Mixture, Pure substances, Compounds and Elements

Mixture

A mixture is a combination of two or more substances which retain to their distinctive properties

e.g. Gravel, Milk.

Pure Substances

Pure substances are substances that have distinct properties and have a constant composition no matter where they are found or how they are made e.g. water, salt, gold, oxygen, petrol.

Elements

Are pure substances that cannot be broken down into simpler substances. These are building blocks for all other substances. All matter is made up of elements and there are 92 natural occuring elements in nature e.g. Oxygen, gold, iron.

Compounds

Are pure substances that can only be broken down by chemical reactions. Compounds can be synthesised (made up) or decomposed (broken down) e.g. water, sugar, acids.

Homogeneous

The same thing throughout (e.g. Distilled Water).

Heterogeneous

Not the same thing throughout (e.g. Milk).