U3AoS2: Le Chateliers Principle, K & Q

An understanding of Le Chatelier’s principle is useful in the chemical industry. A prediction that can be made using this principle is the effect of...

• catalysts on the rate of reaction

• catalysts on the position of equilibrium

• changes in temperature on the rate of reaction

• changes in the concentration of reactants on the position of equilibrium

Tags

NGSS.HS-PS1-5

How does the removal of a product from a system at dynamic equilibrium affect the position of equilibrium?

• It causes the reverse reaction to stop entirely.

• It favours the reverse reaction.

• It favours the forward reaction.

• It does not affect the position of equilibrium.

Tags

NGSS.HS-PS1-5

The concentration-time graph represents a change to an equilibrium system at time t_1. Which one of the following would account for the changes in concentration at time t₁?

• The addition of X _(aq)

• The removal of Y_(aq)

• An increase in temperature

• A decrease in temperature

Tags

NGSS.HS-PS1-5

Which of the following statements is true regarding the effect of changing the pressure on a system in dynamic equilibrium?

• Decreasing the pressure may cause the system to favour the reaction that produces fewer moles of gas.

• Increasing the pressure may cause the system to favour the reaction that produces fewer moles of gas

• Increasing the pressure may cause the system to favour the reaction that produces more moles of gas

• Changing the pressure will never have any effect on the position of equilibrium

Which of the following changes would explain the change at time t1 in the graph shown?

• An increase in the volume of the reaction vessel at constant temperature

• A decrease in the volume of the reaction vessel at constant temperature

• Removal of B_(g) at constant volume and temperature

• An increase in temperature at constant volume

Tags

NGSS.HS-PS1-5

Hydrogen is produced on an industrial scale from methane, as follows. If an inert gas is added to an equilibrium system at a constant temperature and a constant volume, the concentration of hydrogen will...

• increase.

• decrease.

• not change.

• decrease then increase.

The temperature of an equilibrium system with an endothermic forward reaction is increased.

The value of K....

• will increase and the equilibrium position will shift to the right.

• will decrease and the equilibrium position will shift to the right

• will increase and the equilibrium position will shift to the left

• will decrease and the equilibrium position will shift to the left.

Using the following thermochemical equation. If the pressure and volume remain constant when the temperature is increased, the forward reaction rate will

• increase and the [NH₃] will increase.

• increase and the [NH₃] will decrease

• decrease and the [NH₃] will decrease

• decrease and the [NH₃] will remain the same

Tags

NGSS.HS-PS1-5

Hydrogen is produced on an industrial scale from methane, according to the following equation. The expression for the equilibrium constant for the reverse reaction is

• 
• 
• 
• 

Tags

NGSS.HS-PS1-5

Which of the following statements is true about the equilibrium constant, K?

• K depends on the initial concentrations of reactants and products.

• K is always greater than 1 for an exothermic reaction.

• K is always expressed in units of M or mol/L

• K can only change with temperature.