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Unformatted text preview: Chemistry 112 Elementary Inorganic Chemistry Examination #2 Monday, March 12, 2007 Please check to make sure this exam contains 8 pages (including this one)! Also, as a friendly reminder, all answers must be written in this examination booklet in the space provided. Calculators are permitted. In the accompanying booklet, you will find a periodic table, a table of atomic masses, a sheet of equations, and scratch paper. As always, remember to budget your time wisely and attempt to answer every problem. Try to avoid spending too much time on any individual problem. Good luck! BML Important Constants R = 0.08206 L atm K-1 mol-1 1. (50) ____________ = 8.314 J mol-1 K-1 2. (20) ____________ (H 2 O) = 1.00 g mL-1 at 25 C 3. (30) ____________ K w = 1.0 x 10-14 Total: ____________ / 100 Name: StID: Name: ________________________ 2 1. (50 pts. total; 5 pts. each) For each of the following questions, circle the BEST answer (no explanation is required for full credit). a. If 1.67 mL of 6.0 M HCl (aq) is diluted to a final volume of 1000 mL, what is the pH of the resultant solution? -2.00 -1.00 0.00 1.00 2.00 b. What is the pH of a solution prepared from 2.85 g of potassium hydroxide (KOH) and 2.50 L of water? 1.70 2.85 11.1 12.3 14.0 c. Consider the reversible reaction: CCl 3 CO 2 H (aq) H + (aq) + CCl 3 CO 2- (aq) If the equilibrium concentrations in the above reaction are [CCl 3 CO 2 H]=0.0144 M , [H + ] = 0.096 M , and [CCl 3 CO 2- ]=0.129 M , what is the value of K a (CCl 3 CO 2 H)? 0.37 0.65 0.86 9.2 d. If a solution of aqueous ammonia (NH 3(aq) ) has a pH of 8.8, what is the concentration of [OH- ] in the same solution 8.8 x 10-14 M 1.6 x 10-9 M 6.3 x 10-6 M 8.8 M none of these e. The concentration of hydronium ion (H 3 O + ) in a dilute solution of benzoic acid ( pK a = 4.19) is measured to be 0.000517 M . What is the pH of this solution?...
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