70. Solving a chemistry problem

1.25.(21) Given a dispersed system with a dispersed phase mass m, a dispersed phase density m, with particles of the dispersed phase of a certain shape and size: r is the radius of the ball, l is the length of the cube edge (task options are given in Table 1.2).
1. Calculate the dispersion of the system D and the specific surface area Ssp.
2. Calculate the parameters of the particle of the dispersed phase: volume V0, surface S0, mass m0.
3. Calculate the total surface of all particles S and the number of particles N in the dispersed system.
Option 21
Dispersion phase - selenium, dispersion medium - water, particle shape - ball, r (l), m - 2.8 * 10-7, p * 10-3, kg / m3 - 4.28, m, kg -0, 3.