Calculation of Seawater Density

An equation for calculating the density of multicomponent aqueous solutions of electrolytes is proposed and a calculation of the density of seawater is carried out at 20°С. It is established that six salts make the main contribution to the density of the solutions: sodium, magnesium, calcium and potassium chlorides, and sodium sulfate and bicarbonate. The molar volumes of magnesium and calcium chlorides, as well as sodium sulfate and bicarbonate, are determined. Based on these data on molar volumes and the previously found values for sodium and potassium chlorides, we calculate the density of seawater at 20°С. The resulting value is 1023.7 kg/m3, which practically coincides with the value available in the literature of 1023.6 kg/m3, given for 25°С. The applied technique can be used to calculate the density of technological solutions with various salt compositions