VI. Answer the questions:

1. When have petroleum and natural gas been known to man?

2. When did the production of petroleum and natural gas begin?

3. How was petroleum extracted?

4. What was petroleum used in early times for?

5. When did the history of using petroleum as fuel begin?

VII. Speak on:

1. The extraction of petroleum in early times.

2. The use of petroleum.

VIII. Find the predicates and translate the sentences into Russian:

1. Petroleum and natural gas were known long before our era.

2. The production of petroleum and natural gas on an industrial scale was started only last century.

3. At first men used petroleum as fuel for heating their dwellings.

4. Petroleum was used for illumination several centuries B.C.

5. Long ago petroleum was extracted by primitive methods.

6. Gas can be found escaping from the rocks.

7. Asphalt was also used as fuel.

8. This phenomenon was mentioned in ancient writings.

Lesson Three petroleum

I. Words and expressions to be remembered :

1. petroleum – нефть

2. raw material – сырье, сырьевой материал (нефть-сырец)

3. hydrocarbons [´haidrou´kɑ:bǝnz] – углеводороды

4. sample – образец, проба

5. to prove – доказывать

6. to consist of – состоять из

7. to contain – содержать

8. to depend on – зависеть

9. composition – состав

10. to fall into – делиться на

11. colour – цвет

12. odour [´oudǝ] – запах

13. agreeable [ǝg´riǝbl] and disagreeable odour – приятный и неприятный запах

14. specific gravity – удельный вес

15. value – ценность

16. valuable – ценный

17. viscosity – вязкость

18. measure – мера

19. impurity – примесь

20. rock – горная порода

21. compound – соединение

22. hydrogen [´haidridʒǝn] – водород

23. oxygen [´oksidʒǝn] – кислород

24. uniform – однородный

25. the boiling point – точка кипения

26. volatile – летучий

27. nitrogen [´naitrǝdʒǝn] – азот

28. naphthenes [´næfѲi:nz] – нафтены, циклопарафины

29. paraffin(e) [´pærəfin] – парафин; керосин

30. paraffin(e) hydrocarbon – парафин, предельный углеводород, углеводород парафинового ряда

31. unsaturated - ненасыщенный

II. Read and translate the text: Petroleum

Petroleum is a valuable raw material. It is a mixture of hydrocarbons. Analyses of petroleum proved that it consists of carbon and hydrogen. There are also other compounds which contain oxygen, nitrogen and inorganic matter. The physical and chemical properties of different samples of petroleum are not uniform. These depend on the composition of oil and presence of impurities.

Petroleum contains gaseous, liquid and solid hydrocarbons of different composition and properties. Thesе gaseous, solid and liquid hydrocarbons fall into three main classes: the paraffines, naphthenes and aromatic hydrocarbons.

The colour of petroleum varies considerably. Some oils may be almost colourless, others – light yellow, red, green, brown or black.

The odour of crude oil is also determined by its composition. The paraffines and naphthenes give agreeable odours whereas unsaturated hydrocarbons containing nitrogen compounds and sulphur cause the disagreeable odours.

The specific gravity of crude oil is an index of its value. The lighter oils have greater value because they contain larger quantities of gasoline and other valuable products.

The boiling point depends on the presence of hydrocarbons of low and high boiling points. The more volatile hydrocarbons are in the crude oil, the lower the boiling point.

Natural hydrocarbons are widely used as fuel for domestic and industrial needs. They also serve as a raw material in the petrochemical industry.