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### Reversible vs. Irreversible

Posted: Sun Feb 10, 2019 5:08 pm
This may be a really simple answer, but can someone explain the fundamental different between reversible and irreversible processes? I don't have it in my notes anywhere and I'm getting caught up on it. Thanks!

### Re: Reversible vs. Irreversible

Posted: Sun Feb 10, 2019 5:25 pm
In a reversible process, the direction of the process can be "reversed" in incremental steps while irreversible processes can't be reversed and don't occur in discrete steps. Reversible expansion does more work while irreversible expansion does work against constant pressure.

### Re: Reversible vs. Irreversible

Posted: Sun Feb 10, 2019 6:00 pm
For irreversible expansion against a constant external pressure, you use the equation w= -PΔV.
Temperature is not constant along the pathway in this case.

For reversible expansion of an ideal gas you use the equation w= -nRTln(V2/V1)
Temperature would be constant along the pathway in this case.
If the process is isothermal, E/ ΔU= 0 (enthalpy and change in internal energy)
So, w=-q