Canadian Entry To Practice (CETP) Practice Test 2025 - Free CETP Practice Questions and Study Guide

The process of complete combustion of propane, which is a hydrocarbon (chemical formula C3H8), primarily yields water vapor and carbon dioxide as the main products. During complete combustion, propane reacts with oxygen from the air, resulting in a chemical reaction that maximizes the conversion of fuel into energy.

In this ideal scenario, all carbon (C) atoms in propane are converted into carbon dioxide (CO2), and all hydrogen (H) atoms are converted into water (H2O). The combustion reaction can be represented as:

C3H8 + 5 O2 → 3 CO2 + 4 H2O

This reaction illustrates that for every molecule of propane burned, three molecules of carbon dioxide and four molecules of water vapor are produced.

Other options involve products that arise from incomplete combustion, where there is insufficient oxygen. This can lead to the formation of carbon monoxide, soot, or other hydrocarbons, but those are not products of complete combustion. Therefore, the presence of water vapor and carbon dioxide as the correct answer highlights the efficiency and completeness of the combustion process when it is adequately supplied with oxygen.