55. Solving a chemistry problem

14. Silica hydrosol, obtained from sodium silicate by ion exchange, after heat treatment contains amorphous particles with a density of 2.2 g/cm3. Estimate the surface tension of silica at the interface with an aqueous solution if the solubility at 298 K of the macrophase is 0.015% (mass), and particles with a specific surface of 8*104 m2/kg is 0.016% (mass).