Final answer:
An endothermic reaction absorbs energy from its surroundings, resulting in a decrease in temperature. An exothermic reaction releases energy to its surroundings, resulting in an increase in temperature. An instant cold pack gets cold quickly through an endothermic reaction.
Step-by-step explanation:
An endothermic reaction is a reaction that absorbs energy from its surroundings, typically in the form of heat. This results in a decrease in temperature. Examples of endothermic reactions are the evaporation of liquid water, the reaction between baking soda and vinegar to produce carbon dioxide gas, and the reaction between ammonium nitrate and water to produce a cold pack.
On the other hand, an exothermic reaction is a reaction that releases energy to its surroundings, typically in the form of heat. This results in an increase in temperature. Examples of exothermic reactions are the combustion of gasoline in a car engine, the reaction between sodium and water to produce sodium hydroxide and hydrogen gas, and the reaction between calcium oxide and water to produce heat for self-heating canisters.
An instant cold pack gets cold quickly through an endothermic reaction. Inside the pack, there are two compartments that contain dry chemicals separated by a barrier. When the barrier is broken, the chemicals mix and react, causing an endothermic process that absorbs heat from the surroundings and produces a cold sensation.
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