## Question L35

Annie Ye
Posts: 106
Joined: Wed Sep 18, 2019 12:22 am

### Question L35

Sodium bromide, NaBr, which is used to produce AgBr for
use in photographic film, can itself be prepared as follows:
Fe 1 Br2 ¡ FeBr2
FeBr2 1 Br2 ¡ Fe3Br8
FeBr2 1 Na2CO3 ¡ NaBr 1 CO2 1 Fe3O4
What mass of iron, in kilograms, is needed to produce 2.50 t of
NaBr?

How would I balance the last chemical equation?

Sion Hwang 4D
Posts: 51
Joined: Wed Sep 18, 2019 12:21 am

### Re: Question L35

I believe you wrote the final equation wrong. It is supposed to be
Fe3Br8 + Na2CO3 --> NaBr + CO2 + Fe3O4.
With this equation, the Fe's are already balanced on both sides. Thus, you would seek to balance the Br, multiplying NaBr by 8. You will get:
Fe3Br8 + Na2CO3 --> 8NaBr + CO2 + Fe3O4.
Now, you must balance the Na's on both sides, so you multiply Na2CO3 by 4 to match the 8 Na's on the product side.
Fe3Br8 + 4Na2CO3 --> 8NaBr + CO2 + Fe3O4.
Then, balance out the C's (there are 4 on the reactants side and 1 on the product, so multiply CO2 by 8).
Fe3Br8 + 4Na2CO3 --> 8NaBr + 4CO2 + Fe3O4.
The O's balance out, so the final balanced equation is:
Fe3Br8 + 4Na2CO3 --> 8NaBr + 4CO2 + Fe3O4.

Gabriella Bates 2L
Posts: 95
Joined: Thu Jul 11, 2019 12:15 am

### Re: Question L35

I believe that the textbook made an error. The third equation should be written with Fe3Br8 instead of FeBr2. This can then be balanced as explained above.