Given the following balanced chemical equation: N2 + 3H2--> 2NH3, calculate the moles of NH3 that can be made by reacting 12.0 moles of N2 with 17.84 moles of H2.
since it takes 3 moles of H2 for each mole of N2,
it will take 36 moles of H2 to react with 12 moles of N2.
Clearly, there is not enough H2 to exhaust the N2.
So, since you get 2/3 as many moles of NH3 as you have H2,
you will get 2/3 * 17.84 = 11.89 moles of NH3