## 9.23

Boltzmann Equation for Entropy: $S = k_{B} \ln W$

Evelyn L 1H
Posts: 67
Joined: Fri Sep 29, 2017 7:05 am

### 9.23

I don't really understand the solutions manual's explanation about why COF2 has a higher molar entropy than BF3, could someone please explain it? I thought the molecule with the higher molar entropy is the one with the highest molar mass but the molar mass of BF3 is higher than COF2. What are the general rules in determining which molecule has the higher molar entropy?

sahajgill
Posts: 20
Joined: Fri Sep 29, 2017 7:06 am

### Re: 9.23

The positional disorder in COF2 is greater than in BF3 because BF3 can only be arranged in one way--with B as the central atom connected to 3 F atoms. However, COF2 can be arranged in three different ways, giving it a higher molar entropy than BF3 as can be seen through the equation S = k ln(W)

Deap Bhandal L1 S1J
Posts: 77
Joined: Fri Sep 29, 2017 7:05 am
Been upvoted: 2 times

### Re: 9.23

I attached the Lewis structure pictures and Sahaj Gill is right.
Attachments
Carbonyl-fluoride-2D.png (11.63 KiB) Viewed 387 times
boron_trifluoride_formula_1.png (3.71 KiB) Viewed 387 times

David Minasyan 1C
Posts: 54
Joined: Thu Jul 13, 2017 3:00 am

### Re: 9.23

Just to segue off this post, there's molar mass, the positional disorder and what other factors that determine a compound's entropy? And which should we look at first if we were to rank them?

Evelyn L 1H
Posts: 67
Joined: Fri Sep 29, 2017 7:05 am

### Re: 9.23

Is the lewis structure arrangements more important than the molar mass?

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