Which statement best describes an exothermic reaction?

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

Answer: (A)

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 enthalpy (H) is a measure of the total energy of a system, and in an exothermic reaction, the enthalpy of the products is lower than that of the reactants because energy is released.
3. Recognize that when energy is released to the surroundings, the temperature of the surroundings typically increases, not decreases.
4. Compare the given statements to these concepts: the correct description of an exothermic reaction is that energy is released to the surroundings during the reaction.
5. Eliminate incorrect options: products having higher enthalpy than reactants describes an endothermic reaction, energy absorbed from surroundings is endothermic, and a decrease in surroundings' temperature contradicts energy release.