A 0.5962g sample of iron ore is dissolved in acid producing Fe3+. Through a series of reactions, the iron precipitates as the Fe(OH)3. The precipitate is heated, forming solid Fe2O3. What is the mass % of iron in the sample if the analysis produced 0.3210g Fe2O3?

Answer 1

atomic mass of iron, Fe = 55.845 g/mol
molar mass of Fe2O3 = 159.69 g/mol
Iron content in sample of Fe2O3
= 0.3210*(55.845/159.69)
= 0.11226 g
Percentage of iron in ore
= 0.11226 g/ 0.5962 g
= 18.83%