Chem 110, Chapter 14 Rabigh-Summer.pdf

General Chemistry Chem110 Chapter 14 Chemical Equilibrium Objectives ØDefine the concept of equilibrium and the equilibrium constant ØWrite equilibrium constant expression ØApply the equilibrium constant expression ØDiscuss the effect of factors on the chemical equilibrium...

General Chemistry Chem110 Chapter 14 Chemical Equilibrium Objectives ØDefine the concept of equilibrium and the equilibrium constant ØWrite equilibrium constant expression ØApply the equilibrium constant expression ØDiscuss the effect of factors on the chemical equilibrium 2 Outline 14.1 The Concept of Equilibrium and the Equilibrium Constant 14.2 Writing Equilibrium Constant Expression 14.5 Factors That Effect Chemical Equilibrium 3 14.1 The Concept of Equilibrium and the Equilibrium Constant ØFew reaction are proceeding in one direction. 𝐴+𝐵 →𝐶+𝐷 ØMost reactions are reversible 𝐴+𝐵 ↔𝐶+𝐷 ØChemical equilibrium: is achieved when § the rates of the forward and reverse reactions are equal § and the concentrations of the reactants and products remain constant 4 14.1 The Concept of Equilibrium and the Equilibrium Constant 1. Physical Equilibrium 𝐻2𝑂 𝑙 ↔ 𝐻2𝑂(𝑔) 2. Chemical Equilibrium 𝑁2𝑂4 𝑔 ↔ 2𝑁𝑂2(𝑔) 5 The Equilibrium Constant 𝑎𝐴 + 𝑏𝐵 ↔ 𝑐𝐶 + 𝑑𝐷 Øa, b, c, & d: are the stoichiometric coefficients for A, B, C , & D Ø K is the equilibrium constant. #! $ " 𝐾= %#& $ Where, K=Equilibrium constant [C],[D]= concentration of products [A],[B]= concentration of reactants ØThe equilibrium constant: for a reversible reaction at equilibrium and a constant temperature, a certain ratio of reactant and product concentrations has a constant value, K, called the equilibrium constant. 6 The Equilibrium Constant !! " " 𝐾= ##$ $ What K tells us??? ØIf K >> 1 → The equilibrium will favour the PRODUCTS → Larger product concentration ØIf K