分析化学测试题

ⅠSingle choice ( 2 points per question, 30%)(一) 1. When 0.20mol•L -1 NaOH standard solution was used to titrate the mixtures of 0.10 mol•L -1H 2SO 4 and0.10mol•L -1H 3PO 4, ________end points could be observed on the titration curves. （ ）A. 1B. 2C. 3D. 42. Which one of the following is a pair of conjugate acid and base? ( )A. H 2CO 3—CO 32-B. HPO 42-—PO 43-C. H 3PO 4—HPO 42-D. NH 3-NH 3.H 2O3. The solubility of Ag 2S in pure water is________(K SPAg2S =2.0×10-48)( )B. 34sp KC. 32spK D. 34spK4. Which of the following could be used as the primary standard?( )A. KMnO 4B.（NH 4）2CO 3C. HClD. K 2Cr 2O 75. The equilibrium constant for the reaction of MnO 4- and Fe 2+ is ______(E 0 (MnO4-/Mn2+)= 1.51 V; E 0 (Fe3+/Fe2+)=0.77V ) ( )A. 320 B 3.4⨯1012 C 5.2 ⨯1062 D 4.8⨯10636. ε of a absorbing complex is always dependent upon the______( C )A. the stability of the complexB. the thickness of the containerC. the wavelength of the electromagnetic radiationD. the concentration of the comples7. A solution containing commercial cyt c is buffered to pH 7.40 using 85 mmol/L phosphate buffer. If thesolution is diluted with water by a factor of three, what is the resulting pH of the solution? ( D )A. 2.47B. 5.15C. pH > 14D. nothing happens - pH remains same8. The %T of a certain solution at a certain wavelength in a 1.0 cm cell is 50%. The absorbance of this samesolution in a 2.0 cm cell is: ( )a) unknown. We can't calculate it with the information given.b) 0.15 c) 0.30 d) 0.609. What is the ratio of acid to salt in a solution that is pH 7.20 and contains H 3PO 4 and Na 3PO 4 (pKa 1~pKa 3of H 3PO 4 are 2.12、7.20、12.4 respectively) ( ) a) 1:2 b) 2:3 c) 1:1 d) 2:110. A series of solutions containing NaOH, Na 2CO 3, and NaHCO 3 alone or in compatible combination, wastitrated with HCl. The volume of HCl needed to titrate the solution to a phenolphthalein end point isV 1mL. Continuing to titrate the solution to a bromocresol green end point needed V 2 mL. If 2V 1=V 2,the component of the mixture is _____________ ( )A 、NaOH+Na 2CO 3B 、Na 2CO 3+NaHCO 3C 、NaOH+NaHCO 3D 、NaOH+Na 2CO 3+NaHCO 311. Which of the following statements is true? ( )A Precise values may be inaccurateB Determinate errors can be constant or proportionalC The variance is the square of the standard deviationD All of the above12. Which of the following has four significant figures? ( )A [H+] = 0.0005 mol . L-1；B pH =10.56;C w(MgO) =18.96%;D 300013. The molar solubility of calcium phosphate (K sp 10-26) in a saturated solution of calcium phosphate towhich 30 mmol/L calcium nitrate is added: ( )a) 2.47⨯10-6 mol/L b) 9.6 ⨯ 10-12 mol/L c) 2.89 ⨯ 10-13 mol/Ld) 6.31 ⨯ 10-6 mol/L e) cannot determine - not enough information provided14. It is well-known that the conditional electrode potential of Cr2O72-/Cr3+ in 1 mol· L- 1 HCl is 1.00 V, andthe conditional electrode potential of Fe 3+/ Fe 2 + in 1 mol·L- 1 HCl is 0.68V. When K2Cr2O7was used to titrate Fe2+, which of the following ones can be used to indicate the titration end point? ( )A. diphenylbenzidine （E0’ = 0.76V）;B. dimethyphenanthroline iron (III)(E0’ = 0.97V);C. methylene blue （E0’ = 0.53V）；D. phenosafranine（E0’ = 0.24V ）15.When mass of the solid sample is 0.1～10 mg,it iscalled analysis( )(A)meso (B)semimicro (C)micro (D)trace(二)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. 0.0085B. 0.0079C. 0.0274D. 0.0188E. none of these2. What is the gravimetric factor for the determination of the w/w% Mg when precipitated as Mg2P2O3? Atwts: Mg = 24.305 g, P = 30.974 g O = 15.999 gA.0.30658B. 3.26178C. 0.15329D. 6.52355E. none of these3. If the true value of a measurement does not fall within the confidence limits this tells us: ( )A) nothingB) 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 CuCl2 has a concentration of CuCl2.A. 1.0 ppbB. 1.0 ppmC. 1.0 pptD. none of these5. ε of a absorbing complex is always dependent upon the_____A. the stability of the complexB. the thickness of the containerC. the wavelength of the electromagnetic radiationD. the concentration of the comples6. The best way to remove impurities resulting from the mechanical entrapment and occlusion isto__________ the precipitate. ( )A. peptidizeB. reprecipitateC. digestD. washE. none of these7. 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 3.4⨯1012 C 5.2 ⨯1062 D 4.8⨯10638. You are titrating a weak base, CH3NH2, with 0.05000 M HCl. If you start with 25.00 mL of 0.1000 Mbase, what will be the best indicator (pick from those listed below) to detect the endpoint? K b = 4.35 ⨯10-4Indicator pKaA. Bromocresol Green 4.66B. Bromocresol Purple 6.12C. Phenol Red 7.81D. Phenolphthalein 9.4E. None of these9. A series of solutions containing NaOH, Na2CO3, and NaHCO3 alone or in compatible combination, wastitrated 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+Na2CO3B、Na2CO3+NaHCO3C、NaOH+NaHCO3D、NaOH+Na2CO3+NaHCO310. The end point indicator used in the Fajan’s Method is fluoroscein. It is an____ indicator( ).A. acid-baseB. adsorptionC. complexometricD. none of these11. The formation equilibrium constant, K MY, for the reaction: Pb2+ + EDTA4- <==> PbEDTA2- is 1.1 ⨯1018.If the titration is done at pH = 6.0 (α4 = 4.55 ⨯104), what is the conditional formation constant, K MY’, for the reaction.A. 1.1 ⨯1018B. 2.4 ⨯ 1013C. 2.2 ⨯ 10-5D. 4.9 ⨯ 1023E. none of these12. For an electrochemical cell, E anode = 0.287 V and E cathode = 0.698 V. What is the cell voltage for thissystem?A. 0.698 VB. 0.287 VC. 0.411 VD. -0.411 VE. none of these13. The Lambert-Beer’s Law states that the absorbance is proportional to the concentration of the analytemeasured. 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.D The length of the sample cell (cuvet) must be affixed, but the wavelength can be varied at will. 14．The %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 mass of the liquid sample is0.1～10 mL,it iscalled analysis( )(A)meso (B)semimicro (C)micro (D)trace(三)1. Two ammoniac buffer solutions with identical concentration of Cu2+ and identical pH=10.0, A and B, the concentration of free ammonia in solution A is 0.1 mol·L-1, and in B is 0.2 mol·L-1. please point out the wrong result. ( )(A) the [ Cu2+ ] is not the same between solution A and B(B) the [ Cu ′ ] is not the same between solution A and B(C) the αCu(OH) is the same between solution A and B(D) the αCu(OH) is not the same between solution A and B2. The wrong description about spectrophotometric analysis is ( )(A) the reference solution used in colorimetry analysis is called blank solution(B) Commonly, the maximal absorption wavelength is chosen as measurement wavelength in spectrophotometric analysis(C) Commonly, if the molar absorptivity ε is in the range of 105~106 L·mol -1·cm -1, it can be recognized that the sensitivity is high(D) the absorbance at one wavelength is additive3. These is a sample of coal, the value of ash in wet sample is 5.88%, and the value in dry sample is 6.00%, please calculate the water content of the wet sample. ( )(A) 2.50% (B) 3.00% (C) 2.00% (D) 3.50%4. In the medium of 0.5 mol·L -1 H 2SO 4, 4+3+3+2+''C e /C e F e /F e 1.44V , 0.68V E E ΘΘ==. If we use 0.100 mol·L -1 Ce 4+totitrate 0.100 mol·L -1 Fe 2+ to the stoichiometric point in this conditions, please calculate the concentration of reactant reagent and titration product. ( )(A) [Ce 4+]=[Fe 2+]=1.8×10-8 mol·L-1，[Ce 3+]=[Fe 3+]≈0.050 mol·L -1(B) [Ce 4+]=[Fe 3+]≈0.050 mol·L -1，[Ce 3+]=[Fe 2+]=2.0×10-8 mol·L -1(C) [Ce 4+]=[Fe 2+]=0.047 mol·L-1，[Ce 3+]=[Fe 3+]=0.003 mol·L -1(D) [Ce 4+]=[Fe 3+]=0.047 mol·L-1，[Ce 3+]=[Fe 2+]=0.003 mol·L -15. A sample with nitrogen content of 0.2 g is digested and transformed to NH 4+, and then basic compound is added to distil NH 3, which is absorbed by 10 mL of 0.05 mol·L -1HCl, then 9.5 mL of 0.05mol·L -1NaOH is consumed during the back titration. If we want to improve the accuracy, which is the effective method?( )(A) increase the bulk of HCl solution (B) use HCl solution with lower concentration(C) use NaOH solution with lower concentration (D) increase the content of sample6. To prepare a buffer solution with pH=5.1, the best choose is ( )(A) ClCH 2COOH (p K a = 2.86) (B) NH 3· H 2O(p K b = 4.74)(C) Hexamethylenetetraamine (p K b = 8.85) (D) HCOOH (p K a = 3.74)7. Titrate 1.0×10-2 mol·L -1Zn 2+ using 1.0×10-2 mol·L -1EDTA to the stoichiometric point in the following solution, the minimum pZn ' is ( )(A) pH=9.0, [NH 3]=0.01 mol·L -1 (B) pH=10.0, [NH 3]=0.01 mol·L -1(C) pH=9.0, [NH 3]=0.05 mol·L -1 (D) pH=10.0, [NH 3]=0.15 mol·L -18. 10 mL of 0.05 mol·L -1 SnCl 2 is mixed with 20 mL of 0.10 mol·L -1FeCl 3, the equilibrium potential of the system is ( )(3+2+4+2+''Fe /Fe S n /S n 0.68V ,0.14V E E ΘΘ==)(A) 0.14 V (B) 0.32 V(C) 0.68 V (D) 0.50 V9. There are three solutions, H 2C 2O 4 (a)、NaHC 2O 4(b) and Na 2C 2O 4(c), with the same volume and concentration, if they are adjusted to the same pH value with HCl or NaOH, and then add water to achieve the same volume again, what about [HC 2O 4-]? ( )(A) a is lowest (B) b is highest(C) c is lowest (D) they are the same10. The value lgβ1and lgβ2of the complexes consist of sulfosalicylic acid (L) and Cu2+are 9.5 and16.5,respectively. The value of pL with the largest [CuL] is ( )(A) 9.5 (B) 16.5 (C) 7.0 (D) 8.3磺基水杨酸11. In order to avoid the oxidation of Fe2+in preparing Fe2+standard solution in redox titration, which should be added? ( )(A) HCl (B) H3PO4 (C) HF (D) Fe12. Which can be used as the standard buffer solution in the following solution? ( )(A) NaH2PO4 (B) Na2HPO4 (C) dipole ions of Aminoacetic Acid (D) Potassium HydrotartrateE t<0.1%) is ( )(A) lg K MY≥6.0 (B) lg(c M,sp K 'MY)≥6.0(C) lg(c M,sp K MY)≥6.0 (D) lg K 'MY≥6.014. In gravimetric analysis with impurity ions having the same ionic radius as the analyte ions, what would take place during precipitation ( )(A) mixed crystal (B) absorption (C) encapsulation (D) after- precipitating15. The value of x in the equation as follows is ( )11.05+1.3153+1.225+25.0678 = x(A) 38.6581 (B) 38.65 (C) 38.66 (D) 38.65816.Of the following pairs of acids and conjugate bases, which should be used to prepare a buffer solution whose pH is approximately 5.0?(A) H3PO4-NaH2PO4 (K a1=7.1×10-3)(B)HAc-NaAc-( K a =1.8×10-5)(C)H3BO3-NaBO3 (K a =5×10-10)(D) NaHSO4-Na2SO4 (K a =1.2×10-2)17.Which of the following solids is NOT used as a primary standard in chemical analysis?(A) Potassium hydrogen phthalate(B) Sodium thiosulfate(C) Sodium carbonate(D) Sodium oxalate18.Which of the following CANNOT be determined quantitatively by direct titration with a standard potassium permanganate solution under appropriate conditions?Ca( II )Fe(II)Sn( II )As( III )19.The buffer capacity is greatest when the pHa. is equ al to the buffer’s p K a.b. is equal to the buffer’s p K a ±1.c. is equal to the buffer’s p K a ±2.d. is equal to p K w ±2.20.Which of the following statements about acid-base indicators is false?a. Acid-base indicators are typically weak acids or weak bases.b. The color transition range for acid-base indicators is usually within 0.1 pH unitof the indicator’s p K a.c. The color of an indicator at its p K a is a mixture of its acidic (protonated) andbasic (unprotonated) forms.10.Fe3+在某有机相与水相的分配比是99，今有含10mg Fe3+的水溶液，若用等体积该有机溶剂萃取两次，则水相中剩余Fe3+的质量是(A)0.03mg (B)0.01mg (C)0.003 mg (D)0.001mg10.含有0.1250g I2的KI溶液25mL，用25mLCCl4与之一起振荡。