# A combination of chemical symbols and numbers that represents a substance is called what?

A chemical formula is a shorthand that gives the elemental breakdown and proportion of a chemical species: ${O}_{2}$, $L i N {O}_{3}$, $C {H}_{4}$, ${H}_{3} C - C {H}_{3}$, etc. are all chemical symbols in a given proportion that represent a different chemical entity.