Question

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

Answer 1

7/16

Step-by-step explanation:

The general formula for the combustion of alkanes is;

CnH2n+2 + 3n+1/2 O2 -------> nCO2 + (n+1)H2O

So, we have;

CnHn + nO2 ------> 7CO2 + 8H2O

So there are 7 carbon atoms and 16 hydrogen atoms in heptane according to the law of conservation of mass.

Therefore, heptane is; C7H16

The ratio of carbon to hydrogen is now; 7/16