[試題] 96上 何國榮 分析化學乙上 期末考

[charmaxim (子羽)]

課程名稱︰ 分析化學乙上
課程性質︰
課程教師︰ 何國榮
開課學院： 理學院
開課系所︰ 化學系
考試日期（年月日）︰ 2008/1/16
考試時限（分鐘）： 10:20-12:10
是否需發放獎勵金： 是
（如未明確表示，則不予發放）

試題 :

Briefly answer the following questions.

1. For a sparingly soluble salt, explain that the activity decreased when the
   increased of ionic strength.                                              5%

2. For a diprotic acid H2A, please (a) derive the equation for the calculation
   of [H+] (b) show that ignoring the concentration of water and the second
   dissociation, the equation can be simplified to [H+]=√Ka[H2A]. (c) show
   that under the condition Ka/C < 2.5x10^-3, the equation can be simplified
   to √KaC.                                                                12%

3. Explain that the isoionic point is very close to the isoelectric point.   5%

4. Explain how isoelectric focusing works.                                   5%

5. For a buffer solution, describe the major factors to the buffer capacity. 6%

6. Explain the sodium error and its effect to pH measurement.                6%

7. Even if two solutions have the same concentration of [H+], using the same pH
   meter, the pH value may not be the same. Why?                             5%

8. (a) Explain the purpose of using auxiliary complexing agents in EDTA
       titration.                                                            4%
   (b) Explain that multidentate instead of monodentate ligand is used in metal
       ion titration.                                                        4%

9. Explain that the standard reduction potential of AgCl + e- → Ag + Cl- is
   smaller than the standard reduction potential of Ag+ + e- → Ag.          5%

10. (a) Describe the method of iodometry.                                    4%
    (b) Describe the procedure to detect the end point.                      4%

11. (a) 0.010 M HCl, (b) 0.010 M HA with pKa=4, (c) 0.00010 M HCl solutions are
    titrated with NaOH, please draw the three titration curve in the same
    diagram.                                                                 9%

12. (a) 0.0500 M Fe2+, (b) 0.00050 M Fe2+ solutions were titrated with Ce4+,
    please draw the two titration curve in the same diagram.                 6%
    Fe3+ + e- → Fe2+   E°=0.767 V
    Ce4+ + e- → Ce3+   E°=1.70 V

13. A potentiometer consists of a Pt and a Calomel electrode is used in the
    oxidation titration of Fe2+, write down the two half cell reactions.     5%

14. Explain that mercury is a popular material for the study of reduction
    reaction.                                                                5%

15. Explain that voltammetry is performed under complete concentration
    polarization condition.                                                  5%

16. A nickel-metal hydride rechargeable battery for laptop computers is based
    on the following chemistry:
                                 discharged
    Cathode: NiOOH(s) + H2O + e- ────→ Ni(OH)2(s) + OH-
                                 discharged
      Anode:         MH(s) + OH- ────→ M(s) + H2O + e-
    The anode material, MH, is a transition metal hydride or rare earth alloy
    hydride. Explain why the voltage remains nearly constant during the entire
    discharge cycle.                                                         5%

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