anglysky_metodichka_2_semestr

T E X T

AMMONIA

Nitrogen forms several compounds with hydrogen, the most important of which is ammonia, a colourless gas with a characteristic pungent odour, well known to everyone as the odour of ammonia spirit.

Traces of ammonia occur in the atmosphere: bottles containing hydrochloric acid become coated after a time with ammonium chloride. Ammonium chloride NH4Cl, and sulphate (NH4)2SO4 occur in volcanic districts. Small quantities of ammonium salts occur in plants and animals, in the soil as well as in natural waters.

We may prepare ammonia in the laboratory while heating a mixture of ammonium chloride NH4Cl and slaked lime Ca(OH)2.

Ammonia is very soluble in water: one volume of water at ordinary temperature dissolves 700 volumes of ammonia. A concentrated solution containing 25 per cent NH3 has a specific gravity of 0.91. A solution of ammonia in water is sometimes called ammonia spirit.

Ammonia and ammonium salts are widely used in practice and can easily be liquefied. Liquid ammonia has wide application in refrigeration engineering for cooling store houses and for the preparation of artificial ice.

Aqueous ammonium solutions when used in chemical laboratories as a weak volatile base find application also in medicine and in the home. But most of the ammonia produced commercially at present is employed for the preparation of nitric acid and artificial nitrogenous fertilizers.

E X E R C I S E S

I. POINT OUT THE PARTICIPLES, STATE THEIR FUNCTIONS AND TRANSLATE THE SENTENCES INTO RUSSIAN:

1. The smell of iodine is not so obtrusive since it is solid at ordinary temperatures; it too has a faint smell recalling that of chloride. 2. A piece of metallic sodium added to the liquid dissolves, with evolution of hydrogen. 3. Add 3 ml of hydrochloric acid while carrying out the test. 4. When artificially cooled down to 0 °C, the acid gradually deposits crystals, consisting of 3 molecules of anhydrous sulphuric acid and 1 molecule of water. 5. Lime is a white substance (calcium oxide) obtained by burning limestone and is used when making cement and mortar and on field and gardens to improve the soil. 6. The technique worked out at this plant is based on making synthetic crystals growing in alkaline solution under high pressure. 7. Chloride is a compound of chlorine, as chloride

of lime used for bleaching and as on disinfection.

II. DEFINE WHAT PART OF SPEECH THE UNDERLINED WORD IS AND TRANSLATE THE SENTENCES INTO RUSSIAN:

1. Nitrogen forms several compounds with hydrogen, the most important of which is ammonia. 2. There are other forms of sulphuric acid, one of which is known under the name of fumic acid. 3. Pure sulphuric acid is the only liquid without odour at common temperature and of a very acid taste. 4. We may prepare ammonia in the laboratory. 5. In their laboratory work students used test tubes, graduated glasses and other equipment. 6. Pills are sometimes coated with sugar. 7. When we looked into the bottle with hydrochloric acid we saw a specific coat of ammonium chloride there (in it).

III. FORM NOUNS FROM THE FOLLOWING VERBS:

to trace, to liquefy, to employ, to coat, to fertilize, to portion, to distillate, to level, to inhale, to practice, to deliver, to find, to base.

IV. UNDERLINE THE SUFFIXES IN THE FOLLOWING WORDS AND STATE WHAT PART OF SPEECH THE WORD BELONGS TO:

colourless, refrigeration, commercially, fractional, application, fertilizer, distillation, chloride, nitrogenous, slaked, inhalation, soluble, artificial, obtrusive, odourless, ammonium, liquefy, practical.

V. GIVE ANTONYMS OF THE FOLLOWING WORDS:

important, liquid, soluble, volatile, heating, small, easily, strong, liquefy, practice, artificial.

VI. ARRANGE THE FOLLOWING WORDS IN PAIRS OF SYNONYMS:

firing, mostly, portion, some, pungent, disease, cover, altitude, aqueous, base, chiefly, part, several, sharp, illness, foundation, alcohol, but, height, water, coat, spirit, except, fuel.

VII. TRANSLATE THE FOLLOWING SENTENCES INTO ENGLISH:

1. Азот образует несколько соединений с водородом, самым основным из которых является аммиак. 2. Аммиак можно получить в лаборатории при нагревании смеси хлористого аммония и извести. 3. Раствор аммиака в воде называют иногда аммиачным спиртом. 4. Небольшое количество аммиачных солей встречается в растениях, у животных, в почве и естественных водах.

VIII. ANSWER THE FOLLOWING QUESTIONS:

1. What is the most important compound in nitrogen? 2. Do bottles containing hydrochloric acid become coated after a time with ammonium chloride? 3. How can we prepare ammonia in the laboratory? 4. Ammonia is very soluble in water, isn't it? 5. Where is ammonia produced commercially employed at present?

IX. TRANSLATE WITH A DICTIONARY:

ATOMS AND MOLECULES

All matter, be it an element, a compound or a mixture, is made of a comparatively small number of elementary substances. As a matter of convenience, the elements are designated by symbols, which are usually the first letters or letters of their names. Thus, H stands for Hydrogen, O – for Oxygen; N – for Nitrogen, and so on. We designate a compound combining the symbols of its elements. Thus, water expressed by the symbol H2O, the "2" indicates that 2 atoms of Hydrogen have combined with one atom of Oxygen.

The smallest quantity of an element or of a compound that is capable of separate existence is a molecule.

X. TRANSLATE WITHOUT A DICTIONARY:

Oxygen may be prepared by the fractional distillation of liquid air or by the electrolysis of water. If prepared by the first method the gas will contain a small portion of argon and a trace of nitrogen; if prepared by the second method it will contain a small

proportion of hydrogen. It is delivered compressed in metal cylinders. Oxygen occurs as a colourless, odourless and tasteless gas. It supports combustion, and gives with fuel heat producing flames.

Oxygen is mostly used for inhalation, principally in lung diseases. The concentration of oxygen for inhalation over long periods must be about 50 % at sea level. It must never be more than 60 % except at high altitudes, when 80 % may be necessary, or when the administration is for short periods only.

L E S S O N 3

(see Model II)

ANALYZE THE FOLLOWING SENTENCES AND TRANSLATE THEM INTO RUSSIAN:

1. The bulk of the rubber produced is used to make tyres for cars and planes, as well as for the production of footwear. 2. Carbon dioxide is readily solidified in liquid air and when passing through liquid air it forms white flakes resembling snow. 3. For the first time in history, a Soviet spacecraft has flown around the Moon and successfully returned to the Earth at a speed of about 11,000 m per second bringing with it a large amount of scientific data. 4. Mendeleyev was the first chemist who showed the elements arranged according to a definite system. 5. The Periodic Law as stated by Mendeleyev is of great importance for science as it allowed to put into one orderly table almost all known chemical elements and enabled him to make several suppositions proved later by experiments. 6. Most people know that the chemical elements constituting the matter of the Universe are made up of particles called atoms and that an atom is the smallest recognizable particle of an element.

T E X T

PHYSICAL PROPERTIES OF AIR

(LIQUID AIR)

Pure air, free from dust, carbon dioxide and water vapour, is almost absolutely colourless and has neither taste, nor odour. One litre of pure air weighs 1.293 gr at 0 °C and 760 mm Hg. At temperatures below – 140 °C and pressure of about 40 atm air condenses into a colourless liquid boiling at about 190 °C.

The production of liquid air presents no extraordinary difficulties at present. There are many machines of various types for this purpose. The operating principle of most of them depends on the considerable temperature drop caused by the expansion of air under pressure (about 0.25 °C for each atmosphere of pressure lost). Thus, if air is compressed at 200 atm and when expanded rapidly to 1 atm, its temperature will go down to 50 °C. This temperature drop is used to preliminarily cool a second batch of compressed air. When the cooled compressed air is expanded it gets still colder. While repeating this operations several times, a temperature can be reached at which the air begins to condense

into a liquid.

The liquid air obtained directly from the machine is usually turbid, due to the presence of suspended particles of carbonic anhydride, ice and other impurities, which can easily be removed when filtering through a paper filter.

In spite of its very low boiling point liquid air can be kept for a considerable length of time in glass vessels with double walls, between which the air has been pumped out. The "void" between the walls effectively prevents the liquid in the vessel from getting warmer, so that it evaporates very slowly.

E X E R C I S E S

I.INSERT THE FORM OF THE PRESENT OR THE PAST PARTICIPLE FROM THE VERBS GIVEN IN BRACKETS; TRANSLATE THE SENTENCES INTO RUSSIAN:

1.Chemistry supplies agriculture with many substances . . . fertilizers, which help to grow fine crops (to include). 2. When the cyclohexane molecule is converted to benzene, it gives up three molecules of hydrogen, . . . three double bonds between carbon atoms (to form). 3. Weigh the fatty acids . . . and calculate their percentage content in the chosen sample of the substance (to obtain). 4. The plastics . . . on phenol-formaldehyde resins are used to make a very wide variety of goods (to base). 5. The gases and vapours . . . through the U-tube are collected in a jar over water (to pass). 6. Alcohol is a colourless mobile liquid . . . characteristic odour (to have).

II.STATE WHAT PART OF SPEECH THE UNDERLINED WORDS BELONG TO AND TRANSLATE THE SENTENCES INTO RUSSIAN:

1. Ethyl alcohol is a colourless liquid and its boiling point is 78 °C. 2. The production of liquid air depends on the considerable temperature drop caused by the expansion of air under pressure. 3. There is no cause for making this experiment once more. 4. Add one or two drops of hydrochloric acid to this solution. 5. When mixed with about 3 or 4 times its weight of water calcium hydroxide forms a smooth magma (milk of lime). 6. Dissolve about 0.3 g of calcium hydroxide accurately weighed in 10 cc of diluted hydrochloric acid. 7. Liquid air can be kept for a long time in glass vessels. 8. Don't use this glass, it will break easily. 9. The liquid air may be turbid due to the presence of suspended particles of carbonic anhydride. 10. After due preparation, he began describing his experiment. 11. Mercurous chloride is easily reduced to metal and this reduction is due to soda, potash or burnt magnesia added in a tube.

III. TRANSLATE THE SENTENCES INTO RUSSIAN PAYING ATTENTION TO THE WORDS OF THE SAME ROOT:

1. The teacher asked us to heat a very small amount of a mixture of alcohol and

concentrated sulphuric acid. 2. We obtain oxygen by heating some metallic oxides such as oxides of mercury, silver, and platinum metals. 3. This element mixes in all proportions with water. 4. No admixtures were seen in the test tube. 5. The solution must have an acid taste. 6. If we add a few drops of alcohol to a solution of potassium dichromate acidified with dilute sulphuric acid, the solution changes. 7. Ethyl alcohol dissolves well in water and is itself a solvent for many substances. 8. This element remains in the solution forming a soluble substance.

IV. TRANSLATE THE FOLLOWING GROUPS OF WORDS INTO RUSSIAN:

1. to weigh, weight 2. to compress, a compress, compressibility, compressible, compression. 3. to cause, a cause. 4. to remove, removal, removed. 5. to prevent, prevention 6. to evaporate, evaporation. 7. to constitute, constituent. 8. to discover, discovery. 9. to vary, various, variety. 10. to dust, dust. 11. to expand, expansion, expansive. 12. to drop, a drop. 13. to purify, pure, impure, impurity. 14. length, to lengthen,. 15. a glass, glass. 16. to mix, mixture, admixture. 17. to condense, condensed, condenser. 18. to freeze, freezing, frozen.

V. FORM NOUNS FROM THE FOLLOWING VERBS:

to weigh, to cause, to compress, to remove, to pump, to prevent, to evaporate, to pass, to immerse, to emit, to constitute, to discover, to vary.

VI. ARRANGE THE FOLLOWING WORDS IN PAIRS OF SYNONYMS AND TRANSLATE THEM INTO RUSSIAN:

alcohol, bulk, below, thus, spirit, a lot of, down, for example, now, to put into, for instance, at present, to immerse, consequently.

VII. ARRANGE THE FOLLOWING WORDS IN PAIRS OF ANTONYMS AND TRANSLATE THEM INTO RUSSIAN:

to pump in, ordinary, single, indirectly, clear up, to pump out, double, directly, turbid, down, extraordinary.

VIII. ANSWER THE FOLLOWING QUESTIONS:

1. How much does one litre of pure air weigh at 0 °C and 760 mm Hg? 2. When does air condense into a colourless liquid boiling at about 190 °C? 3. The production of liquid air presents no extraordinary difficulties at present, doesn't it? 4. What is the operating principle of machines used for the production of liquid air? 5. Why is the liquid air obtained directly from the machine usually turbid?

IX. TRANSLATE WITH A DICTIONARY:

Alcohol, ether and many gases are readily solidified in liquid air. If, for instance, carbon dioxide is passed through liquid air, it forms white flakes resembling snow, while mercury immersed in liquid air turns into solid malleable metal.

When cooled in liquid air, many substances acquire entirely new properties. Zink and tin become so brittle that they can easily be pulverized, a lead bell begins to emit a pure ringing sound, while a frozen rubber ball breaks into small fragments if dropped on the floor.

As the boiling point of oxygen (- 183 °C) is higher than that of nitrogen (- 196 °C), oxygen liquifies more readily than nitrogen. Therefore, the liquid air is much richer in oxygen than atmospheric. While standing liquid air oxygen due to the evaporation of nitrogen.

In our days, liquid air is produced in large quantities to obtain oxygen and nitrogen from it by fractional evaporation.

X. TRANSLATE INTO RUSSIAN WITHOUT A DICTIONARY:

The atmosphere is a mixture of many gaseous substances. Besides the oxygen and nitrogen, constituting its bulk, air contains carbon dioxide, water vapour, and small quantities of the noble or inert gases, discovered in the XIX century. In addition to the gases enumerated, air contains more or less dust and certain chance admixtures. Oxygen, nitrogen and the inert gases are considered the constant constituent parts of air, as their content in air is practically the same everywhere. On the contrary, the content of carbon dioxide, water vapour and dust may vary depending on various conditions.