1、1 CHEMISTRY AND CHEMISTWithout chemistry our lives would be unrecognisable, for chemistry is at work all around us. Think what life would be like without chemistry - there would be no plastics, no electricity and no protective paints for our homes. There would be no synthetic fibres to clothe us and
2、 no fertilisers to help us produce enough food. We wouldnt be able to travel because there would be no metal, rubber or fuel for cars, ships and aeroplane. Our lives would be changed considerably without telephones, radio, television or computers, all of which depend on chemistry for the manufacture
3、 of their parts. Life expectancy would be much lower, too, as there would be no drugs to fight disease.Chemistry is at the forefront of scientific adventure, and you could make your own contribution to the rapidly expanding technology we are enjoying. Take some of the recent academic research: compu
4、ter graphics allow us to predict whether small molecules will fit into or react with larger ones - this could lead to a whole new generation of drugs to control disease; chemists are also studying the use of chemicals to trap the suns energy and to purify sea water; they are also investigating the p
5、ossibility of using new ceramic materials to replace metals which can corrode.Biotechnology is helping us to develop new sources of food and new ways of producing fuel, as well as producing new remedies for the sick. As the computer helps us to predict and interpret results from the test tube, the s
6、peed, accuracy and quality of results is rapidly increasing - all to the benefit of product development.It is the job of chemists to provide us with new materials to take us into the next century, and by pursuing the subject, you could make your positive contribution to society.Here are some good re
7、asons for choosing chemistry as a career.Firstly, if you have an interest in the chemical sciences, you can probably imagine taking some responsibility for the development of new technology. New ideas and materials are constantly being used in technology to improve the society in which we live. You
8、could work in a field where research and innovation are of primary importance to standards of living, so you could see the practical results of your work in every day use.Secondly, chemistry offers many career opportunities, whether working in a public service such as a water treatment plant, or hig
9、h level research and development in industry. Your chemistry-based skills and experience can be used, not only in many different areas within the chemical industry, but also as the basis for a more general career in business.1 As a qualification, chemistry is highly regarded as a sound basis for emp
10、loyment.You should remember that, as the society we live in becomes more technically advanced, the need for suitably qualified chemists will also increase. Although chemistry stands as a subject in its own right, it acts as the bond between physics and biology. Thus, by entering the world of chemist
11、ry you will be equipping yourself to play a leading role in the complex world of tomorrow.Chemistry gives you an excellent training for many jobs, both scientific and non-scientific. To be successful in the subject you need to be able to think logically, and be creative, numerate, and analytical. Th
12、ese skills are much sought after in many walks of life, and would enable you to pursue a career in, say, computing and finance, as well as careers which use your chemistry directly.Here is a brief outline of some of the fields chemists work in:Many are employed in the wealth-creating manufacturing i
13、ndustries - not just oil, chemical and mining companies, but also in ceramics, electronics and fibres. Many others are in consumer based industries such as food, paper and brewing; or in service industries such as transport, health and water treatment.In manufacturing and service industries, chemist
14、s work in Research and Development to improve and develop new products, or in Quality Control, where they make sure that the public receives products of a consistently high standard.Chemists in the public sector deal with matters of public concern such as food preservation, pollution control, defenc
15、e, and nuclear energy. The National Health Service also needs chemists, as do the teaching profession and the Governments research and advisory establishments.Nowadays, chemists are also found in such diverse areas as finance, law and politics, retailing, computing and purchasing. Chemists make good
16、 managers, and they can put their specialist knowledge to work as consultants or technical authors. Agricultural scientist, conservationist, doctor, geologist, meteorologist, pharmacist, vet . the list of jobs where a qualification in chemistry is considered essential is endless. So even if you are
17、unsure about what career you want to follow eventually, you can still study chemistry and know that youre keeping your options open.What Do Chemistry Graduates Do?Demand for chemists is high, and over the last decade opportunities for chemistry graduates have been increasing. This is a trend that is
18、 likely to continue. Chemistry graduates are increasingly sought after to work in pharmaceutical, oil, chemical, engineering, textile and metal companies, but the range of opportunities also spans the food industry, nuclear fuels, glass and ceramics, optical and photographic industries, hospitals an
19、d the automotive industry. Many graduates begin in scientific research, development and design, but over the years, about half change, into fields such as sales, quality control, management, or consultancy. Within the commercial world it is recognised that, because of the general training implicit i
20、n a chemistry course, chemistry graduates are particularly adaptable and analytical - making them attractive to a very broad spectrum of employers. There has been a growth of opportunity for good chemistry graduates to move into the financial world, particularly in accountancy, retail stores, and co
21、mputer software houses.（Summarized from: A brief of the Royal Society of Chemistry,1992）2 NOMENCLATURE OF INORGANIC COMPOUNDSNaming elementsThe term element refers to a pure substance with atoms all of a single kind. At present 107 chemical elements are known. For most elements the symbol is simply
22、the abbreviated form of the English name consisting of one or two letters, for example:oxygen = O nitrogen = N magnesium = MgSome elements, which have been known for a long time, have symbols based on their Latin names, for example:iron = Fe (ferrum) copper = Cu (cuprum) lead = Pb (Plumbum)A few ele
23、ments have symbols based on the Latin name of one of their compounds, the elements themselves having been discovered only in relatively recent times1, for example:sodium = Na (natrium = sodium carbonate)potassium = K (kalium = potassium carbonate)A listing of some common elements may be found in Tab
24、le 1.Table 1 Names of Some Common ElementsSymbol Name Symbol Name Symbol NameAg Silver Co Cobalt Ni NickelAl Aluminium Cr Chromium O OxygenAs Arsenic Cu Copper P PhosphorusAu gold F Fluorine Pb LeadB boron Fe Iron Pd PalladiumBa Barium H Hydrogen Pt PlatinumBi Bismuth Hg Mercury S SulfurBr Bromine I
25、 Iiodine Se SeleniumC Carbon K Potassium Si SiliconCa Calcium Mg Magnesium Sn TinCd Cadmium Mn Manganese Ti TitaniumCe Cerium N Nitrogen U UraniumCl Chlorine Na Sodium Zn ZincNaming Metal Oxides, Bases and SaltsA compound is a combination of positive and negative ions in the proper ratio to give a b
26、alanced charge and the name of the compound follows from names of the ions, for example, NaCl, is sodium chloride; Al(OH)3 is aluminium hydroxide; FeBr2 is iron (II) bromide or ferrous bromide; Ca(OAc)2 is calcium acetate; Cr2(SO4)3 is chromium (III) sulphate or chromic sulphate, and so on. Table 3
27、gives some examples of the naming of metal compounds. The name of the negative ion will need to be obtained from Table 2.Table 2 Some Common Negative Ions Name Symbol Name SymbolNitrate NO3- Nitrite NO2-Carbonate CO32- Sulphite SO32-Sulphate SO42- Phosphite PO33-Phosphate PO43- Arsenite AsO33-Hydrog
28、en sulphate HSO4- Hydrogen sulphite HSO3-Hydrogen carbonate HCO3- Hypo-chlorite ClO-Arsenate AsO43- Cyanide CN-Iodate IO3- Iodide I-Chlorate ClO3- Fluoride F-Chromate CrO4- Chloride Cl-Dichromate Cr2O72- Bromide Br-Perchlorate ClO4- Sulphide S2-Permanganate MnO4- Oxide O2-Acetate OAc- Hydride H-Oxal
29、ate C2O42- Hydroxide OH-Table 3 Names of Some Metal Oxides, Bases and SaltsFormula NameFeO iron(II) oxide ferrous oxideFe2O3 iron(III) oxide ferric oxideSn(OH)2 tin(II) hydroxide Stannous hydroxideSn(OH)4 tin(IV) hydroxide stannic hydroxideHg2SO4 mercury(I) sulphate Mercurous sulphateHgSO4 mercury(I
30、I) sulphate Mercuric sulphateNaClO sodium hypochloriteK2Cr2O7 Potassium dichromateCu3(AsO4)2 copper(II) arsenate cupric arsenateCr(OAc)3 Chromium(III) acetate Chromic acetateNegative ions, anions, may be monatomic or polyatomic. All monatomic anions have names ending with -ide. Two polyatomic anions
31、 which also have names ending with -ide are the hydroxide ion, OH-, and the cyanide ion, CN-. Many polyatomic anions contain oxygen in addition to another element. The number of oxygen atoms in such oxyanions is denoted by the use of the suffixes -ite and -ate, meaning fewer and more oxygen atoms, r
32、espectively. In cases where it is necessary to denote more than two oxyanions of the same element, the prefixes hypo- and per-, meaning still fewer and still more oxygen atoms, respectively, may be used, for example,hypochlorite ClO- Chlorite ClO2-chlorate ClO3- perchlorate ClO4-Naming Nonmetal Oxid
33、es The older system of naming and one still widely used employs Greek prefixes for both the number of oxygen atoms and that of the other element in the compound 2. The prefixes used are (1) mono-, sometimes reduced to mon-, (2) di-, (3) tri-, (4) tetra-, (5) penta-, (6) hexa-, (7) hepta-, (8) octa-,
34、 (9) nona- and (10) deca-. Generally the letter a is omitted from the prefix (from tetra on ) when naming a nonmetal oxide and often mono- is omitted from the name altogether.The Stock system is also used with nonmetal oxides. Here the Roman numeral refers to the oxidation state of the element other
35、 than oxygen.In either system, the element other than oxygen is named first, the full name being used, followed by oxide 3. Table 4 shows some examples.Table 4 Names of Some Nonmetal OxidesFormula Name NameCO carbon(II) oxide Carbon monoxideCO2 carbon(IV) oxide Carbon dioxideSO3 sulphur(VI) oxide Su
36、lphur trioxideN2O3 nitrogen(III) oxide Dinitrogen trioxideP2O5 Phosphorus(V) oxide Diphosphorus pentoxideCl2O7 chlorine(VII) oxide Dichlorine heptoxideNaming AcidsAcid names may be obtained directly from a knowledge of Table 2 by changing the name of the acid ion (the negative ion ) in the Table 2 a
37、s follows:The Ion in Table 2 Corresponding Acid-ate -ic-ite -ous-ide -icExamples are:Acid Ion Acidacetate acetic acidperchlorate perchloric acidbromide hydrobromic acidcyanide hydrocyanic acidThere are a few cases where the name of the acid is changed slightly from that of the acid radical; for exam
38、ple, H2SO4 is sulphuric acid rather than sulphic acid. Similarly, H3PO4 is phosphoric acid rather than phosphic acid.Naming Acid and Basic Salt and Mixed SaltsA salt containing acidic hydrogen is termed an acid salt. A way of naming these salts is to call Na2HPO4 disodium hydrogen phosphate and NaH2
39、PO4 sodium dihydrogen phosphate. Historically, the prefix bi- has been used in naming some acid salts; in industry, for example, NaHCO3 is called sodium bicarbonate and Ca(HSO3)2 calcium bisulphite. Bi(OH)2NO3, a basic salt, would be called bismuth dihydroxynitrate. NaKSO4, a mixed salt, would be ca
40、lled sodium potassium sulphate.3 NOMENCLATURE OF ORGANIC COMPOUNDSA complete discussion of definitive rules of organic nomenclature would require more space than can be allotted in this text. We will survey some of the more common nomenclature rules, both IUPAC and trivial.AlkanesThe names for the f
41、irst twenty continuous-chain alkanes are listed in Table 1.Table 1 Names of continuous-chain alkanes CH4 Methane C11H24 undecaneC2H6 Ethane C12H26 dodecaneC3H8 Propane C13H28 tridecaneC4H10 Butane C14H30 tetradecaneC5H12 Pentane C15H32 pentadecaneC6H14 Hexane C16H34 hexadecaneC7H16 Heptane C17H36 He
42、ptadecaneC8H18 Octane C18H38 OctadecaneC9H20 Nonane C19H40 NonadecaneC10H22 Decane C20H42 EicosaneAlkenes and AlkynesUnbranched hydrocarbons having one double bond are named in the IUPAC system by replacing the ending -ane of the alkane name with -ene. If there are two or more double bonds, the endi
43、ng is -adiene, -atriene, etc.Unbranched hydrocarbons having one triple bond are named by replacing the ending -ane of the alkane name with -yne. If there are two or more triple bonds, the ending is -adiyne, -atriyne etc. Table 2 shows names for some alkyl groups, alkanes, alkenes and alkynes.Table 2
44、 Some Alkanes, Alkyl, Alkenes, AlkynesAlkenesAlkanes AlkylsIUPAC CommonalkynesMthane MethylEthane Ethyl Ethene Ethylene AcetylenePropane Propyl Propene Propylene PropyneButane Butyl Butene Butylene ButynePentane Pentyl (amyl)Pentene Pentylene PentyneHexane Hexyl Heptane Heptyl Octane Octyl Nonane No
45、nyl Decane Decyl -ane -yl -ene -ene -yneThe PrefixesIn the IUPAC system, alkyl and aryl substituents and many functional groups are named as prefixes on the parent (for example, iodomethane). Some common functional groups named as prefixes are listed in Table 3.Table 3 Some Functional Groups Named a
46、s Prefixes Structure Name Structure Name-OR Alkoxy- * -F Fluoro-NH2 Amino- -H Hydro-N=N- Azo- -I Iodo-Br Bromo- -NO2 Nitro-Cl Chloro- -NO Nitroso-* methoxy-, ethoxy-, etc., depending upon the R groupIn simple compounds, the prefixes di-, tri-, tetra-, penta-, hexa-, etc. are used to indicate the num
47、ber of times a substituent is found in the structure: e.g., dimethylamine for (CH3)2NH or dichloromethane for CH2Cl2.In complex structures, the prefixes bis-, tris-, and tetrakis- are used: bis- means two of a kind; tris-, three of a kind; and tetrakis-, four of a kind. (CH3)2N2 is bis(dimethylamino
48、) and not di(dimethylamino).Nomenclature Priority of Functional GroupsIn naming a compound, the longest chain containing principal functional group is considered the parent. The parent is numbered from the principal functional group to the other end, the direction being chosen to give the lowest num
49、bers to the substituents. The entire name of the structure is then composed of (1) the numbers of the positions of the substituts (and of the principal functional group, if necessary); (2) the names of the substituts; (3) the name of the parent.The various functional groups are ranked in priority as to which receives the suffix name and the lowest position number1. A list of these priorities is given in Table 4.Table 4 Nomenclature Priority* Structure Name Structure Name-N(CH3)3+ (as one
