Question

1. while working, a construction worker is bothered by a hurt muscle. he lays down to rest and places a heat pack under his back to keep his muscles loose. what type of chemical reaction occurs in the heat pack? retrothermic endothermic exothermic infrathermic

Explanation:

An exothermic reaction releases heat. Since the heat pack is giving off heat (to keep muscles loose), it is an exothermic reaction. Endothermic reactions absorb heat. Retrothermic and infrathermic are not standard terms for heat - related chemical reactions in this context.

Answer:

exothermic