Convert the amount of substance in carat to grams.
(5.0 carat) x (0.200 g / 1 carat) = 1 g
The volume of the substance is obtained by dividing the mass by the density,
v = m / d
v = 1 g / (3.51 g/cm³) = 0.2849 cm³
Therefore, the volume of a 5.0 carat diamond is approximately 0.285 cm³.