A 0.250 g sample of hydrocarbon (containing only carbon and hydrogen) undergoes complete combustion to produce 0.845 g of CO2 and 0.173 g of H2O. What is the empirical formula of this compound?

CH

Explanation:

We have to obtain the mass of carbon and hydrogen in CO2 and H2O respectively.

For carbon in CO2;

0.845 * 12/44 = 0.23 g

For hydrogen in H20;

0.173 * 2/18 = 0.019 g

We convert the masses to moles of carbon and hydrogen

For carbon - 0.23/ 12 = 0.019 moles

For hydrogen - 0.019/1 = 0.019 moles

Dividing by 0.019 moles for carbon and hydrogen we have the emperical formula of the compound as CH