Equilibrium and Le Chatelier's Principle

What is chemical equilibrium?

• Chemical equilibrium is the point at which all reactions stop.

• Chemical equilibrium occurs only at high temperatures.

• Chemical equilibrium is the state in which the concentrations of reactants and products remain constant because the forward and reverse reactions occur at the same rate.

• Chemical equilibrium is when reactants are completely converted to products.

State Le Chatelier's Principle.

• If a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust to minimize the effect of that change.

• Decreasing pressure will always favor the formation of reactants.

• Increasing temperature will always shift the equilibrium to the right.

• A system at equilibrium will always remain unchanged regardless of external factors.

How does temperature affect equilibrium?

• Temperature changes only affect solid states in reactions.

• Equilibrium is only affected by pressure changes.

• Temperature changes can shift the position of equilibrium in a chemical reaction.

• Temperature has no effect on equilibrium.

What happens to equilibrium when pressure is increased?

• The equilibrium remains unchanged.

• The equilibrium shifts towards the side with more moles of gas.

• The equilibrium is completely disrupted.

• The equilibrium shifts towards the side with fewer moles of gas.

Explain the effect of concentration changes on equilibrium.

• Increasing concentration always shifts equilibrium to the right.

• Concentration changes have no effect on equilibrium.

• Decreasing concentration always shifts equilibrium to the left.

• Changes in concentration shift the equilibrium position to counteract the change.

What is the equilibrium constant (K)?

• K = [products] / [reactants]

• K = [reactants]^[coefficients] / [products]^[coefficients]

• K = [products]^[coefficients] + [reactants]^[coefficients]

• K = [products]^[coefficients] / [reactants]^[coefficients]

How do catalysts affect chemical equilibrium?

• Catalysts change the equilibrium constant of a reaction.

• Catalysts do not affect the position of chemical equilibrium; they only speed up the attainment of equilibrium.

• Catalysts shift the equilibrium position to favor products.

• Catalysts increase the concentration of reactants at equilibrium.

Describe a shift in equilibrium due to a change in volume.

• The equilibrium shifts towards the side with more moles of gas when volume decreases.

• The equilibrium remains unchanged regardless of volume changes.

• The equilibrium shifts towards the side with equal moles of gas when volume decreases.

• The equilibrium shifts towards the side with fewer moles of gas when volume decreases.

What is the significance of the reaction quotient (Q)?

• The reaction quotient (Q) indicates the direction of a reaction relative to its equilibrium state.

• Q measures the concentration of reactants only.

• Q is only relevant for gas-phase reactions.

• Q determines the rate of a reaction.

Provide an example of a dynamic equilibrium in nature.

• The growth of a single plant species.

• The balance between predator and prey populations.

• The water cycle in the environment.

• The migration patterns of birds.