Chem 4101 – Fall 2009 EXAM 2 November 6, 2009 Write your name in the last page only ! !1! General Instructions: • Time: 9:05 – 10:00 • Points: 15 (maximum points for the course is 100) • Allowed: One-sided, 8.5” x 11” crib sheet for equations and their definitions; one calculator. • Not Allowed: See Syllabus • Regrading: Considered only if the exam was written in ink. 1. Define fluorescence quantum yield. [0.5 points] 2. Sulfur dioxide is a nonlinear molecule. How many vibrational modes are predicted? How many IR bands are predicted? [0.5 points] 3. What is the length of the mirror drive needed to provide a resolution of 0.05 cm-1 in an FTIR instrument? [ 1.0 points]Chem 4101 – Fall 2009 EXAM 2 November 6, 2009 Write your name in the last page only ! !2!4. Draw a simplified diagram of a mass spectrometer. Label the names of the various components. You need to indicate at least six components [1.0 points] 5. 12CO has an IR vibrational band at 2170 cm-1. What is the force constant? What would be the wave number for 14CO? [1.0 points]Chem 4101 – Fall 2009 EXAM 2 November 6, 2009 Write your name in the last page only ! !3! 6. In mass spectrometry, what resolution is required to resolve the ions CH2N+ (28.0187 a.m.u.) and N2+ (28.0061 a.m.u.)? [0.5 points] 7. Draw a diagram of fluorometer. Label the various components. What component will need to be changed if you wish to analyze several compounds that have different emission spectra, but similar excitation wavelengths? [1.0 points]Chem 4101 – Fall 2009 EXAM 2 November 6, 2009 Write your name in the last page only ! !4!8. Explain how a Michelson interferometer works. [1.0 points] 9. In AES, the sodium emission lines at 589.0 and 589.6 nm appear more intense when adding KCL to the solution. Explain. Use chemical reactions in your explanation. [1.0 points] 10. Why is source modulation necessary in AAS? [1.0 points]Chem 4101 – Fall 2009 EXAM 2 November 6, 2009 Write your name in the last page only ! !5! 11. List three chemical species that can be analyzed by chemiluminescence. [0.5 points] 12. What are the molecular formulas of the ions with m/z values larger than that for M+? (Hint: 13C abundance is about 1.0% that of 12C; 37Cl abundance is about 32% that of 35Cl). [1.0 points]Chem 4101 – Fall 2009 EXAM 2 November 6, 2009 Write your name in the last page only ! !6!13. Draw a hypothetical mass spectrum for lysosyme (MW 14,340 a.m.u.’s) obtained by ESI of this protein into a quadrupole mass analyzer. Assume that the mass range of the quadrupole is from 150 – 2000 m/z. [1.0 points] 14. Analytical Problem. a. State your analytical problem. [0.25 points] b. Provide the structure of one of your analytes. If your analyte has a molecular weight >500, just provide its name. [0.25 points] c. List some of the compounds (chemical species) that may be present in the matrix of your analytical samples. [0.25 points]Chem 4101 – Fall 2009 EXAM 2 November 6, 2009 Write your name in the last page only ! !7! d. Mark in the table with an “X” those techniques that are useful for quantification or identification of your analyte or components in your matrix. [2.0 points] e. For each of the techniques explain why (or why not) a technique is compatible with the analysis of your sample. [1.25 points] Technique Matrix Analyte Explanation on whether or not a technique is suitable for analysis of your sample Fluorescence IR AAS AES or ICP-AES MS Name:_________________________________ Signature:
View Full Document
Unlocking...