The analysis of nitrous oxide for physiological work / by Walter M. Boothby and Irene Sandiford.

  • Walter M. Boothby
Date:
[1915?]
Catalogue details

Licence: In copyright

Credit: The analysis of nitrous oxide for physiological work / by Walter M. Boothby and Irene Sandiford. Source: Wellcome Collection.

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    In light of the article by Baskerville and Stevenson6 on the analysis of nitrous oxide in which, on the authority of Lunge,7 the combustion of nitrous oxide with hydrogen is stated to be unreliable, we determined to reinvestigate this point before pro¬ ceeding to the use of the method in physiological work. Deviation from the gas laws. Nitrous oxide is not a perfect gas and its deviation from the gas laws is considerable. At the usual temperatures and pressures existing in a laboratory it is of the order of 0.7 per cent. However, in the method of analysis by which nitrous oxide is combusted with hydrogen to form nitrogen and water and the contraction measured, the above deviation is automatically compensated as the following consideration shows. The litre weight of nitrous oxide at 0° and 760 mm., were it a perfect gas, would equal Molecular weight of nitrous oxide 44.014 ^nA —-—=r-=-r— ~--- = ^ ^ = 1.964 grams Molecular volume 22.412 But the litre weight at 0° and 760 mm. is actually found to be 1.9777 grams.8 That is, at 0° and 760 mm. the deviation of nitrous oxide from the gas laws is ——J _ _ = 0.7 per cent. 1.964 This error need not be taken into consideration in the analysis as shown by the following calculation. Let N be the number of molecules of hydrogen or nitrogen per cubic centimeter at the constant conditions of. the experiment. Hydrogen is added in excess to 1 cc. of nitrous oxide. At 20° and 760 mm., 1 litre of nitrous oxide contains about 1.006 times as many molecules as nitrogen or hydrogen under the same conditions. In this case, 1.006 molecules of nitrous oxide must be decomposed, and there¬ fore 1.006 molecules of hydrogen are required since n2o + h2 n2 + h2o and as hydrogen is nearly/‘perfect” under these conditions, 1.006 cc. of hydrogen will be used up. But at the same time 1.006 6 Baskerville and Stevenson: Contributions to the chemistry of anaesthetics: nitrous oxide. Jour. Indust, and Eng. Chem., 1911, iii, 8. 7 Lunge: Ber. 14, 2188; Kemp: Chem. News, 71, 108 (1895). 8 Landolt and Bornstein: Physikaliseh-Chemische Tabellen, 1912, p. 150.
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