49. Solving a chemistry problem

91. Using the equation of sedimentation-diffusion equilibrium, calculate the height above the Earth´s surface at which the number of particles in 1 m3 of coal smoke aerosol will decrease by 2 times if the radius of spherical particles is r = 1 10-8 m; particle density ρ = 1.2 103 kg/m3; air density can be neglected.