## 2011 Q1C heat capacity, residual entropy

Boltzmann Equation for Entropy: $S = k_{B} \ln W$

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### 2011 Q1C heat capacity, residual entropy

Can someone please explain these to me?
Thank you
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Niharika Reddy 1D
Posts: 127
Joined: Fri Sep 26, 2014 2:02 pm

### Re: 2011 Q1C

Heat capacity increases with molecular complexity. As more atoms are present in a molecule, there are more possible bond vibrations that can absorb added energy. In addition to having more atoms, ethane has a C-C single bond, which allows it to have rotational freedom, whereas ethene has a C-C double bond that makes it more rigid since double bonds don't allow rotation.

NO has 2 distinguishable microstates (NO and ON) whereas BF3 is indistinguishable when the fluorine atoms exchange places. Residual entropy indicates using S=kblnW, and the degeneracy (W) will be greater for NO than BF3, so the residual entropy of NO will be greater as well.

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