Amedeo Avogadro was born on June 9, 1776 in Turin, Italy. As he persued his career in chemistry and physics he based most of his work on the findings of Joseph Gay-Lussac in 1809. Gay-Lussac had discovered that all the gases when subjected to an equal rise in temperature, expand by the same amount. He also made it clear that the gas particles need not be individual atoms but had made a distinction between the atoms of a substance and its molecules. Avogadro therefore derived his hypothesis known as Avogadro's Law. His law states that a given temperature, equal volumes of gases contain the same number of molecules equal to 6.02252E23.
Avagadro no recognition for his work during his lifetime. This was because of a few reasons. One was because he did not back up his hypothesis with enough experimentation to get the respect of the scientific community. He also did not possess a good reputation for experimentation, and he was fairly isolated from the scientific mainstream. Avagadro's work was not recognized for 50 years after he had made his hypothesis.
Two years after his death, his colleague showed how the use of Avogadro's number could solve many of the problems in chemistry. This time Avogadro's paper was looked at more carefully over a wider and more distinguished group of scientists, thus his work was finally recognized. From his hypothesis, using Avogadro's number, scientists arrived at the mole (6.02 x 10²³). Avogadro's work helped other scientists to solve more problems and develop more theories.
Avagadro died on July 9, 1856 in Turin, Italy.