What is the limiting reagent? The number of NH3 molecules formed? The number of molecules in excess?

Question

The illustration to the left represents a mixture of nitrogen ( blue ) and hydrogen ( light blue ) molecules.

If the molecules in the above illustration react to form NH₃ according to the equation

N₂ + 3 H₂  2 NH₃ ,

Answer 1

There are 3 molecules of N₂ and 6 molecules of H₂ in the picture. In order to react 3 molecules of N₂, we need 9 molecules of H₂(which we don't have). But in order to react with 6 molecules of H₂, we need 2 molecules of N₂. So, H₂ is the limiting reagent. 1 molecule of N₂ is left in excess.