Final answer:
The enthalpy change (∆H) of a reaction is used to predict the effect of a change in temperature on an equilibrium constant. For the reaction N₂(g) + O₂(g) ⇒ 2NO(g), which is exothermic, an increase in temperature will lead to a decrease in the equilibrium constant K.
Step-by-step explanation:
The property of a reaction that can be utilized to predict the effect of a change in temperature on the value of an equilibrium constant is the enthalpy change (∆H) of the reaction. According to Le Chatelier's principle, if the temperature is increased for an endothermic reaction, where heat is absorbed during the reaction, the equilibrium will shift to the right to consume the excess heat.
This will increase the production of products and cause the equilibrium constant (K) to increase. Correspondingly, for an exothermic reaction where heat is produced, increasing temperature would shift the equilibrium to the left, resulting in a decrease in the value of K.
Considering the reaction N₂(g) + O₂(g) ⇒ 2NO(g) which has a ∆H value of -181 kJ, this indicates an exothermic process. If the temperature increases, we can predict that the equilibrium constant K for this reaction will decrease because the system will shift to the left to absorb the added heat, favoring reactants.