高中化学竞赛辅导 无机化学 3.1化学反应速率知识点素材-人教版高中全册化学素材

第三章 化学动力学基础Chapter 3 The Basis of Chemical Dynamics化学热力学成功预测了化学反应自发进行的方向，如：2K(s) + 2H2O(l)2K+(aq) + 2OH－(aq) + H2(g) Δ rGm, 298K = 404.82 kJ·mol1 Δ rGm, 298K = 228.59 kJ·mol1 这两个反应的 ΔG298＜0，所以此两个反应在 298K 时向正反应方向进行有利，但它们的化学反应速率却相差十万八千里：钾在水中的反应十分迅速剧烈，以至于燃烧；而把 H2和O2的混合物于常温、常压下放置若干年，也观测不出反应的进行。前一类化学反应属于热力学控制的反应；后一类化学反应属于动力学控制的反应。研究化学反应速率有着十分重要的实际意义。若炸药爆炸的速率不快，水泥硬化的速率很慢，那么它们就不会有现在这样大的用途；相反，如果橡胶迅速老化变脆，钢铁很快被腐蚀，那么它们就没有了应用价值。研究反应速率对生产和人类生活都是十分重要的。在中学，我们已学过影响化学反应速率的因素： 1．The concentrations of the reactants：Steel wool burns with difficulty in air, which contains 20 percents O2 , but burst into a brilliant white flame in pure oxygen.2．The temperature at which the reaction occur：The rates of chemical reactions increase as temperature is increased. It’s for this reason that we refrigerate perishable food such as milk.3．The presence of a catalyst：The rates of many reactions can be increased by adding a substance known as a catalyst. The physiology of most living species depends crucially on enzymes, protein molecules that act as catalysts, which increase the rates of selected biochemical reactions. 4．The surface area of solid or liquid reactants or catalysts：Reactions that involve solids often proceed faster as the surface area of the solid is increased. For example, a medicine in the form of a tablet will dissolve in the stomach and enter the bloodstream more slowly than the same medicine in the form of a fine powder.§3-1 化学反应速率The Rates of Chemical Reactions一、...