Le Chatelier's Principle 1

Le Chatelier's Principle can be used to predict the effect of a perturbance (change in pressure, volume, concentration, and temperature) on a system at equilibrium.
1. True.
2. False.
3. Depends on the situation.
In the reaction
N₂(g) + 2O₂(g) ⇌ 2NO₂(g)
when the pressure increases, what happens to [N₂(g)] and [NO₂(g)]?
1. [N₂(g)] increases and [NO₂(g)] increases.
2. [N₂(g)] decreases and [NO₂(g)] decreases.
3. [N₂(g)] increases and [NO₂(g)] decreases.
4. [N₂(g)] decreases [NO₂(g)] increases.
Consider this reaction:

N₂O₄(g) ⇌ 2NO₂(g)

In the reaction above, describe the changes in concentrations as the pressure decreases.
1. [N₂O₄(g)] increases and [NO₂(g)] increases.
2. [N₂O₄(g)] decreases and [NO₂(g)] decreases.
3. [N₂O₄(g)] decreases and [NO₂(g)] increases.
4. [N₂O₄(g)] increases and [NO₂(g)] decreases.
If the concentration of a substance in the system at equilibrium changes, the system will relieve the stress by counteracting against the change and reaching a new equilibrium.
1. True
2. False
3. Depends on the situation.
The reaction below is allowed to reach equilibrium. If O₂(g) is added to the system, what
is the effect on the value of [CO₂(g)] and the value of Kc?

2CO(g) + O₂(g) ⇌ 2CO₂(g) + heat
1. [CO₂(g)] decreases, Kc stays constant.
2. [CO₂(g)] decreases, Kc will increase.
3. [CO₂(g)] increases, Kc stays constant.
4. [CO₂(g)] increases, Kc will increase.
Consider the reaction
2BrF₂(g) ⇌ 2BrF(g) + F₂(g)
What will happen to the [F₂(g)] when the [BrF(g)] is increased by adding more at equilibrium?
1. It will increase.
2. It will decrease.
3. It will not change.
4. It cannot be predicted based on the information given.
For the reaction
N₂(g) + 3H₂(g) ⇌ 2NH₃(g) + 91.8kJ
as the concentration of H₂ is decreased, what happens to the [N₂(g)]?
1. It increases.
2. It decreases.
3. It remains constant.
4. It changes unpredictably.
If the temperature increases then the products in a reaction releasing heat (exothermic) will be more favored.
1. True.
2. False.
3. Depends on other conditions in the reaction.
Consider this reaction at equilibrium:
N₂(g) + O₂(g) ⇌ 2NO(g) ΔEp = +182.6kJ
Determine whether this reaction is endothermic or exothermic, and predict what will happen to [N₂(g)] if the temperature increases.
1. Endothermic; [N₂(g)] will increase.
2. Endothermic; [N₂(g)] will decrease.
3. Exothermic;[N₂(g)] will increase.
4. Exothermic;[N₂(g)] will decrease.
Given this reaction at equilibrium :
2C(s) + H₂(g) + energy ⇌ C₂H₂(g)
What change will result in an increase in the amount of C₂H₂(g) at equilibrium?
1. Decreasing the pressure.
2. Increasing the concentration of H₂.
3. Decreasing the concentration of C.
4. Decreasing the temperature.

Le Chatelier's Principle 1

Assignment Quiz