Practice

a) Translate the following sentences paying attention to Participle I.

1. This reaction involves the following temperature changes.

2. We have analyzed the following compounds.

3. The remaining admixtures were separated from the end product.

4. Judging by the results, the pressure has fallen.

5. These moving parts are electrically powered.

6. Considering the limited scope of the method it has been used by two researchers.

7. The yield was 12% of the dried wood, varying with the amount of hydrochloric acid.

8. This concerns the following problem.

9. Judging by the recent works one can say that some amount of ketal is present in diethyl.

10. The dialyzed solution was evaporated to dryness and the residue was dried at

50 ^o C, giving nondeliquescent brown powder.

11. One should bear in mind that this information can be misleading.

12. Having determined all parameters we started our experiment.

13. The research being carried out by our Institute in this field is of a great importance.

14. We have obtained these values in the terms of the following formula.

15. Z is favoured by the following data.

16. What is the number of the scientists partaking in the conference ?

17. Having filtered the solution we defined its colour.

18. Having regarded to the summation convention we identified four different products.

19. If the attacking radical had a greater affinity for hydrogen, then the hydrogen-abstraction process would be favoured.

20. Having considered his article we decided to renew our research.

21. The process leading to nitrosation may consist o f a few steps.

22. Last year our researchers obtained remarkable results.

b) Put the following verbs in Participle I: to follow, to plan, to buy, to give, to get, to receive, to write, to do, to make, to recognize, to invent, to see, to reproduce, to measure.

c) Answer the following:

1. How is Perfect Participle formed ?

2. How is Participle I translated ?

Part 2

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

Cobalt

Cobalt is a light-grey transition element; a.n. is 27; r.a.m. is 58.933; r.d. is 8.9; m.p. is 1495°C; b.p.is 2870°C. Cobalt is a ferromagnetic metal. Its Curie point is below 1150°C. Small amounts of metallic cobalt are present in meteorites but it is usually extracted from the ore deposits worked in Canada, Morocco and Zaire. It is present in the minerals: cobaltite, smaltite, but also associated with copper and nickel as sulphides and arsenides. Cobalt ores are usually roasted to the oxide and then reduced with carbon or water gas. Cobalt is usually alloyed for use. Alnico is a well-known magnetic alloy and cobalt is also used to make stainless steels and in high-strength alloys that are resistant to oxidation at high temperatures (for turbine blades and cutting tools).The metal is oxidized by hot air and also reacts with carbon, phosphorus, sulphur and dilute mineral acids. Cobalt salts, usual oxidation states ( +2) and (+ 3), are used to give a brilliant blue colour in glass, tiles and pottery.

Anhydrous cobalt (II) chloride paper is used as a qualitative test for water and as a heat-sensitive ink. Small amounts of cobalt salts are essential in a balanced diet for mammals. Artificially produced cobalt-60 is an important radioactive tracer and cancer-treatment agent. The element was discovered by Georg Brandt (1694-1768) in 1737. Cobalt (II) oxide is a pink solid, CoO; its shape is cubic; r.d.is 6.45; m.p. is 1935°C. The addition of potassium hydroxide to the solution of cobalt (II) nitrate gives a bluish-violet precipitate, which on boiling is converted to pink impure cobalt(II) hydroxide. On heating this in the absence of air, cobalt (II) oxide is formed. The compound is readily oxidized in air to form tricobalt tetroxide and is readily reduced by hydrogen to the metal.

Cobalt (III)is a black grey insoluble solid; its shape is hexagonal or rhombic, r. d. is 5.18; it decomposes at 895°C. It is produced by the ignition of cobalt nitrate; however, the product doesn’t have the composition corresponding to cobalt (III) oxide. On heating it readily forms Co₃O₄ which contains both Co (II) and Co (III) and is easily reduced to the metal by hydrogen. Cobalt (III) oxide dissolves in strong acid to give unstable brown solutions of trivalent cobalt salts. Cobalt steelis any of a group of alloy steels containing 5-12% of cobalt, 14-20% of tungsten, usually with 4% of chromium and 1-2% of vanadium. They are very hard but somewhat brittle. Their main use is in high-speed tools.

<== попередня сторінка	\|	наступна сторінка ==>
Oxygen and ozone	\|	Exercise 8.

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