3 Part One. The Predicate

Oxygen: History and Occurrence
Credit for the discovery of oxygen is shared by two men, Joseph Priestley, an English clergyman and amateur scientist, who later moved to the United States to escape religious persecution, and Carl Wilhelm Schccle, a Swedish pharmacist. Working independently, these two men both obtained the gas which We know as oxygen by heating various compounds of the element, particularly mercuric oxide. They also found evidence that this gas is a component of the atmosphere. Priestley’s work was published in

1774, but although Schcclc’s experiments had probably been performed even earlier, their publication was delayed and no account of them appeared until 1777. Though Priestley recognized that the gas which he had discovered plays an important role in combustion, he remained, along with

Scheele, an ardent adherent of the phlogiston theory of combustion; in fact, he called the gas “dephlogisticated air”.

On the basis of the experimental results of Priestley, Schcelc, and others, as well as some very fine experimental work of his own, in 1777 the brilliant French chemist Lavoisier established the modem concept that the combustion of a substance consists in its combination with the new gas which Priestley and Scheele had described, and which Lavoisier found an important constituent of the atmosphere. Since the combustion of many substances (now known as non-metals) such as phosphorus and sulphur yields products which react with water and give acidic solutions, Lavoisier named this gas oxygen, derived from Greek words meaning “acid former”.

Oxygen occurs in the free state as the second most abundant component of the atmosphere; about one-fifth of the air by volume is oxygen. In the combined state it makes up 88.81% by weight of pure water, and, on the average, 85.79% of sea water. It occurs in the earth’s crust, in the form of a multitude of compounds, to the estimated extent of 46.43%.
Words and Word-Combinations to Be Memorized

abundant, account, acid, air, although, appear, atmosphere, on the average, combination, combustion, component, concept, consist in, constituent, earth, escapc, establish, estimate, even, evidence, fine, free, heat, make up, metal, obtain, occurrence, oxide, oxygen, own, particularly, perform, play a role, probably, product, publication, publish, pure, react, since, solution, though, until, very, as well as, yield

Ex. 6. Give the Uzbek equivalents for the following:

move to, escape smth., obtain, by heating, particularly, find evidence, be a component of smth., although, perform an experiment, even earlier, appear, until, though, along with, in fact, on the basis of, as well as, very fine experimental work, modem concept, work of one’s own, consist in smth., Since, such as, yield products, an acidic solution, the second most abundant component, about one-fifth by volume, in the combined state, on the average

Ex. 7. Give the English equivalents for the following:

turli aralashmalar, isitish orqali, xususan, dalillarni topib, atmosferaning ajralmas qismi bo'lsa-da, asar nashr qilish, e'tirof etish, muhim rol o'ynash bilan bir qatorda, nozik ish, zamonaviy kontseptsiya asosida, bo'lishi kerak, chunki, metall bo'lmagan, Mahsulotlar bering, erkin reaktsiyaga kirishing, atmosferada, taxminan 90% og'irlikda, toza suvda, o'rtacha dengiz suvidan foydalaning

Ex. 8. Fill in the blanks with prepositions and conjunctions where necessary. o f by, in, about, as well as, and, on
1. Scheele ... Priestley obtained ... oxygen ... heating various compounds ... the element. 2. Priestley recognized that the gas obtained ... him plays an important role ... combustion. 3. Priestley ... Scheele remained adherent... the phlogiston theory... combustion. 4___ the basis ... the experimental results ... the earlier workers Lavoisier established his own concept... combustion. 5. The combustion... a substance consists ... its combination with oxygen. 6. Oxygen occurs ... the free state ... the atmosphere. 7. … one-fifth ... the a ir... volume is oxygen.
Ex. 9. Practise the fractional numerals.


Ex. 10. Translate into Uzbek.

a) will be discussed, was being studied, will have been taken, are named, had been discovered, will be obtained, have been written, were being translated, shall have done, are used, is being done, will be produced, was asked, are taught, will be given

b) 1. Oxygen was obtained by Scheele and Priestley independently.2. Oxygen was obtained by heating mcrcuric oxide. 3. Evidence was found that this gas is a component of the atmosphere. 4. The theory of

phlogiston is not much spoken about at present. 5. An important role of oxygen in combustion was discovered by Priestley. 6. The gas obtained was called by him “dephlogisticatcd air”. 7. The modem concept of combustion was established by Lavoisier. 8. Substances such as phosphorus and sulphur are known as non-metals. 9. The name “oxygen” was derived from Greek words meaning “acid former”. 10. Oxygen is found in the free state in the atmosphere. 11. When a substance is attacked by oxygen, it forms an oxide or a number of oxides. 12. Not unfrcqucntly the elements helium, neon, argon, krypton and xenon are referred to as noble gases. 13. Gold is unafTcetcd by oxygen. 14. Many kinds of oxides are met with in the study of chemistry. 1 S. By Dalton’s atomic theory atoms were looked at as indivisible constituents of substances. 16. Potassium is quickly aetcd on by the oxygen of the air. 17. Oxygen is constantly being put back to the atmosphere by trees and other plants. 18. This method has been followed

Since the time of Priestley. 19. The lccturc was followed by the demonstration of experiments. 20. The first succcss was followed by many others. 21. The yield of the reaction is greatly affeetcd by temperature. 22. Attention was drawn to the valence of substances. 23. Attempts were made to obtain pure oxygen. 24. Much attention has been given recently to the study of this group of oxides.
Ex. 11. Translate the sentences into English.

1. Zamonaviy yonish kontseptsiyasi Lavuaze tomonidan 1777 yilda yaratilgan. 2. Ushbu gaz "kislota hosil qiluvchi agent" deb nomlangan. 3. Kislorod yer qobig'ida aralashmalar shaklida topilgan. 4. Kislorod ushbu elementning turli birikmalarini, xususan, simob oksidini qizdirish orqali olingan. 5. Pristli asari 1774 yilda nashr etilgan. 6. Kislorod XVII-asrning ikkinchi yarmida topilgan va tasvirlangan. 7. Kaliy kabi moddalar juda faol metallar deb nomlanadi. 8. Kislorod har qanday haroratda oltinga ta'sir qilmaydi.

Ex. 12. Make up questions to the italicized parts of the sentences.

1. Priestley lived and worked in England and then in the United States (3). 2. Oxygen was obtained by heating various compounds of this clement (3). 3. The word “oxygen" derived from Greek means “acidformer” (2).

Ex. 13. Answer the following questions:

1. What famous scientists worked on the discovery of oxygen? 2. Who was the first to obtain this gas? 3. What was the method of obtaining oxygen? 4. What theory of combustion existed in Priestley’s time? 5. What did the French chemist Lavoisier establish? 6 . What does the modem concept of combustion state? 7. What does the word “oxygen” mean? 8. Where does oxygen occur and in what state?