Relative Density The density of a substance is defined as mass per unit volume. Relative Density $=\frac{\text { Mass }}{\text { Volume }}$ S.I. unit of density is kg/m3 The relative density of a substance is the ratio of its density to that of water Relative Density $=\frac{\text { Density of substance }}{\text { Density of water at 4ºC }}$ Relative density … [Read more...] about Relative Density