<p>AP Chemistry Chapter 14 and 15 Free Response Exam 2014 Name ______</p><p>II. 50% of your grade will come from these last two questions. You may use a calculator with this section. You will have 43 minutes for this section of the test.</p><p>1 1 -11 1. HOI (aq)  H (aq)  OI (aq) Ka = 2.0 x 10</p><p>Hypoiodous acid , HOI, is a weak acid that dissociates in water as represented by the equation above. a. Calculate the value of [H1+] in an HOI solution that has a pH of 5.95.</p><p> b. Write the equilibrium constant expression for the ionization of HOI in water, then calculate the concentration of HOI(aq) in an HOI solution that has [H1+] equal to 1.8 x 10-6 M.</p><p> c. A solution of Ba(OH)2 is titrated into a solution of HOI i. Calculate the volume of 0.215M Ba(OH)2(aq) needed to reach the equivalence point when titrated into a 150.0 mL sample of 0.346 M HOI(aq).</p><p> ii. Indicate whether the pH at the equivalence point is less than, greater than, or equal to 7. Explain.</p><p> d. Calculate the number of moles of NaOI(s) that would have to be added to 145 mL of 0.260M HOI to produce a buffer solution with [H1+] = 5.00 x 10-8 M. Assume that volume change is negligible.</p><p> e. Show all work for calculating the pH of 150 mL of a 0.200 M HOI solution after 050.0 mL of a .150 M NaOH solution has been added.</p><p> f. Predict whether HOBr would be a stronger acid or a weaker acid than HOI, and justify your prediction. + + -10 2. NH4 + H2O  NH3 + H3O Ka= 5.59 x 10</p><p> a. What two substances act as bases in the equation above?</p><p> b. Write an equilibrium expression for the hydrolysis reaction of ammonia.</p><p> c. Solve for the Kb of ammonia.</p><p> d. 100. milliliters of .10 M Ammonium Chloride solution is to be titrated with NaOH. i. How many moles of NaOH would need to be added to the solution to reach the equivalence point.</p><p> ii. What is the pH of the solution at the equivalence point?</p><p> e. 100. milliliters of .10 M Ammonium Chloride solution is mixed with 80.0 milliliters of a .20 M solution of Ammonia.</p><p> i. What is the [H1+] of the solution?</p><p> ii. If 0.200 grams of NaOH were added to the solution, what would the new pH of the solution be?</p>