Antoine Lavoisier

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.


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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.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. It could also have been true that he could have argued against his own ideas.


Pioneer of stoichiometry

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.