47. Solving a chemistry problem

5. 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% (wt.), and particles with a specific surface area of 80 m2/g is 0.016% (wt.).