课程名称︰普通化学乙下 课程性质︰必修 课程教师︰陈逸聪 开课学院：理学院 开课系所︰心理系 森林系 考试日期（年月日）︰2012/04/18 考试时限（分钟）：110 min 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1. Diethyl ether has a boiling point of 34.5°C, and 1-butanol has a boiling point of 117°C. Both of these compounds have the same numbers and types of atoms. Explain the difference in their boiling points. (4%) H H H H H H H H H-C-C-O-C-C-H H-C-C-C-C-OH H H H H H H H H diethyl ether 1-butanol Explain the difference in the melting points of these compounds: NO2 NO2 ︳ OH ︳ ╱＼／ ╱＼ ∣Ｏ｜ ∣Ｏ｜ ＼／ ＼／ ︳ OH m.p. 45C m.p. 115C (Hint: Only one of the two can form intramolecular hydrogen bonds.)(4%) 2. The phase diagram of helium is shown here. Helium is the only known substance that has two different liquid phases called helium-I and helium-II. (a) What is the maximum temperature at which helium-II can exist? (b) What is the minimum pressure at which solid helium can exist? (c) What is the normal boiling point of helium-I? (d) Can solid helium sublime? (e) How many triple points are there? (10%) 3. Pheromones are compounds secreted by the females of many insect species to attract males. One of these compounds contains 80.78% C, 13.56% H, and 5.66% O. A solution of 1.00 g of this pheromone in 8.50 g of benzene freezes at 3.37°C. What are the molecular formula and molar mass of the compound? (The normal freezing point of pure benzene is 5.50°C).(8%) 4. A mixture of NaCl and sucrose (C12H22O11) of combined mass 10.2 g is dissolved in enough water to make up a 250 mL solution. The osmotic pressure of the solution is 7.32 atm at 23°C. Calculate the mass percent of NaCl in the mixture. 5. Consider the reaction N2(g) → 3H2(g) → 2NH3(g) Suppose that at a particular moment during the reaction molecular hydrogen is reacting at the rate of 0.074 Mys. (a) At what rate is ammonia being formed? (b) At what rate is molecular nitrogen reacting? 6. For the reaction X2 + Y + Z → XY + XZ it is found that doubling the concentration of X2 doubles the reaction rate, tripling the concentration of Y triples the rate, and doubling the concentration of Z has no effect.(10%) (a) What is the rate law for this reaction? (b) Why is it that the change in the concentration of Z has no effect on the rate? (c) Suggest a mechanism for the reaction that is consistent with the rate law. 7. Consider this mechanism for the enzyme-catalyzed reaction k1 E + S → ES (fast equilibrium) ← K(-1) k2 ES → E + P (slow) Derive an expression for the rate law of the reaction in terms of the concentrations of E and S. (Hint: To solve for [ES], make use of the fact that, at equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction.)(6%) 8. Consider the following potential energy profi le for the A→D reaction. (a) How many elementary steps are there? (b) How many intermediates are formed? (c) Which step is rate determining? (d) Is the overall reaction exothermic or endothermic? (图在课本p.507右上角) 9. Write the equation ralating Kc and Kp and define all the terms for a reaction of aA + bB → cC + dD (5%) 10. Terminology, description, and illustration (if necessary) (a) Polarizability (3%) (b) (London) dispersion force (3%) (c) Hexagonal and cubic close-packed structures (4%) (d) Critical temperature and pressure (3%) (e) Ideal solution (3%) (f) Half-life(t 1/2).(1%) What is the Half-life of a 1st-order rxn? (4%) (g) Activated complex (or transition state) in a chemical rxn (3%) (h) Arrhenius equation (4%) (i) Molecularity of a reaction (3%) --

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