课程名称︰分析化学乙上 课程性质︰生技系、农化系必修 课程教师︰刘春樱 开课学院：理学院 开课系所︰化学系 考试日期（年月日）︰2013年1月11日 考试时限（分钟）：2小时 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : Analytical Chemistry (Final Examination) Jan. 11, 2013 I. Make a distinction between: (20%) 1.Activity and activity coefficient 2.Iodimetry and iodometry 3.Thermodynamic and concentration equilibrium constant 4.A galvanic cell and electrolytic cell 5.Standard electrode potential and formal potential II.Problems 1.How to prepare a (a) carbonate free sodium hydroxide (b) standard solution? (4%) 2. (a)Define buffer capacity. (b)Find the pH of a 1.00 L aqueous solution containing 12.43 of tris (FM 121.14) plus 4.67 g of tris hydrochloride (FM 157.60). (c)If we add 12.0 mL of 1.00M HCl to the solution in the preceding problem, what will the new pH be? (pKa=8.07) (8%) 3.Write a charge balance equation for an aqueous solution that contains NaCl, Ba(ClO4)2 and Al2(SO4)2. (3%) 4.Consider curves for the titration of 0l10M NaOH and 0.010M NH3 with 0.10M HCl. (a)Briefly account for the difference between curves for the two titrations. (b)In what respect will the two curves be indistinguishable? (4%) 5.The most common method for the determining organic nitrogen (eg. Protein; melamine and cyanuric acid etc.) is the Kjeldahl method. The method, then is based on a neutralization titration with boric acid as collector. Please write all the chemical equations involved. (6%) 6.Derive equations that define α0, α1, α2, and α3 for the acid H3AsO4. (6%) 7.What is the pH of pure water and of 0.1M NaCl? (8%) (αH+ =900 pm; αOH =350pm; Kw=1.0×10-14.) 8.Explain the unusual properties of the following titration curves (a)Phosphoric acid (b)Oxalic acid (c)Sulfuric acid (6%) 9.What is isoelectric focusing? (8%) 10.Give an example of chelation therapy. (3%) 11.State the purpose of an auxiliary complexing agent in the EDTA titration, and give an example of its use. (4%) 12.Find the conditional formation constant for Mg(EDTA)2- at pH 9.00. (log Kr for Mg(EDTA)2- is 8.79; αγ4- at pH 9.00 is 0.041) (3%) 13.Describe how mercury could serve as an indicator electrode of the second kind for the EDTA anion Y4- , when a small amount of HgY2- is added to a solution containing Y4-. [Hint: The formation constant, Kr for HgY2- is very large (6.3×1021), so the concentration of the complex remains essentially constant over a large range of Y4- concentrations.] (5%) 14.Calculate the formation constant Kr for Ag(CN)2-. If the cell develops a potential of -0.625V. where E°SCE = -0.224V SEC|| KAg(CN)2 (7.50×10-3 M), CN- (0.0250M)| Ag (6%) 15.Describe the source of pH dependence in a glass membrane electrode. (6%) 16.How is an oxidation-reduction titration curve generated through the use of standard electrode potentials for the analyte species (Fe2+) and the volumetric titrant (Ce4+)? (6%) 17.Give an example for the potentiomertric biosensing of proteins with ultrasensitive ion-selective microelectrode and nanoparticle labels. (10%) --

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