xxx semester 125 PointsINSTRUMENTAL METHODS OF ANALYSISMID-TERM EXAM IIxxx semester 125 PointsCALCULATION (55 Points)1. (25 pts) The chelate CuA22- exhibits maximum absorption at 480 nm. When the chelating reagent is present in at least a 10-fold excess, the absorbance is dependent only upon the analytical concentration of Cu(II) and conforms to Beer’s law over a wide range. A solution inwhich the analytical concentration of Cu2+ is 2.30x10-4 M and that for A2- is 8.60x10-3 M has an absorbance of 0.690 when measured with a 1.00-cm cell at 480 nm. A solution in which theanalytical concentrations of Cu2+ and A2- are 2.3x10-4 M and 5.00x10-4 M, respectively, has an absorbance of 0.540 when measured under the same conditions. Use this information to calculate the formation constant, K, for the reaction,Cu2+ + 2 A2-  CuA22- Page 1 of 102. (15 pts) In UV/Vis spectrophotometry, what is the relative error in concentration from 1% stray light for a sample with a molar absorptivity of 5.0x104 M-1cm-1 and a concentration of 2 x10-5 M held in a 1.00 cm cell? What is the relative error if the concentration is five times higher, 1.0x10-4 M?3. (5 pts) If a mass analyzer had a resolution of 5000 at an m/z=600, would you be able to resolve masses at 600.00 and 600.05? You must show your calculations to obtain credit for your answer.Page 2 of 104. (10 pts) If the fluorescence quantum yield and lifetime of compound X were 0.5 and 100 nanoseconds, respectively, under anaerobic conditions, what would the quantum yield and lifetime be under aerated conditions, assuming that O2 quenches the excited singlet state with a rate constant of 1x1010 M-1s-1 and the solution concentration of O2 is 2.5x10-4 M?Page 3 of 10INSTRUMENTS (25 points)5. A. (5 pts) Provide a block diagram of an ultraviolet/visible (UV/VIS) diode array spectrophotometer clearly labeling each of the components.B. (5 pts) Provide a block diagram of a scanning dual-beam UV/VIS spectrophotometer clearly labeling each of the components.Page 4 of 10C. (5 pts) Provide a block diagram of a scanning spectrofluorometer, clearly labeling each of the components. D. (5 points) Provide a block diagram of a mass spectrometer, clearly labeling each of the components.E. (5 points) Provide a block diagram of a capillary electrophoresis system, clearly labeling each of the components.Page 5 of 10SHORT ANSWERS (45 points)6. Mass Spectrometry (10 points)A. (2 points) Name two gas phase ionization sources.B. (2 points) What ionization source is used in the mass spectrometer in the 425 laboratory?C. (2 pts) What is the purpose of the “solvent cut time” feature in the GC tab of the method development in the 425 laboratory?The solvent cut time keeps the massspectrometer off during this time whilethe solvent peak elutes. D. (2 pts) Name two ionization sources that are used most commonly for the analysis of high molecular weight polar compounds such as proteins.E. (2 pts; 0.5 pts each) Name four mass analyzers.Page 6 of 107. Capillary Electrophoresis (10 points)A. (2 pts) Provide the order of elution of cations, anions, and neutral species using capillary zone electrophoresis.B. (2 pts) Name a capillary electrophoretic method that can be used to separate neutral specieson the basis of their polarity.C. (2 pts) Which capillary length (length to the detector or the total length) is used in calculating the electrophoretic velocity of the species?D. (2 pts) In isoelectric focusing, would the species with the highest pI focus closer to the cathode or the anode?E. (2 pts) Indicate a way in which electroosmotic flow can be a) repressed and b) reversed.Page 7 of 108. Ultraviolet/Visible Absorption Spectrophotometry (10 points)A. (2 pts) Provide an equation that relates absorbance to concentration. What is this equation called?B. (3 pts) Name three factors that can produce deviations from the relationship provided in Question A. C. (2 pts) Name two types of electronic transitions that have very low molar absorptivities.D. (2 pts) What two light sources are commonly employed in UV/Vis spectrophotometry to provide light in the ultraviolet and visible wavelength ranges, respectively?Ultraviolet: _________________Visible: _________________E. (1 pt) Why are absorbance readings taken at the peak wavelength of maximum absorbance??Page 8 of 109. Fluorescence Spectroscopy (15 points)A. (2 pts) Under what condition is fluorescence intensity proportional to concentration?B. (3 pts) What is the “ratio mode” in spectrofluorometry and why is it employed?C. (2 pts) Define “fluorescence quantum yield” in either words or an equation.D. (2 pts) Define “triplet quantum yield” in either words or an equation.E. (6 pts) Explain the difference between a fluorescence emission spectrum and a fluorescenceexcitation spectrum. Which resembles an absorption spectrum and why? --------------------------------------------------------------------------------------------------------------------------------------------Page 9 of 10END of EXAMPage 10 of