Mole Conversions Tutorial1mole =602,214,150,000,000,000,000,000 Avogadro's Number
The number of carbon-12 atoms in 12 grams of unbound carbon in the ground state.Avogadro's number, the number of particles in a mole, can be experimentally determined by first "counting" the number of atoms in a smaller space and then scaling up to find the number of particles that would have a mass equal to the atomic or molecular mass in grams. Here is some real data from which Avogadro's number can be determined.
X-Ray diffraction studies show that gold consists of a repeating atomic arrangement where the repeating unit (called a cell unit) is a cube containing 4 gold atoms. Each side of the cube has a length of 4.08x10-8 cm. The density of gold is 19.3 g / cm3 and its atomic mass is 197.
The History of the Term"Mole"
The Avogadro constant is named after the early nineteenth century Italian scientist Amedeo Avogadro, who is credited (1811) with being the first to realize that the volume of a gas (strictly, of an ideal gas) is proportional to the number of atoms or molecules. The French chemist Jean Baptiste Perrin in 1909 proposed naming the constant in honor of Avogadro. American chemistry textbooks picked it up in the 1930's followed by high school textbooks starting in the 1950s.
The unit "mole" was introduced into chemistry around 1900 by Ostwald, and he originally defined this unit in terms of gram. Gram is a unit of mass; but what is the mole a unit of? Ostwald did not say;3 however, several years later, he did make it clear that the concept of mole should be linked to the ideal gas. 4
3"...the molecular weight of a substance, expressed in grams, shall henceforth be called mole [. . . das in Grammen augedruckte [. . .] Molekulargewicht eines Stoffes soll fortan ein Mol heissen]" Ref. 7).
4 "That amount of any gas that occupies a volume of 22414 mL in normal conditions is called one mole [eine solche Menge irgendeines Gases, welche das Volum von 22412 ccm im Normalzustand einnimt nennt man ein Mol]"
Ref. 8. Ostwald, W. Grundriss der allgemeinen Chemie, 5th ed.; Dresden: Steinkopff, 1917, p. 44
Real World Moles (wiki)
Mole Conversions Tutorial