## Diagram of Reversible Expansion

$w=-P\Delta V$
and
$w=-\int_{V_{1}}^{V_{2}}PdV=-nRTln\frac{V_{2}}{V_{1}}$

Julia Ward 2C
Posts: 27
Joined: Wed Nov 16, 2016 3:03 am

### Diagram of Reversible Expansion

On the diagram of isothermal reversible expansion from lecture on Wednesday (1/24/18) it said that one side of the piston had an ideal gas, and one side was a vacuum. What exactly is a vacuum (and what does it entail/mean in the diagram)?

Lourick Bustamante 1B
Posts: 50
Joined: Wed Nov 16, 2016 3:02 am

### Re: Diagram of Reversible Expansion

A vacuum is a volume that encloses little or no matter. In other words, it is a region that has a gaseous pressure much lower than that of atmospheric pressure---so that's what it represents in the system with the ideal gas that we were shown in class!

mayapartha_1D
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

### Re: Diagram of Reversible Expansion

A vacuum is a space that has no matter! For example, space is a vacuum because nothing can exist in that space. Because its pressure is lower, work will probably be done on that part of the system!

Amelia Georgius 1K
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### Re: Diagram of Reversible Expansion

A vacuum is a space that does not have any matter in it, not even air. Space is a vacuum