and divide that by the total number of moles (moles of NH3, CH4, and CO2). Than multiply that by the total pressure. Is that correct?
  5. Apr 3, 2007 #4
    yes thats it
  6. Apr 3, 2007 #5
    Thanks for the assistance
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