Analytical Chemistry Test with Multiple Choice Questions Essay

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Choose the best answer and write it to the left of the problem number in the space provided. 1. What is a particular advantage of graphite furnace atomic absorption over flame atomic absorption? (a) higher temperature (b) lower SIN (c) less interference (d) small sample amounts 2. In atomic emission spectroscopy, it is desirable to have a high concentration of the element in the form of: (a) atoms in the ground state (b) atoms in the excited state (c) ions atoms as compounds 3.

Which of the following atomic methods generally provide the best limit of detection? (a) Graphite furnace AS (b) ICP-AWE (C) BAAS (d) ICP-MS 4. What is the desired bandwidth at FM from a source for JIVES absorption? G) 1/6 (b) 1/10 (c) 1/8 (d) 1/3 5. What is the fluorescence quantum yield (OFF) of a molecule excited into the first excited singlet state SSL followed by fluorescence from SSL SO? The deactivation constants for the observed processes are: kef = 2. 0 X 108 s-l, kiss = 2. 0 X 108 s-l, eke = 5.

0 X 107 s-l. Ski, kip, and kid are negligible. (b) 0. 80 (c) 0. 4 (d) 0.

44 6.

Which of the following generally provides the best detection limits? (a) phosphorescence (b) fluorescence (c) absorbency (d) scattering 7 which absorption transition is the most common used I the Spills region? II. Clearly and concisely answer the following. Use diagrams when applicable. (13 pits each) 1. (a) Discuss the relative advantages and disadvantages of flame atomic absorption spectrophotometer (BAAS) versus inductively-coupled plasma atomic emission (ICP- AWE).

(b) Which of these techniques would be best for monitoring the trace level (BP) accumulation of toxic metals in fish, and why? . Describe and illustrate the deviation to Beer’s Law associated with a non- monochromatic source. Show appropriate equations and properly labeled graphs to aid your answer. Clearly discuss the operating principles to deuterium/hydrogen lams used in U Visa molecular absorption spectrometry. What is the wavelength range of this source? 4.

Draw diagrams and explain in a few sentences how a polar solvent will affect n-0* and 0-0* absorption transitions. Which will be blue shifted and which will be red shifted, and why?

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