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### L.35

Posted: Sun Apr 08, 2018 10:39 pm
Sodium bromide, NaBr, which is used to produce AgBr for use in photographic lm, can itself be prepared as follows.
Fe + Br2 --> FeBr2
FeBr2 + Br2 --> Fe3Br8
Fe3Br8 + Na2CO3 --> NaBr + CO2 + Fe3O4
What mass of iron, in kilograms, is needed to produce 2.50 t of NaBr? Note that these equations must first be balanced!

- I was able to balance these equations but I was confused on how to book solved it. So in order to answer this question, we have to use two molar ratios? Can someone further explain please? Thank you!

### Re: L.35

Posted: Mon Apr 09, 2018 1:14 pm
First, we can figure out how many moles of NaBr we want from the mass of NaBr. If our final answer is mass of Fe, we will need the moles of Fe required. To get moles of Fe required from moles of NaBr needed, we have to use three ratios: moles of Fe3Br8 required for each mole of NaBr needed, then the moles of FeBr2 required per mole of Fe3Br8 required, then the moles of Fe required per mole of FeBr2 required.