Chemical Equations

A chemical equation is a brief representation or summary of what is happening in a chemical reaction.

There are two types of chemical equations:

1. word equations

2. symbolic equations

1. Word equations show the names of the chemical substances that react and the names of the chemical substances that are produced. The chemicals that react together are called reactants, and the chemicals that are produced are called products.

The reactants and products are separated by an arrow → and a plus sign, +, is used to separate the chemicals on either side of the arrow.

Reactants → Products

For example:

hydrochloric acid + sodium hydroxide → sodium chloride + water

sulfuric acid + sodium carbonate → sodium sulfate + carbon dioxide + water

nitric acid + sodium carbonate → sodium nitrate + carbon dioxide + water

2. Symbolic equations show the chemical formulae of the chemical substances that react and the chemical formulae of the chemical substances that are produced. Again, the chemicals that react together are called reactants, and the chemicals that are produced are called the products. Symbolic equations must be balanced. There must be the same number of each type of atom on the 'reactants/left hand' side of the equation as there are on the 'products/right hand side' of the equations. Symbolic equations are balanced by putting 'big' numbers in front of the chemical formulae. See the page on writing chemical formulae for help with this.

For example:

HCl + NaOH → NaCl + H₂O

H₂SO₄ + Na₂CO₃ → Na₂SO₄ + CO₂ + H₂O

2HNO₃ + Na₂CO₃ → 2NaNO₃ + CO₂ + H₂O