Magnetite is a mineral having the formulaFe3O4 or FeOFe2O3. A 1.1324-gsample of a magnetite ore was dissolved in concentrated HCl to givea solution that contained a mixture of Fe2+ andFe3+. Nitric acid was added and the solution was boiledfor a few minutes, which converted all of the iron toFe3+. The Fe3+ was then precipitated asFe2O3xH2O by addition ofNH3. After filtration and washing, the residue wasignited at a high temperature to give 0.5394 g of pureFe2O3 (159.69 g/mol). Calculate (a) thepercent Fe (55.847 g/mol) and (b) the percentFe3O4 (231.54 g/mol) in the sample.