All Problems are equilibrium problems because All problems involve stoichiometry: soluble strong acids, strong bases Some problems involve equilibrium: salts, weak acids, weak bases “insoluble” For chemical reactions and are the important quantities Keq, Kc, Kp – For physical changes and are the important quantities Ka, Kb, Ksp, Kionize, Kdissocation – Important points 1. Law of mass action + + +sS + xxx aA bB rR … = [R]r [S]s / [A]a [B]b Kc … … 2. for molarity for ions and trial Kc 3. with atm, or mmHg for gases Kp Relationship / connection between these = (RT)Δn Kp Kc 4. Orientation of collisions 5. Shifting equilibrium Le Chatlier’s Principle – a. solid b. liquid c. catalyst d. inert gas added e. temperature changes (increasing favors endothermic processes) T f. only factors in equation constant will affect eg. CaCO3(s) CaO(s) + CO2(g) Keq g. pressure / volume changes 6. Important vocabulary Driving force Favors (reactants or products) Shifts (in LeChatelier arguments) 7. > 1 products favored K < 1 reactants favored K 8. Excluded: solids, pure liquids, water (in aqueous solution) 9. Typical question: and the starting concentration of reactants, find the concentration (or Kc pH !) of products at equilibrium. Example: of acetic acid = 1.754 × 10-5. Find the pH of a 0.100 solution of acetic acid. Kc M 10. Equilibrium constant for a reverse reaction = 1 / of the of the forward reaction. K
All Problems are equilibrium problems because All problems involve stoichiometry: soluble strong acids, strong bases Some problems involve equilibrium: “insoluble” salts, weak acids, weak bases For chemical reactions – Keq, Kc, and Kp are the important quantities For physical changes – Ka, Kb, Ksp, Kionize, and Kdissocation are the important quantities Important points 1. Law of mass action aA + bB + … rR +sS + xxx Kc = [R]r [S]s … / [A]a [B]b … 2. Kc for molarity for ions and 3. Kp with atm, or mmHg for gases Relationship / connection between these Kp = Kc (RT)Δn 4. Orientation of collisions 5. Shifting equilibrium – Le Chatlier’s Principle a. solid b. liquid c. catalyst d. inert gas added e. temperature changes (increasing T favors endothermic processes) f. only factors in equation constant will affect Keq eg. CaCO3(s) CaO(s) + CO2(g) g. pressure / volume changes 6. Important vocabulary Driving force Favors (reactants or products) Shifts (in LeChatelier arguments) 7. K > 1 products favored K < 1 reactants favored 8. Excluded: solids, pure liquids, water (in aqueous solution) 9. Typical question: Kc and the starting concentration of reactants, find the concentration (or pH !) of products at equilibrium. Example: Kc of acetic acid = 1.754 × 10-5. Find the pH of a 0.100 M solution of acetic acid. 10. Equilibrium constant for a reverse reaction = 1 / K of the of the forward reaction. trial