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Antoine Lavoisier

2007 Schools Wikipedia Selection. Related subjects: Chemists

   CAPTION: Antoine Lavoisier

   Father of modern chemistry
      Born:    August 26, 1743
               Paris, France
      Died:    May 8, 1794
               Paris, France
   Occupation: Chemist, economist and nobleman.

   Antoine-Laurent de Lavoisier ( August 26, 1743 – May 8, 1794) the "
   father of modern chemistry," was a French nobleman prominent in the
   histories of chemistry, finance, biology, and economics.

   He stated the first version of the Law of conservation of mass,
   co-discovered, recognized and named oxygen (1778) as well as hydrogen,
   disproved the phlogiston theory, introduced the Metric system, invented
   the first periodic table including 33 elements, and helped to reform
   chemical nomenclature. He was also an investor and administrator of the
   " Ferme Générale," a private tax collection company; chairman of the
   board of the Discount Bank (later the Banque de France); and a powerful
   member of a number of other aristocratic administrative councils.

   Due to his prominence in the pre-revolutionary government in France, he
   was beheaded at the height of the French Revolution, instructing his
   assistant to count the number of words his severed head attempted to
   mouth.

Early life

   Portrait of Monsieur Lavoisier and his Wife, by Jacques-Louis David.
   Enlarge
   Portrait of Monsieur Lavoisier and his Wife, by Jacques-Louis David.

   Born to a wealthy family in Paris, Antoine Laurent Lavoisier inherited
   a large fortune when his mother died. He attended the College Mazarin
   from 1754 to 1761, studying chemistry, botany, astronomy, and
   mathematics. His education was filled with the ideals of the French
   Enlightenment of the time, and he felt fascination for Maquois's
   dictionary. His devotion and passion for chemistry was largely
   influenced by Étienne Condillac, a prominent French scholar of the 18th
   century. His first chemical publication appeared in 1764. In 1767 he
   worked on a geological survey of Alsace-Lorraine. He was elected a
   member of the French Academy of Sciences, France's most elite
   scientific society, at the age of 25 in 1768 for an essay on street
   lighting and in recognition for his earlier research. In 1769 he worked
   on the first geological map of France.

   In 1771, he married the 13-year-old Marie-Anne Pierrette Paulze, the
   daughter of a co-owner of the Ferme. With time, she proved to be a
   scientific colleague to her husband. She translated documents from
   English for him, including Richard Kirwan's "Essay on Phlogiston" and
   Joseph Priestley's research. She created many sketches and carved
   engravings of the laboratory instruments used by Lavoisier and his
   colleagues. She also edited and published Lavoisier’s memoirs and
   hosted many parties during which eminent scientists would discuss new
   chemical theories. As a result of her close work with her husband, it
   is difficult to separate her individual contributions from his, but it
   is correctly assumed that much of the work accredited to him bears her
   fingerprints.

Contributions to chemistry

   Portrait of Antoine Lavoisier in his youth.
   Enlarge
   Portrait of Antoine Lavoisier in his youth.

Background

   Beginning in 1775, Lavoisier served in the Royal Gunpowder
   Administration, where his work led to improvements in the production of
   gunpowder and the use of agricultural chemistry by designing a new
   method for preparing saltpeter.
   Hand sketch design aparatus for hydrogen combustion experiment made by
   Lavoisier in the 1780s.
   Enlarge
   Hand sketch design aparatus for hydrogen combustion experiment made by
   Lavoisier in the 1780s.

Major works

   Some of Lavoisier's most important experiments examined the nature of
   combustion, or burning. Through these experiments, he demonstrated that
   burning is a process that involves the combination of a substance with
   oxygen. He also demonstrated the role of oxygen in metal rusting, as
   well as its role in animal and plant respiration: working with
   Pierre-Simon Laplace, Lavoisier conducted experiments that showed that
   respiration was essentially a slow combustion of organic material using
   inhaled oxygen. Lavoisier's explanation of combustion replaced the
   phlogiston theory, which postulates that materials release a substance
   called phlogiston when they burn.

Research on hydrogen and his role in disproving the phlogiston theory

   Apparatus for hydrogen combustion experiment made from Lavoisier's
   sketch by Jean Baptiste Meusnier in 1783.
   Enlarge
   Apparatus for hydrogen combustion experiment made from Lavoisier's
   sketch by Jean Baptiste Meusnier in 1783.

   He also discovered that the flammable air of Henry Cavendish which he
   termed hydrogen ( Greek for "water-former"), combined with oxygen to
   produce a dew, as Joseph Priestley had reported, which appeared to be
   water. Lavoisier's work was partly based on the work of Priestley (he
   corresponded with Priestley and fellow members of the Lunar Society).
   However, he tried to take credit for Priestley's discoveries. This
   tendency to use the results of others without acknowledgment, then draw
   conclusions of his own, is said to be characteristic of Lavoisier. In
   "Sur la combustion en général" ("On Combustion in general," 1777) and
   "Considérations Générales sur la Nature des Acides" ("General
   Considerations on the Nature of Acids," 1778), he demonstrated that the
   "air" responsible for combustion was also the source of acidity. In
   1779, he named this part of the air "oxygen" (Greek for "acid-former"),
   and the other "azote" (Greek for "no life"). In "Réflexions sur la
   Phlogistique" ("Reflections on Phlogiston," 1783), Lavoisier showed the
   phlogiston theory to be inconsistent.

Pioneer of stoichiometry

   Laboratory instruments used by Lavoisier circa 1780s.
   Enlarge
   Laboratory instruments used by Lavoisier circa 1780s.

   Lavoisier's experiments were among the first truly quantitative
   chemical experiments ever performed; that is, he carefully weighed the
   reactants and products involved, a crucial step in the advancement of
   chemistry. He showed that, although matter can change its state in a
   chemical reaction, the quantity of matter is the same at the end as at
   the beginning of every chemical reaction. He burnt phosphorus and
   sulphur in air, and proved that the products weighed more than the
   original. Nevertheless, the weight gained was lost from the air. These
   experiments provided evidence for the law of the conservation of
   matter, or in other words, the law of conservation of mass.

Major works on analytical chemistry and chemical nomenclature

   Lavoisier also investigated the composition of water and air, which at
   the time were considered elements. He discovered the components of
   water were oxygen and hydrogen, and that air was a mixture of gases -
   primarily nitrogen and oxygen. With the French chemists Claude-Louis
   Berthollet, Antoine Fourcroy and Guyton de Morveau, Lavoisier devised a
   chemical nomenclature, or a system of names describing the structure of
   chemical compounds. He described it in Méthode de nomenclature chimique
   (Method of Chemical Nomenclature, 1787). Their system facilitated
   communication of discoveries between chemists of different backgrounds
   and is still largely in use today, including names such as sulfuric
   acid, sulfates, and sulfites.
   A replica of Lavoisier's laboratory at the Deutsches Museum in Munich,
   Germany.
   Enlarge
   A replica of Lavoisier's laboratory at the Deutsches Museum in Munich,
   Germany.

   His Traité Élémentaire de Chimie (Elementary Treatise of Chemistry,
   1789, translated into English by Robert Kerr) is considered to be the
   first modern chemical textbook, and presented a unified view of new
   theories of chemistry, contained a clear statement of the Law of
   Conservation of Mass, and denied the existence of phlogiston. Also,
   Lavoisier clarified the concept of an element as a simple substance
   that could not be broken down by any known method of chemical analysis,
   and he devised a theory of the formation of chemical compounds from
   elements.
   Combustion, generated by focusing sun light over flammable materials
   using lenses, experiment conducted by Lavosier circa 1770s.
   Enlarge
   Combustion, generated by focusing sun light over flammable materials
   using lenses, experiment conducted by Lavosier circa 1770s.

   In addition, it contained a list of elements, or substances that could
   not be broken down further, which included oxygen, nitrogen, hydrogen,
   phosphorus, mercury, zinc, and sulphur. It also forms the basis for the
   modern list of elements. His list, however, also included light and
   caloric, which he believed to be material substances. While many
   leading chemists of the time refused to believe Lavoisier's new
   revelations, the Elementary Treatise was written well enough to
   convince the younger generation.
   Lavoisier while conducting combustion experiment.
   Enlarge
   Lavoisier while conducting combustion experiment.

Aftermath

   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 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 made introductory research on physical chemistry and
   thermodynamics in joint experiment with Laplace, when he used a
   calorimeter to estimate the heat evolved per unit of carbon dioxide
   produced, eventually they found the same ratio for a flame and animals,
   indicating that animals produced energy by a type of combustion.
   Constant pressure calorimeter made by Lavoisier for chemical enthalpy
   experiment.
   Enlarge
   Constant pressure calorimeter made by Lavoisier for chemical enthalpy
   experiment.

   He also made remarkable contributions to chemical bonding by stating
   the radical theory, believing that radicals, which function as a single
   group in a chemical reaction, would combine with oxygen in reactions.
   He also introduced the possibility of allotropy in chemical elements
   when he discovered that diamond is a crystalline form of carbon.

   He also updated many chemical concepts, for the first time the modern
   notion of elements was laid out systematically; the three or four
   elements of classical chemistry gave way to the modern system, and
   Lavoisier worked out reactions in chemical equations that respect the
   conservation of mass (see, for example, the nitrogen cycle).
   Lavoisier conducting an experiment in the 1770s.
   Enlarge
   Lavoisier conducting an experiment in the 1770s.

   His contributions are considered the most important in advancing the
   science of chemistry to the level of what had been achieved in physics
   and mathematics during 18th century.

Contributions to biology

   Lavoisier used a calorimeter to measure heat production as a result of
   respiration in a guinea pig. The outer shell of the calorimeter was
   packed with snow, which melted to maintain a constant temperature of 0
   °C around an inner shell filled with ice. The guinea pig in the centre
   of the chamber produced heat which melted the ice. The water which
   flowed out of the calorimeter was collected and weighed. 1 kg melted
   ice = 80 kcal heat production by the guinea pig. He concluded, "la
   respiration est donc une combustion." That is, respiratory gas exchange
   is a combustion, like that of a candle burning.

Law and politics

   Of key significance in Lavoisier's life was his study of law. He
   received a law degree and was admitted to the bar, but never practiced
   as a lawyer. He did become interested in French politics, and as a
   result, he obtained a position as tax collector in the Ferme Générale,
   a tax farming company, at the age of 26, where he attempted to
   introduce reforms in the French monetary and taxation system. While in
   government work, he helped develop the metric system to secure
   uniformity of weights and measures throughout France.

Execution

   As one of 28 French tax collectors and a powerful figure in the
   unpopular Ferme Générale, Lavoisier was branded a traitor during the
   Reign of Terror by revolutionists in 1794. He was tried, convicted, and
   guillotined on the same day in Paris, at the age of 51. Ironically,
   Lavoisier was one of the few liberals in his position. One of his
   actions that may have sealed his fate was a contretemps a few years
   earlier with the young Jean-Paul Marat, who subsequently became a
   leading revolutionary.

   An appeal to spare his life was cut short by the judge: "The Republic
   has no need of geniuses [or, alternately, "scientists"]." His
   importance for science was expressed by the mathematician Joseph Louis
   Lagrange who lamented the beheading by saying: "It took them only an
   instant to cut off that head, but France may not produce another like
   it in a century."

   One and a half years following his death, Lavoisier was exonerated by
   the French government. When his private belongings were delivered to
   his widow, a brief note was included reading "To the widow of
   Lavoisier, who was falsely convicted".

   About a century after his death, a statue of Lavoisier was erected in
   Paris. It was later discovered that the sculptor had not actually
   copied Lavoisier's head for the statue, but used a spare head of the
   Marquis de Condorcet, the Secretary of the Academy of Sciences during
   Lavoisier's last years. Lack of money prevented alterations being made.
   The statue was melted down during the Second World War and has never
   been replaced.
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