## Reversible Expansions

Nicole Nikolov 1K
Posts: 50
Joined: Fri Sep 29, 2017 7:05 am

### Reversible Expansions

I understand that the work a system can do is greatest in a reversible process. For example, if you look at a PV diagram you can see that the area under a curve is greatest for a reversible process. However, I am having trouble understanding it from more of a mathematical viewpoint. Can someone please explain why this is so in a more quantitative way? Thanks.

704887365
Posts: 49
Joined: Sat Jul 22, 2017 3:00 am

### Re: Reversible Expansions

I’m not sure how to explain it quantitatively but work done reversibly does not lose as much heat energy (due to friction and other unwanted processes)

Michael Downs 1L
Posts: 29
Joined: Thu Jul 13, 2017 3:00 am

### Re: Reversible Expansions

^

melissa carey 1f
Posts: 53
Joined: Fri Sep 29, 2017 7:06 am

### Re: Reversible Expansions

In a TA review session he explained that when you have a rev process you are extracting the max work bc you are making such small changes that you can appoximate P-internal = P-external at every instant. PV=nRT. P=nRT/v. substitute w=-nRT/V and integrate w respect to V. this is where you get w = -nRTln(Vf/Vi).
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