Equilibria Practice Questions PDF

1. What is the de nition of a dynamic equilibrium? a) A reaction that has stopped. b) A reversible reaction where the rate of the forward reaction equals the rate of the reverse reaction. c) A reaction that only proceeds in one direction. d) A reaction where the reactants are completely used up. An...

1. What is the de nition of a dynamic equilibrium? a) A reaction that has stopped. b) A reversible reaction where the rate of the forward reaction equals the rate of the reverse reaction. c) A reaction that only proceeds in one direction. d) A reaction where the reactants are completely used up. Answer: b) A reversible reaction where the rate of the forward reaction equals the rate of the reverse reaction. 2. In a dynamic equilibrium, what is the relationship between the rate of the forward reaction and the rate of the reverse reaction? a) The forward rate is greater. b) The reverse rate is greater. c) They are equal. d) The rates uctuate randomly. Answer: c) They are equal. 3. What does Le Chatelier's Principle state? a) Equilibrium constants are always greater than 1. b) Catalysts shift the position of equilibrium. c) If a system at equilibrium is subjected to a change, the system will adjust to counteract the change. d) The rate of a reaction is proportional to temperature. Answer: c) If a system at equilibrium is subjected to a change, the system will adjust to counteract the change. 4. For the reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) (ΔH = -92 kJ/mol), what will happen if the pressure is increased? a) Equilibrium shifts to the left. b) Equilibrium shifts to the right. c) No change in equilibrium position. d) The value of Kc decreases. Answer: b) Equilibrium shifts to the right. fl fi 5. For the reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) (ΔH = -92 kJ/mol), what will happen if the temperature is increased? a) Equilibrium shifts to the left. b) Equilibrium shifts to the right. c) No change in equilibrium position. d) The value of Kc increases. **Answer: a) Equilibrium shifts to the 6. For the reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) (ΔH = -92 kJ/mol), what will happen if a catalyst is added? a) Equilibrium shifts to the left. b) Equilibrium shifts to the right. c) No change in the position of equilibrium; it reaches equilibrium faster. d) The value of Kc increases. Answer: c) No change in the position of equilibrium; it reaches equilibrium faster. 7. What is the expression for Kc for the reaction: aA + bB ⇌ cC + dD? a) Kc = ([A]ᵃ[B]ᵇ) / ([C]ᶜ[D]ᵈ) b) Kc = ([C]ᶜ[D]ᵈ) / ([A]ᵃ[B]ᵇ) c) Kc = ([aA][bB]) / ([cC][dD]) d) Kc = ([cC][dD]) / ([aA][bB]) Answer: b) Kc = ([C]ᶜ[D]ᵈ) / ([A]ᵃ[B]ᵇ) 8. What are the units of Kc for the reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g)? a) mol dm⁻³ b) mol² dm⁻⁶ c) mol⁻² dm⁶ d) No units Answer: c) mol⁻² dm⁶ 9. What does a large value of Kc (>1) indicate? a) Reactants are favored at equilibrium. b) Products are favored at equilibrium. c) The reaction is very slow. d) The reaction is exothermic. Answer: b) Products are favored at equilibrium. 10. What does a small value of Kc (