The compound's empirical formula is
Here's how you can determine your compound's empirical formula.
You know that its percent composition is 84% carbon and 16% hydrogen. This means that a 100-g sample of your compound will contain 84 g of carbon and 16 g of hydrogen.
Use carbon and hydrogen's molar masses to determine how many moles of each you'd get in a 100-g sample.
The simplest ratio between 7 and 16 is actually
You get 7 moles of carbon and 16 moles of hydrogen for every 100-g of your compound.