Inexhaustibility of the Electron

The inexhaustibility¹ of the electron is well known. The breakdown of the concept of the indivisible, immutable atom gave rise to two fundamentally different stands². First the attempt to apply to the newly discovered electrons all the properties previously ascribed to atoms, the belief that electrons (and not atoms) are the fundamental or “ultimate” particles of matter, a knowledge of which exhausts³ the knowledge of all matter and of the world.

The second stand was a diametrically opposite one: the discovery of the electron, which revealed the complex character of the structure of the atom, its “inexhaustibility” proved that the old concepts of the structure of matter were wrong not only with regard to atoms, but they were basically false.

Примечания к тексту

1. inexhaustibility – неисчерпаемость

2. stand – точка зрения

3. exhaust – исчерпывать

X.Расскажите о двух точках зрения на «неисчерпаемость» электрона, пользуясь приведенными ниже словами:

inexhaustibility, stand, electron, particle, fundamental, the first, the second, the structure, complex, atom, nature, according to, infinite

LESSON 9

Грамматика. Объектный инфинитивный оборот.

Предтекстовые упражнения

I.Переведите следующие предложения на русский язык:

1. Experiments proved carbon to occur in many compounds. 2. We know carbon to occur in two crystalline forms. 3. We expect the results obtained to correspond with the formula indicated. 4. We saw the temperature of the solution fall rapidly. 5. The results of this experiment have shown the above compound to contain some unknown element. 6. M. Curie found the element radium to resemble barium in some respects. 7. We know the discovery of radium to have been made by M. Curie in 1910. 8. Scientists assume the production of the rays from uranium compounds to represent a natural process.

II.Переведите следующие предложения, обращая внимание на выделенные слова:

at least – по крайней мере

Arsenic occurs in at least three allotropic forms.

because – потому что, так как

because of –вследствие, благодаря

1. Argon, helium, neon, krypton and xenon are called the inert gases because they are chemically inactive. 2. Phosphorus is never found free in nature because of the ease with which it reacts with oxygen.

III.Прочитайте и переведите следующие слова без словаря:

chlorine ['klɔːriːn], tendency ['tendənsɪ], litre ['lItə], argon ['ɑːgn], helium ['hiːlɪəm], neon ['niːən], product ['prdəkt], catalyst ['kæt(ə)lɪst], methane ['miːθeɪn], mixture ['mɪksʧə], characteristic [ˌkærəktə'rɪstɪk], krypton ['krɪptn], characterize ['kærəktəraɪz], xenon ['ziːnn]

IV.Запомните чтение следующих слов:

weight [weɪt], somewhat ['sʌmwt], violently ['vaɪəl(ə)ntlɪ], certain ['sɜːt(ə)n]

Text 9 A

Chlorine

Because of its pronounced activity as a non-metal and its consequent tendency to combine with metals, chlorine is never found naturally in a free state. In the combined state, however, it is assumed to be one of the moderately abundant elements of the earth's crust. Chemists consider its most abundant natural compounds to be the chlorides of certain metals. Of these, sodium chloride is estimated to be by far¹the most abundant.

Experiments showed chlorine to be only slightly soluble in water. Its density is stated to be almost two and one-half times² that of the air, a litre under normal conditions weighing about 3,2140 grams.

We know chlorine to be a typical non-metal. As such it resembles oxygen in some respects, but differs in showing more pronounced activity in its reactions with the metallic elements. Oxygen, on the other hand, is found to display a somewhat greater tendency to react with the non-metals.

Absolutely dry chlorine does not seem to attack metals; at least the reaction is extremely slow. Experiments prove chlorine to react with almost all of the non-metals. The reaction of hydrogen and chlorine is exothermic.

H₂ + Cl₂ = 2 HCl + 44000 cal.

We should expect, therefore, these two elements to combine very readily and the product to be very stable. In the dark, however, hydrogen does not appear to combine with chlorine with appreciable velocity and the reaction seems to require the presence of a catalyst. In ordinary light the reaction is likely to take place slowly. But if the mixture were exposed to direct sunlight we could see the reaction occur violently.

Since chlorine combines very readily with free hydrogen, we should expect it also to react with compounds containing hydrogen. This is really the case. Natural gas, for instance, which is known to consist largely of methane (CH₄) continues to burn when a lighted jet of the gas is introduced into a cylinder filled with chlorine, hydrogen chloride and free carbon being produced. In bright sunlight a mixture of methane and chlorine reacts more slowly, and the reaction occurs in steps³in which chlorine both combines with and replaces hydrogen.

With certain compounds, chlorine is stated to combine directly to form what are called addition compounds. Besides, chlorine may also be shown to react with compounds with certain chlorides in much the same manner as oxygen reacts with certain oxides. These reactions show chlorine to play its most characteristic role, that of a vigorous oxidizing agent.

Примечания к тексту

1. by far –значительно

2. two and one-half times– в два с половиной раза больше

3. in steps – по этапам, ступенчато

Запомните следующие слова:

at least, appreciable, as such, be likely, burn, by far, certain, consequent, fill, free, for instance, in some respects, in steps, never, non-metal, pronounced, seem, stable, vigorous, violently

Упражнения

I.Переведите следующие предложения на русский язык:

1. Experiments show chlorine to be a bleaching agent. 2. Microscopic determination of silicon shows it to be made up of tiny crystals and fragments of crystals. 3. M. Curie found the atomic weight of radium to be 226. 4. The experiments proved free chlorine to be present in the vapour of chromic chloride at 355°. 5. If we put gold into a beaker with aqua regia we see the metal gradually disappear. 6. We know two atoms of hydrogen to unite with one atom of oxygen when hydrogen burns. 7. The microscope reveals milk to consist of droplets of butter fat dispersed in water fluid. 8. While dissolving calcium chloride in water we saw the temperature fall rapidly. 9. Diffusion shows molecules of any substance to be in motion. 10. Lomonosov’s experiments showed the green colouration of glass to be due to the presence of chromium. 11. M. Curie found natural pitchblende, namely U₃O_8, to be several times more active than purified uranium oxide. 12. We know Joseph Priestly to have discovered oxygen by trying the effect of heat on many substances. 13. Phosphorus pentoxide appears to exist in a number of forms, one of which subliming at about 350°. 14. The hydrogen atom is believed to have one proton as its nucleus, with one electron circling around it. 15. Complex sulphites of silver do not seem to have been isolated though they occur in solutions.

II.Переведите данные в скобках слова или группы слов на английский язык, затем переведите предложения на русский язык:

1. (Из-за) its inactivity this substance does not react with oxygen, (если его не подогреть). 2. (Так как) white phosphorus is poisonous, it must be kept under water. 3. Ground water contains (множество) impurities, (следовательно) it is not pure. 4. (Согласно) this reaction much heat and light is liberated when the substances combine. 5. Silicon resembles carbon in having crystalline, (так же, как) amorphous form. 6. (Что касается) its chemical behaviour oxygen is very reactive. 7. (Кроме того) we know chlorine to be a bleaching agent. 8. Absolutely dry chlorine, (однако), does not seem to attack metals.

III.Найдите в тексте эквиваленты следующих выражений:

в связанном состоянии; как таковой; с другой стороны; действительно; так и есть; почти таким же способом; в свободном состоянии

IV.Переведите следующие предложения, обращая внимание на выделенные слова:

1. There are believed to exist at least two modifications of sulphur. 2. A piece of granite which consists of a mixture of at least four constituents is heterogeneous. 3. Because carbon monoxide is odourless, the presence of this gas is not easily detected. 4. Hydrogen diffuses more rapidly than any other gas because of its very small density.

V.Ответьте на следующие вопросы:

1. Why is chlorine never found in a free state? 2. What ate the most abundant natural compounds of chlorine? 3. What are the properties of chlorine? 4. In what respects does chlorine differ from oxygen? 5. What elements does chlorine react with? 6. What kind of agent is chlorine? 7. What would happen to a mixture of methane and chlorine in the bright sunlight?

VI.Охарактеризуйте приведенные ниже высказывания, относящиеся к тексту, следующим образом: «правильно», «неправильно», «нет в тексте».

1. Chlorine is found in a free state in nature. 2. Chlorine is a typical non-metal. 3. Chlorine exists in two isotope forms. 4. Chlorine reacts with compounds containing hydrogen. 5. Absolutely dry chlorine attacks metals readily. 6. The solution of chlorine in water has the same colour as the gas.

VII. Прочитайте текст 9 B, не пользуясь словарем:

Текст 9 B