Canadian Entry To Practice (CETP) Practice Test

Which of the following best describes the combustion products of propane?

1. Water and sulfur

2. Carbon dioxide and water

3. Nitrogen oxides and carbon monoxide

4. Ozone and methane

The correct answer is: Carbon dioxide and water

The combustion of propane, a hydrocarbon fuel with the chemical formula C3H8, primarily produces carbon dioxide and water when it burns completely in the presence of sufficient oxygen. This reaction can be expressed chemically as follows: C3H8 + 5O2 → 3CO2 + 4H2O Here, propane is oxidized by oxygen to yield carbon dioxide (CO2) and water (H2O), which are the standard combustion products of hydrocarbons when the combustion is complete. This process releases energy, which is why propane is commonly used as a fuel source. The other options do not accurately represent the typical combustion products of propane. Water and sulfur would imply the presence of sulfur compounds, which are not relevant in the complete combustion of propane unless sulfur is added, while nitrogen oxides and carbon monoxide are products of incomplete combustion or specific conditions. Ozone and methane do not appear in the combustion of propane; rather, they are related to other environmental processes or pollutants. Thus, carbon dioxide and water are indeed the primary and expected products of burning propane.