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Homework Help: Thermodynamics - monotomic/diatomig gas heat capacity question

  1. Mar 27, 2013 #1
    Thermodynamics -- monotomic/diatomig gas heat capacity question

    1. The problem statement, all variables and given/known data

    GRADE 12 CHEMISTRY: Why would a monotomic gas like Helium require less heat than a diatomic gas like hydrogen to undergo the same temperature increase?

    2. Relevant equations


    3. The attempt at a solution

    I think it has something to do with bonds and rotational/translational/vibrational energy of molecules but don't know exactly help

    Thank you everyone!
  2. jcsd
  3. Mar 28, 2013 #2
    Hello p.ella,

    The answer to your question maybe twofold.

    First ask yourself this: How do the CP and CV values of helium compare with other gases?

    Secondly, What kind of inter-molecular forces act between helium molecules? How do they compare with other gases?
  4. Mar 28, 2013 #3


    User Avatar

    Staff: Mentor

    Sorry Sunil, but I don't think that intermolecular forces are the right way to go.

    p.ella, have you heard of the equipartition theorem?
  5. Mar 28, 2013 #4
    Thanks anways Sunil :)

    And no, I haven't, not yet atleast :)
  6. Mar 28, 2013 #5


    User Avatar

    Staff: Mentor

    That makes things a bit more difficult, but lets try it this way.

    When heat is put into a monatomic gas, what changes?

    If you have a diatomic molecule instead, what more can happen (in addition to what you just answered for the monatomic gas)?
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