## reversible and irreversible expansion

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

Stephanie tran 1J
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

### reversible and irreversible expansion

if a problem doesn't make it clear if reversible or irreversible expansion is occurring, how do you know which equation to use for work?

Varsha Sivaganesh 1A
Posts: 51
Joined: Thu Jul 13, 2017 3:00 am

### Re: reversible and irreversible expansion

If external pressure is constant then you can use the irreversible equation. In addition, the reversible equation is theoretical, so in most "real world" situations, I feel like it's more likely that we would have to use the irreverisble equation.

juchung7
Posts: 44
Joined: Fri Sep 29, 2017 7:05 am

### Re: reversible and irreversible expansion

Yes, I'm pretty sure for this course we used the equation for irreversible expansion W=P(delta)V.

Kristin Ishaya 1A
Posts: 30
Joined: Fri Sep 29, 2017 7:04 am

### Re: reversible and irreversible expansion

The equation for irreversible expansion is the one that is used more often and is more common. I'm pretty sure you'd only need to use the equation for reversible expansion if the pressure is not constant.