What is the mass percent of Fe2O3 in the iron ore sample?

Question

An iron ore samp;le contains Fe2O3 plus other impurities. A 752-g sample of impure iron ore is heated with excess carbon, producing 453 g of pure iron by the following reaction: Fe2O3 (s) + 3C(s) ---->2Fe (s) + 3CO(g). what is the mass percent of Fe2O3 in the impure iron ore sample? Assume Fe2O3 is the only source of iron and that the reaction is 100% efficient.

Answer 1

Fe2O3 (s) + 3C(s) →2Fe (s) + 3CO(g)

(2*55.847 + 3*15.999) g Fe2O3 → 2*55.847 g Fe

159.691 g Fe2O3 → 111.694 g Fe

1.429719 g Fe2O3 → 1.0 g Fe

647.6626 g Fe2O3 → 453 g Fe

(647.6626)(100)/752 ≈ 86.125% ≈ 86.1%