课程名称︰普通化学甲 课程性质︰必修 课程教师︰佘瑞琳 开课学院：工学院 开课系所︰化工系 考试日期（年月日）︰2011/1/12 考试时限（分钟）：120分钟 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : R=0.082L-atm/mol-K=8.314L/mol-K; pico-,p=10^-12 I. Multiple choices questions(30%) 1.Which of the following molecules is nonpolar? (a)NH3 (b)CO2 (c)trans-ClHC=CHCl (d)SiH4 2.Permanent gases cannot be liquefied at 25℃. According to the critical point, which of the following substances is permanent gas?(p.519) (a)NH3: 132℃ and 111atm (b)N2 :-147℃ and 34atm (c)CH4: -82℃ and 45.8atm (d)SO2: 158℃ and 77.7atm 3.According to the phase diagram of carbon dioxide(figure 12-28), (a)We can obtain supercritical CO2 at temperature and pressure higher than 31.1℃ and 73atm. (b)Point X is the triple point.(point O in figure 12-28) (c)Point Y is the normal boiling point.(point at 1atm, -78.5℃ in figure 12-28) (d)The density of solid CO2 is greater than that of liquid CO2. 4.The structure of crystalline zinc sulfide is shown below.(figure 12-50) (a)The sulfide ions adopt the face-centered cubic structure. (b)The number of sulfide ions per unit cell is 12. (c)The zinc ions occupy the tetrahedral holes. (d)The coordination number of zinc is 4. 5.Which of the following substance is highly soluble in water? (a)iodoform,CHI3 (b)formic acid,HCOOH (c)benzoic acid,C6H5COOH (d)propylene glycol,CH3CH(OH)CH2(OH) 6.Which of the following statements is true? (a)The solubility of solid solutes increases with increasing temperature. (b)The solubility of gaseous solutes increases with increasing temperature. (c)The normal boiling point of seawater is greater than 100℃. (d)The ranking of solubility in n-hexane: sodium chloride, NaCl >benzoic acid, C6H5COOH >naphthalene,C10H8. 7.The following plot shows the vapor pressure of various solutions of components A and B at certain temperature. Which of the following statements is true? Vapor │ │ Pressure │ ╱￣￣—﹁ │PB° (torr) │ ╱ ￣￣│ │ ╱ │ ｜╱ │ PA°│ │ │ │ └──────────┘ (a)The solutions show positive deviations from Raoult's law. (b)ΔH for the mixing of solution is endothermic. (c)The intermolecular forces are stronger in solution than in either pure A or pure B. (d)Pure liquid B is more volatile than pure liquid A. 8.If the human eye has an osmotic pressure of 8.00 atm at 25℃, what concentration of solute particles in water will provide an isotonic eyedrop solution? (a)0.00323M (b)0.0385M (c)0.327M (d)3.90M 9.Rank the following solutions in increasing boiling point: (a)0.10m CH3CH2OH(aq)<0.10m HF(aq)<0.10m CaCl2(aq)<0.10m NH4NO3(aq) (b)0.10m CH3CH2OH(aq)<0.10m HF(aq)<0.10m NH4NO3(aq)<0.10m CaCl2(aq) (c)0.10m CaCl2(aq)<0.10m NH4NO3(aq)<0.10m HF(aq)<0.10m CH3CH2OH(aq) (d)0.10m HF(aq)<0.10m CH3CH2OH(aq)<0.10m NH4NO3(aq)<0.10m CaCl2(aq) 10.Which of the following statement regarding colloids is true? (a)The size of dispersed particles is in the range of 1-1000 pm. (b)The colloidal particles adsorb cations on their surface. (c)Adding electrolytes, such as NH4NO3, may bring about coagulation of colloidal particles. (d)Smoke is a kind of colloids and shows Tyndall effect. 11.Fore a first order reaction:A→P, the following data were obtained Time(min) [A](M) 0.0 0.800 18.0 0.400 36.0 0.200 54.0 0.100 (a)A plot of 1/[A] versus time is linear. (b)The half life for the reaction is 18 min. (c)The rate constant for the reaction is 0.0385 min-1. (d)It takes 90 min. to decrease the concentration of A to 0.025M. 12.By inspection of the reaction profile for the reaction A to D given, choose the true statement.(figure at p.648) (a)There are 4 intermediates in the reaction. (b)There are 3 activated complexes in the reaction. (c)Step 1 has the smallest rate constant. (d)The overall reaction is exothermic. 13.Which of the following substance is the component of photochemical smog? (a)NO (b)NO2 (c)O3 (d)pantanoic acid 14.The rate constant (k) for the gas-phase decomposition of N2O5: N2O5→2NO2+1/2O2 show the following temperature dependence. Calculate the activation energy of the reaction. (a)1020J/mol (b)12447J/mol (c)0.000831kJ/mol (d)103kJ/mol 15.Regarding the catalyst, which of the following statement is true? (a)A catalyst is a substance that speeds up a chemical reaction but does not take part in the reaction. (b)The function of catalyst is to change the mechanism of a reaction and provide an alternative pathway with lower activation energy. (c)Enzyme is a biocatalyst with high specificity and high efficiency. (d)The optimal pH for catalytic activity of enzyme is pH 7.4. II.Problems(70%) 1.According to the data shown in the table, explain the relations of intermolecular forces, boiling points, molar mass,and dipole moments.(6%,P.506) Substance F2 HCl HI μ(D) 0 1.08 0.44 Molar mass(u) 38.0 36.5 127.9 Boiling point(K) 85.1 188.1 237.8 2.The normal boiling point of water is 100℃. Use the Clausius-Clapeyron equation to calculate the boiling point of water at the reduced pressure of 380mmHg. The enthalpy of vaporization of water is 40.7kJ.(6%,p.516) Hint:ln(Pvap)=-(ΔHvap/RT)+C 3.At room temperature, ion crystallizes in a body-centerd cubic structure. By X-ray diffraction, the edge of the cubic cell is found to be 287pm. (a)Indicate the coordination number of iron atom. (b)Calculate the number of iron atoms per unit cell. (c)If the molar mass of iron is 55.85g and Avogadro constant is 6.022*10^23, calculate the density of iron.(8%,p.537) 4. (a)Write the corresponding balanced chemical reactions for the following five enthalpies of reactions. (b)Calculate the lattice energy of potassium fluoride,KF(s). (c)Would you expect the absolute value of the lattice energy of KF is greater then that of KCl?(10%,12.86) ΔH°f[KF(s)],-567.3kJ/mol Enthalpy of sublimation of K(s),89.24kJ/mol Enthalpy of dissociation of F2(g),159kJ/mol F2 First ionization energy for K(g),418.9kJ/mol Electron affinity for F(g),-328kJ/mol 5.An isotonic solution with human blood is that has the same osmotic pressure as 0.92% NaCl(aq)(mass/volume). Another definition is that the solution has a freezing point of -0.52℃. (a)Show that these two definitions are reasonably close agreement. (b)If a solution containing 3.5g NaCl, 1.5g KCl, 2.9gNa3C6H5O7(sodium citrate), and 20.0g C6H12O6(glucose) per liter is a hypotonic, isotonic, or hypertonic solution? Vertify it.(10%,13.116) Atomic mass(amu): Na=23.0, Cl=35.5, K=39.1, C=12.0, H=1.0, O=16.0. Kf for water is 1.86℃/m. 6.At 25℃ the vapor pressure of pure acetone and pure water are 271 and 24 torr respectively. A solution is made by mixing 50.0g of acetone(CH3COCH3) with 50.0g of water(H2O) at 25℃. (a)What is the mole fraction of acetone in the solution? (b)What is the vapor pressure of the solution? (c)What is the composition of the vapor expressed as a mole fraction? Assume ideal solution and gas behavior. (d)Is it reasonable to assume that this is an ideal solution? Why or why not? (8%) 7.The values of van't Hoff factor, i, of various solutions are listed in the following table. What kinds of conclusions could you give depends on data? Give the explanation for the deviation from idea solutions.(8%,p.587) Variation of van't Hoff Factor, i, with Solution Molality Molality,m Solute 1.0 0.10 0.010 0.0010 ... Infinite Dilution NaCl 1.81 1.87 1.94 1.97 ... 2 MgSO4 1.09 1.21 1.53 1.82 ... 2 Pb(NO3)2 1.31 2.13 2.63 2.89 ... 3 8.The rate of the reaction between hemoglobin(Hb) and carbon monoxide(CO) was studied at 20℃, and the following data were obtained: [Hb]o(μmol/L) [CO]o(μmol/L) Initial Rate(μmol/Ls) 2.21 1.00 0.619 4.42 1.00 1.24 4.42 3.00 3.71 (a)Determine the orders of this reaction with respect to Hb and CO. (b)Determine the rate law. (c)Calculate the value of the rate constant. (d)What would be the initial rate for an experiment with [Hb]o=3.40μmol/L and [CO]o=4.20μmol/L?(8%) 9.A mechanism of the reaction 2NO(g)+O2(g)→2NO2(g) is shown as follows. (a)Show that this mechanism is reasonable.(rate=k([NO]^2)[O2]) (b)Indicate the intermediate. (c)Which process is rate-determining step?(8%,p.633) k1 Step1(fast) NO(g)+O2(g)→NO3(g) ←k-1 k2 Step2(slow) NO3(g)+NO(g)→2NO2(g) 10.The decomposition of ethanol(C2H5OH) on an alumina(Al2O3) surface was studied at 600K: C2H5OH(g)→C2H4(g)+H20(g) Concentration versus time data were collected for this reaction, and a plot of [C2H5OH] versus time resulted in a straight line with a slope of -4.00*10^-5mol/Ls. (a)Determine the integrated rate law and the value of the rate constant for this reaction. (b)If the initial concentration of C2H5OH was 1.25*10^-2M, calculate the half-life for this reaction. (c)How much time is required for all the 1.25*10^-2M C2H5OH to decompose?(8%) --

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