A mineral oxide of density 2.8 g cmP3 is broken up into colloid sized particles in a ball mill….

A mineral oxide of density 2.8 g cmP3 is broken up into colloid sized particles in a ball mill. Calculate the total surface area of the crushed material (m2 g-') when the average particle radius is 5 x loP4 cm. What is the total area when the particle radius is 500 A?