Antoine Lavoisier : biography
Antoine-Laurent de Lavoisier (also Antoine Lavoisier after the French Revolution; 26 August 17438 May 1794; ) was a French nobleman and chemist central to the 18th-century Chemical Revolution and a large influence on both the histories of chemistry and biology.
He is widely considered to be the "Father of Modern Chemistry."", He is also considered as the "Father of Modern Nutrition", as being the first to discover the metabolism that occurs inside the human body. " Encyclopædia Britannica. 2007. Encyclopædia Britannica Online. 24 July 2007.
It is generally accepted that Lavoisier’s great accomplishments in chemistry largely stem from the fact that he changed the science from a qualitative to a quantitative one. Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783) and disproved the phlogiston theory, which was universally accepted in his time. Lavoisier helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He predicted the existence of silicon (1787)In his table of the elements, Lavoisier listed five "salifiable earths" (i.e., ores that could be made to react with acids to produce salts (salis = salt, in Latin)): chaux (calcium oxide), magnésie (magnesia, magnesium oxide), baryte (barium sulfate), alumine (alumina, aluminum oxide), and silice (silica, silicon dioxide). About these "elements", Lavoisier speculates: "We are probably only acquainted as yet with a part of the metallic substances existing in nature, as all those which have a stronger affinity to oxygen than carbon possesses, are incapable, hitherto, of being reduced to a metallic state, and consequently, being only presented to our observation under the form of oxyds, are confounded with earths. It is extremely probable that barytes, which we have just now arranged with earths, is in this situation; for in many experiments it exhibits properties nearly approaching to those of metallic bodies. It is even possible that all the substances we call earths may be only metallic oxyds, irreducible by any hitherto known process." — from of: Lavoisier with Robert Kerr, trans., Elements of Chemistry, … , 4th ed. (Edinburgh, Scotland: William Creech, 1799). (The original passage appears in: Lavoisier, Traité Élémentaire de Chimie, … (Paris, France: Cuchet, 1789), vol. 1, .) and was also the first to establish that sulfur was an element (1777) rather than a compound.C.Michael Hogan. 2011. He discovered that, although matter may change its form or shape, its mass always remains the same.
Lavoisier was an administrator of the Ferme Générale and a powerful member of a number of other aristocratic councils. All of these political and economic activities enabled him to fund his scientific research. At the height of the French Revolution, he was accused by Jean-Paul Marat of selling adulterated tobacco and of other crimes, and was eventually guillotined a year after Marat’s death. Benjamin Franklin was familiar with Lavoisier, as they were both members of the "Benjamin Franklin inquiries" into Mesmer and animal magnetism.
Lavoisier’s fundamental contributions to chemistry were a result of a conscious effort to fit all experiments into the framework of a single theory. He established the consistent use of the chemical balance, used oxygen to overthrow the phlogiston theory, and developed a new system of chemical nomenclature which held that oxygen was an essential constituent of all acids (which later turned out to be erroneous). Lavoisier also did early research in physical chemistry and thermodynamics in joint experiments with Laplace. They used a calorimeter to estimate the heat evolved per unit of carbon dioxide produced, eventually finding the same ratio for a flame and animals, indicating that animals produced energy by a type of combustion reaction.