8_Chemical Equilibrium

Chemical Equilibrium Victoria Junior College 1 VICTORIA JUNIOR COLLEGE CHEMISTRY DEPARTMENT Mdm Toh Chui Hoon (toh.chuihoon@vjc.sg) Chemical Equilibrium LECTURE OUTLINE 1 Introduction 1.1 Concept of Dynamic Equilibrium 1.2 Irreversible Reactions 1.3 Reversible Reactions 2 Position of Equilibrium and Equilibrium Constants - Kc and Kp 2.1 Definition of Equilibrium constant, Kc 2.2 Types of reaction mixtures 2.2 Rules for writing Kc and Kp expressions 2.3 Equilibrium constant in terms of partial pressure, Kp 2.4 Significance of the Equilibrium Constants, Kc and Kp 2.5 Use of Le Chatelier’s Principle 3 Factors affecting Position of Equilibrium 3.1 Effect of Concentration changes 3.2 Effect of Pressure changes 3.3 Effect of adding Inert gases 3.4 Effect of Temperature changes 3.5 Effect of Catalyst 4 Calculations involving equilibrium constants Kc and Kp 5 Industrial Application of LCP: The Haber Process 6 Standard Gibbs Free Energy and Position of Equilibrium LECTURE SCHEDULE Lecture no. Lecture contents Tutorial Qs 1 1.1 to 1.3; 2.1 to 2.3 1 & 2 2 2.4 to 2.5; 3.1 to 3.5 3 to 6 3 4, 5 & 6 7 to 10 REFERENCE TEXTS 1. A-level Chemistry by E.N. Ramsden 2. Chemistry in Action by Michael Freemantle

Chemical Equilibrium Victoria Junior College 2 ASSESSMENT OBJECTIVES H2 Candidates should be able to: 1. Explain, in terms of rates of the forward and reverse reactions, what is meant by a reversible reaction and dynamic equilibrium 2. State Le Chatelier’s Principle and apply it to deduce qualitatively (from appropriate information) the effects of changes in concentration, pressure or temperature, on a system at equilibrium 3. Deduce whether changes in concentration, pressure or temperature or the presence of a catalyst affect the value of the equilibrium constant for a reaction 4. Deduce expressions for equilibrium constants in terms of concentrations, Kc, and partial pressures, Kp [Treatment of the relationship between Kp and Kc is not required] 5. Calculate the values of equilibrium constants in terms of concentrations or partial pressures from appropriate data 6. Calculate the quantities present at equilibrium, given appropriate data (such calculations will not require the solving of quadratic equations) 7. Show understanding that the position of equilibrium is dependent on the standard Gibbs free energy change of reaction, ΔG [Quantitative treatment is not required] 8. Describe and explain the conditions used in the Haber process, as an example of the importance of an understanding of chemical equilibrium in the chemical industry H1 Candidates should be able to: 1. Explain, in terms of rates of the forward and reverse reactions, what is meant by a reversible reaction and dynamic equilibrium 2. State Le Chatelier’s Principle and apply it to deduce qualitatively