分析化学B卷英文.doc

学院系班级学号姓名-装-订-线-第1页扬州大学试题纸( 2006 2007 学年第 一 学期)化学化工 学院化学06年级课程 Analytical Chemistry (考试) B卷题目一二三四五六七八总分得分ISingle choice ( 2 points per question, 30%)1. What is the standard deviation value for the data set listed below:1.1668, 1.1559, 1.1833, 1.1622, 1.1713, 1.1699, 1.1655; A. 0.0085 B. 0.0079 C. 0.0274 D. 0.0188 E. none of these2. What is the gravimetric factor for the determination of the w/w% Mg when precipitated as Mg2P2O3? At wts: Mg = 24.305 g, P = 30.974 g O = 15.999 gA.0.30658 B. 3.26178 C. 0.15329 D. 6.52355 E. none of these3. If the true value of a measurement does not fall within the confidence limits this tells us: ( )A) nothing B) that our measurement is not preciseC) that our measurement is neither accurate nor preciseD) that our measurement is not accurateE) that our true value is wrong4. A liter of CuCl2- water solution which contains 1.0 mg of CuCl2has a concentration of CuCl2.A. 1.0 ppb B. 1.0 ppm C. 1.0 ppt D. none of these 5. e of a absorbing complex is always dependent upon the_ A. the stability of the complex B. the thickness of the container C. the wavelength of the electromagnetic radiation D. the concentration of the comples6. The best way to remove impurities resulting from the mechanical entrapment and occlusion is to_ the precipitate. ( )A. peptidize B. reprecipitate C. digest D. wash E. none of these第2页7. The equilibrium constant for the reaction of MnO4- and Fe2+ is _ (E0 (MnO4-/Mn2+)= 1.51 V; E0 (Fe3+/Fe2+)=0.77V ) A. 320 B 3.41012 C 5.2 1062 D 4.810638. You are titrating a weak base, CH3NH2, with 0.05000 M HCl. If you start with 25.00 mL of 0.1000 M base, what will be the best indicator (pick from those listed below) to detect the endpoint? Kb = 4.35 10-4Indicator pKaA. Bromocresol Green 4.66B. Bromocresol Purple 6.12C. Phenol Red 7.81D. Phenolphthalein 9.4E. None of these 9. A series of solutions containing NaOH, Na2CO3, and NaHCO3 alone or in compatible combination, was titrated with HCl. The volume of HCl needed to titrate the solution to a phenolphthalein end point is V1mL. Continuing to titrate the solution to a bromocresol green end point needed V2 mL. If 2V1=V2, the component of the mixture is _ A、NaOH+Na2CO3 B、Na2CO3+NaHCO3 C、NaOH+NaHCO3 D、NaOH+Na2CO3+NaHCO3 10. The end point indicator used in the Fajans Method is fluoroscein. It is an_ indicator ( ).A. acid-base B. adsorption C. complexometric D. none of these11. The formation equilibrium constant, KMY, for the reaction: Pb2+ + EDTA4- PbEDTA2- is 1.1 1018. If the titration is done at pH = 6.0 (a4 = 4.55 104), what is the conditional formation constant, KMY, for the reaction.A. 1.1 1018 B. 2.4 1013 C. 2.2 10-5 D. 4.9 1023 E. none of these12. For an electrochemical cell, Eanode = 0.287 V and Ecathode = 0.698 V. What is the cell voltage for this system?A. 0.698 V B. 0.287 V C. 0.411 V D. -0.411 V E. none of these13. The Lambert-Beers Law states that the absorbance is proportional to the concentration of the analyte measured. Which one of the following conditions must be fulfilled when making a calibration plot for a given analyte species? A. The wavelength must be fixed.B. The length of the light path through the sample cell (cuvet) must be fixed.C. Both of the conditions stated in a) and b) must be fulfilled simultaneously.-装-订-线-第3页D. The length of the sample cell (cuvet) must be affixed, but the wavelength can be varied at will. 14The %T of a potassium permanganate solution, measured at 525 nm in a 1 mm pathlength cuvet is 54%. If the solution is diluted by a factor of five and placed in a 5 mm pathelength cuvet, the absorbance is: a) cannot determine - not enough information providedb) 0.055 c) 0.268 d) 4.6 e) 5415. When a coagulated colloidal precipitate is re-dispersed during the washing step, this process is known as_ ( ) A. digestion B. reprecipitation C. occlusion D. peptidization E. none of theseII Fill in the blanks with the right answers (2 points per question, 20%)1. To see the acid color of an indicator used in an acid-base titration, Hin/In- must be_。2. Please write down the mass- balance equation of 0.1 mol.L-1 H3PO4aqueous solution_.3. According to the rules of significant figures, how many significant figures are included in the following examples? _; pH=0.03_.4. The primary standards for the standardization of HCl are_and_, for the standardization of NaOH is _and_.5. According to Bronsted-Lowry concept, the conjugate base of NH3+CH2COOH is _, and the conjugate acid of OH- is _6. To obtain a solution having analytically useful concentration of iodine, iodine should be dissolved in moderately concentrated solution of potassium iodine, the reason is _.7. The wavenumber of a beam of infrared radiation with a wavelength of 5.00 mm is_8. The pH of an acetic acid solution (HC2H3O2) with Cm = 0.100 M, Ka = 1.75 10-5 is _.9. When the mixed solution containing Ba2+, SO42-, FeCl4-, PtCl62- and Ca2+ passed through the anion ion-exchange resins, _were held by the resins.第4页10. During the complex titration, KMY _(decrease, increase or not change ) with the decrease of pH. Consequently, the change in p-function observed in the equivalence region is _(larger, smaller or not change).III Essay questions (4 points per question, 20%)1Please describe the difference and relationship between the distribution coefficient and distribution ratio. 2. What are the requirements for an indicator for a precipitation titration?3. A solution containing 4.48 ppm KMnO4 has a transmittance of 0.309 in a 1.0-cm cell at 520 nm. Calculate the molar absorptivity of KMnO4.-装-订-线-第5页4. For the set of the replicate measurements, 0.0902, 0.0884, 0.0886, 0.1000, the accepted value is 0.0930. For the mean of the set of data, calculate the (a) absolute error; and (b) the relative error in parts per thousand.5. Calculate the pH of a solution that is 0.200 M in NH3 and 0.300 M in NH4Cl. (The acid dissociation constant Ka for NH4+ is 5.7010-10).第6页III Problems (10 points per question )1. Calculate the hydronium ion concentration for a bu