92年 The urban air pollution is often due to the release of NOx that is mainly consisted of NO and NO2 by the vehicles or industrial production. NOx may be catalytically converted into nitrogen and water with use of ammonia. 19. What role does ammonia play in this process? (A)acid (B)base (C)oxidant (D)reductant (E)catalyst 20. In order to have complete conversion of 6.0L NOx in which the molar ratio of NO and NO2 is 1:2 under the same temperature and atmospheric pressure, how many liters of ammonia will be needed at least? (A)3.0 (B)6.0 (C)12.0 (D)20.0 (E)30.0 这两题看起来好像很简单 但我不会ㄟ... 对之前板上的答案是D跟C 非选 3. The reaction NO(g)+ O3(g)→ NO2(g)+ O2(g) was studied by performing the flooding technique. When [O3]=1.0*10^14 mol/cm3, the change of [NO] with time is shown in Table 1. When[NO]=2.0*10^14 mol/cm3, the change of [O3] with time is shown in Table 2. Table 1 Table 2 Time(ms) [NO] (mol/cm3) Time [O3] 单位同左 0 6.0*10^8 0 1.0*10^10 100 5.0*10^8 50 8.4*10^9 500 2.4*10^8 100 7.0*10^9 700 1.7*10^8 200 4.9*10^9 1000 9.9*10^7 300 3.4*10^9 (a)Using the graphs to determine the rate order with respect to [NO] and [O3]? (b)Determine the rate law and evaluate the rate constant for this reaction. (c)Propose a mechanism and explain how it can match with the experiment data. 主要是找不到规律性 不知道各自的order 就不会算 以及(c)小题是在问什麽 96年 非选 2. The equilibrium constant of H3PO4 are given as: Ka1=7.5*10^-3 Ka2=6.2*10^-8 Ka3=4.8*10^-13 (b) Calculate the ratio [H3PO4]/[HPO4^2-] and determine the the mole fraction of HPO4^2- at pH=7.405 前半段有用Ka1 Ka2及[H+]算出 主要是後面算莫耳分率不晓得怎麽算 3. The best laboratory vacuum system can pump down to as few as 1.0*10^9 molecules per cubic meter of gas. Calculate the corresponding pressure, in atmosphere,assuming a temperature at 0度C. 想用PV=nRT 但V的部分是用22.4L吗? 以上再麻烦强者帮忙解答 另外也谢谢o810418大帮忙解决了很多疑惑 真的非常感恩与感动阿!!! 在考试前夕真的备感温馨 --

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