课程名称︰物理化学 课程性质︰必修 课程教师︰戴子安 开课学院：工学院 开课系所︰化工系 考试日期（年月日）︰102.5.13 考试时限（分钟）：110 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1.(30%)Explain the following terms. Use graph if necessary. (a)Plot a representative potential energy surface diagram for a reaction A+BC-->AB+C at a fixed angle of approach. (b)Two primary assumptions used in the transition state theory. (c)The Eyring equation. (d)The relationship between the Arrhenius parameters and the Eyring parameters (△H++ and △S++)for a bimolecular gas phase reaction. (e)The Beer-Lambert's law. (f)Singlet and triplet states for reaction. (g)Schematically illustrate the absorption/relaxion/emission process for a diamatic molecule under light exposure. (h)Schematically illustrate and name all processes occuring in T1 to S0 transition. (i)Fluorescence resonance energy transfer. (j)Describe one mechanism that chlorofluorocarbon(CFC) destorys ozone. 2.(10 points)A 100cm^3 vessel containing hydrogen and chlorine was irradiated with light of 400nm. Measurments with a thermopile showed that 11x10^-7 J of light energy was absorbed by the chlorine per second. During an irradiation of 1min the partial pressure of chlorine, as determined by the absorption of light and the application of Bee's law, decreased from 27.3s to 20.8kPa (corrected to 0℃). What is the quantum yield?(The Planck constant, h=6.626x 10^-34 Js) 3.(10 points)Based on the hard-sphere model, derive the expression for the rate constant of the reaction, k B1+B2------>P, by assuming that the reaction occurs upon the first collision.(The collision diameter for the two reactant is assumed to be d12.) 4.(10 points)The unimolecular decomposition of urea in aqueous solution is measured at two different temperatures and the following data are observed: Trial number Temperatue(℃) k(s^-1) 1 60.0 1.2x10^-7 2 71.5 4.4z10^-7 (a)Determine the Arrehenius parameters for this reaction. (b)Using these parameters, determine △H++ and △S++ as described by the Eyring equation at T=60℃. 5.(10 points)For phenanthrene, the measured lifetime of the triplet state(τp) is 3.3s, the fluorescence class at 77k. Assume that no quenching and no internal conversion from the singlet state occurs. Determine kp, kT ISC, kS ISC/kF. 6.(10 points) The mechanism for formation and destruction of ozone can be explained as follows: (a) JO2 O2+hv1---------->2O (b) k2 O+O2+M---------->O3+M (c) JO3 O3+hv2---------->O2+O (d) k4 O3+O------------>2O2 Derive the steady state concentration of ozone and explain why the concentration occurs at some altitude on earth. 7.(10 points)The phosphorescence of butyrophenone in acetionitrile is quenced by 1,3-pentadiene(P). The following quantum yields were measured at 25℃. [P]/10^-3 mol/L 0 1.0 2.0 ψ/ψ0 1 0.61 0.43 Assuming that the quenching reaction is diffusion controlled and the rate constant has a value of 10^10 L/mol．s, what is the lifetime of the triplet state? 8.(10 points)Consider the formation and decay of an excited state Absorption S0+hv1--->S1 v=Ia(assumeψ=1) kF Fluorescence S1------>S0+hv2 kIC Inernal conversion S1---------->S0+hv2 kISC Intersystem crossing S1---------->T1 kQ Collisional quenching S1------------>S0+Q Derive the expression for the fluorescence lifetime, Stern-Volmer equation, and the quantum yield for fluorescence. --

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