课程名称︰物理化学 课程教师︰赵基扬 开课学院：工学院 开课系所︰材料系 考试日期（年月日）︰12/5 考试时限（分钟）：9:20~13:00 是否需发放奖励金：是的 感谢~ （如未明确表示，则不予发放） 试题 : 1.(12pts) Agree or disagree the following statement, explain your answers as qualitatively as possible and give the correct anwers with reasonable explaination if tou think the statements given are wrong. (a)The rate of reaction always increases with the increasing temperature. (3pts) (b)The rate of a chemical reaction could be obtianed either by the reaction mechanism or the formulae of the reaction.(3pts) (c)The viscosity of a lighter gas is larger than that of a heavier gas.(3pts) (d)The molar conductivity of a strong electolyte increase linearly with the increase of the concentration of the electolyte.(3pts) 2.(18pts)Explain the following terms, especially their physical meanings and the associated mathematical equations. (a)The compression factor of a gas?(3pts) (b)The principle of corresponding states.(3pts) (c)Convection of a gas and its driving force.(3pts) (d)The kinectic isotope effect of a chemical reaction.(3pts) (e)The zeroth law of thermodynamics.(3pts) (f)Lindmann-Hinshwood mechanisim.(3pts) 3.(16pts)The critical constants of methane are Pc=45.6 atm,Vc=98.7 cm^3 mol^-1 , and Tc=190.6K (a)Derive the relations between the critical values and the van der Walls parameters a,b. Calculate a and b. (8pts) (b)Estimate the radius of the methane molecular. (2pts) (c)Derive the virial equation from the van der Wall equation by expressing the virial parameters with a and b. Calculate the Boyle temperature of the gas. (6pts) 4.(12pts)You were working on a thermal evaporation pocess for depositing thin films of a certian metal on silicon wafers by heating a close chamber with the metal pellets and the Su wafer inside. You found that the deposition rate of the metal film decreased with time unless keeping on increasing the temperature of the chamber. To maimtain the deposition rate a constant without increasing the operation temperature, a piece of advice for you is to use Knudson cell. (a)Do you agree with the advice? Comment on your decision and give the necessary equation to help your explanation. (8pts) (b)If the molar mass of the solid in the cell is 260g mol^-1 and its vapor pressure is 0.835 Pa at 400L, the mass of the metal thin film deposited in 2hr is 104mg by using Knudson cell operated at 400K. Describe the detail design of the cell. (4pts) 5.(10pts)The equilibrium constant for the autoprotolysis of water, H2O→H+ +OH- , is Kw=[H+][OH-]=1*10^-14 at 298K. After a temperature-jump, the reaction returns to equilibrium with a relaxation time of 37μs at 298K and pH≒7. Given that the forward reaction is first-order and the reverse is second-order overall, calculate the rate constants for the forward and the reverse reactions. 6.(18pts)At 298K, the molar ionic conductivities of Li+, Na+, F-, and Cl- are 3.87mSm^2 mol^-1, 5.01mSm^2 mol^-1, 5.54mSm^2 mol^-1 and 7.635mSm^2 mol^-1, respectively. (a)The potential difference between two electrodes placed in the LiCl aqueous solution is 12.0V. If the electrodes are 1.00cm apart, what is the drift speed of the Li+? (3pts) (b)What fraction of the total current is carried by Li+ when current flows throuht the solution in (a). (3pts) (c)What is the limiting molar conductivity of the LiCl aqueius solution?(2pt) (d)Predict the change of the molar conductivity of the LiCl solution with the increasing concentration of LiCl and explain your prediction. (3pts) (e)Calculate the diffusion coefficient of Li+. (2pts) (f)Estimate the effective radius of Li+ in water at 298K given that the viscosity of water is 1.00*10^-3 (Kg m^-1 s^-1). (2pts) (g)It was observed that the molar conductivity of Li+ in water at 298K was smaller than that of K+ while Li+ was a smaller ion. However, the molar conductivity of F- was smaller than that of Cl- while F- was a smaller ion. Explain this conradiction.(3pts) (题目应该有错) 7.(12pts)The following data have been obtained for the decompositon of N2O5(g) at 67C according to the reaction 2N2O5→4NO2 + O2. t/min 0 1 2 3 4 5 [N2O5]/(mol dm^-3) 1.000 0.705 0.497 0.349 0.246 0.173 (a)Determine the order of the reaction, the rate constant, and the half life . It is not necessary to obtain the result graphically, you may do a calculation using estimates of the rates of change of concentration.(6pts) (b)Someone proposed a mechanism shown below for the reaction. What's the rate law based on the mechanism? Evaluate the validity of the mechanism according to the experimental date. (6pts) N2O5 → NO2 + NO3 Ka NO2 + NO3 → N2O5 Ka' NO2 + NO3 →NO2 + O2 +NO Kb NO + N2O5 → NO2 + NO2 + NO Kc 8.(6pts)Two products are formed in reactions in which there is kinectic control of the ratio of products. The activation energr for the reaction leading to Product 1 is greater than that leading to Product 2. Will the ratio of prodcut concentrations [P1]/[P2] increase or decrease if the temperature is raised? 9.(16pts)The 1-dimensional (z-dirction) energy flux of a perfcet gas originated from thermal conduction can be expressed as Jz=-(1/3)cλCv,m[A](dT/dz) where c is the mean velocity of the gas molecules, λis the mean free path, Cv,m is the molar heat capacity and [A] is the molar concentration of the gas molecules. (a)Derive the above equation from the view point of the gas molecules.(8pts) (b)Predict the change in the thermal conductivity when the pressure decrease (under constant temperature). Explain your prediction.(2pts) (c)Predict the change in the thermal conductivity when the temperature increases (under constant volume). Explain your prediction.(2pts) (d)Helium(FW=4.00)(应该是MW) is confined in a cubic vessel of side 10cm with a pressure of 1.0 mbar, one wall being at 310K and the on oppostie at 295K. The rate of flow of energy from one wall to the other is 8.1mW. Estimate the cross section area of helium based om the above information? (4pts) 另外附有一些数学公式 请参考前几届考古题 --

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