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110年 - 110 國立臺灣大學_碩士班招生考試_環境工程學研究所科學與工程丙組:分析化學(B)#105797

科目：研究所、轉學考(插大)-分析化學 | 年份：110年 | 選擇題數：10 | 申論題數：19

試卷資訊

所屬科目：研究所、轉學考(插大)-分析化學

選擇題 (10)

複選題
1. Which of the following statements about the nature of analytical chemistry is (are) correct? (AB) Amaterial is homogeneous if its constituent parts can be distinguished only with the aid of a microscope. (AC) The preparation of a solid Iaboratory sample involves grounding the solid to decrease particle size. mixing to ensure homogeneity, and storing for various lengths of time before analysis begins. (AD) Techniques or reactions that work for only one analyte are said to be selective. (AE) An interferent causes an error in an analysis by attenuating (making smaller) the quantity being measured, whereas an interference causes an error by enbancing the quantity. (BC)We compute the results of a typical quantitative analysis from two mea ments. One is the mass or the volume of sample being analyzed. The second mcasurement is of some quantity that is proportional to the amount of analyte in the sample. (BD) In gravimetric methods. we determine the volume of the analyte or some compound chemically related to it.
複選題

2. Which of the following statements about the Interational System of Units (St) is (are) correct? (AB) The SI is based on seven fundamental base units. (AC) The angstrom unit61e4d5bd2d887.jpgis a SI unit of length. (AD) The mole is a SI unit for the amount of a chemical substance. (AE) Not all non-SI units can be derived from the base units of SI. (BC) The SI base unit of temperature is Celsius. (BD) The SI base unit of mass is gram.
複選題

3. Which of the following statements about analytical calculations is (are) correct? (AB) Mass is a variant measure of the quantity of matter in an object, while weight is the force of attraction between an object and its sur undings, principally the carth. (AC) The molar mass of a substance is the mass in amu of I mole of that substance. (AD) The molar analytical concentration of a solution gives the total number of millimoles in 1 mL of the solution. (AE) The prefix giga- for units is abbreviated as G and represents the multiplier of 61e4d650ad59c.jpg. (BC) The pH is a p-function and is the negative logarithm of [H+]. (BD) The specific gravity is the ratio of the mass of a substance to the mass of an equal volume of water at 0℃.
複選題
4. Which of the following analytical statistics statements is (are) correct? (AB) Systematic error causes the mean of a data set to differ from the accepted value. (AC) Markings on the speedometer always read from a given angle is an exampie of random error. (AD) Instrumental errors are systematic errors. (AE) Personal etrors are random errors. (BC) Placing fingerprints on the vial afier weighing while adding sample to the vial is an example of random errors. (BD) A miscalibrated pipet holding a slightly different volume of liquid than the indicated volume contributes random error.
複選題
5. Which of the following statements related to data treatment is (are) correct? (AB) The mean of a data set is found by adding all numbers in the data set and then dividing by the number of values in the set. (AC) The variance is the square root of the standard deviation. (AD) The standard error of the mean is the standard deviation of the mean. (AE) The coefficient of variation is the percent relative standard deviation. (BC) The standard error of the mean of 5 measurements is larger than the standard deviation of a single result. (BD) As the desired confidence level decreases, the confidence interval increases.
複選題
6. Which of the following statements about normal distribution is (are) correct? (AB) The graph used to depict a normal distribution consists of a symnetrical bell-shaped curve. (AC) The bell-shaped curve is a common feature of nature and psychology. (AD) Normal distributions may not be symmetric around their mean. (AE) Normal distributions a are defined by two parameters. the mean and the standard deviation, only. (BC) The arca under the normal curve is equal to 100. (BD) The tails of normal distribution curves are asymptotic. They meet the horizon (i.e. x-axis).
複選題
7. Which of the following statements about mass spectrometry is (are) correct? (AB) Mass spectrometry measures the charge-to-mass ratio of charged particles. (AC) The main steps a mass spectrometer takes inelude vaporization, ionization, accelcration, scparation, and detection. (AD) The mass spectra of a given substance obtained from mass spectrometers using different ionization sources are the same. (AE) ICP-MS can analyze metals only. (BC) For0.I mL of sample, the ICP-MS absolute detection limit is equal or less than 0.1 yg. (BD) Among different ion sources for molecular mass spectrometry, electron ionization results in higher sensitivities than do chemical and field jonization.
複選題
8. Which of the following statements about calibration is (are) correct? (AB) Calibration deternmines the relationship between the analyical response and the analyte concentration. (AC) Calibration does not inctude adjustment. i.c.. With calibration there is no technical intervention at the measuring instrument. (AD) The chemical standards used in calibration can only be prepared from purified reagents. (AE) Gravimetric methods do not rely on calibration with chemical standards. (BC) Titration is a type of comparison methods. (BD) The least-squares method has two assumptions: (i) A linear relationship exists between the measured response y and the standard analyte concentration x. (i) Erors exist in x values (concentrations) of the data points.
複選題
9. Which of the follow lowing state stements about alpha val lue is (are) correct? (AB) The reiative e equilibrium concea ntrations of the components in a conjugate system (e.g. a conjugate acid/base) are called slipha (a) values. (AC) The alpha values of a conjugate ncid/base depend on pH and Ka. (AD) Tbe alpha values of a conjugate acid/base are independent of the sum of the analytical concontrations of the acid and its conjugate base in a buffer solution. (AE) Plotting the alpha values as a function of the pH of the solution shows curves crossing at pH-pKb, wihere Kb i3 the base dissociation constant of the conjugate base, (BC)Since EDTA is a polyprotic acid, its alpha values affect the complex fornation between EDTA and the metal ion (ABE). (BD) Decreasing the o4 value of EDTA favors the fornation of the EDTA-M complex.
複選題
10. Which of the following nts related to the acid sal: NaHA and polyprotic acid titration is (are) correct? (AB) NaHlA can act as a proton donor and also as the conjugate base of the parent acid I H2A. (AC) Solutions of acid salis are acidic. (AD)The pH of a NaHA solu lution can be cal (AE) A solution having the same e calculated by only treating NatlA as an acid. lution obtained by dissolving NaHtA in pure water cannat be obtained during the process wi "d with NaOH (BC) It is possible to titrate all three protons of phosphoric acid in aqueous solution. (BD)A titration by NaOH of a mixture of H3PO4, and NallbH2PO4containing phensiphthalein to the the second end point gives the numher of millimoles of NaH2PO4.

申論題 (19)

b)_________is the boundary around the mean of a set of replicate analytical results within which the population mean can be

expected to lie within a certain probability.
c)__________is the measured fraction of the volume of a liquid sample.
d)____________is the oxidation of the organic reagents of a sample with oxidizing reagents such as nitric acid, sulfuric acid. hydrogen peroxide, aqueous bromine, or a combination of these reagents.
e)___________are the constituents present in the sample in amounts between 0.01% and 1%.
f)___________is the collection of sampling units or increments corresponding to several small parts taken from different parts of the bulk material, and is representative of the whole in composition and in particle size distribution.
g)_________is a species that has both a positive and a negative charge.
h)__________is a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid that resists changes in pH of a solution.
i)__________of a species is related to its concentration by a factor called the activity coefficient.
j)_________is a systenatic error occurring in a base in which the effective concentration of the base is diminished by absorption of carbon dioxide.
k)_________is the process by which an ester is hydrolyzed in alkaline solution to give an alcohol and a conjugate base.
l)_____________maintains the working electrode potential at a constant value relative to a reference electrode.
m)_________is the mobile phase that exits the chromatographic column.
(a) The buoyancy equation is used to correct the_______

on the mass obtained from a_______. specifically when the  error has its origin in the difference in___________force exerted by the medium (air) on the object and on the masses.
(b) The Henderson-Hasselbalch equation is used to calculate the________of__________  solutions.
 (c) The Debye-Huckel Equation permits the calculation of__________coefficients of ions from their and their average____________.

(d)_______ -balance equations relate the_________concentrations of various species in a solution to one another and to the analytical concentrations of the various____________.

Ill. Full names of abbreviations

13. Write down the full names in English of the following abbreviations used in analytical chemistry:

(a) ppt. (b) CL, (c) RSD, (d) LOL, (e) EDTA, (I SCE, (8) NHE, (h) RDE, (i) DME, 6) UV, (k) FTIR, (I) PMT. (m) CCD

(13%)

14. The HE solution is titrated with a 0.2000 M Ba(OH)2 solution. The results of the titration experiments are shown below.

61e4de7e07ab8.jpg

(a) Calculate the mean w/v percentage of the monoprotic acid in the dilute solution. (b) Use Q test to decide if any anomalous result exists

that should be rejected at the 95% confidence level. (Heavy penalty will be applied if this test is not performed.) (c) Calculate the standard

deviation for the results. (d) Calculate the 95% confidence interval for the mean. (e) Assume that the buret used to measure out the acid

solution has a systematic error of -0.05 mL at all volumes delivered and no other sources of errors exist in the experiments. Calculate the

systematic error in the mean result. (See the related tables in the next page.) (13%)
61e4deee6e773.jpg61e4df0d508a8.jpg

15. Assume that the conjugate base, E', of the monoprotic acid can be used as complexing agent for determination of 61e4df92881b9.jpg61e4dfb18921a.jpg using a direct titration method. An experiment is planned in which standard aqucous solutions of61e4dfcf35992.jpgare prepared and Eriochrome Black T (EBT) is employed as the indicator. In general, there are two types of direct titration

 (non-potentiometric) methods for quantifying metal ions using a complexing agent, depending on the availability of suitable indicators. (a) Using the titration of 61e4dfcf35992.jpg as an cxample, describe the chemistry and the conditions of use for the two different  direct titration methods when a complexing agent E" is used. (b) Sketch and properly label a titration apparatus that can be used in a direct potentiometric titration of 61e4dfcf35992.jpg with E-. (c) Why should an auxiliary complexing agent be used in this titration?

(d) What is the condition of use for the auxiliary complexing agent? (e) The electrode potential of the apparatus you sketched in

(b) is expected to change during the titration. (i) Based on the Nernst expression of the electrode potential, which often involves  both the reduced and the oxidized states, is formality, species molarity, or activity obtained from the titration? Define these three  terms before explanation. (ii) Will a color change be observed if a general redox indicator is also present in the solution of your  apparatus? Explain. (f [Cu(NH3)4H2O]SO4 (FM 245.75) can be prepared by adding concentrated solution of ammonia to a  saturated aqueous solution of copper sulfate followed by precipitation of the product with ethanol. What is the number of  reacting units (eq/mol) for NH3 in the reaction of the preparation? (g) 0.983 g [Cu(NH3)4H2O]SO4 is dissolved in 100.0 mL aqueous solution that contains 0.200 M in NH3. Calculate the potential of a copper electrode immersed in the solution. (β4 for61e4e0e91a6a7.jpg 0.337 V)(h) Assume that both 61e4dfcf35992.jpg  and Et solutions are 0.100 M in NH3 and  0.175 M in NH4CI to provide a constant pH of 9.0. Without actually going through the calculation, show the calculation   procedure for determining pCu at the equivalent point when the complexing agent E- is employed to titrate 61e4dfcf35992.jpg . In the  procedure, use your defined symbols to show variables whose values are not provided in the question. (27%)