課程名稱︰物理化學 課程性質︰必修 課程教師︰陳立仁 開課學院：工學院 開課系所︰化工系 考試日期（年月日）︰2012/5/3 考試時限（分鐘）：60 是否需發放獎勵金：是 （如未明確表示，則不予發放） 試題 : Problem 1 (25%) The following data relate to an enzyme-catalyzed reaction. 10^3 [S]/mol dm^3 Rate, v/mol dm^3 s^-1 0.4 2.41 0.6 3.33 1.0 4.78 1.5 6.17 2.0 7.41 3.0 8.70 4.0 9.52 5.0 10.5 10.0 12.5 Calculate the Michaelis constant Km and the maxium rate V Problem 2 (25%) The reaction between iodide ions and the cobalt complex Co(CN)5OH2 2-, for which the stoichiometric equation is Co(CN)5OH2 2- + I- → Co(CN)5I 3- +H2O Is believe to go by the mechanism k1 Co(CN)5OH2 2- → Co(CN)5 2- + H2O k2 Co(CN)5 2- + H2O → Co(CN)5OH2 2- Co(CN)5 2- + I- → Co(CN)5I 3- Assume that the intermediate exists in a steady state, and derive the general rate equation. Write the rate equation for special cases of low and high iodide concentration, and decide which is the rate-controlling step in each case. Problem 3 (25%) The fokkowing is a slightly simplified version of the mechanism proposed in 1937 by G.K. Rollefson and R.F. Faull [JACS 59,625,1937] to explan the iodine- catalyzed decomposition of acetaldehyde： k1 I2 → 2I k2 I + CH3CHO → HI + CH3CO k3 CH3CO → CH3 + CO k4 CH3 + HI → CH4 + I k5 2I → I2 Apply the steady-state approximation to I, CH3CO and CH3 and obtain an expression for the rate. Problem 3 (25%) Some enzyme reactions involving two substrates A and B occur by the following mechanism. k1 E+A→EA k-1 EA→E+A k2 k3 EA+B←→EAB→E+Y+Z k-2 (This is known as the ordered ternary-complex mechanism; A must add first to E, and the resulting complex EA reacts with B; the complex EB is not formed.) The comcentrations of A and B are much larger than the concentration of E. Apply the steady-state treatment and obtain an expression for the rate. --

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