Difficulty: Medium

Average Score: 64%

For the reaction below, which of the following would result from increasing the temperature of the environment? A + B â‡Œ C + Heat

Rationale

The concentrations of A and B would increase, and the concentration of C would decrease.

Increasing the temperature of an exothermic reaction, such as A + B ⇌ C + Heat, shifts the equilibrium position to the left, favoring the reactants. This results in higher concentrations of A and B while the concentration of C decreases, as the system seeks to counteract the added heat.

A (The concentrations of A and B would increase, and the concentration of C would decrease.) CORRECT

This choice correctly reflects Le Chatelier's principle, which states that if a system at equilibrium is subjected to a change in temperature, the equilibrium will shift in a direction that counteracts the change. By increasing the temperature in this exothermic reaction, the system shifts left, thus increasing A and B while reducing C.

B (The reaction would remain at equilibrium, and there would be no change in the concentrations of A, B, or C.) YOUR ANSWER

This statement is incorrect because increasing temperature in an exothermic reaction disturbs the equilibrium. The system will not remain unchanged; instead, it will adjust the concentrations to restore a new equilibrium state, shifting towards the reactants.

C (The concentrations of A and B would decrease, and the concentration of C would remain the same.) YOUR ANSWER

This choice is false because it contradicts the principles of chemical equilibrium. Increasing temperature leads to a shift towards the reactants, resulting in increased concentrations of A and B, not a decrease, and C's concentration would not remain the same.

D (The concentrations of A, B, and C would all increase.) YOUR ANSWER

This option is incorrect as it implies that all species would increase simultaneously, which is not possible in an exothermic reaction when temperature is raised. The increased temperature causes a shift towards the reactants, leading to a decrease in C’s concentration instead.

Conclusion

In summary, when the temperature of an exothermic reaction is increased, the equilibrium shifts to favor the reactants, resulting in greater concentrations of A and B while reducing C. Understanding this principle is crucial for predicting the behavior of chemical reactions under varying conditions, particularly in industrial and laboratory settings.

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