Who discovered the composition of air?

Lavoisier discovered the composition of air.

Learning history:

18th century, French scientist lavoisier (1743 ~ 1794) measured the air composition by quantitative measurement. He put a small amount of mercury in a closed container and heated it for 12 days. He found that some mercury turned into red powder HgO, and at the same time, the air volume decreased by about 1/5. Through the study of residual gas, he found that this part of gas could not be supplied for breathing or combustion, and he mistakenly thought it was all nitrogen.

Lavoisier collected the red powder produced by heating and reheated it in another smaller container to obtain mercury and oxygen. The volume of oxygen is exactly equal to the volume of air reduced in the closed container. He introduced the oxygen he got into the front container, and the gas he got was exactly the same as air. Lavoisier concluded through experiments that air consists of oxygen and nitrogen, of which oxygen accounts for 1/5.

Physical effects of air:

Due to the strong gravity of the earth, 80% of the air is concentrated in the average range of 15 km from the ground. This air layer has a great influence on human life and production activities. What people usually say about air pollution refers to the air pollution within this range.

Air is a necessary condition for the survival of animals and plants on the earth, and the respiration of animals and the photosynthesis of plants are inseparable from air; The atmosphere can keep the temperature on the earth relatively stable. If there is no atmosphere, the temperature will be high during the day and low at night. The ozone layer can absorb ultraviolet rays from the sun and protect life on earth from harm.

Lavoisier's main achievements:

The father of modern chemistry:

Lavoisier is a gifted boy at school. At the age of 20, he won an award from the French Academy of Sciences for his excellent writing on street lighting design in Paris. A few years later, 1768, he was elected as "honorary academician" of French Academy of Sciences.

His masterpiece, The Outline of Chemistry, marks the birth of modern chemistry. In this paper, lavoisier not only correctly described the phenomena of combustion and absorption, but also listed the exact names of chemical elements for the first time in history.

Law of conservation of mass:

Lavoisier's first contribution to chemistry was to verify and summarize the law of conservation of mass from the experimental point of view. As early as when lavoisier was born, the versatile Russian scientist lomonosov put forward the law of conservation of mass, which he called "the law of immortality of matter" at that time, which contained more philosophical implications.

However, due to the lack of rich experimental basis, especially when Russian science is still very backward, Western Europe does not attach importance to Russian scientific achievements, and the "law of material immortality" has not been widely spread.