Basic Firefighter Written Practice Exam

What is combustion classified as in terms of chemical reactions?

1. Exothermic reaction

2. Endothermic reaction

3. Reversible reaction

4. Inhibitory reaction

The correct answer is: Exothermic reaction

Combustion is classified as an exothermic reaction because it releases energy, typically in the form of heat and light, during the process of burning. In this context, exothermic refers to any reaction where the energy of the products is lower than the energy of the reactants, leading to a release of energy into the surrounding environment. When a combustible material reacts with an oxidizer (commonly oxygen in the air), it forms new products, such as carbon dioxide and water, while also liberating heat. This makes combustion not only a significant process in fire behavior but also crucial for many applications, such as heating and propulsion. In contrast, an endothermic reaction would absorb energy from its surroundings, which is not characteristic of combustion. Reversible reactions can be either exothermic or endothermic, but combustion reactions are generally not reversible under normal conditions. An inhibitory reaction, while it suggests some form of suppression or prevention, does not align with the nature of combustion. Thus, recognizing combustion as an exothermic reaction is foundational in understanding how fires operate and how energy is released during chemical reactions.