The (p, V, T) properties of concentrated aqueous electrolytes I. Densities and apparent molar volumes of NaCl, Na2SO4, MgCl2, and MgSO4 solutions from 0.1 mol·kg-1 to saturation and from 273.15 to 323.15 K

Abstract

The density differences (ρ{variant}-ρ{variant}*) (where ρ{variant} is the density of the solution and ρ{variant}* is the density of water), of NaCl, Na2SO4, MgCl2, and MgSO4 aqueous solutions have been measured from 278.15 to 318.15 K and molality m = 0.1 mol·kg-1 to saturation. The results have been combined with our earlier measurements and literature data and were least-squares fitted by polynomial equations in molality and temperature. The estimated standard errors s of the density equations were better than 25 × 10-6 g·cm-3 over the molality range 0.1 mol·kg-1 ≤ m ≤ saturation and from 273.15 to 323.15 K. At T = 298.15 K, s (10-6 g·cm-3) = 19.3, 9.5, 19.9, and 12.8, respectively, for NaCl, Na2SO4, MgCl2, and MgSO4 solutions. The apparent molar volumes V2.φ determined from the densities have been fitted by a least-squares method to equations in molality and temperature. The estimated standard errors of the V2.φ equations are better than 0.22 cm3·mol-1 for all the solutions from 0.1 mol·kg-1 ≤ m ≤ saturation and 273.15 to 323.15 K. © 1982.