1. The composition of liquid air.

2. Some physical changes produced by liquid air.

3. Some applications of liquid air.

4. The composition of ordinary air.

5. The proportion of water vapour in the air.

6. Low and high humidity.

Ex. 12. Find the right statement:

1. Liquid air can be manufactured

1. in small quantities at a high cost;

2. in large quantities at a high cost;

3. in small quantities at a comparatively high cost;

4. in large quantities at a comparatively low cost.

2. Liquid air is

1. a mixture of solid gases;

2. a compound;

3. an element;

4. a mixture of the liquefied gases.

Ex. 13. Find the pairs of synonyms and remember them:

to use, to produce, due to, to manufacture, quickly, to employ, rapidly, owing to.

Ex. 14. Find the pairs of antonyms and remember them:

active, to solidify, warm, solid, inactive, the same, cool, to liquefy, different, liquid.

Ex. 15. Choose the Russian equivalents from the right column:

both ... and

nearly

near

as well as in terms of due to both

так же, как

оба

близко

около, приблизительно благодаря как ..., так и на основании, исходя из

Ex. 16. Translate the following sentences paying attention to the words ' in bold type:

1. In terms of the given formula N₄0 we can say that air is a mixture of nitrogen and oxygen. 2. Water is sometimes cloudy due to the presence of some particles. 3. They can hardly solve the problem without you. 4. We know that ice can freeze hard if the temperature is low. .5. The lecture was attended by nearly all the students. 6. If we work hard, we shall certainly finish our work soon. 7. Air conditioning re­quires the regulation of both the temperature and humidity.

8. When the air is not in circulation, the layer near the body becomes nearly saturated. 9. The transition point at which a change takes place is described in terms of temperature and pressure.

Ex. 17. Translate the following sentences, state the function of the words in bold type:

1. Both copper and tin melt at a low temperature. 2. The reaction of acids with metal hydroxides is a completed reac­tion because of the low degree of ionization of water. 3. The only manganic compounds which may be prepared in aqueous solution are those of low solubility. 4. If a highly compressed gas composed of molecules is allowed to expand quickly to low pressure, its molecules overcome the forces of attraction, consequently, the temperature of the gas is lowered. 5. Ceramic products could be characterized by low thermal conductivity.

6. The freezing point lowers in this reaction. 7. The scientist tried to lower the concentration of the absorbed substance in the reaction.

Ex. 18. Find the sentence where the word “change” Is a verb. Translate the following sentences into Russian:

1. This is well known that changes take place in all the substances. 2. Chemical changes are^ usually permanent.

3. The changes that take place during the freezing of a liquid are opposite to those that take place during the melting of the solid. 4. There is little change in the concentration of complex anions so long as the solution is acidic. 5. It has been shown that every chemical change could be accompanied by a definite energy change. 6. The vapour pressure of a liquid is affected by changes in temperature. 7. If you changed the temperature, the reaction would go to completion.

Ex. 19. Open the brackets translating the Russian words into English:

1. (На основании) the kinetic theory, the energy of mole­cules increases with rise in temperature. 2. When he was a student he (бывало) spend a lot of time in the reading-room of this Institute. 3. Oxygen is also (используется) to main­tain air composition for respiration at high altitudes. 4. I shall finish my work (как только) I get good results. 5. They can (едва) finish their research without his help. 6. (Послед­нее время) many new articles dealing with this subject have been published. 7. The heat of combustion of acetylene, (t. e.) the number of calories evolved per mole, is large.

8. The most extensive industrial (использование) of oxygen is in the production of high temperatures in oxygen-gas flames. 9. Ozone decomposes slowly at room temperature but rapidly and (легко) at 250°. 10. The reactions of ozone are of the same variety (как) those of oxygen. 11. This (тер­мин) can be (использован) by us. 12. (Еще) in the 16th century the scientists knew this reaction. 13. (Изменение) in temperature results in the (изменениях) of solubility. 14. The velocity of a reaction is (изменяется) by (изменением) in conditions. 15. The ventilation of a room requires (как) a sufficient supply of fresh air (так и) the circulation of the air. 16. Air conditioning requires the regulation of (как) the temperature (так и) the humidity.

Ex. 20. Analyse the Adverbial Clauses of Condition, translate them into

Russian:

1. If there were no dust, the air would become supersaturat­ed with water. 2. If air is cooled sufficiently, it can be con­verted into a liquid. 3. If the liquid air were allowed to evapo­rate, different components would predominate in the fractions obtained at different temperatures. 4. If the atmosphere con­tinued to be of uniform density, we should find that it is 5 miles deep. 5. Were a quantity of silver chloride placed in a quantity of water, silver and chloride ions would begin to leave the surface. 6. Had water been added to the mixture, more alcohol and acid would have been formed. 7. Had not chemistry made possible the production of fundamental materials, radio and TV would have been unknown.

Ex. 21. Supply the appropriate forms of the verb instead of the Infinitives