New York Low Pressure Boiler Certificate of Fitness (COF) Practice Test

What is the chemical union of oxygen in the air with combustible elements in fuel oil known as?

1. Oxidation

2. Combustion

3. Evaporation

4. Reduction

The correct answer is: Combustion

The chemical union of oxygen in the air with combustible elements in fuel oil is known as combustion. This process involves the reaction between fuel and oxygen resulting in the release of energy in the form of heat and light. During combustion, fuel is oxidized as it combines with oxygen, leading to various products like carbon dioxide and water vapor, depending on the type of fuel and the combustion conditions. This concept is fundamental in the operation of boilers and heating systems, where fuel oil is used as the energy source. Understanding combustion helps in ensuring efficient operation and optimal control of heating systems, which is critical for safety and performance in the context of low pressure boilers. The other options, while related to chemical processes, refer to different phenomena. Oxidation is a broader process that involves something losing electrons and increasing its oxidation state but does not specifically refer to the energy release aspect of burning fuel. Evaporation pertains to the transition of a substance from a liquid to a gas, which doesn't involve chemical union with oxygen. Reduction refers to the gain of electrons or decrease in oxidation state, serving as a counter-process to oxidation. Thus, combustion is the most precise term for the chemical union described in the question.