File:The principles of chemistry (1897) (14749972846).jpg

Identifier: principlesofchem01mend (find matches)
Title: The principles of chemistry
Year: 1897 (1890s)
Authors: Mendeleyev, Dmitry Ivanovich, 1834-1907 Kamensky, George Lawson, Thomas Atkinson
Subjects: Chemistry Periodic law Argon
Publisher: London, New York, Longmans, Green and Co.
Contributing Library: Mugar Memorial Library, Boston University
Digitizing Sponsor: Boston University

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to a temperature of132°. When its volume becomes constant it is measured, the height ofthe column of mercury in the tube above the level of the mercury in thecylinder being noted. Let this volume equal v ; it will therefore con-tain ^ V oi oxygen and § ^j of hydrogen. The current of vapour is thenstopped, and the gas exploded ; water is formed, which condenses intoa liquid. The volume occupied by the vapour of the water formed hasnow to be determined. For this purpose the vapour of the amyl alcoholis again passed between the tubes, and thus the whole of the waterformed is converted into vapour at the same temj^erature as that atwhich the detonating gas was measured ; and the cylinder of mercurybeing raised until the column of mercury in the tube stands at the sameheight above the surface of the mercury in the cylinder as it did beforethe explosion, it is found that the volume of the water formed is equalto f V—that is, it is equal to the volume of the hydrogen contained VOL. I. X
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MOLECULES AND ATOMS 307 in it. Consequently the volumetric composition of water is expressedin the following terms : Two volumes of hydrogen combine withone volume of oxygen to form two volumes of aqueous vapour. Forsubstances which are gaseous at the ordinary temperature, this directmethod of observation is sometimes very easily conducted ; forinstance, with ammonia, nitric and nitrous oxides. Thus to determinethe composition by volume of nitrous oxide, the above-describedapparatus may be employed. Nitrous oxide is introduced into thetube, and after measuring its volume electric sparks are passedtluouo-h the lias ; it is then found that two volumes of nitrous oxidehave given three volumes of gases—namely, two volumes of nitrogenand one volume of oxygen. Consequently the composition of nitrousoxide is similar to that of water ; two volumes of nitrogen and onevolume of oxygen give two volumes of nitrous oxide. By decomposingammonia it is found to be composed in such a manner that two

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