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11 Nov 2019
Please answer each question, the questions have multiple parts.
(a) With the aid of a schematic (energy level diagram), discuss the following terms as they relate to molecular emission (i) resonance emission, internal conversion, (ii) radiationless transition (iv) intersystem crossing. (10 points) 1. (b) Discuss the differences between fluorescence and phosphorescence. In each case, show how the process occurs. (10 points) 2. Atomic Absorption Spectroscopy and Molecular Absorption Spectroscopy are among the most widely used analytical measurement techniques. Discuss these techniques. Your discussion should include: (a) The operational principle of each technique. (20 points) (b) Sample preparation and sample handling. (20 points) Starting with an explanation of interference, discuss two types of interference that may be encountered in atomic absorption measurements. (10 points) 3. 4. IR spectroscopy and mass spectrometry provide information that is used in structural determination of chemical compounds. (a) Provide a discussion on how each technique operates and the type of chemical information it provides. Your discussion must include the chemical principles involved, sample requirements and sample processing, and instrumentation. (20 points) (b) The stretching frequency of a chemical bond is estimated by using the equation below. In which region of an IR spectrum would you expect to find the O-H (stretching) absorption band and what is the frequency? (10 points) Equation: v(em) 12xevk/) Where v(cm) frequency of vibration k force constant of the chemical bond (N/m) c- 3x10m/sec N (Newton)- Kg/sec 0-16,H-1 Avogadros number 6x1023 For single bonds k-5x10 N/m
Please answer each question, the questions have multiple parts.
(a) With the aid of a schematic (energy level diagram), discuss the following terms as they relate to molecular emission (i) resonance emission, internal conversion, (ii) radiationless transition (iv) intersystem crossing. (10 points) 1. (b) Discuss the differences between fluorescence and phosphorescence. In each case, show how the process occurs. (10 points) 2. Atomic Absorption Spectroscopy and Molecular Absorption Spectroscopy are among the most widely used analytical measurement techniques. Discuss these techniques. Your discussion should include: (a) The operational principle of each technique. (20 points) (b) Sample preparation and sample handling. (20 points) Starting with an explanation of interference, discuss two types of interference that may be encountered in atomic absorption measurements. (10 points) 3. 4. IR spectroscopy and mass spectrometry provide information that is used in structural determination of chemical compounds. (a) Provide a discussion on how each technique operates and the type of chemical information it provides. Your discussion must include the chemical principles involved, sample requirements and sample processing, and instrumentation. (20 points) (b) The stretching frequency of a chemical bond is estimated by using the equation below. In which region of an IR spectrum would you expect to find the O-H (stretching) absorption band and what is the frequency? (10 points) Equation: v(em) 12xevk/) Where v(cm) frequency of vibration k force constant of the chemical bond (N/m) c- 3x10m/sec N (Newton)- Kg/sec 0-16,H-1 Avogadros number 6x1023 For single bonds k-5x10 N/m
Elin HesselLv2
8 May 2019