143. Solving a chemistry problem

3.4. Determine the height at which, after the diffusion-sedimentation equilibrium has been established, the concentration of SiO2 hydrosol particles will be halved. The sol particles are spherical, particle dispersion: a) 0.2 nm – 1; b) 0.1 nm – 1; c) 0.01 nm – 1. The density of SiO2 is 2.7 g / cm3, the density of water is 1 g / cm3, and the temperature is 298 K.