Endothermic, Endothermic reactions.
Giving off energy and absorbing energy!
An exothermic reaction is a reaction between two or more chemicals which gives of heat and light energy.
A hand warmer is used in outdoor activities to warm your hands or feet. To make it work you usually have to shake it or apply pressure on a certain point this will create a chemical reaction between two reactants located in the bag. It contains iron powder, water and carbon. when it's removed from its packaging the oxygen reacts with the chemicals to create iron oxide which releases heat energy. It is an exothermic reaction.
A heat patch is a medical utensil used to heat damaged muscles. It releases pain and speeds up the healing process. The chemical action that happens is the same one has hand warmers but it is used for different purposes. What happens in a heat patch is a exoteric reaction because it releases heat energy.
An endothermic reaction is a reaction that absorbs heat and light energy.