A 39 g of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 7.9 grams. What was the percent iron in the sample of ore?

Question

A 39 g of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 7.9 grams. What was the percent iron in the sample of ore?
Answer in units of %.
Please help me understand how to solve this problem.

DrBob222 · Accepted Answer

mols Fe2O = grams/molar mass = ? mols Fe = twice that since there are two mols Fe in each mole of Fe2O3. Then %Fe = (mass Fe/mass sample)*100 = ?

Alex · Answer

Thank you!