Oxygen Lavoisier

M. and Mme. Lavoisier. In 1777 Lavoisier gave quantitative proof of the incorrectness of the phlogiston theory. Shortly after Priestley and Scheele discovered oxygen, Lavoisier gave the true explanation of combustion and respiration Ber-thollet, Guyton de Morveau, Fourcroy, and Klaproth were among the first to accept the new views. See also ref. (60)... 

Soon after the discovery of oxygen, Lavoisier had recognized that, as fixed air was obtained by the combustion of charcoal or the diamond, it was composed simply of carbon and oxygen. In his memoir with Laplace, Sur Chaleur, presented in 1782 before the Academy,10 the quantitative composition of the oxide of carbon was approximately estimated. In a treatise presented in the same year (1783, though included in the volume for 1781) Lavoisier made a more accurate estimate from heating charcoal with minium, showing ... 

LAVOISIER. After the fall of the Phlogiston Theory and the discovery of oxygen, Lavoisier studied the combustion of carbon, sulfur and phosphorus in 1777. By dissolving the resulting non-metallic oxides in water, he found that all these solutions show acidic effects. Based on these examples, he defined acids as substances composed of a non-metal and oxygen. In addition, he found out that acids, combined with the bases , the metal oxides, result in well-known salts carbon dioxide forms the carbonates, sulfuric acid the sulfates, phosphoric acid the phosphates - the combination system of acids and bases was discovered ... 

Certainly, Lavoisier was wrong here, oxygen is not the begetter of acids, at least not of all of them. There was, for instance, hydrochloric acid and hydrofluoric acid, recently discovered by Scheele, and already at this time it was realized that they did not seem to contain oxygen. Lavoisier explained this exception to his rule of thumb by blaming faulty analyses, which just illustrates how stubbornly even the greatest scientists sometimes cling to their favorite hypotheses. On the other hand, very many of the acids known at the time, for instance nitric acid, phosphoric acid... 

By the middle of the seventeenth century, scientists recognized that air contained a component associated with burning and breathing. That component was not isolated until 1774, however, when English scientist Joseph Priestley discovered oxygen. Lavoisier subsequently named the element oxygen, meaning acid former. ... 

Ibid. p. 116f. As to animal substances, in addition to charcoal, hydrogen, and oxygen, Lavoisier also considered nitrogen and phosphorus as components, and as an exception the muriatic radical as well (ibid. pp. 117, 149 and 191). 

When Priestley told him of his discovery of oxygen, Lavoisier was surprised , but when Blagden told him of Cavendish s synthesis of water he was incredulous. It will be noticed that Blagden also mentioned Watt s conclusions... 

Lavoisier had found that carbonic acid contains 28 per cent of carbon and the weight of carbon in 67-08 gr. is, therefore, 18-78 gr. The sum 18-78 + 3-80 = 22-58 gr., instead of 21-51. In addition, wax contains about 5 per cent of oxygen. Lavoisier also concluded that olive oil (which contains oxygen) is a compound of carbon and hydrogen only, in this case finding the hydrogen by difference. 

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