46. Solving a chemistry problem

1. A solution containing 0.001 g/ml Al2O3 diluted 10,000 times. Ultramicroscopic counting in dilute solution gave an average of 3 particles per field of view with a diameter of 0.04 mm and a depth of 0.04 mm. Assuming that the particles are spherical and that their density is 3.96 g/cm3. Find what the diameter of the particles is. Calculate the surface energy of 100 ml of sol solution if the surface tension is 690∙10-3 J/m2.