Endothermic vs. Exothermic

A quick difference between endothermic and exothermic involves reactions in the environment. An endothermic reaction takes place when energy is absorbed from surroundings in the form of heat, and exothermic is when energy is released from the system into the surroundings. Both terms are mostly used in science and chemistry, but there are everyday examples as well.

The reaction occurs when two or more molecules interact with each other, and something happens or is produced. Endothermic absorbs heat, and exothermic produces heat. The difference between the words themselves and the prefixes give another hint as to their differences. Thermic refers to heat, endo means inside, and exo means outside. Endothermic, heat absorbed or in something, exothermic, heat being released or sent out.

Endothermic must be supplied with heat and is basically the opposite of exothermic. An everyday reaction is in the cooking of an egg. There must be heat added or absorbed from the environment to cook the egg or any other food item. The two reaction differ because the amount of energy of the reactants is fewer than the products, as opposed to an exothermic reaction.

An endothermic reaction will cool their surroundings because the reactions draw the heat energy into themselves. As heat leaves an area, the temperature will drop. If a person's hand is cold to the touch, it is may be related to their skin having a lower temperature; however, heat is actually leaving the warmer body and being absorbed into the cooler hand.

Endothermic reactions also contain more energy by drawing in and storing energy in the form of chemical bonds. A product contains more net energy than the reactants did in an endothermic reaction at the beginning of the process. This is because of the stored energy. The touching warm hand in the previous example had energy stored in it.

Exothermic reactions, on the other hand, make the surrounding environment hotter since heat energy is released, radiating energy while it progresses. A campfire is an excellent example of this reaction. The energy from the chemical bonds of paper and wood is released in the form of light, and of course, heat. Those sitting around the campfire become warm as a result of the released heat.

Exothermic reactions will contain less energy because it is removed from the chemical bonds in the reactants. Activation energy, like the match for the campfire, is needed to get the process started. Following the process, the product will have lower heat and is more compact.

Other examples of endothermic reactions include photosynthesis when plants absorb energy from the environment and evaporation as sweating cools a person down. Exothermic reactions include rain as the condensation of water vapor into rain expels or releases heat and the formation of concrete when water is added, and chemical reactions release heat.

In summary, endothermic consists of energy or heat being absorbed from its surroundings, and exothermic involves energy or heat being released into the environment. There are many examples of endothermic and exothermic reactions taking place every day.