Le Chatelier's Principle and Reaction Equilibrium

The video explains Le Chatelier's Principle, focusing on how temperature changes affect reactions at equilibrium. It covers both exothermic and endothermic reactions, illustrating shifts in equilibrium with particulate diagrams and reaction quotients. The role of catalysts in speeding up reactions without altering equilibrium composition is also discussed.

What does Le Chatelier's Principle predict when a stress is applied to a system at equilibrium?

• The system will shift to counteract the stress.

• The system will remain unchanged.

• The system will speed up the reaction.

• The system will slow down the reaction.

In an exothermic reaction, what happens to the equilibrium position when the temperature is increased?

• It becomes unstable.

• It remains unchanged.

• It shifts to the left.

• It shifts to the right.

How is the reaction quotient (Qc) calculated for a reaction at equilibrium?

• By adding the concentration of reactants and products.

• By multiplying the concentration of reactants and products.

• By dividing the concentration of reactants by products.

• By dividing the concentration of products by reactants.

What is the effect of increasing temperature on the equilibrium constant (Kc) for an exothermic reaction?

• Kc becomes zero.

• Kc decreases.

• Kc remains the same.

• Kc increases.

In an endothermic reaction, what is the effect of increasing temperature on the equilibrium position?

• It shifts to the right.

• It becomes unstable.

• It remains unchanged.

• It shifts to the left.

What color change is observed when the temperature is increased in the endothermic reaction involving cobalt ions?

• The solution turns yellow.

• The solution turns pink.

• The solution turns blue.

• The solution turns green.

How does a catalyst affect the rate of a chemical reaction?

• It decreases the rate.

• It increases the rate.

• It has no effect on the rate.

• It stops the reaction.

Does the addition of a catalyst change the equilibrium composition of a reaction?

• Yes, it changes the composition.

• No, it does not change the composition.

• Yes, it increases the concentration of products.

• Yes, it decreases the concentration of reactants.

What is the primary role of a catalyst in a chemical reaction?

• To speed up the reaction rate.

• To increase the activation energy.

• To change the equilibrium constant.

• To decrease the concentration of reactants.

In the context of reaction rates, what does a catalyst do to both the forward and reverse reactions?

• Speeds up the reverse reaction only.

• Speeds up both reactions equally.

• Slows down both reactions equally.

• Speeds up the forward reaction only.