## 9.33

$\Delta S = \frac{q_{rev}}{T}$

Virpal Gill 1B
Posts: 32
Joined: Thu Jul 27, 2017 3:00 am

### 9.33

The question asks if the entropy of the process increases or decreases: SO2(g) + Br2(g) + 2 H2O(l) --> H2SO4(aq) + 2 HBr(aq). The solutions manual states that entropy should decrease as the total number of moles decreases. Do they mean the moles of gas or is it a rule that if the total moles decrease then entropy decreases?

Audrey Goodman 1F
Posts: 31
Joined: Fri Sep 29, 2017 7:06 am

### Re: 9.33

If the moles of gas decreases from reactants to products, then the entropy decreases, which is why we can say entropy decreases for this reaction. However, I'm not sure that if the moles overall decreases that we can assume the entropy decreases.