Held annually on October 23, 6:02 a.m. at 6:02 p.m., the Mole Day commemorates the Avogadro Number (6.02 x 1023), which is a basic unit of measurement in chemistry. Topo Day was created as a way to encourage interest in chemistry. Schools throughout the United States and around the world celebrate Topo Day with various activities related to chemistry and / or moles.
For a given molecule, a mole is a mass (in grams) whose number is equal to the molar mass of the molecule. For example, the water molecule has a molar mass of 18, therefore, one mole of water weighs 18 grams. Similarly, a neon mass has a molar mass of 20 grams. In general, a mole of any substance contains the number of molecules or atoms of that substance of Avogadro. This relationship was first discovered by Amadeo Avogadro (1776-1858) and he received credit for this after his death.