## Chemistry and Chemical Reactivity (9th Edition)

$12.8\%$
Number of moles of $KMnO_4$: $0.0123\ M\times 22.25\ mL=0.274\ mmol$ From stoichiometry: $1.37\ mmol$ of iron Mass: $0.00137\ mol\times 55.845\ g/mol=0.0764\ g$ Mass fraction: $0.0764/0.598\times 100\%=12.8\%$