Explain, using Le Châtelier’s principle, why the equilibrium constant for the formation of NO from N2 and O2 increases with increasing temperature, whereas the equilibrium constant for the formation of NO2 from NO and O2 decreases with increasing temperature.

Verified step by step guidance

1. Step 1: Identify the reactions involved. The formation of NO from N2 and O2 is represented by the reaction: N2(g) + O2(g) ⇌ 2NO(g). The formation of NO2 from NO and O2 is represented by the reaction: 2NO(g) + O2(g) ⇌ 2NO2(g).
2. Step 2: Determine the enthalpy change (ΔH) for each reaction. The formation of NO is an endothermic reaction (ΔH > 0), meaning it absorbs heat. The formation of NO2 is an exothermic reaction (ΔH < 0), meaning it releases heat.
3. Step 3: Apply Le Châtelier’s principle to the formation of NO. Since the reaction is endothermic, increasing the temperature will shift the equilibrium to the right, favoring the formation of more NO, thus increasing the equilibrium constant (K).
4. Step 4: Apply Le Châtelier’s principle to the formation of NO2. Since the reaction is exothermic, increasing the temperature will shift the equilibrium to the left, favoring the formation of reactants (NO and O2), thus decreasing the equilibrium constant (K).
5. Step 5: Summarize the effect of temperature on equilibrium constants. For endothermic reactions, increasing temperature increases K, while for exothermic reactions, increasing temperature decreases K, as predicted by Le Châtelier’s principle.