Residual Entropy

[Maaria Abdel-Moneim 2G]

When a problem asks to calculate the residual entropy that means to just use the equation S=kB*lnW, correct?

[Lilyana Villa 3L]

Yes, you are correct! If it says positional entropy, know that's just another way of saying residual entropy and you would still use that equation.

[Pranav Kadiyala 1A]

Yes, and W is the degeneracy, calculated O^n, where O is the number of energy states and n is the number of particles occupying these energy states.

[Jenny Lee 2L]

In addition, residual entropy or positional entropy, ignores thermal energy (thus why we assume that T--> 0K although cannot be true in reality, because then nothing would be moving and we would only be looking at the places/positions substances could be in). This could be another way to recognize that residual entropy is just using S=kBlnW because it only relates entropy with degeneracy (# possible states)^(# particles).

[LeanneBagood_2F]

can someone remind me what residual entropy is please?

[Sabrina Galvan 3J]

can someone remind me what residual entropy is please?

Residual entropy is the entropy that remains present when a system has reached 0 Kelvins, and the entropy itself comes from the different positions molecules and atoms can have within a substance.

[Sharon Kim 2A]

correct, you will be using that equation and ignore thermal disorder. usually residual entropy would be associated with more complex molecules.

[Madison Muggeo 3H]

Yep! You would be using that equation. In this class, we usually ignore thermal disorder, as that would make our calculations more complicated. Hope this helps!

[Norah Gidanian 3D]

Yes! residual entropy is that equation.