## Reversible and Isobaric

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

Jielena_Bragasin2G
Posts: 104
Joined: Sat Aug 24, 2019 12:18 am
Been upvoted: 1 time

### Reversible and Isobaric

Can I assume that an isobaric expansion is irreversible since the equation for irreversible expansion is Next*deltaV ?

Joseph Saba
Posts: 154
Joined: Thu Jul 11, 2019 12:16 am

### Re: Reversible and Isobaric

I would only do the calculation for irreversible reactions if the problem says specifically.

ALegala_2I
Posts: 102
Joined: Thu Jul 11, 2019 12:17 am

### Re: Reversible and Isobaric

The irreversible equation is only used when pressure is constant. If pressure is changing, then you use the reversible equation.

Morgan Carrington 2H
Posts: 54
Joined: Wed Nov 14, 2018 12:22 am

### Re: Reversible and Isobaric

I believe that isobaric means constant pressure and in order for that equation to be used, the external pressure has to be held constant. I would be cautious using this though unless it specifically said that the process was irreversible or reversible.

CameronDis2K
Posts: 51
Joined: Wed Feb 20, 2019 12:18 am

### Re: Reversible and Isobaric

Isobaric means that deltaP = 0, but doesn't say if the process is reversible or irreversible. Therefore, the only assumption one can make is that U = detaH - pdeltaV (as there is only one P value to plug in, usually external pressure).