When the temperature of an exothermic reaction at equilibrium is raised, the equilibrium constant:

1. For an exothermic reaction, heat can be treated as a product. 2. Raising the temperature adds heat, so by Le Chatelier's principle the system shifts to remove it. 3. That shift moves the position backwards, towards the reactants. 4. Since the equilibrium mixture now holds more reactant and less product, $K$ falls. 5. Temperature is the one factor that does change $K$, which is why a catalyst or a pressure change cannot. _Source: NECTA ACSEE 2023 Chemistry 132/1, Question 8: Chemical Equilibrium_