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 H1.26
Multiplying by 4 to get whole numbers gives C4H5 as the empirical formula