Substance and mixture

Examples of pure chemical substances. From left to right: the elements tin (Sn) andsulfur (S), diamond (an allotrope of carbon),sucrose (pure sugar), and sodium chloride(salt) and sodium bicarbonate (baking soda), which are both ionic compounds.

A chemical substance is a kind of matter with a definite composition and set ofproperties.^[48] A collection of substances is called a mixture. Examples of mixtures are air and alloys.^{[citation needed]}