A compound has a chemical composition of. 62 g carbon,.10 g hydrogen,.28 g oxygen. What is the empirical formula?

First we divide the masses by molar masses:

0.62 g carbon / (12.01 g/mol carbon) = 0.0516 mol C

0.10 g hydrogen / (1.01 g/mol H) = 0.099 mol H

0.28 g oxygen / (14 g/mol O) = 0.02 mol O

Since O has the smallest amount, we divide the other values by it:

0.0516 mol C / 0.02 mol O = 2.58 ~ 2.5

0.099 mol H / 0.02 mol O = 4.95 ~ 5

Therefore we have a ratio of C2.5, H5, and O. Since an empirical formula must only contain integers, we multiply everything by two to get:

C5H10O2