## 9.27a

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

Mike Matthews 1D
Posts: 59
Joined: Fri Sep 29, 2017 7:04 am

### 9.27a

Homework 9.27a: Which substance has the higher molar entropy at 298K, HBr (g) or HF (g). Provided that both of these molecules have the same number of microstates, how does one determine the molar entropy difference between these two molecules?

Merzia Subhan 1L
Posts: 33
Joined: Thu Jul 13, 2017 3:00 am

### Re: 9.27a

I think it's because HBr(g) is larger than HF(g) so less compact and would therefore have a higher entropy. This may be wrong so if anyone has a different explanation, please share it.

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

### Re: 9.27a

More particles usually results in a higher entropy, which would explain why HBr (being the bigger molecule) has the higher entropy.

Riya Pathare 2E
Posts: 74
Joined: Sat Jul 22, 2017 3:01 am
Been upvoted: 1 time

### Re: 9.27a

Since HBr is a larger compound than HF it will have more electrons that will be able to occupy more states thus giving it a higher entropy.

Janine Chan 2K
Posts: 71
Joined: Fri Sep 29, 2017 7:04 am

### Re: 9.27a

In general, more complex molecules will have higher entropy. Since HBr is larger than HF, it is more complex, has more particles (and thus more possible states it can exist in), and higher entropy.