What makes endothermic reaction

When a reaction proceeds, it either releases energy to, or absorbs energy from, its surroundings. In thermodynamics, these two types of reactions are classified as exothermic or endothermic, respectively. An easy way to remember the difference between these two reaction types is by their prefixes: endo- means to draw in, and exo- means to give off. We will explore these concepts in more detail after introducing the concept of enthalpy. Enthalpy signified as H is a measure of the total energy of a system and often expresses and simplifies energy transfer between systems.

Since the total enthalpy of a system cannot be measured directly, we most often refer to the change in enthalpy for a particular chemical reaction. At constant pressure, the change in enthalpy is equal to the heat given off, or the heat absorbed, in a given chemical reaction:. Exothermic reactions are reactions or processes that release energy, usually in the form of heat or light. In an exothermic reaction, energy is released because the total energy of the products is less than the total energy of the reactants.

The heat energy for this reaction often comes from automobile exhaust. An example of an endothermic process with which everyone knows is sweating, the process by which the body produces water on the skin as a cooling strategy. It works because water absorbs energy when it changes state from a liquid to a gas. This is an endothermic process, but it isn't a reaction, because a reaction always involves the destruction or formation of chemical bonds. On the other hand, squeezing an instant-cold ice pack does produce an endothermic reaction.

A chemical in the pack reacts with water to absorb energy and freezes the water into ice. During photosynthesis, plants absorb carbon dioxide from the atmosphere and turn it into glucose and oxygen. The process requires energy in the form of sunlight and is more endogenic than it is endothermic. The equation for the reaction is:. A number of endothermic reactions are important for the metabolism of mammals and humans.

Many of these occur inside cells, and when they do, scientists call them anabolic reactions, as opposed to catabolic reactions, which release energy.

Some of these reactions include:. Chris Deziel holds a Bachelor's degree in physics and a Master's degree in Humanities, He has taught science, math and English at the university level, both in his native Canada and in Japan.

He began writing online in , offering information in scientific, cultural and practical topics. His writing covers science, math and home improvement and design, as well as religion and the oriental healing arts. Amino acids joining together to form peptides. Chris You can use energy level diagrams to visualize the energy change during a chemical reaction. To understand these diagrams, compare the energy level of the reactants on one side with that of the products on the other side. Consider, for example, a diagram that charts the energy change when a candle burns.

Because more energy is released when the products are formed than is used to break up the reactants, this reaction is exothermic. Brittny All of this stuff relates to thermodynamics—the study of heat and its relationship to energy and work. Classifying a chemical reaction as exothermic or endothermic is simple.

It comes down to weighing the energy needed to break bonds in the reactants with the energy released when the products are formed.

If you do not respond, everything you entered on this page will be lost and you will have to login again. Skip Navigation. Vimeo ID: Video Transcript. Energy is released when bonds are formed.