What is an exothermic reaction?

• A. Absorbs energy from the surroundings.
• B. Releases energy to the surroundings, causing temperature to rise.
• C. Occurs only in water.
• D. Produces a precipitate.

Answer: (B)

An exothermic reaction releases energy to the surroundings, usually as heat, so the temperature around the reaction rises. This happens because the energy stored in the reactants is converted into heat as new bonds form in the products. That’s why the best description is energy being released to the surroundings and the surrounding temperature increasing. Some reactions do absorb energy (endothermic), and exothermicity isn’t tied to occurring only in water or specifically to forming a precipitate—the defining feature is the heat flow to the surroundings.