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### delta S

Posted: Wed Feb 13, 2019 10:51 am
under what conditions does delta S = 0

### Re: delta S

Posted: Wed Feb 13, 2019 10:57 am
Delta S (surroundings) is zero under free expansion; delta S (universe) is zero under reversible conditions and equilibrium; delta S (system) should be zero when there is no transfer of heat from and to the system and when the temperature and volume are constant in the system.

### Re: delta S

Posted: Wed Feb 13, 2019 11:02 am
Delta S of the system equals zero when there is no heat entering the system, because detla S = q(reversible)/T.

### Re: delta S

Posted: Wed Feb 13, 2019 11:24 am
For a system at equillibrium, the total delta s equals zero. For n irreversible expansion, given that there is no effect on the surroundings, delta s system equals delta s total.

### Re: delta S

Posted: Wed Feb 13, 2019 3:21 pm
Like the replies above, delta S of the universe, or when negative delta S of the system is equal to delta S of the surroundings, is 0 when the reaction is at equilibrium and is reversible. Also, delta U would be 0.

### Re: delta S

Posted: Sat Feb 16, 2019 9:55 pm
$\Delta S = 0$ when q=0, or in free expansion.

### Re: delta S

Posted: Tue Feb 19, 2019 12:38 pm
The change in entropy would be zero when the heat transferred into or out of the system is 0.

### Re: delta S

Posted: Tue Feb 26, 2019 4:34 pm
When volume is constant, changes in pressure/temperature result in a change in entropy