Question

Ammonia is produced by the Haber process, in which nitrogen and hydrogen are reacted directly using an iron mesh impregnated with oxides as a catalyst. For the following reaction, equilibrium constants (Kp values) are seen below as a function of temperature.

N2(g) + 3 H2(g) reverse reaction arrow 2 NH3(g)

300°C 4.34 multiplied by 10-3 atm-2
500°C 1.45 multiplied by 10-5 atm-2
600°C 2.25 multiplied by 10-6 atm-2
This is an exothermic reaction, can you explain why it is exothermic and not endothermic?

Answer 1

Step-by-step explanation:

The reaction of production of ammonia is as follows

N₂ + 3H₂ ⇄ 2NH₃

From the data given , it is clear that

equilibrium constant decreases as temperature increases . In other words

at higher temperature less and less of ammonia is produced .

According to Le Chatelier's Principle , reaction tends to go in the direction so that the effect of external change is minimized. Since the increase in temperature reduces the forward reaction , that means reaction is exothermic .

So , reduction in reaction , helps reduce the production of heat to reduce the effect of temperature increase.