A reaction that releases heat is:

endothermic

exothermic

none of the above

Exothermic reaction

Explanation:

A reaction that releases heat is known as an exothermic reaction. Reactions can be classified as either exothermic or endothermic depending on whether they release or absorb heat from the surrounding. A reaction that absorbs or gains heat from the surrounding is known as endothermic reaction. On the other hand, if a reaction releases heat to the surrounding is known as exothermic reaction. An exothermic reactions results to an increase in temperature of a solution while an endothermic reaction results to a decrease in the temperature of a solution.