Unit 7 Questions 7001- 7006 MCQ Past Paper Questions AP Chemistry Final Revision

This video covers equilibrium concepts with real past paper questions, ensuring a solid understanding of dynamic equilibrium, reaction rates, and equilibrium shifts. These multiple-choice and data-based questions test key exam skills, providing insights into how equilibrium is assessed in chemistry exams. 📖 Topics Covered: ✅ Dynamic Equilibrium – Understanding how forward and reverse reaction rates behave at equilibrium. ✅ Reaction Rates vs. Time Graphs – How rates change as equilibrium is reached. ✅ Equilibrium and Partial Pressures – Data interpretation questions involving pressure changes over time. ✅ Equilibrium Shifts & Le Chatelier’s Principle – Identifying changes in equilibrium due to external factors. ✅ Identifying Equilibrium in Graphs – Examining concentration-time and rate-time graphs for equilibrium points. ⸻ 🔹 Questions Answered in This Video: Q1 Which statement below best describes a dynamic equilibrium? A. The rate of the forward reaction is equal to the reverse reaction, and the concentrations of reactants and products is constant. B. The rate of the forward reaction is equal to the reverse reaction in a closed system, and the concentrations of the reactants and products are equal. C. The rate of the forward reaction is equal to the reverse reaction in a closed system, and the concentrations of the reactants and products is constant. D. The rate of reaction changes in either direction to counteract a change in conditions. ⸻ Q2 When a chemical reaction reaches equilibrium, which of the following can be said about the concentrations of the substances present and the rates of reaction? A. The concentrations of the reactants and products continue to change and the rates of forward and reverse reactions remain the same. B. The concentrations of the reactants and products remain constant and the rates of forward and reverse reactions remain the same. C. The concentrations of the reactants and products continue to change and the rates of forward and reverse reactions are different. D. The concentrations of the reactants and products remain constant and the rates of forward and reverse reactions are different. Q3 A sealed container with a volume of 2.0 L contains 2.0 atm of N₂O₄ (g) at a constant temperature of 350 K. The gas decomposes according to the reaction: The partial pressures of 2NO₂ (g) over time are recorded in the table below:Based on the data, what claim can be made about the system? A. The system is at equilibrium after 60 seconds because the pressure of N₂O₄ is decreasing. B. Equilibrium is reached after 80 seconds because the pressures of both gases remain constant. C. The forward and reverse reactions are still occurring but at unequal rates between 60 and 80 seconds. D. The system is at equilibrium after 100 seconds because the forward reaction has stopped. ⸻ Q4 The graph below shows how rate changes with time for a reversible reaction. Which of the following is not correct about point A? A. The rate of the forward and reverse reactions remain constant. B. Partial pressures remain constant. C. The number of particles of each species remains constant. D. The concentrations of reactants and products are equal. Q5 A reaction occurs in a 1.0 L sealed container at 500 K: Initially, 0.050 M of C₂H₆ (g) is introduced into the container. The following data show the concentration of H₂ (g) over time:Based on the data, what claim can be made about the system? A. Equilibrium was established between 200 and 300 seconds because the concentration of H₂ (g) stopped changing. B. The forward reaction stops after 300 seconds because all of the C₂H₆ (g) has decomposed. C. Equilibrium has not been reached because the concentration of H₂ (g) is less than 50% of the starting C₂H₆ (g). D. It is not possible to determine equilibrium without knowing the concentration of C₂H₆ (g). Q6 A reaction occurs in a sealed container at 673 K: A sample of PCl₅ (g) is introduced, and the reaction proceeds as follows: The system is carefully observed for changes in pressure, color, and concentration. Which of the following observations would provide the strongest evidence that the system has reached equilibrium? A. The total pressure in the container increases steadily as PCl₅ (g) decomposes. B. The concentration of Cl₂ (g) continues to increase as PCl₅ (g) decreases steadily. C. The color of the system fades to colorless as PCl₅ is converted into PCl₃ (g) and Cl₂ (g). D. The pressure in the container becomes constant. ⸻ 🎯 Perfect for: ✔️ A-Level Chemistry ✔️ AP Chemistry ✔️ IB Chemistry ✔️ SABIS & Cambridge Students 📌 Boost your understanding of equilibrium with real exam-style questions! 🚀