課程名稱︰物理化學二 課程性質︰必修 課程教師︰吳嘉文 開課學院：工 開課系所︰化工系 考試日期（年月日）︰2009/06/15 考試時限（分鐘）：110 是否需發放獎勵金：是 （如未明確表示，則不予發放） 試題 : Final Exam of Physical Chemistry June 15, 2009 1. (12%) (a) Write the overall chemical equation and the cell notation for the electrochemical cell shown below. (4%) (b) You are given the following reduction reactions and Eo values: Fe3+(aq) + e- -> Fe2+(aq) Eo = +0.771 V Fe2+(aq) + 2e- -> Fe (s) Eo = -0.447 V Calculate Eo for the electrochemical cell described in (a). (4%) (c) Using the give data in (b) and calculate Eo for the half-cell reaction of Fe3+(aq) + 3e- -> Fe (s). (4%) 2. (8%) Given E’ = 0.08 V for the Fe3+(cyt b)/Fe2+(cyt b) couple and E’ = 0.22 Vfor the Fe3+(cyt c1)/Fe2+(cyt c1) couple, where E’ represent the standard-statereduction potentials at pH = 7.0 at 25 °C and cyt is an abbreviation for cytochromes. Determine E’ and equilibrium constant (K) for the equation Fe3+(cyt c1) + Fe2+(cyt b) -> Fe2+(cyt c1) + Fe3+(cyt b) 3. (13%) (a) Two solutions 1 dm3 in volume are separated by a membrane 1 dm2 in area (A) and 0.1 cm in thickness (l), and this membrane is permeable to K+ and Cl- ions but not to P- ions. The initial concentrations are shown below. Calculate the concentrations on each side of the membrane after equilibrium has become established. (4%) (b) Define the Nernst potential. Calculate the Nernst potential across the membrane if the temperature is 37 °C. (5%) (c) Calculate the number of ions required to produce the Nernt potential in (d). Assume the dielectric constant in vacuum is 8.854 x 10-12 (C2N-1m-2), and the dielectric constant of the membrane is 3. (4%) 4. (10%) Use the following data for the cell to determine the standard reduction potential for the AgCl/Ag couple. m (mol kg-1) 0.00321 0.00448 0.00561 0.00731 0.00913 0.01119 0.01340 E (V) 0.52070 0.50401 0.49274 0.47965 0.46877 0.45878 0.44991 5. (10%) Describe electrochemical cells. (Principle, advantages, current research challenge, etc.) (Choose two from the following three cells, each one is 5%) (a) Fuel cells (b) Photogalvanic cells (or Dye-sensitized solar cells) (c) Lithium ion batteries 6. (8%) The reaction cis-Cr(en)2(OH)2+ trans-Cr(en)2(OH)2+ is first order in both direction. At 25 °C the equilibrium constant is 0.16 and the rate constant k1 is 3.3 x 10-4 s-1. In an experiment starting with the pure cis form, how long would it take for half the equilibrium amount of the trans isomer to be formed? 7. (10%) Derive the integrated rate equation and half-life (t1/2) for an irreversible reaction of stoichiometry 2A + B -> Z. Assume the rate is proportional to [A]2[B] and the reactants present in stoichiometric proportions; take the initial concentration of A as 2a0 and that of B as a0. (hint: t = 0, [Z] = 0; t = t, [Z] = x) 8. (12%) The following data have been obtained for the hydrolysis of adenosine triphosphate, catalyzed by hydrogen ions: Temp (°C) Rate constant k, (s-1) 39.9 4.67 x 10-6 43.8 7.22 x 10-6 47.1 10.0 x 10-6 50.2 13.9 x 10-6 Assume the Arrhenius equation can be applied. Calculate at 40 °C, the energy of activation, the Gibbs energy of activation, the enthalpy of activation, and the preexponential factor. (each one is 3%) 9. (8%) The reaction 2NO + O2 -> 2NO2 is believed to occur by the mechanism Assume N2O2 to be in a steady state and derive the rate equation. Under what conditions does the rate equation reduce to second-order kinetics in NO and first-order kinetics in O2? 10. (9%) The following data apply to an enzyme-catalyzed reaction: Substrate [S] (mol dm-3) Rate v, (mol dm-3 s-1) 2.5x10-4 2.3 x 10-4 5.0x10-3 7.8 x 10-4 The concentration of the enzyme is 3 g dm-3 and its molecular weight is 60000. Assume the Michaelis-Menten equation to apply and calculate the Michaelis constant Km, the limiting rate V, and the rate coefficient k2. (each one is 3%) --

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