Antoine Lavoisier

His Life as a Chemist

CONTRIBUTION IN CHEMISTRY

Lavoisier demonstrated the role of oxygen in the rusting of metal, as well as oxygen's 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 disproved the phlogiston theory, which postulated that materials released a substance called phlogiston when they burned.

Lavoisier discovered that Henry Cavendish's "inflammable air", which Lavoisier had termed hydrogen (Greek for "water-former"), combined with oxygen to produce a dew which, as Joseph Priestley had reported, appeared to be water.

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 "becoming sharp" because he claimed that the sharp taste of acids came from oxygen), and the other "azote" (Greek for "no life").

He showed that, although matter can change its state in a chemical reaction, the total mass of matter is the same at the end as at the beginning of every chemical change.

Lavoisier investigated the composition of water and air, which at the time were considered elements. He determined that 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 systematic chemical nomenclature. He described it in Méthode de nomenclature chimique (Method of Chemical Nomenclature, 1787). This 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.
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.
Lavoisier also contributed to early ideas on composition and chemical changes by stating the radical theory, believing that radicals, which function as a single group in a chemical process, 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.

Overall, his contributions are considered the most important in advancing chemistry to the level reached in physics and mathematics during the 18th century

GROUP 3