College Chemistry : Le Chatelier's Principle

Study concepts, example questions & explanations for College Chemistry

varsity tutors app store varsity tutors android store

Example Questions

Example Question #10 : Equilibrium

Consider the following equation at equilibrium:

What would happen if more  were added to the system?

Possible Answers:

The reaction would shift towards the products.

There is not enough information to determine the effects of adding more  into the system.

There would be no change in the system.

The reaction would shift towards the reactants.

Correct answer:

The reaction would shift towards the reactants.

Explanation:

Recall Le Chatelier's principle: A chemical system at equilibrium will shift in the direction that minimizes the disturbance to the system.

Before the addition of , the system is in equilibrium, meaning the reaction quotient is equal to the equilibrium constant; .

However, after the addition of , a product, the reaction quotient is now less than the equilibrium constant; .

In order to maintain equilibrium, the reaction will then shift left to favor the reactants in this chemical system.

Example Question #1 : Le Chatelier's Principle

Consider the following equation at equilibrium:

What would happen if more  were added into the equation?

Possible Answers:

There would be no change.

More  would be produced.

More  would be produced.

Less  would be produced.

Correct answer:

More  would be produced.

Explanation:

Recall Le Chatelier's principle: A chemical system at equilibrium will shift in the direction that minimizes the disturbance to the system.

Before the addition of , the system is in equilibrium, meaning the reaction quotient is equal to the equilibrium constant; .

However, after the addition of , a reactant, the reaction quotient is now less than the equilibrium constant; .

In order to maintain equilibrium, the reaction will then shift right of favor the formation of more products.

Example Question #2 : Le Chatelier's Principle

Consider the following exothermic equation:

Which of the following actions will cause the products to be favored?

Possible Answers:

Increase the temperature at which the reaction is conducted.

Decrease the amount of .

Increase the amount of .

Decrease the temperature at which the reaction is conducted.

Correct answer:

Decrease the temperature at which the reaction is conducted.

Explanation:

Since the equation is exothermic, you can think of heat as another product of the reaction:

Apply LeChatelier's principle to this equation.

If the temperature at which the reaction is decreased, that is akin to decreasing the amount of product made, thus causing the reaction to shift towards the products.

Learning Tools by Varsity Tutors

Incompatible Browser

Please upgrade or download one of the following browsers to use Instant Tutoring: