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### Isothermal system

Posted: Wed Feb 14, 2018 2:26 pm
Why delta S of the surroundings 0 in an isothermal, free expansion process?

### Re: Isothermal system

Posted: Wed Feb 14, 2018 2:29 pm
Because the surroundings is basically a vacuum. The system is expanding but there is no heat transfer between the system and the surroundings so the surroundings basically remains unchanged.

### Re: Isothermal system

Posted: Wed Feb 14, 2018 2:42 pm
Work = 0 in free expansion because there is no external pressure applied, so P=0 and therefore w=0. Since ΔU = 0, that means that q=0 as well, so no heat is transferred into the surroundings.

### Re: Isothermal system

Posted: Mon Feb 19, 2018 3:08 pm
Hi Tiffany!

Because q=0 as there is no transfer of heat or change in temp (isothermal) there will be no change in entropy of the molecules.

### Re: Isothermal system

Posted: Tue Mar 06, 2018 8:11 am
Work = 0 in free expansion because there is no external pressure applied, so P=0 and therefore w=0. Since ΔU = 0, that means that q=0 as well, so no heat is transferred into the surroundings.

### Re: Isothermal system

Posted: Fri Mar 16, 2018 7:16 pm
The term free expansion implies work is = 0 and in that case q would also be zero as the deltaU value needs to remain 0