Question

Weighing 3104 carats (1 carat = 200 mg), the Cullinan diamond was the largest natural diamond ever found How many carbon atoms were present in the stone?

Answer 1

Mass of the stone
$=3104\times 200=620800mg=620.8g$
Number of atoms of carbon $=\frac{Massingram}{Gram-atomicmass}\times 6.023\times {10}^{23}$
$=\frac{620.8}{12}\times 6.023\times {10}^{23}=3.12\times {10}^{25}$