## (Typo??) HW L.35 - 7th edition

Henri_de_Guzman_3L
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

### (Typo??) HW L.35 - 7th edition

Hi, so I was very stuck on the balancing part of this equation. I googled the answer and found links from Prof. Lavelle's chemistry community and I think there might be typo in my book.

So my book asks the following question for L.35

"Sodium bromide, NaBr, which is used to produce AgBr for use in photographic film, can itself be prepared as follows:
Fe + Br2 -> FeBr2
FeBr2 + Br2 -> Fe3Br8
FeBr2 + Na2CO3 -> NaBr + CO2 + Fe3O4
What mass of iron, in kilograms is need to produce 2.50 t of NaBr? Note that these equations must first be balanced!"

I can not balance the third equation! I googled the question and found these:
viewtopic.php?t=5641
viewtopic.php?t=30529
viewtopic.php?t=21857
viewtopic.php?t=21811

All of them have Fe3Br8 instead of FeBr2 for the third equation!!!!
Using Fe3Br8 instead of FeBr2 I was able to balance the equation and get the right answer (which is even the answer given at the back of my textbook).
So do I have a typo or...?

KylieY_3B
Posts: 31
Joined: Fri Sep 28, 2018 12:24 am

### Re: (Typo??) HW L.35 - 7th edition

I have the 6th edition and it's Fe3Br8 for me. It's probably a typo.

Ashish Verma 2I
Posts: 59
Joined: Fri Sep 28, 2018 12:28 am

### Re: (Typo??) HW L.35 - 7th edition

I have the seventh edition book and solutions manual and I had the exact same issue as you. My third equation in the book is also listed as $FeBr_2+Na_2CO_3->NaBr+CO_2+Fe_3O_4$
But since the solutions manual uses $Fe_3Br_8$ I'm assuming that's a typo like you said and just using that as the first reactant for the third equation instead.
I feel like that being a typo makes a lot more sense, since otherwise the equation doesn't balance and the second equation is essentially rendered useless. I don't think they'd include an extraneous equation that has nothing to do with the problem so yeah I think that has to be a typo based on the solutions manual and since that second equation has to somehow be relevant to the problem, otherwise it wouldn't have been printed.

Henri_de_Guzman_3L
Posts: 88
Joined: Fri Sep 28, 2018 12:25 am

### Re: (Typo??) HW L.35 - 7th edition

Thank you, I figured it's a total typo because otherwise it's impossible. I recommend to those with the same problem to just use Fe3Br8 as Ashish said.