Ammonia is prepared from the elements hydrogen and nitrogen by the Haber process: 3H2 + N2 becomes 2NH3. When 100 grams of N2 and 100 grams of H2 react,what mass of the reactant in excess remains unreacted?

Find the limiting reactant.

3H2 + N2 -> 2NH3

100 grams N2 (1 mole N2/28.02 grams) = 3.569 moles N2
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100 grams H2 (1 mole H2/2.016 grams) = 49.60 moles H2
------Now, I suspect N2 limits

49.60 moles H2 (1 mole N2/3 mole H2) = 16.53 mole N2
------you have nowhere near this and this is the H2 excess, so

16.53 mole * 2.016 grams

= 33.3 grams of hydrogen gas is unreacted
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