## Reversible vs. Irreversible

$\Delta U=q+w$

snehabhargava
Posts: 52
Joined: Thu Jul 13, 2017 3:00 am

### Reversible vs. Irreversible

What is the difference between reversible and irreversible expansion?

Ozhen Atoyan 1F
Posts: 50
Joined: Thu Jul 27, 2017 3:01 am
Been upvoted: 1 time

### Re: Reversible vs. Irreversible

One difference in terms of solving a problem is that you use two different equations for Reversible (w=-nrtln(Vf/Vi) and Irreversible (w=-PextdeltaV) expansion.

nathansalce 3e
Posts: 52
Joined: Thu Jul 27, 2017 3:01 am

### Re: Reversible vs. Irreversible

More specifically, what is their conceptual importance for this chapter? When are they significant and how should I be able to recognize the big differences in between them?

Nathan Tu 2C
Posts: 46
Joined: Fri Sep 29, 2017 7:07 am

### Re: Reversible vs. Irreversible

I think this is how it works. An irreversible expansion is essentially all real life expansions. The change in volume occurs so quickly that it is essentially instantaneous. In the case of an reversible expansion, the instantaneous change in volume dV, is essentially zero, I think but it might be a good idea to clarify. dV I think is zero because the expansion occurs so slowly as a result of the system constantly reaching equilibrium after every infinitely small change in volume. This allows reversible expansion to do more work than the irreversible expansion. As for being able to recognize the difference, I think you will be told whether it is reversible or irreversible. After all, reversible systems do not exist in real life. They are just theoretical concepts that describe the maximum amount of work possible done by expansion.