National Council of Examiners for Engineering and Surveying (NCEES) Fundamentals of Engineering (FE) Other Disciplines Practice Exam

Carbon dioxide and water are the primary products of complete combustion of hydrocarbon fuels. In a complete combustion process, a fuel reacts with an adequate supply of oxygen, resulting in the full conversion of fuel into carbon dioxide and water vapor. This reaction releases a significant amount of energy, making it highly efficient for energy generation. The presence of carbon dioxide as a product indicates that all carbon in the fuel has been oxidized completely, while water signifies that hydrogen has also fully reacted with oxygen.

When carbon dioxide and water are produced, it reflects an optimal combustion process where there is sufficient oxygen available, minimizing the formation of other byproducts that would occur under less ideal conditions, such as caron monoxide or unburned hydrocarbons. Therefore, identifying the presence of carbon dioxide and water as products is a clear indicator that the combustion process was complete, making this interpretation accurate in the context of combustion reactions.