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Homework Help: I don't understand this Vapor Concept problem?

  1. Oct 11, 2012 #1
    1. The problem statement, all variables and given/known data

    If oxygen gas occupies 25mL at -25 'C and 65 mm Hg.
    What is the volume at 25 'C and 350 mmHg?

    2. Relevant equations


    3. The attempt at a solution
    I am really not sure how to do this :(
    I think maybe I figured it out. Please see below!
    Last edited: Oct 11, 2012
  2. jcsd
  3. Oct 11, 2012 #2
    I don't understand P1+P2+P3=Ptotal.

    The volume of a gas changes, depending on pressure and temperature. Do you know a law that describes this? (It is a law that describes an ideal gas)
  4. Oct 11, 2012 #3
    The ideal gas law equation

    Ok I think I might have the answer this is what I cam up with but Im not sure.....
    Here it is:

    25mL/248K = X/298K

    Which equals 30.04mL (I still don't believe this is right)
    Last edited: Oct 11, 2012
  5. Oct 11, 2012 #4


    User Avatar

    Staff: Mentor

    It has nothing to do with the ideal gas equation. If anything, it looks like Dalton's law.

    Correct approach, but you need to hone your calculator skills.
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