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Specific Heat: Bond or Freedom of Degree Based, Or Size?

  1. Aug 12, 2012 #1
    Specific Heat: Bond or Freedom of Degree Based, Or Size??

    Okay so Ive been trying to understand what causes one substance to have a higher specific heat then other but Ive read quite a few conflicting sources in which one says its due to the freedom of degree, while another says the weight of the atom, and then another says its due to the strength of the bonds. For example both ammonia in a solution (NH4+) and water have hydrogen bonding and both have high specific heats, but then they are both larger yet light polyatomic molecules.

    So if anyone could shed some light and help me get my head around this, it would be much appreciated. Thanks Heaps :)
  2. jcsd
  3. Aug 12, 2012 #2


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    Re: Specific Heat: Bond or Freedom of Degree Based, Or Size??

    More degrees of freedom per atom => higher specific heat
    More atoms per mass (lighter atoms) => higher specific heat (expressed in J/(K*kg))
    The strength of the bonds can influence the available degrees of freedom. For example, you cannot excite vibrations in N2 molecules at room temperature (in significant amounts), the required energy is too high. With other molecules, it can be possible to excite them.
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