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Homework Help: Finding the amount of heat required to double volume?

  1. May 8, 2012 #1
    1. The problem statement, all variables and given/known data

    In an experiment, 1.35 mol of oxygen (02) are heated at constant pressure starting at 11.0°C. How much heat must be added to the gas to double its volume? You may assume without proof, that the molar specific heats are cp=7R/2 and cv=5R/2.

    2. Relevant equations

    3. The attempt at a solution

    My working so far...



    Q= 1.35(7R/2)(s-11) -----> where s= Tf

    But I need some equation linking change in volume to this....

    ie Q= -PΔV

    But I dont Know what P is?

    Perhaps I need something with ΔEint but im not to sure.
    I was thinking I will need to solve the first equation simultaneously with one with ΔV

    I'm stuck as to where to go from here??

    Please help any advice is greatly noted.
  2. jcsd
  3. May 8, 2012 #2
    Hint: Use the ideal gas law followed by a conservation of mass.
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