课程名称︰普通化学丙 课程性质︰必修 课程教师︰张焕正 开课学院： 开课系所︰ 考试日期（年月日）︰100/01/11 考试时限（分钟）：110分钟 是否需发放奖励金：是，谢谢 （如未明确表示，则不予发放） 试题 : General Chemistry Final Exam (A) I. Multiple choice questions: (total 50points) 1. The equilibrium constant for A+2B →3C is 1x10^-6. Determine ← the equilibrium constant for 4A+8B→12C. ← (A) 4x10^-6 (B) 1.0x10^-24 (C) 1.0x10^-6 (D) 4x10^-24 (E) 1.0x10^24 。 2. At-75 C,K for the reacction N2O4(g)→2NO2(g)is 4.66x10^-8. ← 。 We introduce 0.036 mol of N2O4 into a 2.1-L vessel at -75 C and let equilibrium be established. The total pressure in the system at equilibrium will be (A) 0.23 atm. (B) 0.28 atm. (C) 0.11 atm. (D) 0.56 atm. (E) 4.66x10^-8 atm. 3. Identify the strongest base. _ (A) CH3O (B) CH3OH _ (C) CN (D) H2O_ (E) NO3 4. What concentration of HF (Ka=7.2x10^-4) has the same PH as that of 0.068 M HCl? (A) 6.4 M (B) 0.068 M (C) 4.9x10^-6 M (D) 1.1x10^-2 M (E) 0.16 M 5. The PH of a 0.100 M solution of an aqueous weak acid (HA) is 3.20. What is Ka for the weak acid? (A) 6.3x10^-4 (B) 7.2x10^-5 (C) 4.0x10^-6 (D) 3.2 (E) none of these 6. As water is heated, its PH decreases. This means that (A) the water is no longer neutral. + _ (B) [H ]>[OH ]. _ + (C) [OH ]>[H ]. (D) Two of these are correct. (E) None of these is correct. 7. What combination of substances will give a buffered solution that has a PH of 5.05? Assume each pair of substances is dissolved in 5.0 L of water. (Kb for NH3=1.8x10^-5;Kb for C5H5N=1.7x10^-9) (A) 1.0 mol NH3 and 1.5 mol NH4Cl (B) 1.5 mol NH3 and 1.0 mol NH4Cl (C) 1.0 mol C5H5N and 1.5 mol C5H5NHCl (D) 1.5 mol C5H5N and 1.0 mol C5H5NHCl (E) none of these 8. A first-order reaction is 43% complete at the end of 18 min. What is the value of the rate constant? (A) 3.1x10^-2 min^-1 (B) 0.21 min^-1 (C) 0.31 min^-1 (D) 4.7x10^-2 min^-1 (E) 1.4x10^-2 min^-1 9. A strip of copper is placed in a 1 M solution of copper nitrate, and a strip of silver is placed in a 1 M solution of silver nitrate. The two metal strips are connected to a voltmeter by wires, and a salt bridge connects the solutions. The following standard reduction potentials apply: + _ 。 Ag (aq)+e → Ag(s) E = +0.8 V 2+ _ 。 Cu (aq)+2e → Cu(s) E =+0.34 V When the voltmeter is removed and the two electrodes are connected by a wire, which of the following does not take place? (A) Electrons flow in the external circuit from the copper electrode to the silver electrode. (B) The silver electrode increases in mass as the cell operates. (C) There is a net general movement of silver ions through the salt bridge to the copper half-cell. (D) Negative ions pass through the salt bridge from the silver half-cell to the copper half-cell. (E) Some positive copper ions pass through the salt bridge from the copper half-cell to the silver half-cell. 。 。 10. For a reaction in a voltaic cell, both delta H and delta S are positive. Which of the following statements is true? 。 (A) E cell will increase with an increase in temperature. 。 (B) E cell will decrease with an increase in temperature. 。 (C) E cell will not change when the temperature increases. 。 (D) delta G >0 for all temperatures. (E) None of the above statements is true. 11. Which one of the following statements is false? (A) The change in internal energy, delta U, for a process is equal to the amount of heat absorbed at constant volume,qv. (B) The change in enlthalpy, delta H, for a process is equal to the amount of heat absorbed at constant pressure, qp. (C) A bomb calorimeter measures delta H directly. (D) If qp for a process is negative, the process is exothermic. (E) The freezing of water is an example of an exothermic reaction. 12. Which of the following are state functions? (A) work, heat (B) work, heat, enthalpy, energy (C) enthalpy, energy (D) work, heat, enthalpy (E) heat, enthalpy, energy 13. C2H5OH(l)+3O2(g)→2CO2(g)+3H2O(l), delta H=-1.37x10^3 kJ For rhe combustion of ethyl alcohol as described in the above equation, which of the following statements is(are) true? I. The reaction is exothermic. II. The enthalpy change would be different if gaseous water were produced. III. The reaction is not an oxidation-reduction one. IV. The reoducts of the reaction occupy a larger volume than reactants. (A) I, II (B) I, II, III (C) I,III,IV (D) III,IV (E) I only 14. Which statement is true of a process in which 1 mol of a gas is expended from state A to state B? (A) When the gas wxpands from state A to state B, the surroundings are doing work on the system. (B) The amount of work done in the process must be the same, regardless of the path. (C) It is not possible to have more than one path for achange of state. (D) The final volume of the gas will depend on the path taken. (E) The amount of heat released in the process will depend in the path taken. 。 15. One mole of an ideal gas at 25 C is expanded isothermally and reversibly from 125.0 L to 250.0 L. Which statement is correct? (A) delta S gas = 0 (B) delta S gas + Rln2 (C) delta S univ = 0 (D) delta S surr = 0 (E) delta S gas = delta S surr 16. Which of the following result(s) in an increase in the entropy of the system? I.(See the right diagram)因为我画不出来，所以只好用文字描述，反正就是两个 气缸接在一起，左边的图只有左边的气缸有气体，中间以活塞隔开，右边的气缸真空 ，至於右边的图亦是两个气缸相接，只是中间互通，气体均匀分布於两气缸 II. Br2(g)→ Br2(l)_ III. NaBr(s) → Br (aq) IV. O2(298K)→ O2(373K) V. NH3(1 atm, 298K)→ NH3(3 atm, 298K) (A) I (B) II, V (C) I, III, IV (D) I, II, III, IV (E) I, II, III, V 17. Which of the following is not the property of lithium battery? (A) Lithium has the most negative standard reduction potential value. (B) Lithium is the lightest metal. (C) Lithium battery can be recharged literally hundreds of times without deterioration. (D) Lithium has the smallest mass per mole of electrons. (E) Lithium is use as a cathode. 18. Who invented the first battery in history? (A) Josiah Gibbs (B) Walther Nernst (C) Alessandro Volta (D) Luigi Galvani (E) Albert Einstein 19. Which of the following solutions cannot be classified as a buffer? (A) CH3COOH/ CH3COONa (B) KH2PO4/ H3PO4 (C) NaClO4/ HClO4 (D) C5H5N/ C5H5NHCl (E) NaHCO3/ H2CO3 20. Which of the following is not the extensive property of a system? (A) internal energy, U (B) enthalpy, H (C) pressure, P (D) volume, V (E) entropy, S II. Fill the following blanks:(total 30 points) 1. (6%) When the concentration of A in the reaction A→B was changed from 1.20 M to 0.60 M, the half-life increased from 2.0 min to 4.0 min 。 at 25 C. The order of the reaction is______ order, and the rate constant is________. 2. (3%) Staring at A, an ideal gas undergoes a cyclic process involving expansion and compression at constant temperature as shown. Calculate the total work done. The work is________J. ┌───────────────────┐ │ │ 2│ B______________________→C │ │ ↑ │ │ P(bar)│ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ 1│ │ _______________________↓ │ │ ← D │ │______________________________________│ 1 V(L) 2 3. (3%) How many milliliters of a strong monoprotic acid solution at pH= 4.12 must be added to 528 mL of the same acid solution at pH 5.76 to change its pH to 5.34? Assume that the volumes are additive. The answer is________mL. 4. (3%) Calculate the entropy change for the following process: 。 10.0 g of oxygen (O2) gas at a pressure of 1.0 bar and 25 C is combined in a 30.0-L container with 20.0 g of nitrogen (N2) gas initially at a 。 pressure of 2.0 bar and 50 C. The resulting mixture is then heated at 。 constant pressure to 100 C. The answer is________(in Jmol^-1K^-1) 。 5. (3%) The vapor pressure of benzene (C6H6) is 40.1 mmHg at 7.6 C. 。 What is its vapor pressure at 60.6 C? The molar heat of vaporization of benzene is 31.0 kJmol^-1. The answer is________mmHg. 6. (6%) Classify each of following species as a Lewis acid or a Lewis base: (a) CO2, (b) H2O, (c) BCl3. 7. (6%) A constant current is passed through an electrolytic cells containing molten MgCl2 for 18 h. Write the half-cell reactions:____________ If 4.8x10^5 g of Cl2 are obtained, what is the current in amperes?________ III. Answer the following questions: (total 30 points) 1. (8%) The contributions of several scientists to the development of modern chemistry have been discussed in the class. Give a brief description of two of them. 2. (4%) Several examples of biomedical applications of chemistry have been given in the textbook. Give a brief description of an example that is of most interest to you. 3. (8%) A molecular interpretation of heat capacities is given in Chapter 7. (A) What is "molecular degree of freedom"? (B) What is the constant-volume heat capacity of monoatomic gas? (C) What is the constant-volume heat capacity of linear gas? (D) What is the constant-volume heat capacity of non-linear gas? 4. (5%) What are the three laws of thermodynamics? 5. (5%) In biochemistry, the Michaelis-Menton kinetics is one of the simplest and best known models of enzyme kinetics. What is your understanding of the kinetics? --

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