化学专业英语ppt课件

1、Lesson 2 THE CLASSIFICATION OF INORGANIC COMPOUNDS 无机化合物分类,1,词汇,2,3,The Classes of Compounds 1.Thousands and tens of thousands of compounds are known to the chemist today. It would be impossible to learn properties and behavior of even a fraction of this number if it had to be done on the basis of i

2、ndividual compounds. Fortunately, most chemical compounds can be grouped together in a few classes. Then, if we can properly classify a compound, we are at once aware of the general properties of the compound from knowledge of the properties of that class or group of compounds. For example, HCl is c

3、lassed as an acid, and by becoming familiar with the behavior of acids as a distinct class, we are at once aware of the general properties of the compound. A great many of the compounds we are to study may be classified as acids, bases, salts, metallic oxides, or nonmetallic oxides. Of these five cl

4、asses of compounds, the first three-acids, bases, and salts-are by far the most important.,4,The Classes of Compounds Thousands and tens of thousands of compounds are known to the chemist today.,化合物分类 现今，化学家知道了成千上万的化合物。,thousands and tens of thousands成千上万 be known to被所知,chem(o) 化学（的） chemistry 化学 ch

5、emical 化学的，化学药品 chemosynthesis 化学合成,5,It would be impossible to learn properties and behavior of even a fraction of this number if it had to be done on the basis of individual compounds.,如果根据个别化合物来了解这么多化合物的性质，即使其中的一小部分也是不可能的。,a fraction of 一小部分 on the basis of 根据, 在基础上,6,Fortunately, most chemical c

6、ompounds can be grouped together in a few classes.,幸运的是，大多数化合物能够组合在一起分成几类。,7,Then, if we can properly classify a compound, we are at once aware of the general properties of the compound from knowledge of the properties of that class or group of compounds.,那么，如果我们能够恰当地将一个化合物归类，我们立刻就能从这类化合物的性质来了解这个化合物

7、的一般性质。,be aware of 知道，意识到,8,For example, HCl is classed as an acid, and by becoming familiar with the behavior of acids as a distinct class, we are at once aware of the general properties of the compound.,become (be) familiar with熟悉，通晓,例如，盐酸归类为酸，由于已熟悉作为不同类别 的酸的性质，我们就会立即知道这一化合物的一 般性质。,9,A great many

8、of the compounds we are to study may be classified as acids, bases, salts, metallic oxides, or nonmetallic oxides. Of these five classes of compounds, the first three-acids, bases, and salts-are by far the most important.,我们将要研究的众多化合物可以分类为酸、碱、盐、金属氧化物或非金属氧化物。这五类化合物中的前三类酸、碱和盐是最重要的。,a great （good）many

9、of 很多，大量,10,2. When an acid, base, or salt is dissolved in water the resulting solution is a conductor of the electric current and is termed an electrolyte. If no conduction of current occurs, the compound is known as a nonelectrolyte.,11,2. When an acid, base, or salt is dissolved in water the resu

10、lting solution is a conductor of the electric current and is termed an electrolyte. If no conduction of current occurs, the compound is known as a nonelectrolyte.,酸、碱或盐溶于水中得到的溶液是电流的导体，它们被定义为电解质。如果没有电流的传导发生，这种化合物被称为非电解质。,conductor 导体 electric current 电流 term 被称作 electrolyte/nonelectrolyte 电解质，非电解质,12

11、,3. Classification of Common Compounds By looking at the chemical formulas we may classify many common compounds in the following way. 1. Acids, in the conventional sense, may be recognized by noting that the H is written first in the formula and that the rest of the compound is generally nonmetalli

12、c. Ex., HCl, H2SO4, HClO. 2. Conventional bases have OH radicals written last in the formula. The first part of the formula is usually a metal. Ex., NaOH, Ca(OH)2, Fe(OH)3. 3. A salt consists of a metal, written first, combined with a non-metal or radical written last in a formula. Ex., NaCl, Fe2(SO

13、4)3, Ca(ClO)2. 4. Oxides are compounds containing oxygen and only one other element.,13,Classification of Common Compounds By looking at the chemical formulas we may classify many common compounds in the following way.,普通化合物分类 我们可以根据化学式按着下面的方法分类许多普通化合物。,Class n, 类别 Classify Vt.分类 Classification n. 分

14、类,14,1. Acids, in the conventional sense, may be recognized by noting that the H is written first in the formula and that the rest of the compound is generally nonmetallic. Ex., HCl, H2SO4, HClO.,in the conventional sense按传统的观念（常识）,1.按传统的观念，可以通过在分子式中将H写在第一位并且化合物中的其余部分通常是非金属来辨认出酸，例如， HCl, H2SO4, HClO

15、。,15,2. Conventional bases have OH radicals written last in the formula. The first part of the formula is usually a metal. Ex., NaOH, Ca(OH)2, Fe(OH)3.,2. 传统碱的分子式中将OH基写在最后面。分子式的第一部分通常是一种金属。例如， NaOH, Ca(OH)2, Fe(OH)3。,16,3. A salt consists of a metal, written first, combined with a non-metal or radic

16、al written last in a formula. Ex., NaCl, Fe2(SO4)3, Ca(ClO)2.,3. 盐的分子式由写在第一位的金属和写在最后一位的非金属或原子团组成。例如，NaCl, Fe2(SO4)3, Ca(ClO)2。,17,4. Oxides are compounds containing oxygen and only one other element.,4. 氧化物是由氧和唯一一种其它元素组成的化合物。,18,4. If the element other than oxygen is a nonmetal, the oxide classed as

17、 a nonmetal oxide or an acidic anhydride. The latter name comes about because water added to nonmetal oxides under certain conditions produces acids. Likewise, if water is removed from an acid containing oxygen, the acid anhydride (without water) results.,19,If the element other than oxygen is a non

18、metal, the oxide classed as a nonmetal oxide or an acidic anhydride.,other than 除了，不同于 anhydride 酐 anhydr(o)脱水，无水，酐 anhydration脱水，干化 anhydrous 无水的 anhydroglucose脱水葡萄糖,如果除氧以外的元素是非金属，这种氧化物被称为非金属氧化物或酸酐。,20,The latter name comes about because water added to nonmetal oxides under certain conditions produ

19、ces acids.,酸酐的名称来源于在一定条件下将水加到非金属氧化物中能够生成酸。,come about 产生，发生，出现,21,Likewise, if water is removed from an acid containing oxygen, the acid anhydride (without water) results.,同样，如果将水从含氧酸中除去，就会生成酸酐（没水）。,acid containing oxygen含氧酸,22,5. The other class of oxides, metallic oxides or basic anhydrides, consi

20、st of oxygen combined with a metal. When water is added under proper conditions to basic anhydrides, bases result and vice versa.,23,The other class of oxides, metallic oxides or basic anhydrides, consist of oxygen combined with a metal.,basic anhydride 碱酐,另一类氧化物，金属氧化物或碱酐，由氧和一种金属组成。,24,When water is

21、 added under proper conditions to basic anhydrides, bases result and vice versa.,在合适的条件下将水加到碱酐中就会产生碱，反之亦然。,vice versa 反之亦然,25,6 Acids All acids in the conventional sense contain hydrogen, which may be replaced by metals. The negative portion of the acid molecule is composed of a nonmetal or a radica

22、l (negative valence group). These negative valence groups (except oxide and hydroxide) are often referred to acid radicals. All acids are covalent compounds in which the atoms are held together by a sharing of electrons. When an acid is dissolved in water, ions are formed as a result of the transfer

23、 of a hydrogen ion (proton) from the acid molecule to the water molecule-for example,26,Acids All acids in the conventional sense contain hydrogen, which may be replaced by metals.,酸 按传统意义，所有酸都含有氢，并且氢能够被金属取代。,27,The negative portion of the acid molecule is composed of a nonmetal or a radical (negati

24、ve valence group).,酸分子中负电部分由一种非金属或原子团(负价基团)组成。,Radical 根、原子团,28,These negative valence groups (except oxide and hydroxide) are often referred to acid radicals.,这些负价基团（除氧化物和氢氧化物外)通常被定义为酸根。,valence 化合价 acid radicals 酸根,29,All acids are covalent compounds in which the atoms are held together by a shari

25、ng of electrons.,所有酸都是共价化合物，在化合物中原子通过电子共享结合在一起。,covalent compounds共价化合物,30,When an acid is dissolved in water, ions are formed as a result of the transfer of a hydrogen ion (proton) from the acid molecule to the water molecule-for example,当酸溶于水中，酸分子中的氢离子（质子）从酸中迁移到水分子中形成离子，例如：,31,7. This is a case of

26、 coordinate valence, in which an unused pair of electrons from the water molecule combines with a hydrogen ion to from a hydronium ion. The hydronium ion is a hydrated hydrogen ion or proton ( H+ H2O) and, while the ionization of acids in aqueous solution depends on its formation, we shall ordinaril

27、y use the simple H+ in writing equations. Such equations are thereby simplified and easier to balance.,32,This is a case of coordinate valence, in which an unused pair of electrons from the water molecule combines with a hydrogen ion to form a hydronium ion.,这是配位键的一个例子，在配位键中水分子中未被使用的电子对同氢离子结合形成水合氢离子

28、。,coordinate valence 配位键 combine with 与结合 hydronium ion 水合氢离子,33,The hydronium ion is a hydrated hydrogen ion or proton ( H+ H2O) and, while the ionization of acids in aqueous solution depends on its formation, we shall ordinarily use the simple H+ in writing equations. Such equations are thereby si

29、mplified and easier to balance.,水合氢离子是一种含水的氢离子或质子( H+ H2O) ，并且酸通过形成水合氢离子在水溶液中电离，在书写方程式时，我们通常写成简单的H+ 。因此，方程式被简化了，并且更容易配平。,hydronium ion = hydrated hydrogen ion 水合氢离子 Hydrate 与水化合 ；Hydrated 与水化合的，含水的 Ionization 离子化、电离 Equations 方程式 Thereby 因此,34,8. The chief characteristic of an acid is its ability to

30、 furnish hydrogen ions (protons); therefore, an acid is usually defined as a substance which may furnish protons.,35,The chief characteristic of an acid is its ability to furnish hydrogen ions (protons); therefore, an acid is usually defined as a substance which may furnish protons.,furnish 提供，供给 be

31、 defined as 定义为,酸的主要性质是能够提供氢离子（质子），因此，酸通常被定义为能够提供质子的物质。,36,9. Properties of Acids. In general, aqueous solutions of acids are characterized by the following properties: 1. They have a sour taste. Lemons, oranges, and other citrus fruits owe their sour taste to the presence of citric acid; the taste

32、of sour milk is due to the presence of lactic acid. 2. They turn blue litmus paper red. Litmus is a dye which has a red color in acid solution and a blue color in basic solution; paper which has been soaked in litmus is referred to as litmus paper. Substances of this type, which enable us to determi

33、ne whether a given solution is acid or basic, are called indicators. Methyl orange and phenolphthalein are other indicators frequently used by chemists. 3. They react with certain metals to produce hydrogen. Reactions of this type were studied in connection with the preparation of hydrogen. 4. They

34、react with bases to produce salts and water.,37,Properties of Acids. In general, aqueous solutions of acids are characterized by the following properties:,酸的性质。通常，酸的水溶液具有下面的性质：,aqueous 水的 properties 性质,38,1. They have a sour taste. Lemons, oranges, and other citrus fruits owe their sour taste to the

35、 presence of citric acid; the taste of sour milk is due to the presence of lactic acid.,1. 它们有酸味。柠檬、橙子和其它柑桔属水果由于含有柠檬酸而有酸味；酸牛奶的酸味是由于乳酸的存在。,39,2. They turn blue litmus paper red. Litmus is a dye which has a red color in acid solution and a blue color in basic solution; paper which has been soaked in l

36、itmus is referred to as litmus paper.,2. 它们使蓝色石蕊试纸变红。石蕊是一种在酸溶液中显红色，在碱溶液中显蓝色的染料；已经被浸渍在石蕊中的纸称为石蕊试纸。,40,Substances of this type, which enable us to determine whether a given solution is acid or basic, are called indicators. Methyl orange and phenolphthalein are other indicators frequently used by chemi

37、sts.,enable to 使能够 Indicators 指示剂 Methyl orange 甲基橙 phenolphthalein 酚肽,能够用来确定某一特定溶液是酸性或碱性的这类物质称为指示剂。甲基橙和酚酞是经常被化学家使用的另一些指示剂。,41,3. They react with certain metals to produce hydrogen. Reactions of this type were studied in connection with the preparation of hydrogen. 4. They react with bases to produc

38、e salts and water.,3. 它们和某些金属反应产生氢气。这类反应在氢气制备方面被研究。 4. 它们和碱反应生成盐和水。,in connection with 与有关，在.方面,42,10. Common strong acids are H2SO4, HNO3, HCl, HBr, and HI. Most other acids are generally only partially ionized and consequently only moderately strong or weak.,43,Common strong acids are H2SO4, HNO3,

39、 HCl, HBr, and HI. Most other acids are generally only partially ionized and consequently only moderately strong or weak.,普通的强酸有H2SO4、HNO3、HCl、HBr和 HI。大多数其它酸通常只部分电离，因此它们只是中强酸或弱酸。,44,11. Bases All metallic hydroxides are classed as conventional bases. Of the common bases only NaOH, KOH, Ca(OH)2 and B

40、a(OH)2 are appreciably soluble in water. If these compounds are dissolved in water, the OH- is common to all of their solutions.,45,Bases All metallic hydroxides are classed as conventional bases. Of the common bases only NaOH, KOH, Ca(OH)2 and Ba(OH)2 are appreciably soluble in water. If these comp

41、ounds are dissolved in water, the OH- is common to all of their solutions.,appreciably 略微，有一点,所有的金属氢氧化物被归类为传统的碱。在普通的碱中，只有NaOH, KOH, Ca(OH)2 和 Ba(OH)2 略微可溶于水。如果这些化合物溶于水中，均产生OH-。,46,An aqueous solution of NH3 is also classed as a base, since OH- ions are present in the solution.,NH3的水溶液也归类为碱，这是因为在水溶液中

42、存在OH- 。,47,12. In each of these compounds we find a combination of a metal (or NH4) with the hydroxide group. Just as the characteristic part of an acid is hydrogen ion, so the characteristic part of a base in water solution is the hydroxide ion, OH-. Later the concept of a base will be extended to

43、include substances which do not furnish hydroxide ions in solution.,48,In each of these compounds we find a combination of a metal (or NH4) with the hydroxide group.,我们发现这些化合物中的每一个都由一种金属（或NH4 ）和氢氧根组成。,49,Just as the characteristic part of an acid is hydrogen ion, so the characteristic part of a base

44、 in water solution is the hydroxide ion, OH-.,正如酸的特征部分是氢离子，碱在水溶液中的特征部分是氢氧根离子，OH-。,Just as, so正如那样,50,Later the concept of a base will be extended to include substances which furnish hydroxide ions in solution.,后来，碱的概念被扩展到包括在溶液中没有提供氢氧根离子的物质。,51,13.Properties of Bases. In general, water solutions of m

45、etallic hydroxides (bases) exhibit the following properties. 1. Bitter taste. 2. Soapy or slippery feeling. 3. Turn red litmus paper blue. 4. React with acids to form salts and water. 5. Most metallic hydroxides are insoluble in water. Of the common ones, only NaOH, KOH, Ca(OH)2, Ba(OH)2, and NH3 ar

46、e soluble. The common strong bases are NaOH, KOH, Ca(OH)2, and Ba(OH)2.,52,Properties of Bases. In general, water solutions of metallic hydroxides (bases) exhibit the following properties.,碱的性质。通常，金属氢氧化物（碱）具有下面的性质。,53,1. Bitter taste. 2. Soapy or slippery feeling. 3. Turn red litmus paper blue. 4. R

47、eact with acids to form salts and water.,1. 苦味。 2. 滑腻感。 3. 使红色石蕊试纸变蓝。 4. 同酸反应生成盐和水。,54,5. Most metallic hydroxides are insoluble in water. Of the common ones, only NaOH, KOH, Ca(OH)2, Ba(OH)2, and NH3 are soluble. The common strong bases are NaOH, KOH, Ca(OH)2, and Ba(OH)2.,5. 大多数金属氢氧化物难溶于水。普通的氢氧化物中，只有NaOH, KOH, Ca(OH)2, Ba(OH)2和NH3是可溶的。 普通强碱有NaOH, KOH, Ca(OH)2和Ba(OH)2。,55,14. Salts An acid reacts with a base to produce a salt and water. Hydrogen from the acid