A 37.5 g sample of iron ore is treated as

Question

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 17.8 g.
What was the mass of iron in the sample of
ore?
Answer in units of g

Answer 1

percent of iron in ore:

2*atomicmassFe/(formulamassFe2O3)

now multiply that by 17.8 grams.