## Residual Entropy?

$\Delta S = \frac{q_{rev}}{T}$

aisteles1G
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Joined: Fri Sep 28, 2018 12:15 am

### Residual Entropy?

One of the examples in the 7th edition text book in chapter 4G gives an example of calculating entropy and they get 11.52 which they say is "reasonably close" to the given S=10.1, my question is what qualifies as being reasonably close for the two entropy values to determine if the molecules are randomly aligned or not? How big of a difference would there have to be between two values for it not to be considered 'reasonably close'? Thanks!

Chem_Mod
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### Re: Residual Entropy?

Great question.

There is no specific cut-off value that one can give. It will depend and vary from system to system. Certainly on the order of a couple of Joules per Kelvin is close as this is a small difference.

A difference of 1 kJ.K-1 would clearly not be close as this is a 1000 J difference per Kelvin.