Consider the following balanced reaction between hydrogen and nitrogen to form ammonia:

3H2 (g) + N2 (g) →2NH3 (g)

How many moles of NH3 can be produced from 19.0 mol of H2 and excess N2?

Three moles of H2 produce 2 moles of NH3. Since the reactinng ratios are constant, then the ratio of hydrogen consumed:ammonia is 3:2

Mathematically, 3 Mol H2=2mol NH3

19 Molly H2=?

Cross-multiplying gives;

(19*2) / 3=12.67 moles