1. The problem statement, all variables and given/known data N2 reacts with H2 to form NH3 assume equal moles of N2 and H2 in container, and react to form NH3 with 100% yield. there are 2.0 moles of excess reactants left over. How many moles of each reactant was originally present? 2. Relevant equations AY/TY = % yield 3. The attempt at a solution I know that the answer is 3 moles after much trial and error. Cause if i had started with 3 moles of each reactant, then i used 1 mole of N2. Which means 2 moles in excess. How could i have shorten this problem without doing trial error?