课程名称︰普通化学乙下 课程性质︰系必修 课程教师︰简淑华 开课学院：生农院 开课系所︰森林环资系 考试日期（年月日）︰2008年6月18日 考试时限（分钟）：110分钟(後来题目实在太多，延长至160分钟) 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : (因为课本没上完，考试范围只有 Chapter 14 到 Chapter 19) 1. Briefly explain, distinguish or give definations for the following terms: [20%] (1) acid and base defined by Arrhenius, Bronsted-Lowry and Lewis (2) conjugated acid and base (3) acidic, basic and amphoteric exides (4) a galvanic cell and electrolytic cell (5) anode and cathode (6) equivalence point, midpoint and endpoint in an acid-base titration (7) enthalpy, entropy and Gibbs free energy (8) leveling effect on the acidity of aqueous solutions 2. Arrange in order of decreasing the acid strength and give an explanation: [10%] (1) HF, HCl, HBr, HI (2) HOF, HOCl, HOBr, HOI (3) HClO, HClO2, HClO3, HClO4 (4) HClO4, H2SO4, H3PO4 (5) CH3COOH, CH2ClCOOH, CHCl2COOH, CCl3COOH, CF3COOH 3. Calculate the pH of the following solutions: [8%] (a) 1.00mM HCl; (b) 0.010M NaOH; (c) 0.010M H2SO4 (Ka2 = 0.012) (d) 0.10M CH3COOH (Ka = 1.8 ×10^-5) (e) 0.50M Ca(CH3COO)2 (f) a buffered solution containing 0.50M CH3COOH and 0.10M CH3COONa (g) adding 0.010 mole gaseous HCl to 1.0L of the buffered solution in (f) 4. For synthesis of ammonia from nitrogen and hydrogen. [20%] (a) Write the balanced chemical equation. (b) Calculate ΔH。,ΔS。，ΔG。 per mole of ammonia formed at 25C by using the thermodynamic data given below. Entropy, S。: N2(g): 191.6J/K; H2(g): 130.7 J/K; NH3(g): 192.8 J/K Enthalpy of formation ΔHf。[NH3(g)] = -45.9kJ/mole (c) What is the equilibrium constant Kp for the chemical equation as written in (a) at 25C (d) What is the equilibrium constant K expressed by molar concentration at 25C (e) Assuming that enthalpy and entropy are independent of temperature, calculate the ΔG and Kp at 400C (f) Discuss the effect if temperature on the reaction spontaneity. What is the temperature at which this reaction changes from spontaneous to nonspontaneoas? (g) Discuss the effect of pressure on the reaction sponraneity. Predict the effect of a two-fold increase of pressure in the composition of the ammonia synthesis at equilibrium. (f) State the achivements of the Harber process for ammonia synthesis by the Le Chatlier Principle 5. Given the standard reduction potentials at 25C, E。(Cu2+/Cu) = 0.34V and E。(Ag+/Ag) = 0.80V [10%] (a) Construct the Galvanic cell using the abive couples, write the cell diagram. (b) Write the half cell reactions and the overall chemical reaction for the cell. (c) Calculate E。, ΔG。, and the equilibrium constant K for the cell reaction. (d) Suppose that the cell initially contain 1.0M Ag+ and 1.0 x 10^-5M Cu2+. Write the Nernst equation and calculate the initial voltage measured when the cell is connected. 6. Answer the following: [32%] (1) State the three laws of thermodynamics and indicate which state function is mainly concerned in the law. Also show the law by using an equation. (2) The rate of a precess is found to be twice as fast at 300K as at 290K. Write the Arrhenius equation and calculate the activation energy of the process. (3) Explain qualitatively why the endothermic decomposition of calcium carbonate to calcium oxide and carbon dioxide is spontaneous at high temperature but not in room temperature. (4) Calculate the standard reduction potential of the Fe3+/Fe couple, given the standard reduction potential E。(Fe3+/Fe2+) = 0.77V and E。(Fe2+/Fe) = -0.45V. (5) Specify the type of electrode and the corresponding type of chemical reactopm fpr the positive, "+", pole of a battery. (6) An electrolysis cell that deposits gold (from Au+(aq)) operates for 10.0 minutes at a current of 2.50A. What mass of gold is deposited? (Given Au = 197amu) (7) The Ksp of Ca3(PO4)2 is 2.07*10^-33. Determine its molar solubility in water and in 0.20M CaCl2 respectively. Give your comment on the results. (8) Given 100mL of a solution that contains 0.80mM Ag+ and 0.80mM Cu+, can the two metal ions be saperated by selective precipitation as the insoluble bromide salts by adding 10mL of an 8.0mM solution of KBr? Given Ksp values are 6.27*10^-9 for CuBr and 5.35*10^-13 for AgBr. What maximum [Br-] will saperate the ions? -- Imagine...if you had suddenly learned that, the people, the places and the moments most important to you were not gone, not dead, but worse-- Had never been. What kind of hell would that be? --

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