Unformatted text preview: er to form the conjugate acid and OH. • Be able to rank acids or bases in terms of increasing strength given Ka, Kb, or information on relative strength. • Autoionization of water: 2 H2O(l) H3O+(aq) + OH(aq) Kw = [H+][OH–]=1.010–14 at 25°C Kw = water’s ion product constant CHEM 162 Exam 2 Review – Winter2014 pH scale: pH = 7: neutral & pH < 7: acidic & pH > 7: basic (or alkaline) [H+] = 10pH [OH] = 10pOH pH = log [H+] pOH = log [OH] pH + pOH = 14.00 Calculate pH of Strong Acids and Strong Bases – Strong acids and bases ionize completely. – Accounting for all the H+ and OH– ions, [H+] = original molarity of strong acid [OH–] = molarity of base (# of OH– in base) pH Calculations for a Weak Acids – Weak acids remain mostly undissociated. – Write the equation for the dissociation of acid. – Set up ICE table with [HA] given or calculated. – Calculate pH of weak acid solution. – Use percent ionization of solution to get Ka. x
– Use [HX] – x ≈ [HX] approx. for: <5% [HA]
– Use Quadratic Method or method of successive x
≥0.05% approximations for: [HA] Percent ionization = [H ] at equilibri...
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