The first step we have to follow to answer this question is to convert the mass of Fe2O3 to moles using its molecular mass:
[tex]639kgFe_2O_3\cdot\frac{kmolFe_2O_3}{159.68kgFe_2O_3}=4.00kmolFe_2O_3[/tex]According to its formula, each kmol of Fe2O3 contains 2 kmol of Fe. Use this information to find the amount of moles of iron:
[tex]4kmolFe_2O_3\cdot\frac{2kmolFe}{1kmolFe_2O_3}=8kmolFe[/tex]Use the molecular mass of iron to find the mass of iron that can be recovered from the Fe2O3:
[tex]8kmolFe\cdot\frac{55.845kgFe}{kmolFe}=446.76kgFe[/tex]It means that 446.76kg of iron can be recovered.
