Which of the following best describes an exothermic reaction?

• A. A reaction that only occurs at very low temperatures.
• B. A reaction that releases energy to its surroundings, usually in the form of heat.
• C. A reaction in which the products have higher energy than the reactants.
• D. A reaction that absorbs energy from its surroundings.

Answer: (B)

Verified step by step guidance

1. Understand the definition of an exothermic reaction: it is a chemical reaction that releases energy to its surroundings, often as heat.
2. Recall that in an exothermic reaction, the energy of the products is lower than that of the reactants because energy is given off.
3. Contrast this with an endothermic reaction, where energy is absorbed from the surroundings and the products have higher energy than the reactants.
4. Analyze the given options to identify which one matches the characteristics of an exothermic reaction.
5. Select the option that states the reaction releases energy to its surroundings, usually in the form of heat, as this best describes an exothermic reaction.