Why is formation of bonds exothermic

The strength of bonds between different atoms varies across the periodic table and is well documented. Each bond in a molecule has its own bond dissociation energy, so a molecule with four bonds will require more energy to break the bonds than a molecule with one bond.

As each successive bond is broken, the bond dissociation energy required for the other bonds changes slightly. Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:. Skip to main content. Basic Concepts of Chemical Bonding. In endothermic reactions, more energy is absorbed when the bonds in the reactants are broken than is released when new bonds are formed in the products.

Endothermic reactions are accompanied by a decrease in temperature of the reaction mixture. 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: Whether a reaction is endothermic or exothermic depends on the difference between the energy needed to break bonds and the energy released when new bonds form. Energy diagrams show the level of energy of the reactants and of the products. The bigger the difference between the energy of the reactants and the energy of the products, the more energy is given out or taken in. It is easy to see from an energy level diagram whether the reaction is exothermic or endothermic:.