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Amedeo Avogadro
Born	August 9, 1776 Turin
Died	July 9, 1856
Nationality	Italian
Fields	Chemistry
Institutions	University of Turin
Known for	Avogadro's Law Avogadro's number

Lorenzo Romano Amedeo Carlo Avogadro di Quaregna e di Cerreto, Count of Quaregna and Cerreto (August 9, 1776 – July 9, 1856) was an Italian savant. He is most noted for his contributions to the theory of molarity and molecular weight and also formulated Avogadro's Law. In tribute to him, the number of elementary entities (atoms, molecules, ions or other particles) in one mole of a substance, 6.02214199 x 10²³, is known as Avogadro's number. Image File history File links This is a lossless scalable vector image. ... Albert Avogadro (1149-September 14, 1214), was a canon lawyer who served as Latin Patriarch of Jerusalem from 1204 until his death. ... Avogardro is an ancient lunar crater that is located in the northern hemisphere on the far side of the Moon. ... is the 221st day of the year (222nd in leap years) in the Gregorian calendar. ... For other uses, see 1776 (disambiguation). ... Torino redirects here. ... is the 190th day of the year (191st in leap years) in the Gregorian calendar. ... 1856 was a leap year starting on Tuesday (see link for calendar). ... For other uses, see Chemistry (disambiguation). ... The University of Turin (Italian Università degli Studi di Torino, UNITO) is a university in the city of Turin in the Piedmont region of north-western Italy. ... This article does not cite any references or sources. ... Avogadros number, also called Avogadros constant (NA), named after Amedeo Avogadro, is formally defined to be the number of carbon-12 atoms in 12 grams (0. ... Coronet of a count This article is about the style or title of nobility. ... Quaregna is a comune (municipality) in the Province of Biella in the Italian region Piedmont, located about 70 km northeast of Turin and about 4 km northwest of Biella. ... is the 221st day of the year (222nd in leap years) in the Gregorian calendar. ... For other uses, see 1776 (disambiguation). ... is the 190th day of the year (191st in leap years) in the Gregorian calendar. ... 1856 was a leap year starting on Tuesday (see link for calendar). ... Look up savant in Wiktionary, the free dictionary. ... This page refers to concentration in the chemical sense. ... This article does not cite any references or sources. ... For other uses, see Atom (disambiguation). ... 3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ... This article is about the electrically charged particle. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... Avogadros number, also called Avogadros constant (NA), named after Amedeo Avogadro, is formally defined to be the number of carbon-12 atoms in 12 grams (0. ...

Biography

Amedeo Avogadro was born in Turin to a noble family of Piedmont, Italy. Torino redirects here. ... For other uses, see Piedmont (disambiguation). ...

He graduated in ecclesiastical law at the early age of 20 and began to practice. Soon after, he dedicated himself to physics and mathematics (then called positive philosophy), and in 1809 started teaching them at a liceo (high school) in Vercelli, where his family had property. In Western culture, canon law is the law of the Roman Catholic and Anglican churches. ... A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... For other meanings of mathematics or uses of math and maths, see Mathematics (disambiguation) and Math (disambiguation). ... Vercelli (Varséj in Piedmontese; Vercellae in Latin) is a commune and city of about 46,000 inhabitants in the Province of Vercelli, Italy. ...

In 1811, he published an article with the title Essai d'une manière de déterminer les masses relatives des molécules élémentaires des corps, et les proportions selon lesquelles elles entrent dans ces combinaisons ("Essay on Determining the Relative Masses of the Elementary Molecules of Bodies and the Proportions by Which They Enter These Combinations"), which contains Avogadro's hypothesis. Avogadro submitted this essay to a French journal, De Lamétherie's Journal de Physique, de Chimie et d'Histoire naturelle (Journal of Physics, Chemistry and Natural History) so it was written in French, not Italian. (Note: In 1811, northern Italy was under the rule of the French Emperor Napoléon Bonaparte.) Bonaparte as general Napoléon Bonaparte (15 August 1769 – 5 May 1821) was a general of the French Revolution and was the ruler of France as First Consul (Premier Consul) of the French Republic from November 11, 1799 to May 18, 1804, then as Emperor of the French (Empereur des Français...

In 1820, he became professor of physics at the University of Turin. After the downfall of Napoléon in 1815, northern Italy came under control of this kingdom. Torino redirects here. ...

He was active in the revolutionary movements of 1821 against the king of Sardinia (who became ruler of Piedmont with Turin as his capital). As a result, he lost his chair in 1823 (or the university officially declared, it was "very glad to allow this interesting scientist to take a rest from heavy teaching duties, in order to be able to give better attention to his researches")^{[citation needed]}. The House of Savoy was a dynasty of nobles who traditionally had their domain in Savoy, a region between Piedmont, Italy, France and French-speaking Switzerland. ... Sardinia (pronounced ; Italian: ; Sardinian: or ) is the second-largest island in the Mediterranean Sea (after Sicily). ...

Eventually, Charles Albert granted a Constitution (Statuto Albertino) in 1848. Well before this, Avogadro had been recalled to the university in Turin in 1833, where he taught for another twenty years. Charles Albert (October 2, 1798_July 28, 1849) was the Duke of Savoy, Piedmont, Aosta and King of Sardinia from 1831 to 1849. ... The so-called Statuto Albertino (Albertine Statute) is the constitution that King Charles Albert of Savoy conceded to the Kingdom of Sardinia (including also most parts of north-western Italy, such as Piedmont) on March 4, 1848. ...

Little is known about Avogadro's private life, which appears to have been sober and religious. He married Felicita Mazzé and had six children.

Some historians suggest that he sponsored some Sardinian revolutionaries, who were stopped by the announcement of Charles Albert's constitution.

Avogadro held posts dealing with statistics, meteorology, and weights and measures (he introduced the metric system into Piedmont) and was a member of the Royal Superior Council on Public Instruction. The International System of Units (symbol: SI) (for the French phrase Syst me International dUnit s) is the most widely used system of units. ...

In honour of Avogadro's contributions to the theory of molarity and molecular weights, the number of molecules in one mole was named Avogadro's number, N_A or "Avogadro's constant". It is approximately 6.0221415 × 10²³. Avogadro's number is used to compute the results of chemical reactions. It allows chemists to determine the exact amounts of substances produced in a given reaction. This page refers to concentration in the chemical sense. ... The mole (symbol: mol) is the SI base unit that measures an amount of substance. ... Avogadros number, also called Avogadros constant (NA), named after Amedeo Avogadro, is formally defined to be the number of carbon-12 atoms in 12 grams (0. ...

Johann Josef Loschmidt first calculated the value of Avogadro's number, often referred to as the Loschmidt number in German-speaking countries (Loschmidt constant now has another meaning). Jan or Johann Josef Loschmidt (March 15, 1821 - July 8, 1895) who referred to himself mostly as Josef (omitting his first name), was a notable Austrian scientist who performed groundbreaking work in chemistry, physics (thermodynamics, optics, electrodynamics) and crystal forms. ... In chemistry and physics, the Loschmidt number is the number density of an ideal gas at standard temperature and pressure, . It is named after the Austrian chemist Johann Josef Loschmidt, who calculated, in 1865, the number of molecules of such a gas in one cubic centimeter. ... Avogadros number, also called Avogadros constant (NA), named after Amedeo Avogadro, is a constant used in chemistry and physics. ...

Accomplishments

Avogadro's Law states that the relationship between the masses of the same volume of different gases (at the same temperature and pressure) corresponds to the relationship between their respective molecular weights. Hence, the relative molecular mass of a gas can be calculated from the mass of sample of known volume.

Avogadro developed this hypothesis after Joseph Louis Gay-Lussac had published in 1808 his law on volumes (and combining gases). The greatest problem Avogadro had to resolve was the confusion at that time regarding atoms and molecules. One of his most important contributions was clearly distinguishing one from the other, stating that gasses are composed of molecules, and these molecules are composed of atoms. For instance, John Dalton did not consider this possibility. Avogadro did not actually use the word "atom" as the words "atom" and "molecule" were used almost without difference. He believed that there were three kinds of "molecules," including an "elementary molecule" (our "atom"). Also, more attention was given to the definition of mass, as distinguished from weight. Joseph Louis Gay-Lussac. ... The Law of Charles and Gay-Lussac (frequently called simply Charles Law) is one of the gas laws, and relates the volume and temperature of an ideal gas held at a constant pressure. ... John Dalton John Dalton (September 6, 1766 – July 27, 1844) was an English chemist and physicist, born at Eaglesfield, near Cockermouth in Cumberland. ... For other uses, see Mass (disambiguation). ... For other uses, see Weight (disambiguation). ...

In 1814, he published Mémoire sur les masses relatives des molécules des corps simples, ou densités présumées de leur gaz, et sur la constitution de quelques-uns de leur composés, pour servir de suite à l'Essai sur le même sujet, publié dans le Journal de Physique, juillet 1811 ("Note on the Relative Masses of Elementary Molecules, or Suggested Densities of Their Gasses, and on the Constituents of Some of Their Compounds, As a Follow-up to the Essay on the Same Subject, Published in the Journal of Physics, July 1811") ([1]), about gas densities.

In 1821 he published another paper, Nouvelles considérations sur la théorie des proportions déterminées dans les combinaisons, et sur la détermination des masses des molécules des corps (New Considerations on the Theory of Proportions Determined in Combinations, and on Determination of the Masses of Atoms) and shortly afterwards, Mémoire sur la manière de ramener les composès organiques aux lois ordinaires des proportions déterminées (Note on the Manner of Finding the Organic Composition by the Ordinary Laws of Determined Proportions).

In 1841, he published his work in Fisica dei corpi ponderabili, ossia Trattato della costituzione materiale de' corpi, 4 volumes.

Response to the theory

The scientific community did not give great attention to his theory, so Avogadro's hypothesis was not immediately accepted. André-Marie Ampère achieved the same results three years later by another method (in his Sur la détermination des proportions dans lesquelles les corps se combinent d'après le nombre et la disposition respective des molécules dont leurs particules intégrantes sont composées -- On the Determination of Proportions in which Bodies Combine According to the Number and the Respective Disposition of the Molecules by Which Their Integral Particles Are Made), but the same indifference was shown to his theory as well. André-Marie Ampère (January 20, 1775 – June 10, 1836), was a French physicist who is generally credited as one of the main discoverers of electromagnetism. ...

Only through studies by Charles Frédéric Gerhardt and Auguste Laurent on organic chemistry was it possible to demonstrate that Avogadro's law explained why the same quantities of molecules in a gas have the same volume. Charles Frédéric Gerhardt (August 21, 1816 - August 19, 1856) was a French chemist. ... Auguste Laurent (November 14, 1807 _ April 23, 1853) was a French chemist who discovered anthracene, discovered phthalic acid, and identified carbolic acid. ... Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting primarily of carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, the halogens as...

Unfortunately, related experiments with some inorganic substances showed seeming exceptions to the law. This was finally resolved by Stanislao Cannizzaro, as announced at Karlsruhe Congress in 1860, four years after Avogadro's death. He explained that these exceptions were due to molecular dissociations at certain temperatures, and that Avogadro's law determined not only molecular masses, but atomic masses as well. Stanislao Cannizzaro (July 13, 1826 - May 10, 1910) was an Italian chemist. ... Karlsruhe (population 285,812 in 2006) is a city in the south west of Germany, in the Bundesland Baden-Württemberg, located near the French-German border. ...

In 1911, a meeting in Turin commemorated the hundredth anniversary of the publication of Avogadro's classic 1811 paper. King Victor Emmanuel III attended. Thus Avogadro's great contribution to chemistry was recognised. Torino redirects here. ... Victor Emmanuel III (Italian: ; 11 November 1869 – 28 December 1947) was King of Italy (29 July 1900 – 9 May 1946), Emperor of Ethiopia (1936–43) and King of Albania (1939–43). ...

Rudolf Clausius, with his kinetic theory on gases, gave another confirmation of Avogadro's law. Jacobus Henricus van 't Hoff showed that Avagadro's theory also held in dilute solutions. Rudolf Clausius - physicist and mathematician Rudolf Julius Emanuel Clausius (January 2, 1822 – August 24, 1888), was a German physicist and mathematician. ... Jacobus Henricus van t Hoff (August 30, 1852 - March 1, 1911) was a Dutch physical and organic chemist and the winner of the inaugural Nobel Prize in chemistry. ...

Avogadro is hailed as a founder of the atomic-molecular theory. This article focuses on the historical models of the atom. ...

Further reading

• Pierson (1984), "Avogadro and His Work: Amedeo Avogadro.", Science 226 (4673): 432-433, 1984 Oct 26, PMID:17799933, doi:10.1126/science.226.4673.432, <http://www.ncbi.nlm.nih.gov/pubmed/17799933> 
• Hinshelwood & Pauling (1956), "Amedeo Avogadro.", Science 124 (3225): 708-713, 1956 Oct 19, PMID:17757602, doi:10.1126/science.124.3225.708, <http://www.ncbi.nlm.nih.gov/pubmed/17757602> 
• CAVANNA, D (1956), "[Centenary of the death of Amedeo Avogadro.]", Minerva farmaceutica 5 (6): 134-7, 1956 Jun, PMID:13369233, <http://www.ncbi.nlm.nih.gov/pubmed/13369233> 
• Crosland, M.P. (1970). "Avogadro, Amedeo". Dictionary of Scientific Biography 1. New York: Charles Scribner's Sons. 343-350. ISBN 0684101149. 
• Morselli, Mario. (1984). Amedeo Avogadro, a scientific biography. Kluwer. ISBN 9027716242.

This article is about the year. ... Science is the academic journal of the American Association for the Advancement of Science and is considered one of the worlds most prestigious scientific journals. ... PMID is an acronym for PubMed Identifier or more specifically PubMed Unique Identifier which is a unique number assigned to each PubMed citation of life sciences and biomedical scientific journal articles. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A car from 1956 Year 1956 (MCMLVI) was a leap year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... Science is the academic journal of the American Association for the Advancement of Science and is considered one of the worlds most prestigious scientific journals. ... PMID is an acronym for PubMed Identifier or more specifically PubMed Unique Identifier which is a unique number assigned to each PubMed citation of life sciences and biomedical scientific journal articles. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A car from 1956 Year 1956 (MCMLVI) was a leap year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... PMID is an acronym for PubMed Identifier or more specifically PubMed Unique Identifier which is a unique number assigned to each PubMed citation of life sciences and biomedical scientific journal articles. ... The Dictionary of Scientific Biography is a reference work consisting of extensive biographies of scientists from antiquity to modern times, excluding scientists who were alive when the Dictionary was first put out. ...

See also

• Avogadro (lunar crater)
• Avogadro's constant