JAMB/WAEC Chemistry 2027 EP 96 - Chemical Equilibrium (Intro) + Free JAMB/WAEC Past Questions

JAMB/WAEC Chemistry EP 96 - Chemical Equilibrium (Introduction) + Free JAMB/WAEC Past Questions In this lesson, we introduce Chemical Equilibrium, one of the most important topics in Physical Chemistry. Chemical equilibrium explains what happens when the rate of the forward reaction becomes equal to the rate of the backward reaction. This topic is frequently tested in JAMB, WAEC, NECO, and Post UTME examinations and forms the foundation for understanding Le Chatelier's Principle and reversible reactions. Topics Covered • Chemical Equilibrium • Reversible Reactions • Forward Reactions • Backward Reactions • Dynamic Equilibrium • Equilibrium Conditions What Is Chemical Equilibrium? Chemical equilibrium is the state in a reversible reaction where the rate of the forward reaction equals the rate of the backward reaction. At equilibrium: ✔ Reactants and products are present. ✔ Concentrations remain constant. ✔ Forward and backward reactions continue. ✔ No observable change occurs. Reversible Reactions A reversible reaction is a reaction that can proceed in both forward and backward directions. Example: N₂ + 3H₂ ⇌ 2NH₃ Nitrogen and hydrogen combine to form ammonia, while ammonia can also decompose back into nitrogen and hydrogen. Dynamic Nature of Equilibrium Chemical equilibrium is said to be dynamic because reactions continue to occur even though no visible change is observed. At equilibrium: ✔ Forward reaction continues. ✔ Backward reaction continues. ✔ Both occur at equal rates. Characteristics of Chemical Equilibrium ✔ Occurs only in reversible reactions. ✔ Takes place in a closed system. ✔ Concentrations remain constant. ✔ Rate of forward reaction equals rate of backward reaction. ✔ No net change is observed. Conditions Necessary for Equilibrium ✔ Reaction must be reversible. ✔ System must be closed. ✔ Temperature must remain constant. ✔ Reactants and products must remain in contact. Importance of Chemical Equilibrium ✔ Manufacture of ammonia in the Haber Process. ✔ Manufacture of sulphuric acid in the Contact Process. ✔ Industrial production of chemicals. ✔ Understanding reaction yields. Free JAMB/WAEC Past Questions 1. Chemical equilibrium is established when? A. Reactants are completely used up B. Products stop forming C. Forward and backward reaction rates become equal D. Temperature becomes zero Answer: C 2. Chemical equilibrium occurs in? A. Irreversible reactions only B. Reversible reactions only C. Combustion reactions only D. Decomposition reactions only Answer: B 3. At equilibrium, the concentration of reactants and products? A. Becomes zero B. Continues changing rapidly C. Remains constant D. Becomes equal Answer: C 4. Chemical equilibrium is described as dynamic because? A. The reaction stops completely B. Reactants disappear C. Forward and backward reactions continue simultaneously D. Temperature increases continuously Answer: C 5. Which of the following is necessary for equilibrium to be established? A. Open system B. Closed system C. High pressure only D. Presence of catalyst only Answer: B Quick Revision Note ✔ Equilibrium occurs in reversible reactions. ✔ Forward reaction rate = Backward reaction rate. ✔ Equilibrium is dynamic, not static. ✔ Concentrations remain constant at equilibrium. ✔ Equilibrium is established in a closed system. This lesson is highly recommended for all JAMB, WAEC, NECO, and Post UTME candidates preparing for Chemistry examinations. #JAMBChemistry #WAECChemistry #ChemicalEquilibrium #ReversibleReaction #PhysicalChemistry #ChemicalKinetics #ChemistryTutorial #JAMBPastQuestions #WAECPastQuestions #NECOChemistry #PostUTME #O3Schools #StudySmart #ExamPreparation #ChemistryLessons