Many first aid kits include an instant cold pack. A cold pack utilizes a chemical reaction that has a significant change in energy in order to make the pack feel cold. Explain which type of reaction, an endothermic reaction or an exothermic reaction, would be most useful for making a cold pack.

Endothermic reaction

Explanation:

A cold pack is used as a cold compress in order to numb pain caused by minor injuries. it is useful in first aid treatment of bruises, sprains, cuts and burns in addition to the application of a bandage.

A cold pack functions by absorbing heat away from the surrounding thereby decreasing the temperature and making the surface to feel cool. This is an endothermic reaction.

In an endothermic reaction, heat is absorbed from the environment and the reaction surface feels cool. Hence, an endothermic reaction is most useful in making a cold pack because the product of the endothermic reaction will feel cool to touch making it suitable to be used as a cold pack in first aid.

four atoms of oxygen

Explanation:

two atoms of hydrogen

one sulphur atom