What is the density of mercury in kg/m^3? What is it's density in g/cm^3? What is it's relative density?
The term "relative density" means the same as "specific gravity." It is a measure of how dense one thing is when compared to a given reference. The reference is usually water. With respect to water, the relative density of mercury is 13.56 because it is 13.56 times as dense as water.
The absolute density (how much a given volume of the substance weighs) of mercury is 13593 kilograms per cubic meter. This can also be stated as 13.56 grams per cubic centimeter (by definition, the density of a substance in kg/m^3 is 1000 times the density in g/cm^3).
The density means the mass per unit vume of any substance. In the standard metric system, we express mass in kilograms distance or length in metres. And that is for all purpose the standard units in science. Therefore, the density of any substance in the standard units is how much of mass of it is there in a volume of one cube of a meter or how much of the substance is there occupying one cubic meter volume .
The density of mercury = 13534kg/m^3 or 13.534gram/cubic centimeter
The realtive density means the the ratio of density of mercury to that of another substance. The relative density of mercury with respect to iron = density of mecury / the density of iron.
The relative density of iron with respect to mercury = density of iron/ density of mercury.
But normally we say relative density meaning the ratio of sensity of a substance with respect water. It is also called the specific density. And it has no units. It is a costant and remains same irrespective of dimensional units.