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. Octane is a hydrocarbon that is found in gasoline. Complete combustion of octane produces 8 L of carbon dioxide for every 9 L 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 octane?

Answer 1

Answer:

$\frac{4}{9}$

Explanation:

First, we need to write the balanced equation of the combustion of octane, which is an alkane (has only hydrogen and carbons and saturated bonds), that has molecular formula CnH2n, so for n = 8: C₈H₁₈.

C₈H₁₈ + (25/2)O₂ → 8CO₂ + 9H₂O

Because of the pressure and temperature remains constant, volume is equal to the number of atoms. So, carbon dioxide has 1 atom of C, and water has two atoms of H, then:

$\frac{C}{H} = \frac{8}{2X9} = \frac{8}{18} = \frac{4}{9}$

It's proven by the molecular formula of octane showed above.

Answer 2

Answer:

carbon and hydrogen

Explanation: