National League for Nursing (NLN) Science Practice Exam

Which of the following describes a reaction that absorbs heat from its surroundings?

1. Exothermic.

2. Endothermic.

3. Combustion.

4. Neutralization.

The correct answer is: Endothermic.

A reaction that absorbs heat from its surroundings is defined as an endothermic reaction. In this type of reaction, the system takes in energy in the form of heat, resulting in a drop in temperature in the surrounding environment. This characteristic is crucial in identifying endothermic reactions, as they typically require a continuous input of energy to proceed. Endothermic reactions are common in processes like photosynthesis, where plants absorb heat and light energy to convert carbon dioxide and water into glucose and oxygen. Understanding the nature of these reactions is important for recognizing their applications in various scientific fields, such as thermodynamics and chemistry. In contrast, exothermic reactions release heat, leading to an increase in temperature of the surroundings. Combustion reactions, which are a specific type of exothermic reaction, involve the burning of a substance in the presence of oxygen and typically produce heat and light. Neutralization reactions can also be exothermic when an acid and a base react to form water and a salt, releasing heat in the process. Thus, the definition and behavior of endothermic reactions clearly distinguish them from these other types.