define exothermic reactions
Any process that rearranges the atoms of one or more substances to become a new substance is known as a chemical reaction. Chemical reactions are routinely completed in labs and occur as natural processes in the environment. Many chemical reactions absorb or release heat and energy as part of their process. An exothermic reaction is any reaction that releases or gives off energy during the reaction. This means that the reaction gives out energy to its surroundings.