Mole Day 2023

National Mole Day is celebrated annually on October 23rd from 6:02 a.m. to 6:02 p.m. It commemorates “Avogadro's Number” 6.02 x 10²³ - a basic measurement unit used in chemistry - in honour of the Italian physicist Amedeo Avogadro (1776-1858). Mole Day was created by chemistry teacher Maurice Oehlerto to foster interest in the world of chemistry amongst students. Now schools around the world celebrate Mole Day with various chemistry and mole-related activities.

What is a MOLE?

The mole (symbol mol) is the unit of measurement for amount of substance, a quantity proportional to the number of elementary entities of a substance. It is a base unit in the International System of Units (SI)​.

For a given molecule, one mole is a mass (in grams) whose number is equal to the atomic mass of the molecule. For example, the water molecule has an atomic mass of 18, therefore one mole of water weighs 18 grams.

An atom of neon has an atomic mass of 20, therefore one mole of neon weighs 20 grams. In general, one mole of any substance contains Avogadro’s Number of molecules or atoms of that substance. This relationship was first discovered by Avogadro and he received credit for this after his death.