说专业应用化工技术煤制油气专业课件

1、Lesson 1.2 Chemical bonding contentwords1Expressions and Technical Terms2Text3Valves and process flow 4Words化学键bondbnd vt. 【化学】以化学键使结合在分子结晶体内 n. 化学键metallicmitlik adj. 金属的；金属性的，金属质的；金属制的nonmetallic adj. 非金属的elementelimnt n. 【化学】元素configuration knfigjurei n n. 【化学】(分子中原子的)组态，排列ion ain n. 【物理学】离子metha

2、nemi:ein n. 【化学】甲烷，沼气alloyli n. 合金valenceveilns n. 【化学】(化合)价；(原子)价其他magnitudemgnitju:d n. 大小；积；量；【数学】量值；electrostaticilektrusttik adj. 静电的，静电学的characterize krktraiz vt. 表示的特性；以为特性；使带有的特征geometry imitri n. 几何学; 几何形状extremity n.末端，尽头；极端，极度classical klsikl adj.古典的，传统的，权威的，经典的neonnin n. 【化学】氖；氖光灯,霓虹灯arg

3、ona:gn n. 【化学】氩元素名，符号为 AExpressions and Technical Terms规格对应职业岗位chemical bonding 化学键covalent bonding共价键metallic bonding金属键 ionic bonding离子键Van der Waals bonding范德华键Sodium chlorine 氯化钠the valence electrons 原子价电子electron cloud电子云ion core 离子芯，离子实inert gas 惰性气体text There are three principal kinds of bond

4、s that form between atoms: metallic, ionic, covalent.形成原子的化学键主要有三种:金属键,离子键,共价键. It is the electronegativities of atoms that determine what bond type forms.原子的电负性决定了键的类型. If the atoms have high electronegativity, they share electrons in a covalent bonding between individual pairs of atoms.如果原子们有高的电负性

5、,原子间以共价键的形式共用电子; If the atoms have low electronegrativity, they share electrons amongst all of the atoms in a metallic bonding.如果原子们有低的电负性,在所有原子中以金属键的形式来共用电子; If some of the atoms have high and some low electronegativity, the electrons are transferred from one atom to another resulting in an ionic b

6、onding. 如果原子中的一些原子是高电负性的,而另外一些为低电负性的,则电子将从一个原子转移到另一个原子中形成金属键. textThe first to the third are strong bonds, roughly equal in magnitude, while the fourth is weak (about 1/100th as strong). . The forces between atoms are electrostatic, and for the strong bonds depend direct-ly on the electrons that sur

7、round the atoms.原子间的力是静电性的,对于较强的化学建这种力直接依靠或取决于围绕原子运动的电子. The different bond types are characterized by how electrons are shared, which controls the geometry of the atom packing, and by the relative strength of the bond (revealed in the temperature needed to melt the material and break the bonds).不同的

8、键可以用来控制原子堆积的几何形状的电子共用形式和键的强度来表示其特性. textPerhaps ionic bonding is the easiest to describe and visualize.也许离子键是最容易描述和想象出来的. It is always found in compounds that are composed of both metallic and nonmetallic element, elements that are situated at the horizontal extremities of the periodic table.离子键总是在由

9、金属元素和非金属元素所组成的化合物中存在.这些元素会在相应的元素周期表中的相应的水平方向上的尽头可以饱和.Atoms of a metallic element easily give up their valence electrons to the nonmetallic atoms.金属原子的原子很容易将价电子传给非金属原子.textA sodium atom can assume the electron structure of neon(and a net single positive charge) by a transfer of its one valence 3s ele

10、ctron to a chlorine. After such a transfer, the chlorine ion has a net negative charge and an electron configuration identical to that of argon.钠原子可以将3s上的一个价电子转移给氯原子,从而形成氖的电子结构,在这样的电子就换后,氯离子就会有一个负电荷.它的电子结构与氩的电子结构相同.In sodium chloride, all the sodium and chlorine exist as ions. This type of bonding i

11、s illustrated schematically in Fig 3.在氯化钠中所有的钠核氯都是以离子的形式存在的,这种形式的键可以用图3来解释. text In the process all the atoms acquire stable or inert gas configurations and, in addition, an electrical charge; that is, they become ions.在这个过程中所有的原子都变成了稳定的或惰性气体的结构.同时还有电子的变化,也就是说他们变成离子. Sodium chlorine (NaCl) is the cl

12、assical ionic material.氯化钠是典型的离子化合物. Many nonmetallic elemental molecules (H2, Cl2, F2, etc.) as well as molecules containing dissimilar atom, such as CH4,H2O, HNO3, and HF, are covalently bonded许多非金属元素组成的分子,例如H2、Cl2、F2等等和包含不同原子的分子如:CH4、H2O、HNO3和HF是共价键形式结合. In covalent bonding stable electron config

13、uration are assumed by the sharing of electrons between adjacent atoms.共价键中可以用相邻原子间电子的共用形式来假设稳定的电子结构. text Two atoms that are covalently bonded will each contribute at least one electron to the bond, and the shared electrons may be considered to belong to both atoms.在两个形成共价键的原子每一个贡献至少一个电子形成共价键.这共用电子

14、可以认为属于两个原子.Covalent bonding is schematically illustrated in Figure 4 for a molecule of methane (CH4).共价键是可以用甲烷分子的结构在图示中展现. textFig 4 Schematic representation of covalent bonding in a molecule of methane (CH4) To describe any molecule we need to know the angles, lengths, and strength of all of its bo

15、nds.对于描述分子需要用键角、键长、键能来体现For methane these parameters are that H-C-H bond angle is 109o28, C-H bond length is 0.11nm, C-H bond strength is 104 Kcal/mol对于甲烷分子而言这些参数如下.H-C-H的键角是10928,C-H键长是0.11nm,C-H键能是104Kcal/mol. Metallic bonding is found in metals and their alloy.金属键存在金属和金属合金中. Metallic materials ha

16、ve one, two, or at most, three valence electrons, with this model; these valence electrons are not bound to any particular atom in the solid and are more or less free to drift throughout the entire metal.金属原子有一个,两个,至多有三个价电子,金属键中这些原子价电子并非束缚在固体中的任何一个特定的原子中.它可以在整个金属中移动. They may be though of as belongi

17、ng to the metal as a whole, or forming a “sea of electron” or an “electron cloud”.这些电子作为一个整体是属于金属的.我们可以认为它们形成了电子海或电子云.The remaining non-valence electrons and atomic nuclei form what are called ion cores, which possess a net positive charge equal in magnitude to the total valence electron charge per

18、atom. 这剩余的非原子价电子和原子核形成了离子芯,离子芯拥有正电荷,在数量上等于每个原子的原子价电子之和. texttextVan der Waals bonding (secondary bonding) exists between virtually all atoms or molecular, but its presence may be obscured if any of the three primary bonding type is present.范德华键在所有原子和分子中都存在,但是如果上述三种键其中之一存在的话,那么范德华力就变模糊Secondary bonding is evidenced for the inert gases,