A 44.6 g of iron ore is treated as follows. The

Question

iron in the sample is all converted by a series
of chemical reactions to Fe2O3. The mass of
Fe2O3 is measured to be 10.1 grams. What
was the percent iron in the sample of ore?
Answer in units of %

Answer 1

What fraction, F, of the mass of a Fe2O3 molecule is FE ?

total mass of molecule = 2(atomic mass Fe)+3(atomic mass O)

mass of Fe in that molecule = 2 (atomic mass Fe)
so
F = 2(atomic mass Fe)/[ the sum ]

then
Mass Fe = 10.1 * F

and percent = (Mass Fe/44.6)100