Understanding Chemical Equilibrium

What is chemical equilibrium?

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

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

• 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 occurs only at high temperatures.

Describe the characteristics of a reversible reaction.

• A reversible reaction does not reach equilibrium.

• A reversible reaction can only proceed in one direction.

• A reversible reaction can proceed in both directions, reaches dynamic equilibrium, and has constant concentrations of reactants and products.

• A reversible reaction always produces more products than reactants.

What does Le Chatelier's principle state?

• A system at equilibrium will always remain unchanged.

• Le Chatelier's principle only applies to chemical reactions in gases.

• Changes in pressure have no effect on equilibrium systems.

• 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.

How does temperature affect chemical equilibrium?

• Temperature affects chemical equilibrium by shifting the position of equilibrium depending on whether the reaction is exothermic or endothermic.

• Temperature has no effect on chemical equilibrium.

• Increasing temperature always favors the formation of products.

• Temperature only affects the rate of reaction, not equilibrium.

What is the equilibrium constant (K) and what does it signify?

• The equilibrium constant (K) only applies to gases and not to liquids.

• The equilibrium constant (K) is the sum of product and reactant concentrations.

• The equilibrium constant (K) is a ratio of product concentrations to reactant concentrations at equilibrium.

• The equilibrium constant (K) indicates the speed of a reaction.

Explain the difference between dynamic and static equilibrium.

• Dynamic equilibrium involves ongoing processes at equal rates, whereas static equilibrium is a state of no movement or change.

• Dynamic equilibrium is only found in chemical reactions.

• Static equilibrium involves constant movement.

• Dynamic equilibrium is a state of complete rest.

What role do catalysts play in chemical reactions at equilibrium?

• Catalysts increase the rate of reaching equilibrium without changing the equilibrium position.

• Catalysts slow down the rate of reactions at equilibrium.

• Catalysts change the equilibrium position to favor products.

• Catalysts are consumed in the reaction and do not affect equilibrium.

How can changes in concentration shift the position of equilibrium?

• Decreasing concentration always shifts equilibrium to the left.

• Increasing concentration always shifts equilibrium to the right.

• Changes in concentration have no effect on equilibrium.

• Changes in concentration shift the position of equilibrium by favoring the side of the reaction that reduces the change.

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

• Q determines the temperature of the reaction.

• Q measures the concentration of reactants only.

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

• Q is used to calculate the rate of a reaction.

Provide an example of a chemical reaction that reaches equilibrium.

• N2(g) + 3H2(g) ⇌ 2NH3(g)

• 2H2(g) + O2(g) ⇌ 2H2O(g)

• CaCO3(s) ⇌ CaO(s) + CO2(g)

• C6H12O6 + 6O2 ⇌ 6CO2 + 6H2O