Molar mass of

= 12

7 + 5 + 14 3 + 16 6

= 227 gm

Given mass of

= 681 gm

Moles of

In one molecule of

, 3 N atoms present.

In 1 mole , 3 moles of N atoms presents.

In 3 moles of , 3 3 = 9 moles of N atoms presents.

We know, 1 mole of N atoms = 6.02

10²³ N atoms.

9 moles of N atoms = 9 6.02 10²³ = 54.18 10²³ = 5418 10²¹