111. Solving a chemistry problem

In the study of aerosols by the method of flow ultramicroscopy, the number of spherical particles of oil mist that passed through the counting field of the microscope in a volume of 0.0133 mm3 was counted. The average radius of these particles turned out to be 0.445 µm, the density was 900 kg/m3, and the concentration was 0.025 g/m3. How many oil mist particles have passed through the microscope count in the indicated volume?