## Reversible processes

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

Anjali_U_3L
Posts: 16
Joined: Wed Sep 21, 2016 2:57 pm

### Reversible processes

On page 9 of the course reader, after the derivation of energy used as a work of expansion, it says "Since the system is at equilibrium, it is a reversible process." Does that mean all systems at equilibrium involve reversible processes? Why?

Pauline Tze 3B
Posts: 57
Joined: Sat Jul 09, 2016 3:00 am
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### Re: Reversible processes

All systems at equilibrium are reversible processes because any heat absorbed or work done on the system is canceled out by heat released or done by the system. This occurs such that infinitesimal changes in pressure do not increase entropy (because if entropy increases, it cannot be reversed according to the 2nd law of thermodynamics).

I hope that helps!