Question

How many carbon atoms are there in a diamond (pure carbon) with a mass of 56 mg ?

Answer 1

56 mg x (1g / 1000 mg) x (1 mol / 12.0 g) x (6.02 x 10^23 atoms / 1 mol) = 2.8 x 10^21 atoms C
I hope I helped you at least a little! :)