16.pH and Ka recitation

16.pH and Ka recitation - How is pK b related to pK a ? c....

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Chem 105 Nielson Recitation 12/04/07 pH, pOH, pK a , pK b pH (pOH) and calculating K a (K b ) acid or base structure Lewis acid/base 1. pH or pOH calculations a. What is the pH of a 0.029 M H 2 SO 4 solution? b. What is the pOH of a 0.50 M Ca(OH) 2 ? The pH? c. Determine the pH of a 0.0151 M solution of ortho-nitrophenol whose K a = 6.0 x 10 -8 . Note: You can check if your assumption of [H3O+] << [HA] is good, but calculating the % ionization. If the % ionization < 5.0%, then the assumption is good. Go back and calculate % ionization for this reaction. d. What is the pH of a 0.20 M solution of the base CH 3 NH 2 ? K b = 4.2 x 10 -4 . 4. Cooking vinegar is about 1.0 M and has a pH of 2.4. Calculate the K a of the CH 3 COOH in the vinegar. Assume the pH of the solution is only due to the acetic acid.
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5. The K a of CH 2 ClCOOH is 1.4 x 10 -3 . a. What is the pK a of CH 2 ClCOOH? b.
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Unformatted text preview: How is pK b related to pK a ? c. Write the equilibrium reaction associated with the pK b of this problem and calculate pK b for the reaction. 6. What is the percent ionization of a 5.0 M H 3 PO 4 solution? Use Table 16.3 for K a values for H 3 PO 4 . 7. Think about acid and base structure to answer the following questions. a. Select the stronger acid in each pair and briefly give a chemical reason why it is stronger. (1) HNO 2 HNO 3 (2) CH 2 BrCO 2 H CH 2 ClCO 2 H b. Select the stronger base in each pair and briefly give a chemical reason why it is stronger. (1) CH 3 CH 2 O-CH 3 CH 2 NH-(2) CH 3 OCH 2 NH 2 CH 3 CH 2 NH 2 8. Draw the reaction of the following Lewis acid/base reactions, showing the electrons being accepted/donated. a. OH + H-Br -------&gt; b. OH + H 3 C-Br -------&gt;...
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16.pH and Ka recitation - How is pK b related to pK a ? c....

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