Санкт-петербургского государственного университета высшее профессиональное образование т. А. Степанова, И. Ю. Ступина
particles arc no longer considered to be non-existent. 3. Radioactivity is
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1stepanova t a english for chemists
particles arc no longer considered to be non-existent. 3. Radioactivity is known to be affected by the presence of other elements which are not radioactive. 4. Air was later found not to be an element. 5. Hydrogen docs not appear to react quickly with chlorinc in the dark. 6 . Pure liquid HC1 docs not seem to be conductor of electricity. 7. Under certain conditions an atom of hydrogen may be regarded to be acting as a bond. 8 . There appears to be no difficulty in determining the rate of this reaction. 9. There seems to be no evidence in favour of your idea. 10. The phenomenon has never been observed to occur under ordinary conditions. 11. Chlorinc is stated to have been discovered in 1774.12. Solid carbon is usually said to exist in three modifications. 13. Mendeleyev is known to have been bom in Tobolsk. 14. The law of conservation of mass is known to have been definitely stated by the great Russian scientist М. V. Lomonosov in 1756. IS. H 2 S 0 4 docs not appear to have been known to the ancient world. b) 1. The symbol H 2 SO 4 is interpreted as representing one molcculc of sulphuric acid. 2. Acids arc usually thought of as being liquids. 3. According to the atomic theory, a molcculc is considered as being composed o f atoms. 4. The periodic classification should be mentioned as having been the principal discovery of the 19th century. 5. A nucleus is now regarded as being composed of fundamental particles. 6 . All substanccs may be regarded as soluble in water. 7. Atoms arc no longer considered “imaginary”. 8 . The valency of carbon is usually thought of as four. 9. Water is known as composed o f two elements: hydrogen and oxygen. 10. Substanccs arc usually defined as having a definite composition. Ex. 10. Translate the sentences into English. 1 . Джои Дальтон был химиком и физиком. 2. Он жил в Англии с 1766 по 1844 год. 3. Более всего он известен своем атомистической теорией. 4. Дальтон выдвинул свою теорию строения элементов в 180S году. 5. Эта теория была подтверждена дальнейшими исследова ниями. б. Позднее она была развита в соответствии с современными исследованиями. 7. Современная наука располагает точными знания ми о структуре и свойствах атомов и молекул. 8 . Теперь никто больше не может утверждать, что структура и состав атомов неизвестны. 108 1. When was Dalton’s atomic hypothesis put forward? 2. What was the main idea o f this hypothesis? 3. In what way was the hypothesis verified? 4. What docs sometimes happen to a hypothesis in the coursc of history? S. Was Dalton’s hypothesis forgotten later? 6. What do modem scientists think about Dalton’s theory? жүктеу/скачать 5,96 Mb. Достарыңызбен бөлісу:
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