So what u need to understand first, is the balanced chemical reaction. Im not sure but i think this forms ammonia with the following rxn:
N_2 + 3H_2 -> NH_3
So now we know that for every one mole of N2, we need 3 moles of H2.
There are (92g)/(28g/mol)= 3.3 mol N2
So we need 9.9 mol H2
This is going to be about 20 grams if i am correct
