Which of the following processes is endothermic? A. a hot cup of soup (system) cools on a countertop B. the combustion of butaneC. the chemical reaction in a "hot pack" often used to treat sore musclesD. the vaporization of rubbing alcohol E. the freezing of water

Answer: Option (D) is the correct answer.

Explanation:

A reaction in which heat energy is absorbed by the molecules of a substance is known as an endothermic reaction.

Whereas when energy is released by the molecules of a substance in a reaction then it is known as an exothermic reaction.

So, when a hot cup of soup (system) cools on a countertop then energy is released into the surrounding by the soup. Hence, it is an exothermic reaction. Also, combustion reactions are always exothermic in nature. The chemical reaction in a "hot pack" often used to treat sore muscles because heat is released to the muscles. Therefore, it is an exothermic reaction. When rubbing alcohol vaporizes then heat is absorbed by the molecules of alcohol. Due to which they gain energy and escape into the surrounding. Therefore, it is an endothermic reaction. Freezing of water is an exothermic reaction because during this process energy is released by the molecules of water. Hence, it is an exothermic reaction.

Thus, we can conclude that the vaporization of rubbing alcohol is endothermic.