Seawater-A test of multicomponent electrolyte solution theories. I. The apparent equivalent volume, expansibility, and compressibility of artificial seawater

Frank J. Millero

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The apparent equivalent volume ΦV, expansibility ΦE, and compressibility ΦK of an artificial seawater solution containing 10 ionic components (Na+, Mg2+, Ca2+, K+, Sr2+, Cl-, SO42-, HCO3-, Br-, and F-) and one nonionic component (H3BO3) has been determined from 0 to 40°C (in 5° intervals) and from 0.1 to 0.8 m ionic strength at 1 atm. The concentration dependence (Iv=volume ionic strength) of the ΦV's, ΦE's, and ΦK's have been examined by using a Masson-type equation, Φ = Φ° +S'IV1/2, and a Redlich-type equation, Φ = Φ° +SIV1/2 +BIV, where Φ° is the infinite-dilution value, S′ is the empirical Masson slope, S is the theoretical Debye-Hückel slope, and B is an empirical deviation constant. By using Young's rule, Φ = ∑Eiφ(i), the apparent equivalent volumes, expansibilities, and compressibilities for "sea salt" have been estimated from the ionic and nonionic components making up the mixture. The estimated apparent molal quantities agree very well with the directly measured values providing the concentration terms, Si and Bi, are weighted according to the methods of Wood and Reilly.

Original languageEnglish (US)
Pages (from-to)1-22
Number of pages22
JournalJournal of Solution Chemistry
Issue number1
StatePublished - Feb 1 1973



  • Compressibility
  • Young's rule
  • expansibility
  • molar volume
  • seawater

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Physical and Theoretical Chemistry

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