Analytical Chemistry MCQs with Answer Key PDF

Summary

This document contains multiple choice questions (MCQs) about analytical chemistry, covering various topics such as solutions, titrations, and chemical reactions. The questions are designed to assess understanding of fundamental concepts and principles in analytical chemistry.

Full Transcript

Question 1 M, and 0.089 M for each titration performed. Which of the When potassium iodide reacts with lead(II) nitrate, a yellow following best describes these results? precipitate (PbI2) is produced. If 0.78 g of lead(II) iodide was pro...

Question 1 M, and 0.089 M for each titration performed. Which of the When potassium iodide reacts with lead(II) nitrate, a yellow following best describes these results? precipitate (PbI2) is produced. If 0.78 g of lead(II) iodide was produced, how many grams of lead(II) nitrate was used? You A. The results are accurate but not precise. may assume the reaction yield was 100%, and an excess of B. The results are precise but not accurate potassium iodide was used. C. The results are neither accurate nor precise. D. The results are both accurate and precise. A. 0.78 g E. The results are not enough information is given to B. 1.6 g determine accuracy or precision. C. 0.46 g D. 0.56 g Question 7 E. Not enough information is given. Concentrated hydrochloric acid is 12 M and has a density of 1.18 g/mL. What is the weight percent (% w/w) of Question 2 concentrated HCl? If 4.94 grams of KOH is dissolved in water to make a final volume of 2.0 L, what is the molarity of the solution? A. 14% B. 5.1% A. 0.088 M C. 12% B. 0.044 M D. 98% C. 2.5 M E. 37% D. 0.025 M E. 0.18 M Question 8 A stock solution of sodium acetate is 1.0 M. To make Solution Question 3 A, 2.00 mL of the stock solution is transferred and diluted to a If 21.3 g of glucose (C6H12O6) is dissolved in 5.00 L of total volume of 100 mL. Solution B is made by transferring 5.0 deionized water, what is the molality of the solution? (The mL of Solution A and diluting it to a total volume of 250 mL. density of water is 1.00 g/mL.) Solution C is made by transferring 1.0 mL of Solution B and diluting it to a total volume of 25 mL. What is the A. 0.0237 m concentration of solution C? B. 0.592 m C. 0.118 m A. 1.6 µM D. 4.26 m B. 16 µM E. 0.00426 m C. 1.6 mM D. 0.16 mM Question 4 E. None of the above Which of the following is the equivalent of 4.3 ppm sodium ion (Na+) concentration? Question 9 The equation for a normal calibration curve for the detection A. 0.0043 ppb of iron(II) is determined experimentally to be: S = 12.93 M - 1 B. 0.043 ppb * C + 0.0017. Analysis of a sample with unknown C. 430 ppb concentration gives an absorbance reading of 0.106. What is D. 4300 ppb the concentration of iron(II) in the unknown? E. None of the above A. 1.37 M Question 5 B. 6.50 mM How many milliliters of a 0.100 M potassium permanganate C. 9.90 mM stock solution would be needed to make 100 mL of 0.0250 M D. 8.06 mM potassium permanganate? E. 8.83 mM A. 10.0 mL Question 10 B. 4.00 mL When performing calculations for standard additions, which C. 40.00 mL of the following must be true? D. 2.50 mL E. 25.0 mL A. The volume of the standard added must be added with the volume of the sample used to give a new sample Question 6 volume. The concentration of a solution is known to be 0.101 M. A B. The volume of the standard added is subtracted from the student determines the concentration to be 0.088 M, 0.087 total volume of the sample used. C. The volume of the standard added can be ignored, E. The law of gravity because it is so small. D. The volume of the standard added can be ignored, Question 15 because volumes are not used in the calculations. Coprecipitates (inclusions, occlusions, and surface adsorbates) E. The volume of the standard added can be ignored, are a common problem in gravimetric analysis, but can be because it is part of the blank correction. controlled by which of the following? Question 11 A. Carefully controlling the solution conditions Which of the following statements about the sensitivity of an B. Reprecipitation of the solid analytical method is true? C. Digestion of the precipitate D. Thoroughly washing and drying the filtrate A. The sensitivity of an analytical method is the same as its E. All of the above detection limit. B. The sensitivity of an analytical method is a measure of Question 16 ability to determine whether slight differences in Volatilization gravimetry would be most useful in determining experimental results are significant. which of the following? C. The sensitivity of an analytical method is the smallest amount of analyte that the instrument is able to measure. A. The amount of silver in a solution of silver nitrate B. The acidity of a water sample D. The sensitivity of an analytical method is the response of C. The amount of water in eposom salts the instrument to human error. D. All of the above E. None of the above E. None of the above Question 12 Question 17 Which of the following statements is true of the detection Which of the following statements about the equivalence limit of an instrument? point of an acid-base titration is true? A. The detection limit of an instrument is the same as its A. The equivalence point of an acid-base titration is the sensitivity. same as the indicator endpoint. B. The detection limit of an instrument is a measure of B. The equivalence point of an acid-base titration is the ability to determine whether slight differences in point where there is an equivalent amount of titrant and experimental results are significant. titrand. C. The detection limit of an instrument is the smallest C. The equivalence point of an acid-base titration is where amount of analyte that the instrument is able to measure. the pH = 7.0 (neutral). D. The equivalence point of an acid-base titration is where D. The detection limit of an instrument is the ability of the the entire volume of the buret has been used. instrument to respond to an error. E. The equivalence point of an acid-base titration is the E. None of the above average value of the dissociation constants. Question 18 Question 13 What is the stoichiometry of EDTA with metal ions? Fill in the blank. Precipitation, volatilization, and particulation are all types of ____________________. A. It is 1:6, because EDTA is a hexaprotic weak acid with six distinct acid dissociation values. A. Electrochemical analysis methods B. It is 1:4, because EDTA has four binding sites upon loss of B. Gravimetric analysis methods the four carboxylic acid protons. C. Tritrimetric analysis methods C. It is 1:2, because EDTA has two binding sites upon loss of D. Spectroscopic analysis methods the two ammonium protons. E. Photochemical analysis methods D. It is 1:1, because EDTA forms a cage-like structure around the metal ion. Question 14 E. It is dependent on the metal ion present. Fill in the blank. Gravimetric analysis relies heavily on the principle of __________________. Question 19 A 58.3 mg sample containing Sn2+ is dissolved in 1.0 M HCl. If A. Conservation of energy 23.6 mL of 0.010 M Tl3+ was required to titrate to endpoint, B. Conservation of mass what is the mass percent (w/w%) of tin in the original sample? C. Constant compostition D. Definite proportions A. 48% B. 28% C. σ → π* C. 24% D. n → π* D. 40% E. 14% Question 25 Which of the following typically exhibits the largest molar Question 20 absorptivities? A 0.357 g sample contains only lead(II) iodide and sodium iodide in 100 mL of distilled water. Titration to the Fajan's A. σ → σ* absorbances end point requires 22.37 mL of 0.050 M silver nitrate. What is B. σ → n absorbances the mass percent (w/w%) of lead(II) iodide in the sample? C. σ* → π* absorbances D. π → π* absorbances A. 18% E. Metal to ligand charge transfer (MLCT) absorbances B. 36% C. 1.6% Question 26 D. 53% Which of the following is the correct order in which light E. 47% passes through a UV-Vis spectrometer? Question 21 A. Detector, sample, source, monochromator Which variable in Beer's law represents how well a chemical B. Source, monochromator, sample, detector species absorbs light at a given wavelength? C. Source, sample, monochromator, detector D. Monochromator, source, sample, detector A. c - concentration E. Sample, source, monochromator, detector B. ε - molar absorptivity coefficient C. A - absorbance Question 27 D. b - path length of the sample What is the purpose of a monochromator? E. λ - wavelength A. To remove stray light from the room Question 22 B. To serve as a polychromatic light source According to Beer's Law, what happens to the absorbance C. To interpret the photon signal into a digital readout reading if the concentration of the solution is halved? D. To allow only light of a certain wavelength to pass from the source to the sample A. The absorbance will double. E. To focus light from the sample onto the detector B. The absorbance will quadruple. C. The absorbance will be halved. Question 28 D. The absorbance will be quartered. The regression line from a plot of absorbance vs. E. There is no way to tell, because concentration and concentration yields: A = 2.31 c + 0.002. If the absorbance of absorbance are not a linear relationship. an unknown is measured to be 0.124, what is the concentration of the analyte? Question 23 Why must solutions with high concentrations be diluted prior A. 0.29 M to analysis via Beer's Law? B. 0.053 M C. 1.86 M A. The relationship between absorbance and concentration D. 0.093 M is not linear at high concentrations. E. 2.43 M B. The detector will reach its detection threshhold. C. The photon source is too weak to provide accurate Question 29 results. The method of continuous variations, also known as Job's D. The molar absorptivity of a compound is dependent on method, uses the intersection of the ligand-line and the its concentration. metal-line to determine which of the following? E. There is no need to work with dilute concentrations; any concentration will work. A. The concentration at which the detector can no longer respond to the signal Question 24 B. The mole ratio between the metal and ligand in a Which of the following transitions is NOT possible in UV-Vis complex absorption? C. The maximum intensity of source photons transmitted A. σ → σ* D. The number of dimeric molecules formed B. σ → n E. The oxidation number of the metal Question 30 Question 36 Ultraviolet and visible radiationaffect which of the following? Complete the sentence. All of the following are detectors used in infrared spectroscopy, EXCEPT: A. Core electrons B. Valence electrons A. A charge-coupled diode. C. Nuclear spin B. A thermocouple. D. Molecular vibrations C. A pyroelectric detector. E. Molecular rotations D. A photoelectric detector. Question 31 Question 37 Infrared radiation affects which of the following? Fill in the blank. NMR affects a molecule's ________________. A. Core electrons A. Nuclear spin B. Valence electrons B. Valence electrons C. Molecular vibrations C. Core electrons D. Molecular rotations D. Molecular vibrations E. Nuclear spin E. Molecular rotations Question 32 Question 38 Complete the sentence. All of the following are used to In 1H-NMR spectroscopy, if a CH2 neighbors a CH3, the describe the bending modes in infrared spectroscopy, EXCEPT: hydrogen nuclei of the CH3 will appear as which of the following? A. In-plane rocking. B. In-plane scissoring. A. A doublet, with a peak integration of 2 C. Assymetric stretching. B. A doublet, with a peak integration of 3 D. Out-of-plane twisting. C. A triplet, with a peak integration of 2 E. Out-of-plane wagging. D. A triplet, with a peak integration of 3 E. A single peak, with an integration of 5 Question 33 What is the advantage of using a silver chloride sample cell Question 39 rather than a sodium chloride sample cell for IR spectroscopy? Where does spin-lattice relaxation occur? A. Aquesous samples can be measured; AgCl is not A. It occurs between neighboring nuclei with identical water soluble. frequencies but different quantum states via energy B. There is no advantage. transfer. C. Silver chloride does not absorb IR radiation. B. It occurs between the excited nuclei and nuclei D. Silver chloride is translucent. within the sample matrix. E. Sodium chloride is less expensive. C. It occurs between atoms in the same molecule. D. It occurs between the nuclei of the sample and the Question 34 signal source. In order for a compound to be IR active, it must undergo E. All of the above which of the following? Question 40 A. A change in polarizability The value of the chemical shift in NMR spectroscopy is B. A change in dipole moment directly related to which of the following? C. Emission of an electron D. Transfer of an electon A. The amount of shielding E. Metal-ligand charge transfer B. The applied magnetic field C. The identity of the reference sample Question 35 D. The electronegativity of the nucleus Complete the sentence. All of the following are infrared E. All of the above sources, EXCEPT: Question 41 A. The Nernst glower. Fluorescence occurs as a result of which of the following? B. The Globar source. C. An incandescent wire. A. Relaxation from a singlet excited state to a singlet D. A pyroelectric glower. ground state B. Relaxation from a triplet excited state to a singlet A. Because the photon sources are too weak to ground state vibrationally excite the samples C. Nonradiative (vibrational) relaxation B. Because sample cells are small D. Intersystem crossing (isc) C. Because they supply a reference signal E. All of the above D. Because fluorescence intensities are usually low E. None of the above Question 42 Phosphorescence occurs as a result of which of the following? Question 47 Why is fluorescence spectroscopy often carried out in a liquid A. Relaxation from a singlet excited state to the singlet nitrogen environment? ground state B. From a triplet excited state to the singlet ground A. Phosphorescence is more likely to occur at low state temperatures in a viscous medium. C. Intersystem crossing (isc) B. Phosphorescent molecules tend to also have D. Nonradiative (vibrational) relaxation explosive properties. E. All of the above C. The monochromator slows down the radiation before it hits the sample. Question 43 D. The detector requires lower temperatures for Why are flourescence and phosphorescence spectra operation. measured at a 90 degree angle to the source? E. The source radiation can overheat and destroy the analyte. A. To ensure that incident (source) photons are not observed Question 48 B. Because the sample cell is darkened on two adjacent How does turbidimetry differ from nephelometry? sides C. Because the monochromator directs the light at a 90 A. Turbidimerty measures the decrease in degree angle transmittance of incident radiation; nephelometry D. Because the process of fluorescence and measures the intensity of scattered radiation. phosphorescence are too intense to observe directly B. Nephelometry measures the decrease in E. To make the overall instrument smaller transmittance of incident radiation; turbidimetry measures the intensity of scattered radiation. Question 44 C. Nephelometry measures the total metal ion, or Complete the sentence. Fluorescence and phosphorescence inorganic, content; turbidimetry measures total can be used for detection of all of the following, EXCEPT: organic content. E. Turbidimetry measures the total metal ion, or A. Vitamins. inorganic, content; nephelometry measures total B. Environmental pollutants. organic content. C. Uncomplexed metal ions. F. The terms are synonymous; there is no difference. D. Pharmaceuticals. E. Aromatic amino acids. Question 49 Turbidimetry and nephelometry are analytical methods based Question 45 on which of the following? A fluorescence quantum yield of 0.93 would suggest that most excited state molecules are doing which of the following? A. Light scattering B. Photon emission A. Returning to the ground state by fluorescence C. Photon absorption B. Returning to the ground state by non-radiative decay D. Nuclear repulsion C. Returning to the ground state by intersystem E. Paramagnetism crossing D. Remaining in the excited state past the experimental Question 50 timeframe What is the advantage of an inductively coupled plasma E. None of the above source rather than a flame? Question 46 A. Better atomization and a higher population of Why are photomultiplier tubes often used in fluorescence excited states spectroscopy? B. Lower operating temperatures and less expensive replacement costs C. Minimization of scattering and ionization of analytes D. All of the above A. Ionization of the analyte E. None of the above B. Scattering and absorption by the matrix of the analyte Question 51 C. Reactions between the analyte and matrix Atomic absorption spectroscopy results are highly D. Non-volatilization of the analyte reproducible but have low sensitivity and efficiency. This is due to which of the following? Question 56 Chemical interferences in atomic absorption that cannot be A. The small amount of analyte that actually reaches accounted for using a background correction, but can be the flame minimized, include which of the following? B. The high temperatures of analysis often destroy the atoms A. Nonvolatilization of the analyte C. The amount of dilution due to mixing with large B. Ionization of the analyte volumes of combustion gases C. Absorption or scattering of radiation by the matrix D. A and B only D. All of the above E. A and C only E. A and B only Question 52 Question 57 Fill in the blank. The relationship between the analyte Which of the following are forms of radiationless deactivation concentration and the intensity of measured radiation from of an excited state? thermal excitation methods, such as a flame or plasma, is ________________. A. Intersystem crossing B. Internal conversion A. Linear C. External conversion B. B. Exponential D. Vibrational relaxation C. Parabolic E. All of the above D. Polynomial E. Asymptopic Question 58 When does intersystem crossing occur? Question 53 Flame atomic absorption measures absorption of radiation of A. When a molecule transfers to a higher vibrational analytes in which phase? energy level of a lower energy electronic state with a different spin A. Solid phase B. When a molecule moves to a lower vibrational B. Liquid (neat) phase energy level in the same electronic state C. Gas phase C. When a molecule transfers to a higher vibrational D. Aquesous phase energy level of a lower energy electronic state with E. Plasma phase the same spin D. energy is emitted as a photon from a singlet or Question 54 triplet spin state Why is a hollow cathode tube lamp necessary in atomic E. When energy is passed to the solvent or to another absorption? component of the sample's matrix A. Because cathode lamps are cheaper to operate and Question 59 maintain Fill in the blank. The lowest vibrational energy level of the B. Because continuous spectrum lamps do not emit at lowest electronic singlet state (S0) is referred to as the the proper intensity ___________________. C. Because the width of an atom's absorption band is narrow A. Ground state D. Because continuous spectrum lamps cause B. Zero state ionization of the molecules C. Newtonian state E. All of the above D. Bohring state E. Non-excited state Question 55 Fill in the blank. Background correction in flame atomic Question 60 absorption spectroscopy can minimize the effect of Whether an electron is in the triplet state or singlet state ___________________. depends on which of the following? A. Its spin-pairing with the ground state E. Columns containing more theoretical plates lend B. The amount of radiation it was exposed to themselves to component mixing. C. Its ability to undergo radiationless decay D. Its initial energy level before absorption Question 65 E. Its availability to become excited "Tailing" of a chromatographic peak is a result of which of the following? Question 61 In a chromatographic analysis of an unknown mixture, A. Interactions of the solute with the stationary phase compound A has a retention time of 5.56 minutes and a B. Overloading the column with sample baseline width of 0.87, and compound B has a retention time C. Interactions between the stationary and mobile of 6.32 minutes and a baseline width of 0.53 minutes. Are phases these peaks resolved, and what is the resolution between the D. Too many theoretical plates two peaks? E. Small theoretical plate heights A. Yes, 0.54 Question 66 B. No, 0.54 "Fronting" of a chromatographic peak is a result of which of C. Yes, 1.09 the following? D. No, 1.09 E. There is not enough information given to determine A. Interactions between the stationary and mobile resolution. phase B. Overloading the column with sample Question 62 C. Interactions of the solute with the stationary phase The "void peak" in a chromatogram corresponds to which of D. Small theoretical plate heights the following? Question 67 A. Components that had no interaction with the Band broadening in column chromatography is a result of stationary phase which of the following? B. The peak that arises from poor selection of a stationary phase A. Mass transfer in the stationary phase C. The peak that arises from the mobile phase only B. Mass transfer in the mobile phase D. Components that had no interaction with the mobile C. Longitudinal diffusion phase D. Variations in path lengths (Eddy diffusion) E. All peaks after the first peak in the chromatogram E. All of the above Question 63 Question 68 If a compound has a retention time of 5.30 minutes with a Complete the sentence. All of the following are common baseline width of 0.64 minutes on a 2.0 m silica gel column, carrier gases from gas chromatography, EXCEPT: what is the average height of a theoretical plate? A. Oxygen. A. 1.8 mm/plate B. Nitrogen. B. 15 mm/plate C. Helium. C. 29 mm/plate D. Argon. D. 0.24 mm/plate E. Carbon dioxide. E. 2.7 mm/plate Question 69 Question 64 When using gas chromatography, how is optimum column Which of the following statements about columns containing efficiency obtained? more theoretical plates is true? A. When the samples are injected slowly and in large A. Columns containing more theoretical plates make quantities separations imposssible. B. When the samples are injected slowly and in small B. Columns containing more theoretical plates take a quantities long time to perform separations. C. When the samples are injected quickly and in large C. Columns containing more theoretical plates are quantities better suited to separate a complex mixture. E. When the samples are injected quickly and in small D. Columns containing more theoretical plates interact quantities irreversibly with the analyte. F. None of the above Question 70 B. Hydrophobic molecules What is the most common support material for a packed GC C. Mixed metal sulfides and oxides column? D. Large molecules, such as DNA and RNA E. Cations and anions A. Silica gel B. Alumina Question 76 C. Fused silica Which of the following statements about the mobile phase in D. Glass Supercritical fluid chromatography (SFC) is false? E. Diatomaceous earth A. It requires lower pressures than those needed for Question 71 HPLC. WCOT, SCOT, PLOT, and FSOT are all types of which of the B. It gives better resolution than GC. following? C. It has densities similar to a liquid. D. Its mobile phase has the viscosity properties of a gas. A. Open tubular GC columns E. It has solvent properties of a liquid. B. Capillary GC columns C. Packed GC columns Question 77 D. Both A and B The stationary phase in ion exchange chromatography is a E. Both A and C cross-linked polymer resin with covalently attached functional groups. Which of the following is NOT a typical Question 72 functional group used for IEC? Which of the following GC detectors would most likely allow recovery of a sample after analysis? A. Sulfonic acid (-SO3-) B. Carboxylic acid (-COO-) A. Flame ionization detector (FID) C. Quarternary amine (-CH2N(CH3)3+) B. Thermal conductivity detector (TCD) D. Amine (-NH3+) C. Flame photometric detector (FPD) E. Hydroxyl (-OH-) D. Hall electrolytic conductivity detector E. Nitrogen-phosphorus detector Question 78 Reversed-phase chromatography refers to which of the Question 73 following? Which of the following GC detectors would be least affected by the carrier gas? A. A stationary phase and mobile phase of similar polarities A. Thermal conductivity detector (TCD) B. A nonpolar stationary phase and a nonpolar mobile B. Electron capture detector (ECD) phase C. Photoionization detector (PID) C. A polar stationary phase and a nonpolar mobile D. Flame photometric detector (FPD) phase E. None of these detectors would be affected by the D. A nonpolar stationary phase and a polar mobile carrier gas. phase E. A polar stationary phase and a polar mobile phase Question 74 In size exclusion chromatography, what happens to the larger Question 79 particles? Which of the following would elute first when using capillary zone electrophoresis? A. They elude first, before smaller particles. B. They are broken down into smaller particles. A. Ca2+ C. They become oxidized as they move through the B. CH3NH3+ column. C. Cl- G. They remain on the column longer than smaller D. HCOO- particles. E. CH3COO- H. They bind permanently to the stationary phase. Question 80 Question 75 How are separations by electrophoresis carried out? Fill in the blank. Ion exchange chromatography is best suited to separate ___________________. A. Via applying an electric current B. Via saponification of the analyte A. Hydrophilic molecules C. Via polymerization of the analyte D. Via oxidation reactions at stationary phase sites E. Neutral species E. Via reduction reactions at stationary phase sites Question 87 Question 81 What is the purpose of the salt bridge in a galvanic (voltaic) Fill in the blank. Cd wire used to measure the concentration cell? of cadmium ion is an example of a _______________________. A. To complete the electrochemical circuit B. To provide free electrons for redox processes A. Metallic electrode of the second kind C. To provide a site for oxidative reduction B. Metallic electrode of the first kind D. To serve as a working electrode C. Saturated calomel electrode E. To serve as a reference electrode D. Reference electrode E. Silver/silver chloride electrode Question 88 If a redox couple is at equilibrium in an electrochemical cell, Question 82 then which of the following statements about the current and Fill in the blank. Ag wire used to measure the concentration potential is most accurate? of Br- ion is an example of a ______________________. A. The current is zero, and the potential is given by the a. Saturated calomel electrode Nernst equation. b. Metallic electrode of the first kind B. The current and potential are both zero. c. Metallic electrode of the second kind C. The current is negative, and the potential is zero. d. Silver/silver chloride electrode D. The current is positive, and the potential is zero. e. Reference electrode E. The potential is zero, and the current is given by the Nernst equation. Question 83 What is the process of the loss of an electron called? Question 89 Complete the sentence. The basic setups for electrochemical A. Oxidation measurement include all of the following, EXCEPT: B. Reduction C. Transference A. Measure the potential at zero current. D. Sublimation B. Measure the potential while controlling the current. E. Neutralization C. Measure the potential and current simultaneously. D. Measure the current while controlling the potential. Question 84 E. All of the above What is the process of the gain of an electron called? Question 90 A. Oxidation Which of the following is a static (i = 0) electrochemical B. Reduction technique? C. Sublimation D. Transference A. Potentiometry E. Neutralization B. Controlled-current coulometry C. Controlled-potential coulometry Question 85 D. Cyclic voltammetry Which of the following is a substrate that is oxidized? E. Amperometry A. Cationic species Question 91 B. Anionic species Where does the reduction reaction occur? C. Neutral species D. Reducing agent A. At the anode E. Oxidizing agent B. At the cathode C. Within the potentiometer Question 86 D. Within the salt bridge Which of the following is a substrate that is reduced? E. Within the bulk solution A. Oxidizing agent Question 92 B. Reducing agent Where does the oxidation reaction occur? C. Cationic species D. Anionic species A. Within the potentiometer B. Within the salt bridge C. At the anode A. The concentration of anayte D. At the cathode B. The surface area of the working electrode E. Within the bulk solution C. The number of electrons involved in the redox process Question 93 D. The diffusion coefficient of the electroactive species The use of the Nerst equation to calculate potentials is really E. All of the above a simplistic model. Which of the following does it ignore? Question 98 A. Matrix effects One electrochemical technique involves first depositing an B. Temperature effects analyte on the surface of an electrode, then using an applied C. Junction potentials current to remove the analyte via a reduction or oxidation D. All of the above reaction. What is this method called? E. None of the above A. Hydrodynamic voltammetry B. Stripping voltammetry C. Amperometry D. Polarography Question 94 E. Cyclic voltammetry Fill in the blank. The potential that develops at the interface of two solutions due to differences in concentrations and Question 99 ionic mobility is called the _________________ potential. Which of the following is NOT a variable in voltammetric methods? A. Osmotic B. Bridging A. Type of working electrode C. Coulombic B. How the potential is applied D. Reference C. The inclusion of convection E. Junction D. How the current is applied E. All of the above Question 95 Which of the following statements about the standard Question 100 hydrogen electrode, the calomel electrode, and the Fill in the blank. Coulometric techniques result in a plot of silver/silver chloride electrode is true? ____________________. A. These electrodes combine to make a complete A. Current versus time electrochemical cell. B. Electrochemical potential versus time B. These electrodes are typically used as reference C. Current versus electrochemical potential electrodes. D. Current only C. These electrodes are typically used as working E. Potential only (indicator) electrodes. D. These electrodes are examples of membrane electrodes. E. These electrodes have the same electrochemical potential. Question 96 A pH meter is an example of which type of membrane electrode? A. Glass ion selective electrode B. Potentiometric biosensor (enzyme electrode) C. Solid-state ion selective electrode D. Liquid-based ion selective electrode E. Gas-sensing electrode Question 97 In a cyclic voltammogram, the peak current(i) is directly related to which of the following? ANSWER KEY 58. A 1. D 59. A 2. B 60. A 3. A 61. C 4. D 62. A 5. E 63. A 6. B 64. C 7. E 65. A 8. B 66. B 9. D 67. E 10. A 68. A 11. B 69. D 12. C 70. E 13. B 71. D 14. B 72. B 15. E 73. D 16. C 74. A 17. B 75. E 18. D 76. B 19. A 77. E 20. D 78. D 21. B 79. A 22. C 80. A 23. A 81. B 24. C 82. C 25. E 83. A 26. B 84. B 27. D 85. D 28. B 86. A 29. B 87. A 30. B 88. A 31. C 89. C 32. C 90. A 33. A 91. B 34. B 92. C 35. D 93. D 36. A 94. E 37. A 95. B 38. D 96. A 39. B 97. E 40. E 98. B 41. A 99. D 42. B 100. A 43. A 44. C 45. A 46. D 47. A 48. A 49. A 50. A 51. E 52. A 53. C 54. C 55. B 56. E 57. E

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