Pure substances
'Pure' has a specific meaning in chemistry.
A A pure substance is a single element or compound not mixed with any other substance. substance is a single element or compound not mixed with any other substance.
A Two or more substances that are not joined together and not chemically combined. They are usually easy to separate. contains two or more different substances mixed together, usually easy to separate.
| Pure substances | Mixtures |
| Diamond only contains the element carbon. | Air is a mixture of oxygen, carbon dioxide, nitrogen and other trace gases. |
| Water only contains the compound water. | Mineral water is a mixture of water and dissolved salts. |
| Table salt only contains the compound sodium chloride. | Milk is a mixture of water, lactose, fat and minerals such as salt. |
| Pure substances | Diamond only contains the element carbon. |
|---|---|
| Mixtures | Air is a mixture of oxygen, carbon dioxide, nitrogen and other trace gases. |
| Pure substances | Water only contains the compound water. |
|---|---|
| Mixtures | Mineral water is a mixture of water and dissolved salts. |
| Pure substances | Table salt only contains the compound sodium chloride. |
|---|---|
| Mixtures | Milk is a mixture of water, lactose, fat and minerals such as salt. |
Here are some examples of pure substances and mixtures.