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Thermodynamics of Melting

  1. Nov 2, 2005 #1
    I am wondering about the enthalpies of solids and liquids near the melting temperature. I am familiar with free energy, and I know that above Tm, free energy of the solid becomes higher than liquid. However, we have been asked to think about the same question for enthalpy and draw a schematic. I was thinking that the enthalpy term should be related to intermolecular forces, so that it will always be higher for solids. Can anyone help me out with this? I don't know if it is a very simple question, but I am just a beginner.

    Thank you!
  2. jcsd
  3. Nov 2, 2005 #2


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    The idea is correct, but remember that bond formation releases energy (negative enthalpy change), while bond breaking requires energy (positive enthalpy change). This is why the solid phase has a lower enthalpy than the liquid phase.

    If it were the other way round (as you guessed), then melting would be exothermic - but that's not true.
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