Antoine Lavoisier: Difference between revisions

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[[Image:Hidrogenexp1.jpg|thumb|250px|left|[[Drawing|Hand sketch]] design aparatus for hydrogen combustion experiment made by Lavoisier in the [[1780s]].]]

He also discovered that the inflammable 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 is said to be characteristic of Lavoisier. In ''Sur la combustion en general'' (''On Combustion in general''), [[1777]] and ''Considérations Générales sur la Nature des Acides'' (General Consideration 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 ''Reflexions sur le Phlogistique'', [[1783]], Lavoisier showed the [[phlogiston theory]] to be inconsistent.

[[Image:Hidrogenexp2.gif|thumb|170px|right|Aparatus for hydrogen combustion experiment made from Lavoisier's sketch by Jean Baptiste Meusnier in [[1783]].]]

[[Image:Instruments_lavoisier.jpg|thumb|180px|right|Laboratory instruments used by Lavoisier.]]

[[Image:Hidrogenexp2.gif|thumb|170px180px|right|Aparatus for hydrogen combustion experiment made from Lavoisier's sketch by Jean Baptiste Meusnier in [[1783]].]]

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 changes 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 sulfur in air, and proved that the products weighed more than the original. Nevertheless, the weight gained was lost from the air.

[[Image:Calorimeter.gif|thumb|170px180px|left|Constant [[pressure]] [[calorimeter]] made by Lavoisier for chemical [[enthalpy]] experiment.]]

These experiments provided evidence for the law of the conservation of matter. 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.

His ''Traité Élémentaire de Chimie (Elementary Treatise of Chemistry'', [[1789]], translated into English by [[Robert Kerr (writer)|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.

[[Image:Lavoisiers_lab.jpg|thumb|300px270px|left|A replica of Lavoisier's laboratory at the ''Deutsches Museum'' in [[Munich]], [[Germany]].]]

[[Image:Lentilles_ardentes.jpg|thumb|270px|right|Combustion generated by amplified sun light using lenses; experiment conducted by Lavosier.]]

In addition, it contained a list of elements, or substances that could not be broken down further, which included oxygen, nitrogen, hydrogen, [[phosphorus]], [[mercury (element)|mercury]], [[zinc]], and [[sulphur]]. It also forms the basis for the modern list of elements. His list, however, also included light and [[Caloric theory|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.

[[Image:Zoom_lunette_ardente.jpg|thumb|270px|left|Lavoisier while conducting combustion experiment.]]

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). For the first time the modern notion of elements is 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]]).[[Image:Lavoisier_humanexp.jpg|thumb|350px320px|right|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.