There are lots of different substances but only just over a hundred elements. An element is a substance that is made up of only one kind of atom. The atoms in a particular element are the same as each ...

The word 'pure' is used in chemistry in a different way from its everyday meaning. For example, shops sell cartons labelled as ‘pure' orange juice. The label means that the contents are just orange ...

Liquids and solutions may seem simple, but at the molecular level they are constantly in motion. When sugar dissolves in water, for example, each ...