A 10.00 g sample of a hydrocarbon (which is a compound that contains only carbon and hydrogen) was burned in oxygen, and the carbon dioxide and water produced were carefully collected and weighed. The mass of the carbon dioxide was 30.50 g, and the mass of the water was 14.98 g. What was the empirical formula of the hydrocarbon?

Question

Quizplus · Accepted Answer

The empirical formula of the hydrocarbon is CH2. This is because the mass of carbon in the carbon dioxide is 30.50 g / 44.01 g/mol = 0.693 mol, and the mass of hydrogen in the water is 14.98 g / 18.02 g/mol = 0.831 mol. The ratio of carbon to hydrogen is therefore 0.693 mol / 0.831 mol = 1:2, which gives the empirical formula CH2.

A 1000 G Sample of a Hydrocarbon (Which Is a Compound