课程名称︰普通化学甲下 课程性质︰系上必修 课程教师︰林万寅 开课学院：理学院 开课系所︰物理系 考试日期（年月日）︰98.06.17 考试时限（分钟）：110min 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1. Answer the following questions. 30% (A) For the molecule XeO2F2, draw its geometrical shape and give the hybridization of the central atom. (B) The oxidation states of nitrogen vary from -3 to +5. Identify compounds of nitrogen that have -2, -1, +1, +2 and +3 oxidaton states. (C) Elemental nitrogen exists as N2, whereas in the gas phase, phosphorus exists as N2m whereas in the gas phase, phosphorus exists as P4. Given a possible reason for the difference betweeen N2 and P4. (D) What is the lanthanide contraction? How does the lanthanide contraction affect the properties of the 4d and 5d transition metals? (E) Rank the following complex ions in order of increasing wavelength of light absorbed and explain. [Co(H2O)6]3+, {Co(en)3]3+, [CoI6]3-, [Co(CN)6]3-. 2. Write balanced equations describing the following reactions. 10% (A) Li reacts with N2 (B) Ba reacts with H2O (C) Ga reacts with S8 (D) Sn reacts with Cl2 (E) Sr reacts with P4 3. Answer the following questions. (en=ethylenediamine) 12% (A) Give the three linkage isomers for Co(en)2(NH3)2Cl3 (B) Write the geometric isomers for [Co(en)2(NH3)2]3+ (C) Write the optical isomers for [CO(en)2(NH3)2]3+ (D) Draw the crytal field diagram for [CO(en)2(NH3)2]3+ with a high spin Co(III) 4. Give the structures of the following compounds. 10% (A) cis-2-chloro-2-butene (B) N,N-dimethylethanamide (C) 3,3-dimethlpentanal (D) ethyl ppropanoate (E) 4,5-dibromo-3-hexanone 5. The base sequences in mRNA that encodes certain amino acids are Met:AUG Trp:UGG Phe:UUU, UUC Asp:GAU, GAC His:CAU, CAC Ala:GCU, GCC, GCA, GCG 10% (A) Give the two DNA sequences that would code for the peptide: Met-His-Trp (B) How many different DNA sequences can code for the peptide Ala-Trp-Asp-His? (C) What is the peptide that is produced from the DNA sequence TACCGTCTAAAG? 6. A solid mixture contains NaCl (Fw=58.4) and MgCl2 (Fw=95.2). When 0.30 g of this solid is dissolved in enough water to form 0.50 L of solution, the osmotic pressure at 25℃ is 363 mmHgg. What is the mass percent of NaCl in the solid? Assume ideal behavior for the solutions. 6% 7. The vapor pressure (P) of several soulutions of water-propanol at 45℃ are given below: (x(H2O): mole fraction of water) 10% x(H2O) 0 0.3 0.54 0.83 1 P(torr) 74 77.3 80.2 78.2 71.9 (A) Are solutions of water-propanol ideal? Explain. (B) Find the vapor pressure of solution with x(H2O) = 0.54 if the solution is ideal. (C) Predict the sign of △H solution for water-propanol solutions. (D) Compare the intermolecular forces between water and propanol with those between the pure substances. (E) Which of the solutions in the Table would have the lowest normal noiling point? 8. The molar ratio of 40Ar to 40K can be used to date geometrical materials. K-40 decay by two processes: electron capture (10.7%, t1/2=1.3*10^9 yr) and β-decay. Answer the following questions. 12% (A) Write the nuclear reactions for the two decay processes. (B) Why are 40Ar/40K ratios rather than 40Ga/40K used to date materials? (C) What assumptions must be made in using this technique? (D) A rock has a 40Ar/40K ratio of 0.50. Calculate the age of the rock. 注：所有的计算题均须列出计算式，否则不予计分‧ --

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