Antoine Lavoisier

     Antoine Lavoisier (1743-1794) Antoine-Laurent Lavoisier (lah vwah ZYAY) was one
of the best-known French scientists and was an important government official.

His theories of combustion, his development of a way to classify the elements
and the first modern textbook of chemistry led to his being known as the father
of modern chemistry. He contributed to much of the research in the field of
chemistry. He is quoted for saying, "Nothing is lost, nothing is created,
everything is transformed." Lavoisier was born in Paris, France on Aug. 26,

1743. When he was eleven years old he attended a college called Mazain. For

Lavoisier's last two years in college he found a great deal of interest in
science. He received an excellent education and developed an interest in all
branches of science, especially chemistry. Abbe Nicolas Louis de Lacaill taught

Lavoisier about meteorological observation. On 1763 Lavoisier received his
bachelor's degree and on 1764 a licentiate which allowed him to practice his
profession. In his spare time he studied books all about science. His 1st paper
was written about gypsum, also known by hydrated calcium sulfate. He described
its chemical and physical properties. He was elected to the French Academy of

Sciences in 1768. On 1771 he married Marie Anne Pierrette Paulze. She helped

Lavoisier by drawing diagrams for his scientific works and translating English
notation for him. Unlike earlier chemists, Lavoisier paid particular attention
to the weight of the ingredients involved in chemical reactions and of the
products that resulted. He carefully measured the weights of the reactants and
products. He noted that the weight of the air in which combustion occurred
decreases. He found that when the burning material combined with the air somehow
and that the air weighed less. Lavoisier found that the weight of the products
of combustion equals the weight of the reacting ingredients. This observation
became known as the law of conservation of mass (or matter). He repeated many of
the experiments of earlier chemists but interpreted the results far differently.

On 1772 he was studying on combustion, which he is most known for in science.

Lavoisier presented an important memoir on conversion of water into earth
evaporation. This brought him to the Oxygen Theory of Combustion. On 1774

Lavoisier carried out experiments on calcinations of tin and lead and confirmed
the increase of weight of metals on calcinations from combustion of air. By
demonstrating the nature of combustion, he disproved the phlogiston theory. The
phlogiston theory stated that all flammable materials contained a substance
called phlogiston. According to this theory, materials gave off phlogiston as
they burned. Air was necessary for combustion because it absorbed the phlogiston
that was released. This was thought at the time to be a fact. Lavoisier showed
this theory to be false and made oxygen the reason that things burned, not
phlogiston. Lavoisier burned textbooks that supported the theory. He was trying
to make a point that the phlogiston theory was invalid and oxygen is the new
answer to combustion. He laid the framework for understanding chemical reactions
as combinations of elements to form new materials, or products. He concluded
that combustion results from the rapid chemical union of a flammable material
with a newly discovered gas, which he named "oxygen", previously known
as "dephilogisticated air." The word "oxygen" means acid producer.

Lavoisier and others had found that oxygen is a part of several acids. Lavoisier
incorrectly reasoned that oxygen is needed to make all acids. He developed
endings of the degree of oxygen by adding certain ending such as -ic or -ous.

With French astronomer and mathematician Pierre Simon Laplace, Lavoisier
conducted experiments on the respiration in animals. Their studies showed a
similarity between ordinary chemical reactions and the processes that happen in
living organisms. These experiments were the basis for the science now known as
biochemistry. Lavoisier also helped to develop a system for naming chemical
substances based on their composition. This system is still in use. He made the
very first modern chemistry text named Traité elémentaire de chimie (Elements
of Chemistry). Many consider it the first textbook on modern chemistry. Here for
the first time the elements are laid out systematically. His list included many
compounds, which were thought to be elements at the time. Lavoisier worked out
reactions in chemical equations that respect the conservation of mass. As a
government official, Lavoisier was successful in creating agricultural reform,
serving as a tax collection official, and overseeing the government's
manufacture of gunpowder. On 1775 he was made commissioner of gunpowder. He was
asked to improve the quality of French gunpowder. This boosted his career.

Politically, Lavoisier was a moderate constitutionalist, and Marat and other
radicals hated him because of this. He became involved in the Ferme Generale, a
private tax-collection firm, which became a target during the Terror. When the

Reign of Terror erupted in France, Lavoisier fell victim to its tyranny and

France lost one of her greatest scientist. The leaders of the French Revolution
arrested Lavoisier in 1793. In spite of his achievements, Lavoisier was found
guilty of conspiracy with the enemies of France because of his involvement in
tax collection. Nov. 24, 1793 Lavoisier and his 27 other colleagues were

Bibliography 1999 World

Book Encyclopedia