An industrial chemist is studying the rate of the haber synthesis: n2 + 3h2 → 2nh3. starting with a closed reactor containing 1.50 mol/l of n2 and 0.45 mol/l of h2, she finds that the h2 concentration has fallen to 0.16 mol/l after 30. seconds. what is the average rate of reaction of h2 over this time? (enter in mol/liter/sec).