You've sat through chemistry class, and you now understand how chemical bonds form. But why are chemical bonds important? Believe it or not, chemical bonds are the basis for most substances that exist, as well as the energy that powers them.
Many Forms of Bonds
You've probably spent hours of chemistry class learning about the two main types of chemical bonds - ionic and covalent. You may even have discussed how chemical bonds form or given examples of chemical bonds, but why are chemical bonds important? Believe it or not, the chemical properties of almost any substance or material in the world depend upon the chemical bonds that make it up. If it weren't for chemical bonds, every material in the world would have to be one of the 118 elements in the Periodic Table. Instead, atoms from these elements bond together to create chemical compounds.
For example, think about table salt. The chemical makeup of table salt is sodium (Na) chemically bonded with chlorine (Cl). Sodium is a hard metal, and chlorine is a greenish gas that can be lethal. When sodium and chlorine bond together, however, they create table salt, a safe substance that we eat every day. There are chemical bonds between the atoms in our bodies (especially the elements carbon, hydrogen, and oxygen), the atoms in the air, and the atoms in most plants and synthetic materials. In fact, chemical bonds are everywhere, and when two elements bond together, their properties often change completely.
What Happens when Chemical Bonds Break?
A chemical reaction is the building or breaking (or both) of chemical bonds. Chemical reactions are so important because not only do they change the property of the substances that go into the reaction, they also store or release energy. For example, you need melt table salt and then force energy into it in order to break the bond between the atoms of sodium and chlorine.
This reaction requires energy to break the chemical bonds, and is called an endothermic reaction. There are other reactions, called exothermic reactions, that actually release energy when chemical bonds are broken. Rusting is an example of an exothermic reaction, since when iron and oxygen interact (usually in the presence of water), energy is released into the environment.
Examples of Energy Production
So in essence, the most obvious answer to the question "why are chemical bonds important?" has to do with the fact that building and breaking those bonds is part of the energy cycle, and one of the only ways we have to generate energy. The following are some examples of chemical reactions in which building or breaking bonds leads to the release of energy:
Burning a substance is a prime example of an exothermic reaction. Burning causes a substance to release energy in the form of heat.
Cellular respiration, which is the process the body uses to break down glucose, releases energy in the form of ATP. This is an exothermic reaction as well, and the energy produced by this reaction gives us the energy to grow, move, and perform all bodily functions.
The gasoline in a vehicle causes movement due to the energy produced in an exothermic reaction. Without that reaction, gasoline would have no impact on a vehicle's ability to move.
English Montreal School Board. "Endothermic Versus Exothermic Reactions." http://www.emsb.qc.ca/laurenhill/science/exo.html
Utah State Office of Education. "To React or Not to React? That Is the Question!" http://www.schools.utah.gov/CURR/science/sciber00/8th/matter/sciber/chemtype.htm