Век химии (Английский язык для студентов химического профиля). Учебное пособие

6. Выбор способов очистки шлама зависит от многих факторов.

Text C

1.Pay attention to the following words and word combinations: greenhouse effect – парниковый эффект

in turn – в свою очередь to radiate – излучать

insulating blanket – изолирующее одеяло to be similar to smth. – схожий с чем-либо to escape – улетучиваться

vapour – пар

to depend on smth. – зависеть от чего-либо to determine – определять

2.Read the text and be ready to say if the following statements are true or false. Use the following phrases:

It seems to be wrong (right) …

As far as I know …

Far from it. …

If I am not mistaken…

To my mind…

It’s not true to the fact.

1.The atmospheric gases are strong absorbers of infra-red

energy.

2.Absorption of infra-red energy by atmospheric gases is similar to effect of glass in a greenhouse.

3.Gases which act as an insulating blanket keep the earth very

hot.

4.There wouldn’t be any life on the Earth without natural greenhouse effect.

5.Carbon dioxide is the most important natural greenhouse gas.

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6.The concentration of water vapour is determined by the balance between the processes, which produce it, and those, which absorb it.

7.Greenhouse gases occur naturally in the atmosphere.

GREENHOUSE EFFECT

The energy, which drives our weather and climate, comes from the sun. The Earth receives energy, largely in the form that we see as visible light. The visible light from the sun passes through the atmosphere to warm the earth. In turn the warm earth radiates this energy back toward space as infra-red radiation. On the way some of it is absorbed by gases in the atmosphere. They reradiate some of this energy back toward the earth.

Thus these gases act as an insulating blanket keeping the earth much warmer than it would be without them. If these gases were not present, all of the heat the earth radiates would be lost into space. This is similar to the effect of glass in a greenhouse, which allows the sunlight in but keeps some of the radiated heat from escaping. Hence the gases in the atmosphere, which absorb radiated heat, are called the greenhouse gases, and the process is known as greenhouse effect.

Greenhouse gases occur naturally in the atmosphere. The natural greenhouse effect keeps the temperature of the Earth some 30 ºC warmer than it would be otherwise. Without it the Earth would be too cold to support life, the oceans would freeze. Water vapour is the most important natural greenhouse gas. Its concentration in the atmosphere depends on the Earth′s temperature. The concentration of other natural greenhouse gases is determined by the balance between the processes, which produce them (‘sources’) and those, which absorb them (‘sinks’). The main natural greenhouse gases are: carbon dioxide (CO2), methane (CH2), nitrous oxide (N2O), and ozone (O3).

3.Make up the plan to the text.

4.Give a brief summary of the text.

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Text D

1. Read the text and choose the most suitable title out of the given ones:

a)Sources and Composition of Atmospheric Pollutants.

b)Purification of Air.

c)Consequences of Air Pollution.

Scientists distinguish between natural and artificial sources of atmospheric pollution.

Natural pollution of the atmosphere occurs when volcanoes erupt, dust storms take place, forest fires occur as a result of lightning, and sea salt is washed ashore. The pollution always contains aeroplankton, fungi spores, plant pollen, etc.

Artificial pollution of the atmosphere is characteristic mostly of cities and industrial districts. Cities and suburbs contain numerous industrial enterprises, automobiles and heating systems which pollute the atmosphere and negatively influence the local climate.

Industry pollutes the atmosphere by emissions of harmful gases and industrial dust. Thermal electric plants, metallurgical and chemical factories, oil refineries, cement and other works are sources of air pollution.

The chemical composition of emissions into the atmosphere is different depending on the kind of fuel, of raw materials, technology, etc. For example, blast furnace gas contains poisonous carbon monoxide, while the smoke of aluminum factories pollutes the atmosphere with fluoride compounds. Paper manufacturing enterprises emit soot, sulphurous anhydride, hydrogen sulfide and mercapton into the air. The making of synthetic fibers is accompanied by the emission of toxic carbon disulfide (CS2) and hydrogen sulfide.

City air is polluted not only by exhaust fumes but also by the products of their oxidation, often more toxic than the initial substance. One of them is ozone which is useful in small quantities, but is deadly poisonous in large concentrations.

2. Write out:

а) key words and terms;

b) the sentences expressing the main idea of each paragraph.

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Unit 7

GRAMMAR: Subjunctive Mood. Conditional Sentences.

1. a) Translate the following words, word combinations and chemical terms into Russian:

organic, polymers, resins, glycerol, rubber, compound, fatty acids, proteins, fibres, solution, cellulose, resistance, viscosimeter, starch, durability, substance.

b) Translate into Russian paying attention to the Subjunctive Mood and conditional sentences.

1.It is doubtful whether the observations of these scientists represent a new field of chemistry.

2.This procedure might be expected to support the claims of the Japanese scientists.

3.Magnetically induced changes as small as 0.04 pH unit would have been detectable by the method of measurements at constant flow rate.

4.Several theories have been proposed as to how mercury might go from inorganic form in water or a bottom sediment, into a methylated form of a fish.

5.We might expect that the activation energy necessary to start up a reaction would be equal to the energy needed to break the weakest chemical bond among the reactants.

6.If a substance conducts electricity, it will be heated.

7.If a metal were heated, it would be melt.

8.If a nonmetal had been cooled, it would have become brittle.

9.Provided the temperature were high, a metal would melt.

10.Had the temperature been raised, we should have got a new

alloy.

11.If a chemical substance were heated, it might decompose.

2.Choose the correct forms.

1.If life (didn’t depend on, depended on) organic polymers, we (wouldn’t have, would have) food, clothing, shelter and transportation.

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2.But for the complexity and fragility of the molecules of the natural organic polymers they (wouldn’t have defied, would have defied) the attempts to analyze their molecular structure until very recently.

3.There (would, will) be no industry of man-made organic polymers, (was, were) it not for modern methods of physical and chemical analyses.

4.It (would, will) be necessary to add that polymers have

long-lived durability and resistance to high temperatures.

5. If the chemists (had not, did not) found out that many polymers have the form of long, flexible chains, they (wouldn’t, won’t) have been able to synthesize artificial polymers.

Text A

3. Read the text and translate it using a dictionary.

THE AGE OF POLYMERS

Life depends fundamentally on organic polymers. If it were not so, we wouldn’t have food, clothing, shelter and transportation.

Indeed, nearly all the material needs of man could be supplied by natural organic products. The list of these materials and things made from them might be very long: wood, fur, leather, wool, cotton, silk, rubber, oils, paper, paint and so on. The organic polymers which these things are made from include: proteins, cellulose, starch, resins, and a few other classes of compounds.

There would be no industry of man-made organic polymers, were it not for modern methods of physical and chemical analyses which uncovered the principles that govern the properties of the natural polymers. One could list the principal products as fibres; synthetic rubbers, coatings, adhesives and a lot of materials called “plastics”. Plastics and synthetic coating are already in common use. It is desirable that they should be used on a large scale, and get further developed.

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Synthetic polymers now available already possess several of the properties required in a structural material. They are light in weight, easily transported, easily repaired, highly resistant to corrosion and solvents, and satisfactorily resistant to moisture. It would be necessary to add that they have long-lived durability and resistance to high temperatures. A very important question could arise over whether synthetic polymers could be made inexpensive enough to compete with the structural materials such as metals and ceramics. The answer could be – “yes”.

It might seem odd that man came rather late to the investigation of organic polymers as the principal means of supporting life. The natural polymers such as proteins, cellulose and others dominated his existence and even in ancient times people used these materials.

Yet as late as the end of the 19th century polymer chemistry got little attention.

Chemists attacked sugar, glycerol, fatty acids and other ordinary organic compounds – dissolving, precipitating, crystallizing and distilling them to learn what these substances were composed of.

But only feeble efforts were made to investigate such common materials as wood, starch, wool, and silk. The substances composing these materials couldn’t be crystallized from solutions, nor could they be isolated by distillation.

It was only in the 20th century that the scientists began thorough investigation of these materials. Having used some powerful physical instruments, an electron microscope, viscosimeter, X-ray diffraction apparatus; they could have revealed the polymers in all their intricacy.

Their molecules were incredibly large, the molecular weights running as high as millions of unit, whereas simple organic substances such as, for instance sugar and gasolene have molecular weights in the range of only about 50-500.

The giant molecules can be composed of a large number of repeating units, they being given the name “ polymer ” from the Greek word poly (many) and meros (a part). Many polymers have the form of long, flexible chains. If the chemists had not found that out, they wouldn’t have been able to synthesize artificial polymers. This has led to the establishment of industries producing synthetic fibres and

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numerous polymeric materials, many of which were less expensive and superior in various ways to the natural materials.

4. Answer the questions.

1.What does the life depend on?

2.Why does life depend upon organic compounds?

3.What is the list of materials needed for life?

4.What do organic polymers include?

5.What have modern methods of physical and chemical analyses uncovered?

6.What products appeared on the basis of the discovery of polymers?

7.What properties do synthetic polymers possess?

8.Did people use natural polymers in ancient times?

9.What were those polymers?

10.When did the scientists begin thorough investigation of natural organic polymers?

11.What have they found out about polymers?

12.What are the molecules of polymers composed of?

5. Complete the following sentences using some active words and word combinations (see below ).

1.Life depends fundamentally on …

2.Nearly all materials needs of man could be supplied by …

3.One could list the principal products as fibres, synthetic rubbers, coatings, adhesives and a lot of materials called …

4. ... now available already possess several of the properties required in a structural material.

5.Synthetic polymers have long-lived … and … to high temperatures.

6.Having used some powerful physical instruments, …… , the scientists could have revealed the polymers in all their intricacy.

7.The name “polymer“ came from … poly (many) and meros (a part).

8.Many polymers have the form of …

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plastics; durability; long, flexible chains; organic polymers; resistance; synthetic polymers; the Greek word; an electron microscope; viscosimeter; X-ray diffraction apparatus; natural organic products.

6. Retell the text using the scheme (see Un.1).

Text B

1. Match the English words and word combinations in A with their Russian equivalents in B.

A

1. fibre

2. synthetic polymers

3. thermosetting plastics

4. branch

5. chemicals

6. molecule

7. to synthesize

8. resin

9. cellulose

10. chain

2. Read the text trying to understand its main idea.

PLASTICS

Plastics are non-metallic, synthetic, carbon-based materials. They can be moulded, shaped, or extruded into flexible sheets, films, or fibres. Plastics are synthetic polymers. Polymers consist of longchain molecules made of large numbers of identical small molecules (monomers). The chemical nature of a plastic is defined by the monomer (repeating unit) that makes up the chain of the polymer. Polyethene is a polyolefin; its monomer unit is ethene (formerly called

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ethylene). Other categories are acrylics (such as polymethylmethacrylate), styrenes (such as polystyrene), vinys (such as polyvinyl chloride (PVC), polyesters, polyurethanes, polyamides (such as nylons), polyethers, acetals, phenolics, cellulosic, and amino resins. The molecules can be either natural — like cellulose, wax, and natural rubber — or synthetic — in polyethene and nylon. In copolymers, more than one monomer is used.

The giant molecules of which polymers consist may be linear, branched, or cross-linked, depending on the plastic. Linear and branched molecules are thermoplastic (soften when heated), whereas cross-linked molecules are thermosetting (harden when heated).

Most plastics are synthesized from organic chemicals or from natural gas or coal. Plastics are light-weight compared to metals and are good electrical insulators. The best insulators now are epoxy resins and teflon. Teflon or polytetrafluoroethene (PTFE) was first made in 1938 and was produced commercially in 1950.

Plastics can be classified into several broad types. Thermoplastics soften on heating, then harden again when

cooled. Thermoplastic molecules are also coiled and because of this they are flexible and easily stretched.

Typical example of thermoplastics is polystyrene. Polystyrene resins are characterized by high resistance to chemical and mechanical stresses at low temperatures and by very low absorption of water. These properties make the polystyrenes especially suitable for radiofrequency insulation and for parts used at low temperatures in refrigerators and in airplanes. PET (polyethene terephthalate) is a transparent thermoplastic used for soft-drinks bottles. Thermoplastics are also viscoelastic, that is, they flow (creep) under stress. Examples are polythene, polystyrene and PVC.

Thermosetting plastics (thermosets) do not soften when heated, and with strong heating they decompose. In most thermosets final cross-linking, which fixes the molecules, takes place after the plastic has already been formed. Thermosetting plastics have a higher density than thermoplastics. They are less flexible, more difficult to stretch, and are less subjected to creep. Examples of thermosetting plastics include urea-formaldehyde or polyurethane and epoxy resins, most polyesters, and phenolic polymers such as phenol-formaldehyde resin.

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Elastomers are similar to thermoplastics but have sufficient cross-linking between molecules to prevent stretching and creep.

3.Divide the text into some logical parts and entitle them.

4.Translate the following sentences into English using lexical material of the text.

1.Длинные цепи молекул полимеров состоят из одинаковых небольших молекул мономеров.

2.Сополимеры состоят из двух и более мономеров.

5. Малый вес пластмасс и хорошие электроизоляционные свойства позволяют использовать их в радиоэлектронике и

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