In the appropriate reaction conditions hydrogen and nitrogen react to form ammonia. If a reaction vessel primarily contained 500 hydrogen molecules and 150 nitrogen molecules, which molecules would stay after the reaction went to completion?

50 hydrogen molecules + 0 nitrogen molecules + 300 ammonia molecules

0 hydrogen molecules + 50 nitrogen molecules + 500 ammonia molecules

0 hydrogen molecules + 0 nitrogen molecules + 300 ammonia molecules

350 hydrogen molecules + 0 nitrogen molecules + 150 ammonia molecules