Part 2

Exercise 1. Read and translate the text. Make the summary.

Aluminium

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Aluminum is a silvery-white lustrous metallic element belonging to the group 3 (formerly IIIB) of the periodic table; a.n.is 13; r.a.m. is 26.98; r.d. is 2.7; m.p. is 660°C; b.p. is 2467°C. The metal itself is highly reactive but is protected by a thin transparent layer of the oxide, which is formed quickly in air. Aluminium and its oxide are amphoteric. The metal is extracted from purified bauxite (A1₂O₃) by electrolysis. The main process uses a Hall-Heroult cell but other electrolytic methods are under development, including conversion of bauxite with chlorine and electrolysis of the molten chloride. Pure aluminium is soft and ductile but its strength can be increased by work-hardening. A large number of alloys are manufactured. Alloying elements include copper, manganese, silicon, zinc and magnesium. Its lightness, strength (when alloyed), corrosion resistance and electrical conductivity make it suitable for a variety of uses, including vehicle and aircraft construction, building (window and door frames) and overhead power cables. Although it is the third most abundant element in the Earth's crust (8.1% by weight) it was not isolated until 1825 by H. С. Oersted.

Aluminium chloride is a whitish solid, A1C1₃, which fumes in moist air and reacts violently with water (to give hydrogen chloride). It is known as the anhydrous salt (hexagonal; r. d. is 2.44 (fused solid); m. p. is 190°C (2.5 atm.); it sublimes at 178°C) or the hexahydrate A1C1₃.6H₂O (rhombic; r. d. is 2.398; it loses water at 100°C), both of which are deliquescent. Aluminium chloride may be prepared by passing hydrogen chloride or chlorine over hot aluminium or by passing chlorine over heated aluminium oxide and carbon. The chloride ion is polarized by the small positive aluminium ion and the bonding in the solid is intermediate between covalent and ionic. In the liquid and vapour phases dimer molecules exist, A1₂C1₆, in which there are chlorine bridges that make coordinate bonds to aluminium atom. The A1C1₃ molecule can also form compounds with other molecules that donate pairs of electrons (e.g. amines or hydrogen sulphide); i.e. it acts as a Lewis acid. Aluminium chloride is used commercially as a catalyst in the cracking of oils. It is also used as a catalyst in certain organic reactions, especially in the Friedel-Crafts reaction

Vocabulary

lustrous - блестящий

transparent - прозрачный

bauxite - боксит

to purify - очищать

pure - чистый

molten - расплавленный

ductile - плавкий , ковкий

manganese - марганец

zinc- цинк

lightness - легкость

abundant - распространенный

liquid - жидкость

corrosion resistance - коррозионная стойкость

work-hardening - механическое упрочнение

deliquescent - растворяющийся

aircraft - самолет

vehicle - транспортное средство

to sublime - сублимироваться

to donate - передавать

cracking - крекинг

oil - масло

overhead power cable - воздушный силовой кабель

Exercise 2. Answer the following questions.

1. How is aluminium extracted?

2. W

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   hat are the properties of aluminium?

3. Why is aluminium suitable for variety of uses?

4. How is aluminium chloride prepared?

5. Where is aluminium chloride used?

Exercise 3. Put questions to the bold-typed words.

1. Aluminium chloride is a whitish solid.

2. Alloying element is copper.

3. Strength of any metal can be increased by work-hardening.

4. Aluminium chloride sublimes at 178^o C.

5. Copper oxide is prepared by electrolysis.

6. Aluminium chloride is soluble in water.

7. In the liquid and vapour phases dimer molecules exist.

8. The A1C1₃ molecule can also form compounds.

9. Aluminium chloride is used commercially as a catalyst.

10. Aluminium chloride is also used in certain organic reactions.

11. Pure aluminum is soft and ductile.

12. The metal is protected by a thin transparent layer of the oxide.

Exercise 4. Give the equivalents for the following words and make up sentences with them: copper, zinc, manganese, electrolysis, to exist, to sublime, vehicle, aircraft, work-hardening, corrosion resistance, liquid, to extract, deliquescent, abundant, to increase, conversion, silicon, magnesium.

Exercise 5. Match the following words with the correct definition.

1. Acid rain is a) a chemical used for killing insects.

2. Corrosive substance is b) a material that produces heat when

3. Flammable means it burns.

4. Chlorine is c) a poisonous greenish-yellow gas.

5. Fuel is It has strong smell. It is a non-metal

element.

6. Pesticide is d) a substance that can damage through

chemical action, e.g. stone or metal.

e) fire-catching and easily - burning.

f) rain that contains factory gases that

damage crops and buildings.

7. Citric acid is g)an acid contained in orange or lemon juice.

8. Oxide is h) a chemical element found in rocks and sand.

9. Silicon is i) a compound of oxygen and another chemical

element.

Exercise 6. Give the explanation for the following words: corrosion resistance, electrical conductivity, bauxite, zinc, silicon, liquid.

Exercise 7. Find and correct the mistakes in the text based on the text from Ex.1:

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