All substances have properties. These describe how a substance looks and behaves. There are two types of properties: physical and chemical. Watch this video about how physical and chemical properties ...

Everything we can see and touch, and quite a lot that we can’t as well, is made of tiny particles called atoms. Some substances, like particles of this iron, contain only one kind of atom. Iron is an ...

A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent ...