Q. For the reaction N2(g) + 3H2(g) ⇌ 2NH3(g), what is the effect of decreasing the volume of the container?
A.
Shifts equilibrium to the right
B.
Shifts equilibrium to the left
C.
No effect on equilibrium
D.
Increases the concentration of NH3
Solution
Decreasing the volume increases the pressure, and according to Le Chatelier's Principle, the equilibrium will shift to the side with fewer moles of gas, which is to the right in this case.
Correct Answer:
A
— Shifts equilibrium to the right
Q. If the temperature of an exothermic reaction at equilibrium is increased, what is the expected effect on the equilibrium position?
A.
Shifts to the right
B.
Shifts to the left
C.
No effect
D.
Reaction rate increases
Solution
For an exothermic reaction, increasing the temperature shifts the equilibrium to the left, favoring the reactants, as the system attempts to absorb the added heat.
Q. In a reaction at equilibrium, what effect does increasing the pressure have if the number of moles of gas on the reactant side is greater than that on the product side?
A.
Shifts to the right
B.
Shifts to the left
C.
No effect
D.
Reaction rate decreases
Solution
Increasing the pressure will shift the equilibrium to the right, favoring the side with fewer moles of gas, according to Le Chatelier's Principle.
Q. In an exothermic reaction at equilibrium, what effect does increasing the temperature have?
A.
Shifts equilibrium to the right
B.
Shifts equilibrium to the left
C.
No effect on equilibrium
D.
Increases the rate of the forward reaction
Solution
Increasing the temperature of an exothermic reaction shifts the equilibrium to the left, favoring the reactants, as the system attempts to absorb the added heat.
Correct Answer:
B
— Shifts equilibrium to the left
Q. What happens to the equilibrium position when the concentration of a reactant is increased in a system at equilibrium?
A.
The equilibrium shifts to the right
B.
The equilibrium shifts to the left
C.
No change occurs
D.
The reaction rate increases
Solution
According to Le Chatelier's Principle, increasing the concentration of a reactant will shift the equilibrium position to the right to favor the formation of products.
Correct Answer:
A
— The equilibrium shifts to the right
Q. What is the effect of adding an inert gas at constant volume to a reaction at equilibrium?
A.
Shifts equilibrium to the right
B.
Shifts equilibrium to the left
C.
No effect on equilibrium
D.
Increases the reaction rate
Solution
Adding an inert gas at constant volume does not change the partial pressures of the reactants or products, thus it has no effect on the position of the equilibrium.
Q. What is the effect of adding an inert gas to a reaction at equilibrium at constant volume?
A.
Shifts the equilibrium to the right
B.
Shifts the equilibrium to the left
C.
No effect
D.
Increases the reaction rate
Solution
Adding an inert gas at constant volume does not change the partial pressures of the reactants or products, thus having no effect on the equilibrium position.
