Hydrobromic acid dissolves solid iron according to the following reaction:
Fe(s) + 2 HBr(aq) → FeBr2(aq) + H2(9)

Part A
What mass of HBr (in g) would you need to dissolve a 3.2 - g pure iron
Express your answer using two significant figures.

Part B
What mass of H, would be produced by the complete reaction of the iron

A. 9.3 g

B. 0.11 g

Explanation:

PART A

First we convert 3.2 grams of pure iron into moles, using its molar mass:

Now we convert 0.0573 moles of Fe into moles of HBr, using the stoichiometric coefficients:

Finally we convert 0.115 moles of HBr into grams, using its molar mass:

PART B

This time we convert the 0.0573 moles of Fe from last time into H₂ moles:

Finally we convert H₂ moles into grams:

a is the correct answer

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