Chemistry 14C Spring 2018 Final Exam Part A Page 1

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hemistry 14 Spring 2018 Final Exam Part A Page 1 The Deepwater orizon was a petroleum-drilling rig that exploded and sank in the Gulf of Mexico on April 22, 2010.

1 hemistry 14 Spring 2018 Final Exam Part A Page 1 The Deepwater orizon was a petroleum-drilling rig that exploded and sank in the Gulf of Mexico on April 22, This incident caused a massive crude oil leakage from the seafloor oil well below the rig. Some of the oil floated on the Gulf's surface, and a small portion dissolved in the water. The amount of oil eventually decreased through evaporation, remediation, and chemical degradation. rude oil is a complex mixture of many substances, a few of which are shown below. 2 Benzene aphthalene Toluene Xylene Ethylbenzene 1. (3) Evaporation was just one way in which the amount of spilled oil was reduced. Rank the ease of evaporation by writing a boiling point in the blank after each name. Each number will be used exactly once. Boiling point choices: 80 o, 111 o, 136 o, 144 o, and 218 o. Benzene: o aphthalene: o Toluene: o Xylene: o Ethylbenzene: o 2. (4) Write the names of two noncovalent molecular forces that influence the boiling points of question 1. Write the name of the dominant force in the 'dominant force' blank. If the forces you list are of equal strength it does not matter which force goes in which blank. Dominant force = Weaker force = 3. (4) Write the names of two noncovalent molecular forces not listed in question 2. ne of the forces you list here must be obviously stronger than the other. Dominant force = Weaker force = ver time, toluene can also be removed by oxidation, either by air or by bacteria. The oxidation products may then evaporate or dissolve in water Toluene (Ph ) Benzyl alcohol (Ph 2 ) Benzaldehyde (Ph) Benzoic acid (Ph) 4. (4) Write the molecule in each blank. Answer choices: Ph, Ph 2, Ph, or Ph. ighest boiling point:. Most soluble in water:. 5. (2) oncerning your answer to question 4, write one or more letter in the answer blank for all of the factor(s) that favor or enhance the water solubility of the most water-soluble molecule. Answer(s):. (a) umber of hydrogen bonding acceptor sites in this molecule. (d) Anion-cation interactions. (b) umber of hydrogen bonding donor sites in this molecule. (c) The molecule's molecular weight. (e) ydrogen bonding between 2 molecules. (f) Pi stacking. Page 1 score =

2 hemistry 14 Spring 2018 Final Exam Part A Page 2 Does ionization help enhance the solubility of toluene (Ph ) in water? In other words, how much of toluene's conjugate base (Ph 2 - ) is present in aqueous solution? onsider this equilibrium: Ph + 2 Ph pk a 41 pk a 14 pk a 0 6. (2) omplete this statement by writing one molecule (Ph, 2, or 3 + ) in each blank. f the three molecules with pk a values given, is the most acidic and is the least acidic. 7. (2) At equilibrium, how much toluene is ionized? Answer choices: (a) Ph is not ionized; (b) there are about equal amounts of Ph and Ph 2 - ; or (c) Ph is completely ionized. Best answer (a, b, or c):. 8. (4) Spraying with a surfactant (i.e., a soap) is another effective method to disperse an oil spill. omplete this statement by writing exactly one word in each blank. To be an effective soap, a molecule must have both and regions in its molecular structure. The remaining questions on part A of this exam have nothing to do with oil spill remediation. 9. (12) In the each Molecule box write the molecule with the indicated property. In the ame of Force box write the name of the one noncovalent molecular force that is most influential in determining this property. Molecule ame of Force Lowest boiling point: F 2 l 2 Br 2 I 2 ighest boiling point: l 2 2 l 2 2 l l Least soluble in ( 2 ) 4 : K (6) In each blank write the most acidic molecule in each set. (a), 2, F 2, and. (b) 2,, 2 2, and 2 S. (c) Si 4, 2 S, 3 S +, and P 3. Most acidic molecule: Most acidic molecule: Most acidic molecule: Page 2 score =

3 hemistry 14 Spring 2018 Final Exam Part A Page (4) Phenol (Ph) has pk a 10. Write the best pk a choice in each blank. (a) Thiophenol (PhS) has pk a =. Answer choices: 12, 10, or 8. (b) has pk a =. Answer choices: 13, 10, or (5) Draw curved arrows to illustrate hydroxide ion deprotonation of the most acidic proton of methyl propionate. Include the product(s) of this mechanism step. Include all formal charges and lone pairs in the product molecule(s). Methyl propionate ydroxide ion Product(s) 13. (2) In the box draw a methyl propionate isomer that is obviously more acidic than methyl propionate itself. Methyl propionate is More acidic isomer 14. (4) omplete this statement by adding no more than 25 words. Be very specific. The methyl propionate isomer that I drew in question 13 is more acidic than methyl propionate itself because... Page 3 score =

4 hemistry 14 Spring 2018 Final Exam Part A Page 4 l X 15. (2) onsider this pk a data: l pk a 3.32 pk a 3.65 pk a 4.42 Write one answer choice in the blank. X might be. Answer choices: l, F,, or. 16. (9) Each lipid structure and accompanying description below may contain an error, or it may be correct. If you find an error, clearly label and describe the error (or the appropriate correction) using no more than ten words in each case. If there is no error write "no error". (a) This is a triglyceride: ( 2 ) 16 ( 2 ) 16 P 2 2 ( ) 3 + Error/correction: 3 (b) This is a steroid: 3 Error/correction: (c) This is a prostaglandin: Error/correction: Page 4 score =

5 hemistry 14 Spring 2018 Final Exam Part A Page (2) omplete this statement by adding no more than ten words. ne significant feature or phenomenon that is common to all lipids is... int: "They all have carbon" is not significant. 18. (3) Draw the structure of a polyunsaturated fatty acid highly likely to be found in a human being. Do not use any abbreviations. Less likely examples will earn less credit. Questions refer to the tripeptide Phe-ys-Ser. The corresponding amino acid side chains are 2 Ph in Phe, 2 S in ys, and 2 in Ser. 19. (4) In each blank write one or more amino acid(s) with the indicated side chain. Answer choices: Phe, ys, Ser, or on (for none). An acidic side chain: A hydrophobic side chain: 20. (2) What is the relationship between Phe-ys-Ser and Ser-ys-Phe? Write one choice in the answer blank. Answer choices: 'I' (for identical), '' (for constitutional isomers), 'S' (for stereoisomers), or '' (for none of these). Answer:. 21. (6) omplete this drawing of Phe-ys-Ser in its zwitterionic form. eatness counts! int: Practice your answer elsewhere before writing your final answer here. Page 5 score =

6 hemistry 14 Spring 2018 Final Exam Part A Page 6 2 S 2 2 S Questions 22 and 23 concern cysteine and methionine, the two amino acids containing sulfur: 2 2 ysteine Methionine 22. (1) Which sulfur-containing amino acid(s) can form a disulfide bridge? In the blank write '' if cysteine can form a disulfide bride, and/or 'M' if methionine can form a disulfide bridge. Answer(s): 23. (3) Using one or both of the amino acids you selected in question 22, draw a disulfide bridge involving exactly two amino acids. eatness counts! int: Practice your answer elsewhere before writing your final answer here. 24. (4) omplete is statement by writing 'T' (for true) or 'F' (for false) in the blank. If you write 'T' you are done with this question. If you write 'F' complete the statement by adding no more than ten words in each case. (a) DA is not a lipid (T/F): because... (b) DA is not a protein (T/F): because (6) Shown below are the four DA nucleobases: ucleobase A ucleobase B ucleobase ucleobase D (a) Write one word in the blank. Spelling counts! ucleobase A is called. (b) Write one letter in the blank. In a normal DA base pair, nucleobase A is paired with nucleobase (B,, or D). (c) Write a number in the blank. In base pair mentioned in part (b), nucleobase A shares hydrogen bond(s) with the other nucleobase in this base pair. Page 6 score =

Chemistry 14C Spring 2016 Final Exam Part B Page 1

Chemistry 14C Spring 2016 Final Exam Part B Page 1 hemistry 14 Spring 2016 Final Exam Part B Page 1 In lecture we discussed the possibility that the first cells may have been formed in boiling mud puddles, which have been shown (in the lab) to produce