The following changes to the system at equilibrium have no effect on Kc except:
Correct answer: C. Increasing temperature.
- A. Increasing reactant concentrations.
- B. Equal number of reactant and product gas molecules.
- C. Increasing temperature.
- D. Using a catalyst.
Explanation
Increasing the temperature will either increase or decrease the concentration of the reactants or products depending on whether the forward reaction is endothermic or exothermic. Where the forward reaction is endothermic, increasing the temperature increases the value of the equilibrium constant. The position of equilibrium also changes if you change the temperature. So, temperature influences Kc.
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About Le Chatelier's Principle
Le Chatelier's principle predicts how an equilibrium responds when concentration, pressure or temperature changes. Questions apply it to reversible reactions, identify the direction of shift and distinguish genuine equilibrium changes from the effect of a catalyst, which changes the rate of reaching equilibrium but not its position.
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