Table of Contents
Relative density definition
Relative density is a measure of the density of a material relative to the density of another material. It is calculated by dividing the density of the material being measured by the density of the reference material.
The ratio of the mass of a substance to the mass of an equal volume of water.
Relative Density Measurement
Relative density is a measure of the ratio of the density of a substance to the density of a reference substance. The reference substance is usually water for liquids and solids, and air for gases.
Relative density is often expressed as a percent, where the density of the substance is divided by the density of the reference substance and multiplied by 100.
For example, the relative density of iron is 7.87 g/cm³ divided by 1 g/cm³ (the density of water) equals 7.87. So, the relative density of iron is 787%.
Relative Density Formula
Relative density is defined as the ratio of the density of a substance to the density of a reference substance. The reference substance is usually water for liquids and solids, and air for gases.
Relative density is usually expressed as a dimensionless quantity, i.e. it is a ratio with no units. However, in some cases it is expressed as a percentage or as specific gravity.
Relative density is also known as specific gravity.
Applications of Relative Density
The relative density of a substance is used in many different industries and applications. The relative density of a substance can be used to determine the purity of a substance, the amount of impurities in a sample, the weight of a substance, and the density of a substance.
In the pharmaceutical industry, relative density is used to determine the purity of drugs and other substances. The relative density of a substance can also be used to determine the amount of impurities in a sample.
In the food industry, relative density is used to determine the density of food products. The relative density of a substance can also be used to determine the weight of a substance.
In the cosmetics industry, relative density is used to determine the density of cosmetics. The relative density of a substance can also be used to determine the amount of impurities in a sample.
In the mining industry, relative density is used to determine the density of minerals. The relative density of a substance can also be used to determine the weight of a substance.
Density = Mass / Volume
Density and Specific Gravity are related by the following relationships.
Density (g/cm3) = Specific Gravity * Density of Water (g/cm3)
Density (lb/ft3) = Specific Gravity * Density of Water (lb/ft3)
Density (kg/m3) = Specific Gravity * Density of Water (kg/m3)
Density (lb/gal) = Specific Gravity * Density of Water (lb/gal)
Density (lb/ft3) = Density (kg/m3) * 0
Factors Affecting Measurement of Relative Density
There are several factors affecting the measurement of relative density. The determination of the true volume of a material is difficult. The expansion of solids and the compaction of powders make the determination of the true volume of the material difficult. There is also the difficulty in measuring the exact weight of the material. The use of glass containers for the determination of relative density is preferable to metal containers. It is difficult to clean the metal containers, and the residue of the previous determination may affect the result.
Measurement of Relative Density
by means of a Le Chatelier Flask
A Le Chatelier flask is a glass bulb with a small neck that is bent over to form a small loop. A Le Chatelier flask is used to determine the relative density of a liquid.
To use a Le Chatelier flask, fill the flask with the liquid to be measured. Suspend the flask from a balance so that the neck of the flask is pointing downwards. Place a weight on the neck of the flask. The weight should be equal to the weight of the liquid in the flask.
Now, gently heat the flask. The liquid in the flask will expand and the weight on the neck of the flask will be lifted. The amount by which the weight is lifted is a measure of the relative density of the liquid.
