Lavoisier, a French chemist who overthrew phlogiston, originally studied law. 1763, at the age of 20, he obtained a bachelor's degree in law and a lawyer's practice certificate. His father is a lawyer and his family is very rich. So lavoisier did not aspire to be a lawyer, but became interested in botany. Collecting specimens in the mountains often made him interested in meteorology. Later, at the suggestion of his teacher, geologist Gertrude, lavoisier studied chemistry with the famous Parisian professor Runje.

Lavoisier's first chemical paper was about the composition of gypsum. He synthesized gypsum from sulfuric acid and lime. When he heats plaster, he gives off steam. Lavoisier carefully measured the mass of gypsum losing water vapor at different temperatures with a balance. From then on, his teacher Rouiller began to use the term "crystal water". This success enabled lavoisier to use the balance frequently and summed up the law of conservation of mass. The law of conservation of mass became his belief and the basis of his quantitative experiment, thinking and calculation. For example, he used this idea to express the fermentation process of converting sugar into alcohol as the following equation:

Glucose = = carbonic acid (CO2)+ alcohol

This is the embryonic form of modern chemical equations. Using an equal sign instead of an arrow to represent the process of change shows his conservation thought. Lavoisier in order to further clarify the profound meaning of this expression, specially wrote:

"I can imagine that the substances involved in fermentation and the products after fermentation are listed as an algebraic expression. Then assume that one item in the equation is unknown, and then calculate their values item by item through experiments. In this way, we can check our experiments with calculations, and then verify our calculations with experiments. I often use this method to effectively correct the preliminary results of experiments, so that I can re-experiment in the right way until I succeed. "

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.

/kloc-in the autumn of 0/772, lavoisier once weighed a certain amount of white phosphorus to make it burn. After cooling, it was also called the quality of combustion product P2O5, and it was found that the quality increased! He also burned sulfur and found that the quality of combustion products was greater than sulfur. He thinks it must be some gas absorbed by white phosphorus and sulfur. So he made a more detailed experiment: put white phosphorus on the surface of mercury and tie a bell jar, which left some air. When mercury is heated to 40℃, white phosphorus burns rapidly, and then the mercury level rises. Lavoisier described: "This shows that part of the air is consumed, and the remaining air can neither burn white phosphorus nor extinguish the burning candle;" 1 oz of white phosphorus can obtain about 2.7 ounces of white powder (P2O5 should be 2.3 ounces). The added weight is almost the same as the consumed air weight 1/5 volume. "

The phlogiston theory holds that combustion is a decomposition process, and the products of combustion should be lighter than combustible materials. But lavoisier's experimental results are the opposite. He wrote the experimental results into a paper and submitted it to the French Academy of Sciences. Since then, he has done many experiments to prove that phlogiston is wrong. 1773 In February, he wrote in the experiment record book: "The experiment I did fundamentally changed physics and chemistry." He named "new chemistry" "anti-phlogiston chemistry".

1774, lavoisier experimented with baking tin and lead. He put the weighed metal into different sizes of flask, sealed it, weighed the metal and flask, and then fully heated it. After cooling, the mass of the metal and the bottle was weighed again, and no change was found. Open the bottle and air will enter. This time, the quality has increased. Obviously, the increase is the quality of the incoming air (set to a). He opened the bottle again, took out the metal forging ash (there was residual metal in the bottle) and weighed it. He found that the added mass was the same as the air entering the bottle (that is, A). This shows that forging ash is a compound of metal and air.

Lavoisier further thought that it would be more telling if you tried to separate air directly from metal forging ash. He tried to decompose iron forging ash (rust), but the experiment was unsuccessful.

After lavoisier produced oxygen,

In 10, the priest visited Paris. At the welcome banquet, he talked about "defluorination gas can be obtained from red precipitate (HgO) and lead (Pb3O4)". For lavoisier, who is helpless, this news is a direct encouragement. 165438+1In June, lavoisier heated the red water and silver ash to produce oxygen. Inspired by Scheler, lavoisier even made a locomotive-sized heating device with a condenser in the center. Below the platform are six big wheels, so as to rotate with the sun at any time.