## Irreversible vs Reversible

isochoric/isometric:
isothermal:
isobaric:

Glendy Gonzalez 1A
Posts: 52
Joined: Fri Sep 29, 2017 7:07 am

### Irreversible vs Reversible

In simple terms, what is the difference between a reversible and irreversible expansion? How can you quickly identify them in a problem?

Ashin_Jose_1H
Posts: 51
Joined: Fri Sep 29, 2017 7:04 am

### Re: Irreversible vs Reversible

A reversible process is one that can be reversed by an infinitely small change. For example, assume we have a system where the External Pressure matches the pressure of a gas in the system. In this case, the piston won't move. If we increase or decrease the external pressure by an infinitely small number, the piston will start to move (slowly, but surely), because there is a change in pressure.

An Irreversible process is a process where an infinitely small change would not affect the direction of travel of the piston. For example, assume that the pressure of a system is 2.0 Atm and the External Pressure is 1.0 atm. This system is undergoing expansion. Increasing the external pressure by an infinitely small number does not change the system from an expansion to a compression. Therefore, the process is considered irreversible.

Mitch Mologne 1A
Posts: 74
Joined: Fri Sep 29, 2017 7:04 am

### Re: Irreversible vs Reversible

If the pressure is constant, you known the process is irreversible.

Anne 2L
Posts: 35
Joined: Fri Sep 29, 2017 7:05 am

### Re: Irreversible vs Reversible

Mitch Mologne 1A wrote:If the pressure is constant, you known the process is irreversible.

How would you know if a process is reversible though?