Lavoisier, Antoine-Laurent (1743-1794) French Chemist (Scientist)

Widely regarded as the founder of modern chemistry, Antoine-Laurent Lavoisier was a versatile and talented scientist who made numerous contributions not only to chemistry but also to geology, physiology, economics, and social reform. Through experimental observations Lavoisier discovered oxygen and its role in combustion. He also isolated the major components of air and introduced the method of classifying chemical compounds. Lavoisier was also instrumental in the development of thermo chemistry.

The father of Lavoisier, Jean-Antoine, was a wealthy Paris lawyer who inherited his family’s estate in 1741. He married Emilie Punctis, the daughter of an attorney, in 1742; on August 26, 1743, she gave birth to Lavoisier. She died when he was five years old. He was educated at the College des Quatre Nations, commonly known as the College Mazarin, beginning in 1754, when he was 11. The school had an outstanding reputation, and Lavoisier gained a thorough classical and literary education and the best scientific training available in Paris.

Antoine-Laurent Lavoisier is regarded by many as the founder of modern chemistry.

Antoine-Laurent Lavoisier is regarded by many as the founder of modern chemistry.

In 1761, Lavoisier began to study law, intending to follow the family tradition. He earned his degree in 1763 and received his license to practice law the following year. The pull of science was strong, however, and his friend Jean-Etienne Guettard, a geologist, encouraged him to study geology, mineralogy, and chemistry, which Guettard considered to be imperative for the analysis of rocks and minerals. From 1762 to 1763, Lavoisier took courses in chemistry given by the popular Guillaume Francois Rouelle. He also expanded his knowledge of geology under Guettard’s guidance. Lavoisier completed the first geological map of France, which earned him an invitation to the Royal Academy of Sciences in 1768. Also that year, he invested in a tax-collecting company, which was prosperous enough to allow him to build his own laboratory.

Lavoisier is best known for his studies of combustion. During that time it was believed that combustible matter contained a substance known as phlogiston, which was emitted when combustion occurred. The primary flaw of this theory was that substances sometimes increased in weight as a result of combustion. Lavoisier sought to solve this problem and carried out a range of experiments. He burned phosphorus, lead, and a number of other elements in closed containers and observed that the weight of the solid increased, but the weight of the container and its contents did not. In 1772, he found that burning phosphorus and sulfur caused a gain in weight when combined with air.

Lavoisier then heard of Joseph Priestley’s discovery that mercury oxide released a gas when heated and left behind mercury; Priestley referred to the gas as dephlogisticated air. Expanding on Priestley’s findings, Lavoisier determined in 1778 that the gas that mixed with substances during combustion was the same gas that was emitted when mercury oxide was heated. Lavoisier called the gas oxygen. He also recognized the existence of a second gas, which later was named nitrogen.

In 1776, Lavoisier worked at the Royal Arsenal, in charge of gunpowder production. It was there that Lavoisier collaborated with Marquis Pierre-Simon de Laplace to create an ice calorimeter and measure the heats of combustion and respiration. This work marked the beginning of thermochemistry. In 1787, Lavoisier worked with three other French chemists to propose a method of classifying chemical compounds. This system is still used today. Lavoisier published an important and influential work in 1789 called Elementary Treatise on Chemistry. It summarized his observations, discussed the law of conservation of mass, and provided a list of the known elements.

In addition to his combustion studies, Lavoisier explained the formation of water from hydrogen and sought to discover a method for improving the water supply to Paris. He also worked toward social reform, endorsed scientific agriculture, and was a member of the commission that promoted the metric system in France. In 1771, Lavoisier, at age 28, married Marie Anne Pierrette Paulze, who was 14 years old. The couple had no children, but Lavoisier’s wife became his close collaborator. Lavoisier’s life was cut short in 1794, when he was executed during the Reign of Terror.

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