# What are some examples of chemical reactions?

May 25, 2014

A chemical reaction is when new substances are formed. Substances that react together are called reactants; and the substances formed are called products. Some examples of chemical reactions are combustion (burning), precipitation, decomposition and electrolysis.

An example of combustion is methane + oxygen forms carbon dioxide and water. This can be written as a balanced symbol equation:
$C {H}_{4}$ + $2 {O}_{2}$ forms $C {O}_{2}$ + $2 {H}_{2} O$

An example of precipitation is:
carbon dioxide + calcium hydroxide forms calcium carbonate + water
- calcium carbonate is an insoluble solid, i.e. the precipitate

another example of precipitation is: