Answer:
An impure substance is a material that contains the mixture of two or more pure substances. A pure substance can be an element, which is made up of only one atom or a compound, which is formed by the chemical bonding of one or more atoms. Some examples of pure substances include: water (H2O), Gold(Au), Salt(NaCl), Oxygen(O2), etc. Impure substances do not have a fixed boiling and melting points.