# Amount of Substance Calculation

Amount of Substance is also called as material quantity. The amount of substance refers to a standards-defined quantity that measures the size of an ensemble of elementary entities, such as atoms, molecules, electrons, and other particles. Amount of substance appears in thermodynamic relations such as the ideal gas law, and in stoichiometric relations between reacting molecules as in the law of multiple proportions. The unit symbol of amount of substance is mole.
Amount of substance (n) Calculation
 Mass kg Molar Mass g/mol Amount of Substance mole
Formula
Amount of substance (n) = Mass (m)/Molar mass (M)
The mole is defined as the amount of substance that contains an equal number of elementary entities as there are atoms in 0.012kg of the isotope carbon-12. One mole is equal to approximately 6.022169 x 10 23 , and is also called the Avogadro constant.

Example:
Calculate the amount of substance when mass and molar mass of substance is known.
Mass (kg) = 25
Molar Mass (g/mol) = 20

Solution:
Apply Formula:
Amount of substance (n) = Mass (m)/Molar mass (M)
Amount of Substance (n) = 25/20

Amount of Substance (n) = 1.25 mole