## Free expansion and irreversible expansion

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

Sue Xu 2K
Posts: 58
Joined: Fri Sep 29, 2017 7:06 am

### Free expansion and irreversible expansion

Is the term "free expansion" the same as irreversible expansion?

Mitch Walters
Posts: 45
Joined: Fri Sep 29, 2017 7:07 am

### Re: Free expansion and irreversible expansion

I believe free expansion is when there is no opposing pressure on a system, so it is allowed to expand without doing any work. Irreversible expansion is what allows for the maximum amount of work.

Jenny Cheng 2K
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### Re: Free expansion and irreversible expansion

No work is done in free expansion; an example of free expansion is a gas pushing against a piston and into a vacuum. Free expansion is an irreversible process, but it is not the same as irreversible expansion. For an irreversible expansion, P(external) does not equal P(internal).
Reversible expansion allows for the maximum amount of work to be done because P(external) equals P(internal).