[Encyclios]

Classification of matter

Matter can be classified into different categories, but the main ones are mixtures and pure substances. A pure substance (usually referred to simply as a substance) is matter that has distinct properties and a composition that does not vary from sample to sample. Water and table salt (sodium chloride) are examples of pure substances. All substances are either elements or compounds.

The matter can be classified according to the states of aggregation, or divided into organic or inorganic and can belong to one of the three kingdoms of nature (mineral, vegetable, animal). All these classifications, however, cease to be rigorous when the matter is studied in its elementary constituents (molecules, atoms, etc.).