Which of the following is released by an exothermic reaction?

• A. Heat energy
• B. Cold energy
• C. Reactants
• D. Light energy only

Answer: (A)

Verified step by step guidance

1. Understand the definition of an exothermic reaction: it is a chemical reaction that releases energy to its surroundings.
2. Identify the forms of energy that can be released during a chemical reaction, such as heat, light, or sound.
3. Recall that in most exothermic reactions, the primary form of energy released is heat energy, which increases the temperature of the surroundings.
4. Note that 'cold energy' is not a scientifically recognized form of energy; rather, the sensation of cold is the absence or removal of heat.
5. Conclude that among the given options, 'Heat energy' is the correct choice because it is the energy released by an exothermic reaction.