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Unformatted text preview: Acid-Base Equilibrium Exercise 1 &¡¢ £¤¥¥¦§¦£¨¦©ª«¬®¯ °±ª²³´µ«¦¶·¸ª¥ª¹ª¸©º »¸¼¼¥¦©¦½¬µ®¶ ¦±ª«¦ 1. Identify the conjugate pairs in each of the following reactions: (a) NH 3 (aq) + H 2 O (aq) & NH 4 + (aq) + OH- (aq) Base acid C.A. C. B. (b) HNO 3 (aq) + OH- (aq) & NO 3- (aq) + H 2 O (l) Acid base C. B. C.A. (c) H 2 O (l) + H 2 O (l) & H 3 O + (aq) + OH- (aq) Base Acid C.A. C. B. 2. The self-ionization of water is an endothermic process : 2H 2 O (l) & H 3 O + (aq) + OH- (aq) = 6.5 kJ mol-1 Is the concentration of hydrogen ions in pure water at 40 ° C less than or greater than the value at 25 ° ? Explain your answer. Greater. increase temperature favors endothermic reaction according to Le Chatelier s Principle 3. Calculate the pH of pure water at 10 ° t which temperature K w = 0.30 x 10-14 . Kw = [ H3O+] [OH-] For pure water, [ H3O+] = [OH-] So pH = 7.26 4. Predict the direction of each of the following reactions in aqueous solution (a) HNO 2 (aq) + CN-(aq) & HCN (aq) + NO 2- (aq) HNO 2 > HCN in acidity So to the Right (b) CH 3 COOH (aq) + HCOO-(aq) & CH 3 COO- (aq) + HCOOH (aq) HCOOH > CH 3 COOH in acidity So to the Left Acid-Base Equilibrium Exercise 2 5. Calculate the pH of a 0.036 M nitrous acid (HNO 2 ) solution at 25 ° C....
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This note was uploaded on 02/22/2012 for the course CHEM yscn0027 taught by Professor Drtong during the Fall '10 term at HKU.
- Fall '10