2 N2 + 3 H2 → 2 NH3
2 moles N2 need 3 moles H2 to form 2 moles NH3
One mole of N2 has 28 g
So 2000 g N2 has 1000/28 = 35.71 moles
and 1000 g H2 has 1000/2 = 500 moles
To find out the limiting reagent divide the no of moles of reactants with their stoichiometric coefficient.
For N2: 35.71/2 = 17.855
For H2: 500/3 = 166.66
The lowest number indicates the limiting reagent which in this case is nitrogen.
B) One mole nitrogen forms 2 moles of ammonia so 35.71 moles will form 2*35.71 moles ammonia.
Mass of ammonia formed = (17*2*35.71) = 1214.14 g.
A) Since hydrogen is in excess it will be left unreacted.
Amount of hydrogen required for 34 g = 6 g
Amount of hydrogen required for 1214.14 g = 6/34*1214.14 g = 214.26 g
Amount left = 785.74 g