2 N2 (g) + 3 H2 (g) → 2 NH3 (g) How many moles of NH3 are produced if 21 mol of N2 reacts?

Question

I'm so frustrated and I do not get how to do these problems. PLEASE HELP ME

Answer 1

Don’t be frustrated. Look closely at the balanced equation.

N₂ + 3H₂ ==> 2NH₃. The equation you present is incorrect. Maybe that’s why you’re having trouble.

It tells you that TWO moles of NH₃ are produced from ONE mole of N₂. We can use dimensional analysis to find moles NH₃ made from 21 moles of N₂.

21 moles N₂ x 2 moles NH₃/mole N₂ = 42 moles NH₃

Looking at it another way, the correctly balanced equation tells you that the moles of NH₃ is TWICE the number of moles of N₂ as the ratio of NH₃ to N₂ is 2:1