5.22kg of H2 reacts with 31.5kg of N2, which one is the limiting reactant?

Answer 1

I assume we are talking about:

3 H2 + N2 --> 2 NH3

H2 is 2*1 = 2 g/mol
N2 is 2*14 = 28 g/mol

forget g vs kg because we are only interested in ratios here
3 mol H2 is 6 g
so we need 6 g of H2 for every 28 g of N2
31.5 g of N2 needs 31.5 * 6/28 = 6.75 g H2 needed
BUT we only have 5.22 g H2 so the H2 limits the reaction.