Understand What is Meant by a Pure Substance

Have you heard the word 'pure' before? Pure orange juice. Pure-bred puppy. Pure soap. There are different uses of the word pure, but the term 'pure' in chemistry is what concerns us here.

In chemistry, we refer to a pure substance as a substance made from only one element or one compound. And nothing else.

Let's just recap on what an element and a compound are:

An element is made from only one type of atom, and elements are listed on the periodic table - so oxygen is an element, as well as carbon and magnesium.

A compound is made from two or more elements chemically bonded together - so water is a compound, copper chloride is a compound and ethanol is a compound. 

A pure substance can be a solid, liquid or gas, but it must be made up of only one type of element, or one type of compound. Got it? Let's try some questions.