A treatise on chemistry / by Sir H.E. Roscoe, F.R.S., and C. Schorlemmer.

  • Henry Enfield Roscoe
Date:
1905-
Catalogue details

Licence: In copyright

Credit: A treatise on chemistry / by Sir H.E. Roscoe, F.R.S., and C. Schorlemmer. Source: Wellcome Collection.

    934/954 page 916
    Argon has also been found, together with helium, in the gas evolved on heating numerous minerals, and also from one specimen of meteoric iron. It is isolated from the air by the methods already described 1 (p. 907), but it is now usual to replace the magnesium by a strongly ignited mixture of magnesium and lime, which contains metallic calcium, and to remove the last traces of nitrogen by passing the gas over heated calcium.2 In order to obtain it quite pure, the crude gas is submitted to fractional condensation and evaporation. The actual pro- portion of the other inert gases present in crude atmospheric argon is, however, very small, and does not exceed about 025 per cent., nearly 85 per cent, of this impurity being neon. Argon has been condensed to a colourless liquid which boils at 86°‘9 Absolute ( —1860 I C.), at which temperature its den- sity is 1 4046,3 and solidifies only a few degrees below its boiling point at 8,T'4 Absolute ( —189°'6 C.). Its critical temperature is 155 6 Absolute ( —117°‘4 C), and the critical pressure 52’9 atmospheres (Ramsay and Travers). Argon is considerably more soluble in water than nitrogen, its coefficient of solubility4 being 0 05612 at 1 and 0-02567 at 50°; hence in the gases expelled from water saturated with air the ratio of argon to nitrogen is higher than in the atmosphere. The gas has the refractivity5 01)655 (air = 1); it passes through rubber more quickly than nitrogen6 or carbon dioxide 7 and does not pass through heated platinum or palladium. Its rate of effusion is about 5 per cent, less than would be expected from its molecular weight.8 Pure argon has the density 1983 (H = 1) or 19 955(0 = 16), and one litre of the gas under normal conditions weighs T7828 grams. As the gas has been shown to be monatomic it follows that its atomic weight is 39‘6 (H = l). All attempts to combine argon with other elements have hitherto failed. As has been stated, it does not combine with oxygen under the influence of the electric discharge, nor with 1 Ramsay and Travers, Proc. Roy. Sor., 1898, 64, 183. 2 Moissan and Rigaut, Compt. Rand., 1903, 137, 773 :t Raly and Donnan, Journ. Cham. Soc., 1902, 914. 4 Estreieher, Ze.it. phynkal. Cham., 1899, 31, 170. r' Ramsay and Travers, Proc. Roy. Sor., 1899, 64. 183. ,! Rayleigh, Phil. May., 1900, [5], 49, 220. ' Kistiakowski, ./. Rn«x. Chem. Sor., 1898, 30, ”>7(i. H Donnan, Phil. May., 1900, [d], 49, 423.
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