Residual Molar Entropy?

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Sophia Bozone 2G
Posts: 51
Joined: Fri Sep 29, 2017 7:07 am

Residual Molar Entropy?

Postby Sophia Bozone 2G » Fri Feb 02, 2018 8:39 pm

Question 9.25 asks about the residual molar entropy of a disordered crystal, and I'm not quite sure what it's asking or how to go about answering the problem.

Jessica Yang 1J
Posts: 55
Joined: Fri Sep 29, 2017 7:03 am

Re: Residual Molar Entropy?

Postby Jessica Yang 1J » Fri Feb 02, 2018 9:49 pm

Residual molar entropy is the entropy that still exists due to positional disorder at T=0, because at T=0, there should hypothetically be no entropy if the molecule is a crystal, as seen by the third law of thermodynamics.

I drew the different orientations of SO2F2, with S being the central atom because it is the least electronegative and positioned the surrounding four atoms in different ways around it to find the number of different microstates, which is W.

Kaelie Blanes-Ronda 2L
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Re: Residual Molar Entropy?

Postby Kaelie Blanes-Ronda 2L » Fri Feb 02, 2018 9:57 pm

There are 6 different possible configurations for SO2F2 so the degeneracy (W) is equal to 6.
So all you have to do is make S=kln[6^(6.02x10^-23)] with k being Boltzmann's constant.

andrewr2H
Posts: 29
Joined: Fri Sep 29, 2017 7:05 am

Re: Residual Molar Entropy?

Postby andrewr2H » Fri Feb 02, 2018 11:06 pm

Residual entropy refers to the entropy that exists at T = 0 K. Residual entropy results from the different micro states that exist because of the different orientations a molecule may have.


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