## Entropy of Surroundings vs Entropy of Systems

Volume: $\Delta S = nR\ln \frac{V_{2}}{V_{1}}$
Temperature: $\Delta S = nC\ln \frac{T_{2}}{T_{1}}$

805329408
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### Entropy of Surroundings vs Entropy of Systems

For reversible reactions, the delta s system is always equivalent to negative delta s surroundings which is equal to delta s system. However, for irreversible reactions, is delta s surroundings always equal to 0? Why? Thanks in advance!

jisulee1C
Posts: 149
Joined: Thu Jul 25, 2019 12:17 am

### Re: Entropy of Surroundings vs Entropy of Systems

In a reversible reaction there is a change of entropy and because it is isothermal delta U will be zero. However, in an irreversible reaction there is no work done because only free expansion occurs. Therefore since w = 0 and delta U = 0 the q = 0 so the q of surroundings =0 and delta S of the surroundings = 0. There's a section in the textbook that explains this concept more into detail (4I.2 example 4I.3).