(Torino 1776 - 1856)
Italian Physician and Chemist. He noted that gases in same condition of temperature and pressure contains same molecules number in same volume. He classifies substances in atoms and molecules. He defined the Avogadro Number as the number of molecules in a gram-molecule. By dividing the atomic weight of a substance for the Avogadro Number is possible to find the mass of a single molecule. The Avogadro Number is equal for all substances.
