作业：1，2，5，11阅读：AI 26.1 26.2(AII 27.1 27.2)Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.第十二章第十二章 化学动力学基础化学动力学基础Chapter 12 Fundamental of Chemical KineticsChapter 12 Fundamental of Chemical Kinetics引言： 1. 热力学的作用及没有解决的问题：作用：能量转换，方向和限度，平衡性质计算问题：化学反应快慢反应速率例如： 25标准状态下 2H2(g) + O2(g) 2H2O(l)(1) rGm(1) = -474.4 kJ.mol-1 化学反应的机理 MechanismHCl + NaOH NaCl + H2O (2) rGm(2) = -80 kJ.mol-1Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.(2) 反应机理2. 化学动力学的任务(1) 反应速率各种因素对速率的影响唯象规律速率理论 微观3. 动力学理论的现状Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.121 基 本 概 念一、反应速率 定义： 0 =BB 单位时间内单位体积中 反应进度的变化。mol.m-3.s-1即(对等容反应)等容反应的速率定义Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.即等容反应的速率定义(1) r与B的选择无关，但与方程式的写法有关(2) 反应速率的测定：当方程式写定以后，r取决于ct产物反应物Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.二、（基）元反应和反应分子数 (Elementary reaction and molecularity)气相反应H2 + I2 2HI (or 2H2 + 2I2 4HI )机理： (1) I2 2I(2) 2I I2(3) 2I + H2 2HI元反应(写法唯一)反应分子数：在元反应中直接发生碰撞的粒 子数。以双分子反应最多。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.三、简单反应和复合反应 (Simple reaction and complex reaction)例 I2+H22HI简单反应：机理中只包含一个元反应例 CH2CHCHCH2(丁二烯)+C2H4(乙烯) (环己烯)复合反应：机理中包含多个元反应r = f(c, T, 催化剂，溶剂，光)，以下分别讨论Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.122 物质浓度对反应速率的影响一、速率方程 定义：描述rc 的关系式例： I2+H22HI r = kH2I2Cl2+H22HCl r = kH2Cl20.5Br2+H22HBr(1) 速率方程有两种形式：rc微分式 ct 积分式Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.(2) 速率方程的作用：动力学学习，工程 设计，机理研究。(3) 速率方程的确定：实验。所以，速率方程是经验方程。二、元反应的速率方程质量作用定律对元反应 aA + bB P 则 r = kAaBb The Law of Mass ActionEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.三、反应级数和速率系数许多反应的速率方程可表示成幂函数形式(1) 、 、：分级数，表示各物质 浓度对r的影响程度。 n = + + +：反应级数。n与反应分子数的意义、数值特点均不同。(Reaction order and rate coefficient)Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.(2) k：速率系数 意义：各物质浓度均为1mol.m-3时的r 与浓度无关，k=f(T，催化剂，溶剂等) k的单位决定于反应级数：例：n=1, s-1；n=2, m3.mol-1.s-1123 具有简单级数的化学反应 若0, 1, 2, 3, n=1，称一级反应，n=2，称二级反应，等等。Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.一、一级反应例A B + C a(mol.m-3)00t=0 tcAEvaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.即令y为反应物A的消耗百分数，则 cA=(1-y)alncA slope=-kt特点：(1) k单位：s-1, min-1, h-1(2) lncAt呈直线 且 slope = -k(3) 半衰期：y = 1/2半衰期与初始浓度无关Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd.Copyright 2004-2011 Aspose Pty Ltd.二、二级反应例A + B P a0t=0 t二级反应： =1, =1 b a-xb-xx则1. 若a =b： 则Evaluation only.Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd