Name______________________ SID_______________________ Score__________ _________ Points on this page Page 1 of 4 CHE 226 Analytical Chemistry Exam IV May 6, 2004 Answer the following questions in the space provided. Use pencil only. Do not scribble over unwanted answers; erase carefully. Show all work. If you show only the numerical answer, and the answer is not exactly right, you get no partial credit. Correct set-up of problems gets 80-90% credit regardless of whether the arithmetic is correct. Circle final numerical answers. 1) (20 points) a) Write the complete charge balance equation for a solution of MgCl2. b) Write the mass balance expression for a 0.1 M solution of the weak acid HNO2. 2) Define, explain, or otherwise describe the term activity coefficient. 3) (20 points) Consider the titration curves for 25.00 mL of 0.1000 M malonic acid with 0.1000 M NaOH. For malonic acid, Ka1 = 1.42 × 10-3 and Ka2 = 2.01 × 10-6 c) Calculate the pH before any base is added. d) Find the pH when 37.50 mL of base is added.Name______________________ SID_______________________ Score__________ _________ Points on this page Page 2 of 4 a) . 4) (20 points) Consider the titration curves for 25.00 mL of 0.1000 M malonic acid with 0.1000 M NaOH. For malonic acid, Ka1 = 1.42 × 10-3 and Ka2 = 2.01 × 10-6 e) Calculate the pH before any base is added. f) Find the pH when 37.50 mL of base is added.Name______________________ SID_______________________ Score__________ _________ Points on this page Page 3 of
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