Humber Admissions Practice Test 2025 - Free Practice Questions and Study Guide for Humber College Admissions

Combustion reactions are chemical processes that involve the rapid combination of a fuel with oxygen, resulting in the production of heat and often light. The key characteristic of combustion is the release of energy; this energy manifests primarily as thermal energy (heat) and can also produce visible light, particularly in the case of flames.

In essence, the energy released during combustion is a result of the breaking and forming of chemical bonds, which releases more energy than is consumed in the reaction. This is why the statement regarding energy release in the form of heat and light is indeed true.

The other statements do not accurately describe combustion reactions. For instance, combustion typically requires an oxidizing agent like oxygen, and while it can involve different states of matter for the fuel (not exclusively liquid), the process is not limited to any particular state. Additionally, combustion reactions often produce gases, such as carbon dioxide and water vapor, as byproducts, making the statement about not producing any gases incorrect.