This question is incomplete. The source of the nitrogen is not given and this will affect the answer.
Assuming that one starts with molecular nitrogen, the following equation holds:
0.5N2 + 3H2 = NH3
The number of grams of hydrogen is equivalent to 10,000 moles which means that
about 3300 moles of NH3 will be formed.
Multiplying 3300 by Avogadros number(the number of molecules in a mole) gives
about 2x10?27 molecules of NH3.
Avogadros number =6.02X10?23. The questioner can figure out the exact number of molecuoles of NH3 if he or she wishes.
