Amedeo Avogadro Italian physicist who originated the hypothesis that the equal volumes of all gasses, under the same pressure and temperature conditions, contain the same number of molecules. Avogadro made this hypothesis in 1811. It has since been fully proven and is now known as Avogadros law. Avogadro was born in Turin, Italy, an August 9th, 1776, to an artistic family. Avogadro practiced law and then studied physics and mathematics.
He was appointed professor of physics at Vercelli in 1809. In 1811 he set forth his famous hypothesis, now known as Avogadros law. The law stated that equal volumes of all gasses at the same emperature and pressure contain the same number of molecules. Avogadros law helped overcome flaws in John Daltons atomic theory. Avogadro also distinguished between an atom and a molecule, and made it possible to determine a correct table of atomic weights.
The correction and standardization of atomic weights began in 1858 when Stanislao Cannizzaro, an Italian chemist, reminded other chemists about Avogadros work. The hypothesis was virtually ignored by chemists because when it was tested in 1881 appropriate temperatures were not used by other scientists. 6. 0221367 x10 23 Avogadros number stated that a mole of any ubstance is that quantity of the substance that weighs (in grams) the same as its molecular weight.
For example, molecular oxygen, has a weight of 32 grams (16 for each oxygen atom); one mole of oxygen weighs 32 grams. A mole of a substance always contains the same number molecules –the Avogadros lawas a mole of any substance. Therefore, Avogadros law can be stated in terms of moles, namely that equal volumes of gases at the same temperature and pressure contain the same number of molecules by simply weighing out an equal number of moles. Avogadros number itself holds true for all substances, what ever there state.
