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Homework Help: Entropy Question

  1. Jul 20, 2004 #1
    Hi, this is my first time using this forum. I have a question dealing with entropy and thermodynamics.

    Here goes:

    According to Debye’s law, the molar heat capacity at constant volume of a
    diamond varies with temperature according to the relation

    Cv = (12*pi^4*R / 5) x (T / TD)^3

    where TD = 2230 K. For a diamond of mass 1. 20 g, what is its entropy change when it is heatedat constant volume from 10. 0 K to 350 K? The molar mass of carbon is 12. 0 g/mol.

    I know Ih ave to first find the molar mass, but I am not sure of which form of the entropy equation to use. Any help is appreciated.
  2. jcsd
  3. Jul 20, 2004 #2
    To solve the problem you can use this equation to find the molar entropy

    [tex]\Delta S = \int_{T_1}^{T_2} C_v \frac{dT}{T}[/tex]

    Multiply this result by the numer of moles (1.2/12) to get entropy in terms of energy/time.
  4. Jul 21, 2004 #3
    Thanks a lot....imma try this.
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