Amedeo Avogadro, known for enacting the law that bears his name

August 9, 1776, Turin (Italy) – July 9, 1856, Turin (Italy)

His full name was Lorenzo Romano Amedeo Carlo Avogadro and he was an Italian physicist and chemist who pursued his career as a physics professor at the University of Turin.

The son of a magistrate belonging to an ancient Piedmont family, he followed in his father's footsteps and obtained a licentiate in canon law in 1796. He registered as a lawyer in his hometown, Turin, but his passion for physics and mathematics, which was cultivated alone, pushed him to undertake scientific studies obtaining, in 1809, at the age of 33, a position as professor of physics at the Royal College of Vercelli.

He is known for formulating his Law of Avogadro, which states that “equal volumes of different gases, under the same conditions of pressure and temperature, contain the same number of molecules”. To do this, he relied on John Dalton's atomic theory and Gay-Lussac's Law on the movement vectors in the molecule.

The greatest difficulty that he had to overcome was related to the existing confusion at that time between atoms and molecules and that the scientific community did not give a good reception to his theories, not immediately accepting his hypotheses. We had to wait for the work of Gerhardt, Laurent, and Williamson on organic molecules to show that Avogadro's Law was essential to explain why equal numbers of molecules occupied the same volume in the gaseous state.

In his honor, the name was given to Avogadro's number or constant (L or NA) which is the number of constituent particles (usually atoms or molecules) that are found in the amount of a substance of one mole. Therefore, it is the proportional factor that relates the molar mass of a substance to the mass of a sample. Its value is equal to 6.023 x 1023.