An iron ore, magnetite, contains only iron and oxygen. In refining 100.0 g of the ore, 72.35 g of iron are obtained. What is the empirical formula of the ore? A)Fe₂O₃ B)FeO₂ C)Fe₂O₅ D)Fe₃O₄ E)FeO

Question

Quizplus · Accepted Answer

The mass of oxygen in the ore is 100.0 g - 72.35 g = 27.65 g. The moles of iron are 72.35 g / 55.85 g/mol = 1.295 mol, and the moles of oxygen are 27.65 g / 16.00 g/mol = 1.728 mol. The ratio of moles of Fe to O is approximately 3:4, which corresponds to the empirical formula Fe₃O₄.

An Iron Ore, Magnetite, Contains Only Iron and Oxygen