专业英语课程考试试卷

1、专业英语课程考试试卷A卷姓名学号班级得分考生请注意：请将答案写在答题纸上，写在试卷上一律无效。考试完毕请将试卷和答题纸一并交上，不得将试卷带出考场。READING MATERIAL A:Plastic are remarkably useful materials, but one of their greatest advantages over other materials, their durability, is also one of their greatest handicaps. They dont disintegrate. Once we dump them into t

2、he environment, they just stay there. Some plastic seem to last forever. One way to keep discarded plastics from overwhelming us is to recycle them, to use them over and over again. But there are different kinds of plastics, and one sort doesnt mix well with another. To reuse plastics we have to sep

3、arate one kind from another so that we can combine all compatible plastics into one group and reprocess them as a whole. One way to sort them is by taking advantage of differences in the densities of different kinds of plastics.If an era is known by the kinds of materials its people use to build the

4、 world they live in, then the Stone Age, the Bronze Age, and the Iron Age have given way to our own Plastic Age. Plastics form much of our packing and wrapping materials, many of our bottles and containers, textiles, plumbing and building materials, furniture and flooring, paints, glues and adhesive

5、s, electrical insulation, automobile parts and bodies, television, stereo and computer cabinets, medical equipment, video and audio tapes, records and compact disks, personal items including pens, razors, toothbrushes, and hairsprays, and even the plastic trash bags we use to discard our plastic tra

6、sh, Except for our food, air, and water, almost every ordinary thing we come in contact with each day contains some kind of a plastic somewhere in, on, or around it. Or it comes to us wrapped in plastic. So many of our throwaway goods are made of plastic that, despite its lightness, the material cur

7、rently makes up an estimated 7% of the total weight of all solid municipal wastes and is expected to grow to 10% by the year 2000. Whats more, plastics are a highly visible part of what we discard, making up roughly a quarter of the entire volume of our trash. Durable or fragile, rigid or flexible,

8、sturdy or flimsy, dense or light, strong or weak, plastics provide us with inexpensive materials of virtually unlimited properties. With chemical ingenuity we can transform them into almost whatever shapes we wish with almost whatever properties we desire. And at their root, in the polymeric molecul

9、es that make up these extraordinary substances of our everyday world, lies not only one of the shining achievements of modern chemistry but, as well see at the end of this chapter, perhaps even the secret of life itself. Well begin, though, by examining the difference between the plastics of our wor

10、ld and the polymers that form them.Plastics and PolymersPlastics, especially the plastics of our most common commercial products, are extraordinary kinds of materials that we can shape into virtually any form we want. The word itself comes from the Greek plastikos, suitable for molding or shaping. W

11、e can form them into round, hard, resilient bowling balls, draw them out into the thin, flexible threads of synthetic fibers, mold them into intricately designed, long-running machine parts, or flatten them into flimsy but tough sheets of clinging kitchen film. Today, the word plastic refers mostly

12、to a property of a material: its ability to be shaped into the myriad forms of todays commercial and consumer products.When we speak of a polymer, though, we return to the molecular level of matter. All the plastics of our everyday lives, as well as all the proteins and the starch and cellulose of o

13、ur foods, the cotton, silk, and wool of our textiles, and even the DNA that carries the genetic code within the nucleus of the cell are formed of enormously large polymeric molecules. The combination of the Greek words poly, meaning many, and meros, parts, gives us the word for the molecules that co

14、mpose these substances, polymer. A polymer is a molecule of very high molecular weight, composed of many - a great many much smaller parts joined together through chemical bonds. .As the word implies, polymers are extremely large molecules, sometimes called macromolecules to emphasize their very lar

15、ge size. The individual parts that combine to form them, monomers from the Greek mono, one, join to each other in enormously large numbers to produce polymers with molecular weights ranging from the tens of thousands to millions of atomic mass units. Often the monomers unite to form an enormously lo

16、ng, linear molecular thread, very much like a long chain we might find in a hardware store. In other polymers the chains may be branched to various degrees, or they may be interconnected at occasional junctions, or so frequently that they form a web or even a rigid, three-dimensional lattice. In any

17、 event, a polymer is a substance composed of huge molecules, sometimes in the form of very long chains, sometimes as sheets, sometimes as intricate, three dimensional lattices. A plastic, on the other hand, is a material that can be molded readily into a variety of shapes. All of todays commercial p

18、lastics are polymers, even though some of our most important polymers are not at all plastic.Condensation PolymerizationThe actual linking of the monomers through covalent bonds occurs during polymerization, a chemical process easily divided into two broad categories: condensation polymerization and

19、 addition polymerization. The products are condensation polymers and addition polymers, respectively.Well look first at a few condensation polymers, then well return to addition polymers. The naturally occurring polysaccharides and proteins provide us with good examples of condensation polymers, eve

20、n though they form through complex enzymatic reactions, far removed from the relatively straightforward industrial processes that produce our everyday polymers. Regardless of what kinds of chemical reactions actually produce them, these polysaccharides and proteins do provide us with fine illustrati

21、ons of the structures of condensation polymers.In a condensation reaction two molecules combine with the formation and loss of another, smaller molecule, usually water or a simple alcohol. (The general term condensation reaction probably originated as early chemists observed water or similar liquids

22、 forming droplets of condensate on the sides of flasks during this sort of reaction.) Each of the condensing molecules contributes some portion of the smaller molecule being eliminated.The first and probably the best known of all the synthetic condensation polymers is nylon, a plastic developed by t

23、he Dupont Corporation. In 1928 Wallace H. Carothers (1896-1937), an Iowa-born chemist, left his post as instructor in organic chemistry at Harvard University to lead a research group in Duponts Wilmington, Delaware, laboratories. There he began a program of fundamental research into polymers, studyi

24、ng how they form and what factors affect their properties. Within a few years he and his co-workers found that by polymerizing a mixture of adipic acid and 1,6-diaminohexane, they could produce a plastic (nylon) that can be drawn out into strong, silky fibers.Nylons first practical application to a

25、consumer product came in 1938, when the new polymer was introduced to the public in the form of toothbrush bristles. But it was the polymers use in stockings, first sold to consumers on a trial basis in October 1939, that made it an overwhelming commercial success. Similar to silk in its properties

26、but far less expensive, nylon became the ideal replacement for the silk of stockings and other fashionable clothing. With the coming of World War II, fashion had to make way for the war effort. The government used most of the nations limited supplies of nylon for making parachutes, ropes, and other

27、military supplies. Since there wasnt enough nylon for both military and civilian uses, nylon stockings, which had become very popular and were in high demand, were rationed until the end of the war. During the war and shortly afterward, nylon stockings became a valuable item of barter in Europe and

28、achieved the status of an informal currency. Not until the early 1950s was there sufficient production capacity to fill the popular demand for nylons, as the stockings came to be known, and also to provide enough of the plastic for other consumer and commercial uses.Addition PolymerizationDespite th

29、e immense initial popularity of nylon, a condensation polymer, a different class of plastics dominates todays chemical economy. Addition polymers such as polyethylene and several of its close molecular relatives account for more than half of all the plastics currently produced in the United States.

30、These addition polymers form as their individual, unconnected monomers join together to form a polymeric chain in much the same way as people standing next to each other can form a human chain by holding the hands of those next to them.Despite differences at the molecular level, nylon, which is a co

31、ndensation polymer, and polyethylene, an addition polymer, show an important physical similarity in their behavior as bulk plastics: They both soften when heated and become firm again when cooled, much like the fats we examined in Chapter 13. Whats more, they repeat this behavior as they are alterna

32、tely heated and cooled. (We could draw an analogy to the cyclical melting and freezing of water as well, but plastics often tend to soften a bit before they melt, as do fats, rather than melt sharply like ice.) Plastics that respond to heating and cooling in this way are called thermoplastics.A seco

33、nd category of plastics, the thermosets or thermosetting plastics, are soft enough to be molded when they are first prepared, but on heating they firm up permanently. Reheating may cause them to decompose but it certainly wont soften them again. Bakelite and epoxy resins are good examples of these t

34、hermosetting plastics. Since bakelite is a strong material and a poor conductor of heat and electricity, its used in making handles for cooking utensils and for molding parts for electrical goods, such as the familiar three-way adapter for electrical outlets. It is also used to make such diverse ite

35、ms as buttons and billiard balls. Epoxy resins are used for making fiberboard and plywood. While thermoplastics mimic fats in their response to heat, the thermosets are more like eggs. Heating produces irreversible changes in both thermosets and eggs.READING MATERIAL B:The Haber Process For Ammonia

36、SynthesisThe process requires several inputs: energy, nitrogen and hydrogen. Nitrogen is easy to extract from air, but hydrogen is another problem. Originally it was derived from coal via coke which can be used as a raw material (basically a source of carbon) in steam reforming, where steam is react

37、ed with carbon to give hydrogen, carbon monoxide and carbon dioxide. Now natural gas (mainly methane) is used instead, though other hydrocarbons from oil can also be used. Ammonia plants always include hydrogen-producing plants linked directly to the production of ammonia.Prior to reforming reaction

38、s, sulfur-containing compounds must be removed from the hydrocarbon feedstock as they poison both reforming catalysts and the Haber catalysts. The first desulphurization stage involves a cobalt-molybdenum catalyst, which hydrogenates all sulphur-containing compounds to hydrogen sulfide. This can the

39、n be removed by reaction with zinc oxide (to give zinc sulfide and water).The major reforming reactions are typified by the following reactions of methane (which occur over nickel-based catalysts at about 750):CH4 + H2OCO + 3H2 Synthesis gasCH4 + 2H2OCO2 + 4H2Other hydrocarbons undergo similar react

40、ions.In the secondary reformers, air injected into the gas stream at about 1100. In addition to the other reactions occurring, the oxygen in the air reacts with hydrogen to give water, leaving a mixture with close to the ideal 3:1 ratio of hydrogen to nitrogen with no contaminating oxygen. Further r

41、eactions, however, are necessary to convert more of the carbon monoxide into hydrogen and carbon dioxide via the shift reaction:CO + H2OCO2 + H2This reaction is carried out at lower temperatures and in two stages (400 with an iron catalyst and 220 with a copper catalyst) to ensure that conversion is

42、 as complete as possible.In the next stage, carbon dioxide must be removed from the gas mixture, and this is accomplished by reacting the acidic gas with an alkaline solution such as potassium hydroxide and/or mono- or di-ethanolamine.By this stage there is still too much contamination of the hydrog

43、en-nitrogen mixture by carbon monoxide (which poisons the Haber catalysts), and another step is needed to get the amount of CO down to ppm levels. This step is called methanation and involves the reaction of CO and hydrogen to give methane. The reaction operates at about 325 and uses a nickel cataly

44、st.Now the synthesis gas mixture is ready to go into a Haber reaction.The output from the Haber stage will consist of a mixture of ammonia and synthesis gas so the next stage needs to be the separation of the two so that the synthesis gas can be recycled. This is normally accomplished by condensing

45、the ammonia (which is a good deal less volatile than the other components, ammonia boils at about 40).Questions考生请注意：请将答案写在答题纸上，写在试卷上一律无效。考试完毕请将试卷和答题纸一并交上，不得将试卷带出考场。.Translate the following passages into Chinese:(50%)The invention comprises a method of removing sulfur oxides from flue gas which incl

46、udes providing a wet flue gas desulfurization scrubber having a scrubbing zone located above an internal reaction tank, and then contacting the flue gas in the scrubbing zone with a liquid reagent to convert sulfur oxides in to a scrubbing byproduct and produce an effluent slurry of liquid and solid

47、s containing partially reacted liquid reagent and scrubbing byproduct.Modern cracking furnaces are designed for rapid heating at the radiant coil inlet, where reaction velocity constants are low because of the low temperature. Most of the heat transferred simply raises the reactants from the inlet t

48、emperature to the necessary reaction temperature. In the middle of the coil, the rate of temperature rise is lower, but cracking rate are appreciable. In this section, endothermic heat of reaction absorbs most of the heat transferred to the mixture. At the coil outlet, the rate of temperature rise a

49、gain increases but never becomes as rapid as at the inlet. The rate of disappearance of the reactant is the product of its reaction velocity constant times its localized concentration. At the end of the coil, reactant concentration is low. To obtain additional cracking, process gas temperature is in

50、creased.A catalyst is a substance that increases the rate of a reaction and can be recovered chemically unchanged at the end of the reaction. The rate of a reaction depends on the rate constants in the elementary steps of the reaction mechanism. A catalyst provided an alternate mechanism that is fas

51、ter than the mechanism in absence of the catalyst. Moreover, although the catalyst participates in the mechanism, it must be regenerated. “C1 Chemistry” refers to the utilization of single-carbon compounds to make chemicals or fuel products. Carbon monoxide, formaldehyde, methanol, and methane are examples of C1 feedstocks. The gasification of coal to make carbon monoxide and hydrogen was considered the most promising avenue for the future production of chemicals. However, with the recent global decline in energy prices, the att