By Little Pro on 2016-01-13 Views: Update:2017-01-18
Relative density is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material (i.e., water). It is usually measured at room temperature (20 Celcius degrees) and standard atmosphere (101.325kPa). It is unitless. You can often find it in the section 9 of a safety data sheet (SDS).
Relative density is often used to calculate the volume or weight of samples needed for preparing a solution with a specified concentration. It also helps us understand the environmental distribution of insoluble substances (i.e, oil spill) in aquatic eco-system (on water surface or bottom sediment) if the substance is released to water.
Relative density test is not required for every chemical. Under REACH, the study does not need to be conducted if: