How do you Find the empirical formula for each compound from its percent composition?

Question

a. 74.2% Fe and 27.6% O

b. 65.2% Sc and 34.8% O

c. 52.8% Sn, 12.4% Fe, 16.0% C and 18.8% N

Answer 1

Chase, I'll do one for you:

a. 74.2% Fe and 27.6% O

Assume you have 100 g

74.2 g Fe x 1 mole Fe/ 55.85 g = 1.33 mole Fe

27.6 g O x 1 mole O/16 g O = 1.725 mole O

Divide both molar amounts by the least:

1.33/1.33 = 1 Fe

1.725/1.33 = 1.3 O

Multiply by 3 to derive a whole number: 3 Fe 3.9 = 4O

Fe3O4

You can do the next two.