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Simple (Frustrating) Combined Gas Law Problem

  1. Nov 9, 2008 #1
    1. The problem statement, all variables and given/known data

    If 562L of a gas is prepared at 700 torr and 213 degrees C, and it is then pumped into a 25.3L tank at 35 degrees C, what pressure will the tank have to withstand?

    2. Relevant equations




    3. The attempt at a solution

    This is pretty straight forward. That's why I'm getting so frustrated. I just plug and play and I should get the right answer.

    [tex]\frac{35degC}{213degC}*\frac{562L}{25.3L}*700torr=~2600torr or 3.421 atm[/tex]

    According to my professor, the answer is supposed to be 13atm or 9880torr.

    I just don't understand how this approach is not working since I am only missing one variable. It seems perfect for the combined gas law. Thank you for your time.


    P.S. Sorry about the botched latex attempt. I tried :)
  2. jcsd
  3. Nov 9, 2008 #2


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    Homework Helper

    Hi DDNow,

    The Celsius temperature scale is not a thermodynamic temperature scale, and so cannot be used here. Try converting your temperatures to the Kelvin scale.
  4. Nov 9, 2008 #3
    Hey! Thank you for that. Worked perfectly. I assumed since it was a temperature divided by a temperature that the ratio would be the same for C or K. Obviously, I was wrong. I really appreciate your time alphysicist!

    Edit: I'm not sure if I need to mark this as resolved or whatnot. If someone wants to tell me if there is another step I would appreciate it.
    Last edited: Nov 9, 2008
  5. Nov 9, 2008 #4


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    Homework Helper

    Sure, glad to help! As far as C or K, temperature differences are the same for both scales, but as you found the ratios are different.

    There used to be a way to mark the threads as solved, but I don't believe that function is available right now.
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