Which of the following statements best describes an exothermic reaction?

• A. The temperature of the surroundings decreases as the reaction proceeds.
• B. Energy is released to the surroundings during the reaction.
• C. The reaction absorbs heat from the surroundings.
• D. The products have higher enthalpy than the reactants.

Answer: (B)

Verified step by step guidance

1. Understand the definition of an exothermic reaction: it is a chemical reaction that releases energy, usually in the form of heat, to the surroundings.
2. Recall that when energy is released to the surroundings, the temperature of the surroundings typically increases, not decreases.
3. Recognize that if a reaction absorbs heat from the surroundings, it is called an endothermic reaction, which is the opposite of exothermic.
4. Know that in an exothermic reaction, the enthalpy of the products is lower than that of the reactants because energy is given off.
5. Therefore, the best description of an exothermic reaction is that energy is released to the surroundings during the reaction.