Air inflammable

Verbrennbarkeit, /. combustibility, verbrennen, v.t. b irn scorch, tan, scald bake, verbrennlich, a. combustible (in)flammable. — verbreunliche Luft, inflammable air (old name for hydrogen). 

Henry Cavendish (1731-1810) isolates and characterizes inflammable air , which he believes to be phlogiston... 

The Discovery of Hydrc en.—The discovery of hydrogen should be attributed to Turquet de Mayeme, who in 1650 obtained, by the action of dilute sulphuric acid on iron, a gas, or inflammable air, , which we now know to have been hydrogen. 

His name for hydrogen was inflammable air. However, he had no doubt that this gas he had discovered was phlogiston. In science, theory often determines what we observe. Cavendish was simply interpreting his results in terms of the accepted theory of his day. He was far from the only scientist who did so. For example, when Priestley discovered oxygen, he named it dephlogistated air. ... 

The existence of hydrogen has been known since the 16th century. The gas, however, was reported in different ways, such as inflammable air. Henry Cavendish was the first to elucidate the chemical nature of hydrogen in 1776 and prepared it by several methods. Lavoisier in 1783 named this element hydrogen, which means, water former. Practically all gaseous hydrogen from earth s atmosphere escaped into outer space during formation of the earth. 

Containing Experiments on Factitious Air. His presentation is a model of clarity and simplicity well illustrated by his opening sentence By factitious air, I mean in general any kind of air which is contained in other bodies in an unelastic state, and is produced from thence by art. In the three parts Cavendish describes his experiments relating to inflammable air, fixed air, and the air produced by fermentation and putrefaction. 

Inflammable air from the solution of metals in acids had been observed and commented on for at least a hundred years, but only after the attention of chemists had been directed toward gases generally did a systematic study appear. Cavendish obtained the inflammable air by dissolving zinc, iron, and tin in dilute vitriolic acid or in spirit of salt. The same metals also dissolved readily in nitrous (nitric) acid, and in concentrated vitriolic (sulfuric) acid with heat, but the resulting airs were not at all inflammable. He interpreted these reactions as follows ... 

Similarly, Lavoisier had no explanation for the origin of the inflammable air obtained when metals were dissolved in acids. In the phlogistic view metals contained phlogiston combined with the metallic calx. When the metal was dissolved in acid, the calx combined with the acid to form the neutral salt and the phlogiston was liberated as inflammable air. For Lavoisier, the metal and the water were considered elemental and the acid consisted only of oxygen combined with a simple acidifiable basis. There was no possible source for the inflammable air produced. As a further puzzle, inflammable air when burned ought to produce an acid, but earlier experiments had failed to confirm that hypothesis. As the gas had always been burned in the presence of water, the actual production of more water was overlooked. 

News of Henry Cavendish s experiments showing that water was the only product of the combustion of inflammable air reached Lavoisier in... 

June of 1783. He immediately repeated the experiments with special attention to the quantitative production of the water. After a systematic investigation he concluded that the solution of metals in acids was just as much an oxidation process as their calcination in air, that the metals had to combine with oxygen to form the calx before they could dissolve in acids. The oxygen required was provided either by the acid, in which case the reduced acid gas was liberated (SO2 or NO) or by the water, in which case the gaseous product was inflammable air (hydrogen). The resulting metallic calx then combined with additional acid to form the neutral salt. 

Once gases were recognized as important in chemical reactions, they were immediately handled in quantitative ways, most conveniently through the measurement of their volumes and densities. Henry Cavendish was apparently the first to measure the densities of gases, as he did with inflammable air (hydrogen) and fixed air (carbon dioxide) in 1766. 

By the action of marine acid on the black oxide of manganese, Scheele obtained chlorine gas and described its principal characteristic properties. He called it dephlo-gisticated marine acid. The name was reasonable from his point of view, since inflammable air (hydrogen) was conceived to be chiefly phlogiston and the above action deprived marine acid of its hydrogen. Chlorine was not conceived to be elementary in its nature even by Lavoisier Sir Humphry Davy, in 1810, was the discoverer of its elementary nature, and he it was who suggested the name chlorine. ... 

The first of the three papers is on inflammable air, the second on fixed air, and the third on certain experiments on the air produced by fermentation and putrefaction, an examination to see whether they yield any other sort of air besides fixed air as shown by Dr. Macbride. 

Inflammable air was first clearly noted by Boyle about... 

Cavendish determined that from nitrous (nitric) acid, or concentrated oil of vitriol, no inflammable air was produced by these metals, also that from copper and spirit of salt (hydrochloric acid) there was nearly no action in the cold and that from hot acid no inflammable air was produced, but that the air that was then given off, lost its elasticity when in contact with water. This he notes as remarkable enough to deserve mentioning. Evidently this was hydrochloric acid gas, though Cavendish does not examine it further than to describe its sudden absorption by the water. 

Cavendish studied the inflammable air obtained by different acids on the metals, and found no difference between the properties of the gas from these sources, lie showed this gas to be insoluble in water or alkalies, fixed or volatile. He found inflammable air to be about 10% to 10% times lighter than common air. The real value is about 14.4 times lighter, but Cavendish s method at this period of his work of weighing cither common air or in-... 

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