Atoms, elements and compounds - AQAWord equations

A word equation represents a chemical reaction using the names of the substances involved. Word equations do not show any chemical symbols or formulae.

Reactants and products

Reactants are substances that react together in a chemical reaction. In a chemical reaction, the atoms or ions in reactants separate from one another. They join back together in a different way to form products.

Word equations always take this form:

reactants → products

A + sign separates two or more reactants, or two or more products.

Example word equations

Potassium hydroxide reacts with sulfuric acid. Potassium sulfate and water are formed in the reaction. This means that:

• the reactants are potassium hydroxide and sulfuric acid
• the products are potassium sulfate and water
• the word equation is: potassium hydroxide + sulfuric acid → potassium sulfate + water

There can be different numbers of reactants and products. For example:

• sodium + chlorine → sodium chloride
• calcium carbonate → calcium oxide + carbon dioxide