Density is an intensive physical property that relates the mass of an object to its volume. density, which is simply the mass of an object divided by its volume, is expressed in the si derived unit g/mlg/ml for a liquid or g/cm3g/cm3 for a solid. most substances expand or contract when heated or cooled, so the density values for a substance are temperature dependent. a particular brand of gasoline has a density of 0.737 g/ml at 25 ? c. how many grams of this gasoline would fill a 14.6gal tank?