Chemical equation

A chemical equation is a formula that scientists use to visualize how different materials react to one another chemically to form new substances. These equations are similar to mathematical equations in that they require a balance of factors on both sides of the equation before the statement can be proven true. Because of their mathematical nature, chemical equations are foolproof ways of determining what new materials can be produced by combining a diverse range of chemicals.

Development of Chemical Equations

Atoms and elements are two primary concepts used in chemistry. An atom is the smallest building block of all matter, or physical substance, in the universe. Elements are naturally occurring materials composed of these atoms. One atom is the smallest form in which a particular element can exist. An atom of the gas helium, for example, cannot be made any smaller without ceasing to be helium. Two or more elements can combine to create new substances called compounds.

By the 1600s in Europe, scientists had already discovered ways of manipulating various elements of their environment, but they had yet to invent a method of visually expressing a chemical reaction on paper. Chemical reactions are the processes by which elements can undergo changes to transform into new substances. In 1615 the French chemist Jean Beguin became the first person to draw an early form of what would become the chemical equations of modern science.

Chemical Equation Basics

Chemical equations are horizontally written formulas that closely resemble math problems, with numbers and letters being added to one another to produce a result. Scientists write out these chemical equations because they provide reliable information about the exact ways in which certain substances may react with others to yield something entirely new. In this way, scientists can predict the results of a future chemical experiment or understand a past experiment.

Though each chemical equation is unique unto itself, all such equations share the same basic parts. The reactants are the chemicals that will be changed in the equation, while the products are what is created by those changes. The addition of one reactant to another to yield a product can be written as two different types of chemical equations.

The first, less common type of equation is the word equation. As its name suggests, a word equation consists simply of the names of the chemicals being combined and the substance eventually produced. A small "plus" sign is placed between the reactants, and an arrow pointing to the right is used to show the reactants becoming the products.

In general, however, scientists use symbol equations more frequently because they display more specific information about the chemical changes taking place. Symbol equations use chemical symbols, singular letters or certain configurations of multiple letters, to replace the full name of an element or compound. Instead of using the complete word Hydrogen, for example, a symbol equation employs that gas's chemical symbol, "H." Writing symbols instead of words makes a chemical equation shorter and simpler to view. Another advantage to using symbol equations is that they show the number of atoms of each element in the chemical reaction. The quantity of these atoms are displayed as subscripted numbers in the bottom right corner of the chemical symbol. Two atoms of hydrogen would be written as the symbol "H₂."

Chemical equations can range from simple to highly complex, depending on the substances being changed. The common compound sodium chloride, or table salt, contains only two elements, sodium and chlorine. The chemical symbol for sodium is "Na," while the symbol for Chlorine is "Cl." The symbol equation for the chemical reaction that produces sodium chloride looks like this:

Na + Cl ------> NaCl

In this equation, the sodium and chlorine on the left side are the reactants. The arrow is usually read as "yields." The sodium chloride that is created on the right side is the product.

Balancing Chemical Equations

Writing the chemical equation for sodium chloride involves few mathematical skills because only one atom each of sodium and chlorine are present. Therefore, the number of atoms does not need to be displayed near the chemical symbols, and only letters are involved in writing the formula. Slightly more complex chemical equations often include more than one atom of an element. These numbers are important. When an equation has been completed, an element must exist in exactly the same amount of atoms on both sides of the equation. Ensuring this numerical uniformity among reactants and products is called balancing.

Balancing a chemical equation is always necessary because of the law of conservation of mass. This is a fundamental scientific principle stating that atoms can be neither created nor destroyed in a chemical process. If a finished chemical equation shows that an element possesses more atoms among the reactants on the left than it does in the products on the right, the equation is incorrect and must be balanced.

For instance, to produce the compound copper oxide, represented by the symbol "CuO," copper, or "Cu," must be combined with oxygen, or "O₂." The initial formula for this reaction would look like this:

Cu + O₂ ------> CuO

This equation is incorrect because two atoms of oxygen are on the left but only one is on the right. To remedy this violation of the law of conservation of mass, the equation requires balancing. To balance equations, scientists must multiply the number of elemental atoms evenly on one or both sides until all atoms are equal. In the preceding equation, two atoms of oxygen must be created on the right side. To do this, copper oxide is multiplied by two: 2CuO.

However, this also creates two atoms of copper on the right when only one is present on the left. Now, the reactant copper atom on the left is also multiplied by two: 2Cu. This mathematical work has now successfully balanced the chemical equation that produces copper oxide:

2Cu + O₂ ------> 2CuO

These basic components of chemical equations can be taken to increasingly intricate levels to observe and quantify any number of advanced chemical reactions.

Bibliography

"Chemical Equations." BBC Bitesize. BBC. Web. 16 Dec. 2014. http://www.bbc.co.uk/schools/gcsebitesize/science/add‗ocr‗pre‗2011/periodic‗table/chemicalequationsrev1.shtml

"Elements, Compounds and Chemical Equations." BBC Bitesize. BBC. Web. 16 Dec. 2014. http://www.bbc.co.uk/schools/gcsebitesize/science/add‗gateway‗pre‗2011/periodictable/fundamentalrev1.shtml

"How to Balance Chemical Equations." Chemistry Equations & Answers. Newark, DE: Speedy Publishing, LLC, 2014. Web. 16 Dec. 2014. https://books.google.com/books?id=iDFLBAAAQBAJ&pg=PA6&dq=chemical+equations&hl=en&sa=X&ei=GkWQVOb8IfS1sQTm9oGoDA&ved=0CCYQ6AEwAA#v=onepage&q=chemical%20equations&f=false

Moore, John W. "Chemical Equation." Chemistry: The Molecular Science, Volume II, Chapters 12–22. Ventura, CA: Cram101 Publishing, 2013. Web. 16 Dec. 2014. https://books.google.com/books?id=3Ryj2-5zTYgC&pg=PT74&lpg=PT74&dq=jean+beguin+chemical+equation&source=bl&ots=lWQVhWiua‗&sig=Y6q728P8QjlNg8bs2OcSx-oOE40&hl=en&sa=X&ei=mkmQVLqhF-O1sQS‗6ID4BQ&ved=0CCYQ6AEwAzgK#v=onepage&q=jean%20beguin%20chemical%20equation&f=false