Question

Calculate the number of carbon atoms present in 120 grams of pure carbon powder

Answer 1

Number of moles = amount in g/ molar mass

= 120g/ 12.01 g/ mole

= 9.99 mole

1 mole = 6.022*10^23 atoms  

Therefore  

9.99 mole * 6.022*10^23 atoms / 1.0 mole

= 6.02*10^24 atoms C