Question

How many carbon atoms are there in a 2.8-carat diamond? diamonds are a form of pure carbon. (1 carat = 0.20 grams)\?

Answer 1

2.8 carat C x (0.20g C/ 1 carat C) x (1 mole C/ 12.01 g C) x (6.02 x 10^23 atoms C/ 1 mole C) = 2.8 x 10^9 atoms C
       
Use factor label method in order to determine the amount of atoms, make sure the units cancel.

Answer 2

First let us calculate the mass of diamond (pure Carbon).

mass = 2.8 carat * (0.20 grams / carat)

mass = 0.56 grams

 

The molar mass of Carbon is 12 g / mol and the Avogadros number is 6.022 x 10^23 atoms / mol, therefore:

Carbon atoms = 0.56 grams * (1 mol / 12 g) * (6.022 x 10^23 atoms / mol)

Carbon atoms = 2.81 x 10^22 atoms