How many moles of ammonia will contain 1.55 x 1021 atoms of hydrogen?

Question

Thanks for any help

Answer 1

there are three hydrogen atoms in each ammonia molecule

(1.55E21 / 3) is the number of ammonia molecules needed

the number of moles is ... (1.55E21 / 3) / 6.02E23

Answer 2

1.55E21 atoms H is how many moles? That's
1.55E21 atoms x (1 mol /6.02E23 atoms = estd 0.25E-2 or about 0.0025.
But 1 mol NH3 has three mols H atoms; therefore,
0.0025 mols H x (1 mol NH3/3 mols H) = ?