A combustion reaction involves the reaction of a substance with oxygen gas. The complete combustion of any hydrocarbon (binary compound of carbon and hydrogen) produces carbon dioxide and water as the only products. Heptane is a hydrocarbon that is found in gasoline. Complete combustion of heptane produces 7 liters of carbon dioxide for every 8 liters of water vapor (both measured at the same temperature and pressure). What is the ratio of carbon atoms to hydrogen atoms in a molecule of heptane