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Homework Help: Heat question

  1. Feb 3, 2012 #1
    A quartz tube contains one mom of gAs at 20 deg c. The gas is heated at constant volume to 300 deg c. How much thermal energy is transferred to the gas? If the same amount were heated at constant pressure, how muh energy would be required?

    I know how to solve this for constant volume using E= 3/2 nRT to get 3490.2 j but I don't know what difference constant pressure makes???
  2. jcsd
  3. Feb 3, 2012 #2

    I like Serena

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    Homework Helper

    Welcome to PF, calculusisrad! :smile:

    In the formula E= 3/2 nRT you are using that the heat capacity at constant volume of an ideal monatomic gas is Cv = 3/2 nR.
    The heat capacity at constant pressure of an ideal monatomic gas is Cp = 5/2 nR.

    Btw, you did not mention the type of gas, but is it perhaps one of the noble gasses?
    Because that's basically what you need for that formula to hold.
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