Stoich help?!?

Question

If steel wool (iron) is heated until it glows and is placed in a bottle containing pure oxygen, the iron reacts spectacularly to produce iron(III) oxide.
Fe(s) + O2(g) Fe2O3(s)

If 1.15 g of iron is heated and placed in a bottle containing 0.0211 mol of oxygen gas, what mass of iron(III) oxide is produced?

Answer 1

The reaction is 4 Fe + 3 O2 ---> 2 Fe2O3

1.15 g of Fe is 0.0205 moles of iron. Given the 4:3 ratio, and having 0.0211 moles of O2, your limiting reactant is the iron.

0.0205 moles iron will produce 0.01025 moles of Fe2O3, or 1.64 g.