Answer :
The given balanced chemical reaction is,

<u>For part (1) :</u>
As, 1 mole of
molecule contains
number of
molecule
So, 3 mole of
molecule contains
number of
molecule
Hence, the number of molecules of
are, 
<u>For part (2) :</u>
As, 1 mole of
contains
number of nitrogen atoms
Hence, the number of nitrogen atoms represented in the reactants are, 
<u>For part (3) :</u>
By the stoichiometry we can say that, 1 mole of nitrogen molecule react with 3 moles of hydrogen molecule to give 2 moles of ammonia molecule.
Hence, the mole of
(ammonia) formed are, 2 moles.