水之语城
石蜡一词,来自拉丁美洲parum竹(略有姻亲) ,指的是惰性化学性质的物质,并也适用于蜡obtanable从石油和组成的混合物较高的烷烃(他为什么老师比我快!- -喂,同学。你公平点,一人一分吧)
大胃王与王囡囡
请楼主放心采纳,你还在别的地方发了帖,我也已答复。请一并采纳。Electron dot formulas clarify the mechanism of forming a coordinate bond in the neutralization of a Lewis acid. Neutralization of a proton by an ammonia molecule is A电子点方程澄清了在路易斯酸的中和作用中形成配位键的机理。一个质子被氨分子的中和为A The acid — base pair Al3+ and H2O undergoes Lewis neutralization by forming six coordinate bonds.酸碱对Al3+ 和H2O通过形成6个配位键经受路易斯中和作用。 Many displacement reactions illustrate the relative strength of the Lewis acid or base. For example, the cyanide ion is a stronger base than the fluoride ion by virtue of its ability to displace the fluoride ion from the hexafluoroferrate (III) ion: FeF63- + 6CN- ------→ Fe(CN)63- + 6F-很多置换反应表示了路易斯酸或碱的相对强度。例如,氰化物离子就其从六氟高铁酸盐(III)离子中置换氟化物离子来说是一种比氟化物离子更强的碱:FeF63- + 6CN- ------→ Fe(CN)63- + 6F- There are many reactions that fit the Lewis acid-base concept. In contrast to proton loss or gain in the Bronsted-Lowry concept, the Lewis concept emphasizes the electron pair ------a Lewis acid lacks an electron pair in an empty orbital, or has an orbital that can be vacated and a Lewis base has a nonbonding electron pair and can supply this pair to another substance lacking an electron pair.有很多反应符合路易斯酸-碱概念。与质子在Bronsted-Lowry概念中的损耗或增益相反,路易斯概念强调电子对——路易斯酸在一条空的轨道上缺少一个电子对,或者有一条可以是空的轨道,而路易斯碱则有一个非键合的电子对,并能够将此电子对提供给另一种缺少一个电子对的物质。 It is evident that the Lewis concept applies, not only to the chemical behavior correlated by the Bronsted-Lowry concept, but also to many chemical reactions that do not involve proton transfer, and for this reason it is most useful. Its generality precludes the establishment of a scale of acid and base strengths for all Lewis acids and bases, but comparisons can be made between selected substances.显然,路易斯概念不仅适用于由Bronsted-Lowry概念相关的化学行为,而且适用于很多不设计质子传递的化学反应,由于这个理由,它是最有用的。它的通用性妨碍了对所有路易斯酸和碱来说一定范围的酸碱强度的确立,但是在所选择的物质之间可做比较 The terms nucleophilic, and electrophilic are sometimes applied to bases and acids. Lewis acids that accept an electron pair are electrophilic, and the strength of Lewis bases is measured by their tendencies to supply electrons. For example,H2O is a stronger base than Cl- because H2O displaces Cl~ in supplying an electron pair for the proton: HCl+H2O------→H3O+ + Cl-术语“亲核的”和“亲电子的”有时被用于碱和酸。接受一个电子对的路易斯酸是亲电子的,而路易斯碱的强度用它们提供电子的倾向来衡量。例如H2O就是一种比Cl-强的碱, 因为H2O在为质子提供一个电子对能置换ClConsequently , H2O is a stronger nucleophilic agent than Cl-. 因此,H2O是一种比Cl强的亲核剂
jason86122
两种材料被用来作为支持,为贵金属: 1锆掺杂介孔氧化硅与硅/锆摩尔比5 ,其中准备基本上是根据该方法描述别处[ 24,36 ] ,但由该搅拌暂停一天只有加快合成。 第二个支持是一个商业孔氧化铝二氧化硅制备溶胶-凝胶法( 40:60 /宽) , 提供安格。支撑分别在煅烧550 ( 1架C敏) 1供热率)为6 h和人用字母sizr和西亚尔,分别。该钯/铂钯/铑催化剂,在不同的原子比率,分别准备由起初湿润浸渍用悬浮物纳米粒子在二甘醇(度) , 其中编写的多元醇介导的合成法报,在其他地方〔 37 〕 。平均粒子尺寸测量动态光散射用马云zetasizer纳米第浸渍后的催化剂完全干涸,在170 C和煅烧,然后在550 C的5小时,磨浆,形成一个网状14-20 颗粒大小。该催化剂用字母sizr (西亚尔) - xpd /铂(铑) - y ,其中X指以总金属含量( wt. % )和Y向钯/铂( RH )的摩尔比。