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Homework Help: Help please. I dont understand

  1. Jan 3, 2012 #1
    1. The problem statement, all variables and given/known data

    The estimated average concentration of carbon monoxide in air in the United States in 1991 was 6.0 ppm. Calculate the number of CO molecules in 1.0 L of this air at a pressure of 601 torr and a temperature of 20.°C.

    2. Relevant equations


    3. The attempt at a solutionI tried this and using pv=nrt
    pressure was converted to torr
    volume was 1
    r was taken as 8.31
    temp was converted into K
    and then...
    n was solved for, and muktiplied by avagadro's number
    Am i missing something? am i supposed to include the ppm?
    i am so confused.
    please help.
  2. jcsd
  3. Jan 4, 2012 #2


    User Avatar

    Staff: Mentor

    ppm is a concentration, so yes, it should be included in your calculations - otherwise you calculated just the number of molecules of all gases in the given volume.

    Unfortunately, question is ambiguous - it doesn't state whether ppm is weight/weight or volume/volume.
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