Seawater-A Test of Multicomponent Electrolyte Solution Theories. I. The Apparent Equivalent Volume, Expansibility, and Compressibility of Artificial Seawater

The apparent equivalent volume (Phi(V)), expansibility (Phi(E)), and compressibility (Phi(K)) of an artificial seawater solution containing 10 ionic components (Na(+), Mg(2+), Ca(2+), K(+), Sr(2+), Cl(-), SO(4)(2-), HCO(3)(-), Br(-), and F(-)) and one nonionic component (H(3)BO(3)) has been determined from 0 to 40 degrees C (in 5 degrees intervals) and from 0.1 to 0.8 m ionic strength at 1 atm. The concentration dependence (I(V) = volume ionic strength) of the Phi(V)'S, Phi(E)'S, and Phi(K)'s have been examined by using a Masson-type equation, Phi = Phi degrees + S' I1/2/V, and a Redlich-type equation, Phi = Phi degrees + SI 1/2/V + BI(V), where Phi degrees is the infinite-dilution value, S' is the empirical Masson slope, S is the theoretical Debye-Hiickel slope, and B is an empirical deviation constant. By using Young's rule, Phi = Sigma E(i) phi(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 welt with the directly measured values providing the concentration terms, S(1) and B(1), are weighted according to the methods of Wood and Reilly.