Mole History Timeline

Mole History

A brief timeline about the

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1805 John dalton published the first table of standard atomic weight, wich was based in wich the relative atomic number of hydrogen is one.

1807 Dalton's friend Thomas Thompson published his article on "equivalent weight", there were some people who were not happy on thins article because they didn't accept that he changed the terms form the atomic weight to the equivalent weight.

1808 John Dalton used Proust and Richter’s work as an empirical reference for his atomic hypothesis. He suggested that chemical combinations were made by discrete units, atom by atom and that all atoms belonging to the same element are identical.

1808 Joseph Louis Gay-Lussac conducted a cavendish experiment of water formation, after many hours of abservations and tests he concluded that "‘‘It appears to me that gases alwayscombine in the simplest proportions when they act on one another; and we have seen in reality in all the preceding examples that the ratio of combinations is 1 to 1, 1 to 2 or 1 to 3’’ Dalton did not accept Gay-Lussac’s results, because whole numbers were not obtained in those experiments.

1811 Amedeo Avogadro formulated his first hypothesis, based on Bernoulli’s kinetic model of gases, which also explained Gay-Lussac’s law.

1814 There were some people who didn't agree with Dalton's publication back in 1807, Willian Wollaston was one of the people who didn't agree with Dalton's work, he published a paper in 1814 Dalton’s ideas to promote the equivalent term.

1828 Jöns Jacob Berzelius was the first chemist to use oxygen as the standard to which other masses were referred. he also was instrumental in the determination of relative atomic masses to ever-increasing accuracy. Oxygen is a useful standard, unlike as hydrogen, it forms compounds with most other elements, especially metals. However, he chose to fix the atomic mass of oxygen as 100, which did not catch on.

1860 Charles Frédéric Gerhardt, Henri Victor Regnault and Stanislao Cannizzaro expanded and modified Berzelius' works, resolving many of the problems of unknown stoichiometry of compounds, and the use of atomic masses attracted a large consensus by the time of the Karlsruhe Congress.

1894-1897 The name mole in 1897 translation from the German unit Mol, this name was given by the qemist Wilhelm Ostwald from the german word Molekül, wich means molecule, the concept was related to the concept of "equivalent masses" wich has been used in the previous century.

1961 The term ‘mole’ represented, within the atomistic paradigm, ‘the amount of substance that contains the same number of elementary entities (atoms, ions, molecules, etc.) as atoms contained in 12 grams of 12C’. Guggenheim defined ‘amount of substance’ as a different magnitude to mass and weight, but proportional to them.

Fact The mole history is connected with the history of molecular mass, atomic mass units, and the Avogadro number.