Name the substance having highest density and state the density of mercury in kg/m^3.

Density is a measure of the mass of a substance in a given volume and is thus given as the ratio of mass and volume of a substance. That is,

density = mass / volume.

Among the naturally occurring materials, the element Osmium is the densest and has a density of 22.5872 g/cm^3 or 22,587.2 kg/m^3. The element Iridium is a very close second, with a density of 22.56 g/cm^3. 

We can also make denser particles or substances. The densest man-made substance is the quark-gluon plasma, created in the Large Hadron Collider (LHC). 

The density of the element mercury is 13.5336 g/cm^3. 

It can be converted to kg/m^3, using the fact that there are 1000 grams in a kilogram and 1 million cm^3 in a m^3.

Thus, density = 13.5336 g/cm^3 x 1 kg/1000 g x 10^6 cm^3/m^3 

= 13,533.6 kg/m^3. 

Hope this helps.