6. A solution of red Kool-Aid transmits light at a wavelength range of nm.

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1 I. Multiple Choice (15 pts) 1. FRET stands for a. Fluorescence Recovery Electron Transfer b. Fluorescence Resonance Energy Transfer c. Fluorescence Recovery Energy Transfer 2. Fluorescence involves the excitation and emission of light based on the theory that a. the emission wavelength and excitation wavelength are the same b. the emission wavelength is shorter than the excitation wavelength c. the emission wavelength is longer than the excitation wavelength 3. If the refractive index of a medium is lower then air, then the speed of light through that medium will a. be lower b. be higher c. stay the same 4. If you want your molecule s fluorescence to not be quenched then you should a. decrease temperature b. increase temperature c. add O 2 5. The correct order of increasing frequency of the following types of electromagnetic radiation is a. Radio < UV < visible < x-ray b. Radio < visible < UV < x-ray c. X-ray < UV < visible < radio II. True or False (If False, Explain why (15 pts total) 6. A solution of red Kool-Aid transmits light at a wavelength range of nm. 7. All p orbitals form pi bonds. 8. Absorption of visible radiation is a higher energy transition than absorption of ultraviolet radiation. 9. The emission wavelength is red shifted from the absorption wavelength involved in fluorescence, 10. The visible light wavelength range of the electromagnetic spectrum is 400 nm 700 nm with the 400 nm corresponding to red light and 700 nm corresponding to violet light.

2 III. Solve (30 pts) 11. Beryllium(II) forms a complex with acetylacetone (166.2 g/mol). Calculate the % transmittance when measured in a 1 cm cell at 295 nm if the molar absorptivity of a 1.34 ppm solution of the complex is 3.15 x Use the information below to determine with the correct number of significant digits the wt% of phosphorous in a urine sample µl of a urine sample was diluted with 500. ml of water and then analyzed for the concentration of Phosphorous Solution Concentration of Phosphorus Absorbance 3.22 x 10-5 M x 10-5 M x 10-5 M x 10-4 M Urine sample 0.518

3 IV. Short Answer (30 pts) Each question is worth 5 pts 13. Draw the following transitions a. Fluorescence b. IR c. UV E 2 E 1 E 0 d. Visible 14. a. Draw benzene. How many absorption maxima would you expect to see in the UV/Vis spectrum of benzene? b. What orbital transitions would the absorptions that you mentioned above correspond to? c. Would you expect another absorption if you added an amine group to the benzene molecule? If so, what would this orbital transition be?

4 15. Explain (in detail) why gas phase UV/Vis spectra do not contain a broad Gaussian peak as in the solution phase but many little peaks. 16. Would the following molecules be IR active? Draw the Lewis Structures for each. a. O 2 b. SO a. Explain why fluorescein emites fluorescence light. b. If the following is an image of a cell labeled with fluorecein, what color light does fluorescein absorb?

5 18. Devise an experiment to study the diffusion of molecules from a cell s membrane to a cell s nucleus. What technique would you use and how does it work? V. A Blast from the Past (10 pts) 19. How much mass in grams of Magnesium Chloride will you produce from mixing 10.0 ml of 37.2wt% HCl (density 1.19 g/ml) with 10.0 ml of 25.5 wt% Magnesium Hydroxide (density 1.30 g/ml)?

6 BONUS (+5 pts) Use Correct Significant Figures No Partial Credit How many grams of solid calcium acetate are needed to make 500.0mL of a 1.00M acetate solution?

7 Name Points Earned I. Multiple Choice (15 points) #1 #2 #3 #4 #5 II. True of False (15 points) #6 #7 #8 #9 #10 III. Solve (30 points) #11 #12 IV. Short Answer (30 points) #13 #14 #15 #16 #17 #18 V. A Blast from the Past (10 points) #19 Chem 220 EXAM IV Fall 2008 Date SHOW ALL WORK!!!!!! - Remember to RELAX BONUS (5 points) Total Points