The Physical Chemistry of Sea Water 



LARS GUNNAR SILLEN 



Department of Inorganic Chemistry, Royal Institute of Technology, Stockholm, Sweden 



IN discussing the physical chemistry of sea water, I shall consider 

 especially the equilibria in the ocean, and the form in which the 

 various elements are present in sea water. 



Average Composition and Volume 



In discussing chemical equilibria in a solution, it is convenient 

 to express all concentrations in the same unit M, mole/liter, as is 

 used in the equilibrium constants. Table I gives the average 

 concentrations of the major constituents in sea water (Sverdrup 

 et al., 1942, p. 173). Evaporation or fresh water may vary these 

 concentrations somewhat, whereas their ratios are as a rule 

 maintained practically constant. 



Table I. Major Constituents of Sea Water 



For the acid-base and redox equilibria we shall use the average 

 values (Harvey, 1957, p. 155; Sverdrup et al., 1942, p. 210): 



pH = 8.1 ± 0.2 = -log {H+} 



pE = 12.5 ± 0.2 = -log {e-\ 



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