Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-30T17:01:36.708Z Has data issue: false hasContentIssue false

The vapour pressure and osmotic equivalence of sea water

Published online by Cambridge University Press:  11 May 2009

R. A. Robinson
Affiliation:
Professor of Chemistry, University of Malaya, Singapore

Extract

Sea water is a complex solution in which the principal ions are sodium, potassium, calcium, magnesium, chloride and sulphate. The vapour pressure (V.P.) of such a solution can be calculated approximately by making the assumption that each salt contributes to the vapour pressure lowering in amount proportional to its concentration, but such a calculation would ignore the interactions between the various ions. The theory of these interactions has been worked out only for very dilute solutions and it is, therefore, better to rely on direct experimental determinations. Measurements have now been made by the isopiestic vapour-pressure method (Robinson & Sinclair, 1934), in which samples of sea water are equilibrated with sodium chloride solutions until they have the same vapour pressure. The results are expressed in terms of chlorinities of sea water and molalities (moles per kilogram of H2O) of sodium chloride solution which have the same vapour pressure. It is hoped that the results will be of use to physiologists who have occasion to make up salt solutions equivalent to sea water.

Type
Research Article
Copyright
Copyright © Marine Biological Association of the United Kingdom 1954

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Robinson, R. A., 1945. The vapour pressures of solutions of potassium and sodium chloride. Trans, roy. Soc. N.Z., Vol. 75, pp. 203–17.Google Scholar
Robinson, R. A. & Jones, R. S., 1936. The activity coefficients of some bivalent metal sulfates in aqueous solution from vapour pressure measurements. J. Amer. chem. Soc, Vol. 58, pp. 959–61.Google Scholar
Robinson, R. A. & Sinclair, D. A., 1934. The activity coefficients of the alkali chlorides and of lithium iodide in aqueous solution from vapour pressure measurements. J. Amer. chem. Soc, Vol. 56, pp. 1830–5.Google Scholar
Robinson, R. A., Smith, P. K. & Smith, E. R. B., 1942. The osmotic coefficients of some organic compounds in relation to their chemical constitution. Trans. Faraday Soc, Vol. 38, pp. 6370.Google Scholar
Robinson, R. A. & Stokes, R. H., 1940. The activity coefficients of magnesium halides at 25°. Trans. Faraday Soc, Vol. 36, pp. 733–4.Google Scholar
Robinson, R. A., Wilson, J. M. & Stokes, R. H., 1941. The activity coefficients of lithium, sodium and potassium sulfate and sodium thiosulfate at 25° from isopiestic vapor pressure measurements. J. Amer. chem. Soc, Vol. 63, pp. 1011–13.Google Scholar
Scatchard, G., Hamer, W. J. & Wood, S. E., 1938. The chemical potential of water in aqueous solutions of sodium chloride, potassium chloride, sulfuric acid, sucrose, urea and glycerol. J. Amer. chem. Soc, Vol. 60, pp. 3061–70.Google Scholar
Scatchard, G. & Prentiss, S. S., 1933. The freezing point of aqueous solutions. IV. Potassium, sodium and lithium chlorides and bromides. J. Amer. chem. Soc, Vol. 55, pp. 4355–62.Google Scholar
Stokes, R. H., 1945 a. Properties of calcium chloride solutions up to high concentrations at 25°. Trans. Faraday Soc, Vol. 41, pp. 637–41.Google Scholar
Stokes, R. H., 1945 b. Concentrated solutions of magnesium chloride at 25°. Trans. Faraday Soc, Vol. 41, pp. 642–5.Google Scholar
Stokes, R. H. & Levien, B. J., 1946. The osmotic and activity coefficients of zinc nitrate, zinc perchlorate and magnesium perchlorate. Transference numbers in zinc perchlorate solutions. J. Amer. chem. Soc, Vol. 68, pp. 333–7.Google Scholar
Thompson, T. G., 1932. The physical properties of sea water. Physics of the earth. Vol. 5, Oceanography, pp. 6394. Bull. nat. Res. Coun., Wash., No. 85. [Quoted byGoogle Scholar
Sverdrup, H. U., Johnson, M. W. and Fleming, R. H., 1942, The Oceans, New York.]Google Scholar
Witting, R., 1908. Untersuchungen zur Kenntnis den Wasserbewegungen und der Wasserumsetzung in den Finnland umgebenden Meeren. Finnl. hydrogr.-biol. Untersuch., No. 2, p. 173. [Quoted byGoogle Scholar
Sverdrup, H. U., Johnson, M. W. and Fleming, R. H., 1942, The Oceans, New York.]Google Scholar