## delta(S) total

$\Delta U=q+w$

Lina Petrossian 1D
Posts: 77
Joined: Fri Oct 05, 2018 12:16 am

### delta(S) total

Under what circumstances does delta(S)tot = delta(S)sys + delta(S)surr = 0. And under what circumstances does delta(U) = q + w = 0.

Posts: 37
Joined: Fri Sep 28, 2018 12:22 am
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### Re: delta(S) total

Delta S system + delta S surroundings = 0 at equilibrium

makenzie2K
Posts: 31
Joined: Fri Sep 28, 2018 12:20 am

### Re: delta(S) total

As mentioned above, change in entropy = 0 occurs at equilibrium and also when the degeneracy state (W) value = 1 meaning each particle only has one possible state. No matter how many particles there are in the system, if they can only occupy one position the entropy = 0. An example of this would be a perfect crystal.