※ [本文轉錄自 NTU-Exam 看板] 作者: Jman208 (is a good guy) 看板: NTU-Exam 標題: [試題] 94上 陳昭岑 有機化學丙 第一次期中考 時間: Thu Oct 27 22:52:28 2005 課程名稱︰ 有機化學丙 課程性質︰ 必修/選修 課本為Solomons & Fryhle, Organic Chemistry 8th Edition 課程教師︰ 陳昭岑 開課系所︰ 農化系、公衛系 考試時間︰ Oct. 27, 05 試題 : 總分105分 1) Write Lewis structures and the formal charge on each oxygen atom for each of the following compounds. (4 pts. each) a) NO3- b) SOCl2 c) O3 (ozone) d) DMF (N,N-dimethylformamide) 2) Cyanic acid and isocyanic acid differ in the positions of their electron but their structures do not represent resonance structures (2 pts. each) a) Explain b) Loss of a proton from cyanic acid yields the same anion as that obtained by loss of a proton from iscyanic acid. Explain. H－O－C≡N H－N＝C＝O Cyanic acid isocyanic acid 3) Write a three-dimensional formula for ethane. (3 pts.) 4) Write the contributing resonance structures and resonance hybrid for the following and designate the one that would contribute most to the hybrid (if the resonance structures are equally stable, then write down both of them are important). (3 pts. each) 註: 黃色為雙鍵 a) b) CH2+ H3C-NO2 ／＼／ 　　　｜　｜ 　　　 ＼／ 5) Draw molecular orbital of σ,σ*,πandπ* (showing the component of the atomic orbitals as well) and state the difference between these orbitals. (total 12 pts.) 6) Use the arguments based on resonance and electrogenativity effects to explain the trend in carbonyl IR stretching frequencies from higher frequency for esters and carboxylic acids to lower frequencies for amides (5 pts.) 7) Explain why IR spectroscopy can use to differentiate primary, secondary, and tertiary amine. (5 pts) 8) Cetylethyldimethylammonium bromide is the common name for, (CH3)2－N+－(CH2)15CH3Br- a compound with antiseptic properties. ｜ Predicts its solubility behavior in water and CH2CH3 diethyl ehter (6 pts.) 9) Alkenes can interact with metal ions such as Ag+. What is the nature of this interaction? (6 pts.) 10) Predict the products of the following acid-base reactions. If the equilibrium would not result in the formation of appreciable amounts of products, you shold so indicate. In each case label the stronger acid, the stronger base, the weaker acid, and the weaker base. If the reaction does proceed, use the curved arrow notation to illustrate how the reaction occurs (10 pts.) 11) Classify the following alcohol, amine, and alkyl bromide as primary, secondary or tertiary (2 pts. each) a) 　＿ b)　　＿ c) CH3 CH2CH3 　　　　／ ＼ ／　＼ ｜ ｜ ＼＿／￣OH 　＼＿／￣CH－NHCH3 CH3CHCH2CHCH2CH2Br ｜ ／＼ 　　　　　　　　　　　　　　　 ｜　｜ 　　　　　　　　　　　　　　　 ＼／ 12) Designate the Lewis acid and Lewis base in the following reaction (5 pts.) 　　　　　　CH3 CH3 　　　　　／ ｜ CH3－C+ ＋ H2O 　　　→　　　CH3－C－OH2+ ＼ ｜ CH3 CH3 13) Malonic acid, CO2HCH2CO2H, is a diprotic acid. The pKa for the loss of the first proton is 2.86; the pKa for the loss of the second proton is 5.69. a) Explain why malonic acid is a stronger acid than acteic acid (pKa = 4.75). b) Explain why the anion, -C02CCH2CO2H, is so much less acidic than malonic acid itself (10 pts.) 14) Squaric acid is a diprotic acid, with both protons being more acidic than acetic acid. In the dianion obtained after the loss of both protons, all of the carbon-carbon bonds are the same length as well as all of the carbon-oxygen bonds. Provides a resonance explanation for these observations (10 pts.) O OH 　＼ _ ／ 　　　　|_| Squaric acid 　 　／ 　＼　 O OH --

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