What Is The Difference Between A Pure Substance And A Compound?

Water (h2o) salt (NaCl) refined sugar and others are considered a pure substance - the distinction arises in organic chemistry (pertaining to carbon)

Pure substance - A sample of matter, either an element or a compound, that consists of only one component with definite physical and chemical properties and a definite composition.

Compound -  in chemistry, a substance made up of two or more elements in union. The elements are united chemically, which means that each of the original elements loses its individual characteristics once it has combined with the other element

A Compound is a Substance which can be broken down into other substances.

A Substance is made of only one kind of matter and is part of a mixture.