what is the empirical formula?

Question

the compound xylene consists of 90.49% C and the rest is hydrogen.What is the empirical formula?

Answer 1

Assume you have 100.00 g of material.  Then...

C: 90.49 g x 1 mole/12 g = 7.54 moles C

H: 100.00 - 90.49 = 9.51 g H x 1 mole/1 g = 9.51 moles H

Divide by smallest mole value to get C₁ and H_1.26

Multiplying by 4 to get whole numbers gives C₄H₅ as the empirical formula