|
in, at, of, except, from, for, on account o f
Berzelius introduced the modern symbols... the elements... 1818.
Some elements had been known ... prehistoric times ... their ease ...
extraction. 3. The symbols ... these elements were derived ... their Latin names. 4. There arc elements which can exist... two different forms ...
the same physical state. 5. Reactions... ozone arc completely different...
those ... oxygen. 6. White phosphorus catches fire ... air ... room temperature. 7. The atoms... all common gaseous elements exist... pairs
... the inert gases.
Ex. 9. Supply the definite or indefinite article.
1. Mendeleyev is ... famous Russian chemist. 2. Mendeleyev is ...
founder of the Periodic Law. 3. Professor N is ... author of a great number of papers and books. 4. Swedish chcmist Berzelius was... great discoverer. 5. Do you know who ... discovcrer of the atomic theoiy was? 6. Niels Bohr was ... Danish physicist. 7. Chemistry is ... branch of knowledge. 8. Section II is concerned with ... nature of radioactivity. 9. Dr. N dis covered ... new law. 10. Faraday was ... well-known English physicist.
Ex. 10. Translate the sentences into Russian, paying attention to the predicates.
1. Chemistry concerns the compositions of matter and their transformations. 2. A great number of Russian scientists, among them Mendeleyev, Lomonosov, Butlerov ct al., could be mentioned as contributors to the world science. 3. There arc several fields of chcmistry
in which Russian scientists have achieved significant progress. 4. The Periodic Law laid the foundation for the modem development of chcmistry. 5. In the molten state metals are able to interact with one another. 6. Alloys which contain only two metals arc referred to as bimetallic. 7. Science has become an important part of the modem world. 8. Chemists are needed almost in every field of life. 9. The theories and laws of chemistry are no less exact as those of physics. 10. Silicon, the fourteenth element in the periodic table might be called a congener of carbon, in Group IV.
11. Attempts to arrange the elements in a definite order were followed by a great discovery, the discovery of the Periodic Law. 12. The periodic tabic may be interpreted in terms of electronic structure of atoms.
.13. Radioactivity was discovered by Henry Becqucrcl in 1896. 14. The change of the program of experimentation could have given more accurate results. IS. Before definite chemical evidence for the compound nature of a substance was obtained, the substancc had been considered an clement.
16. In 1903 scientists recognized that radioactivity involves the spontaneous transmutation of elements. 17. Here wc arc going to give a detailed account of this phenomenon. 18. Heating was to have an important influence on the rate of the reaction. 19. Two points should have been determined: the composition of the sample and the relative weights of its constituent parts.
20. The result of the comparison may be completely the opposite. 21. The next step was to arrange the data in a table. 22. At any given temperature a molecule of a light gas such as helium or hydrogen will have the same average kinetic energy. 23. Chemists must have known a great number of
reactions that can procccd without catalysts. 24. Few chcmical reactions involve just a single elementary proccss. 25. Wc have prevented the formation of by-products. 26. New methods of investigation arc being developed, they are much more effective than the older ones.
Ex. 11. Translate the sentcnccs into English.
В 1818 году Бсрцслмус опубликовал список «атомных вссов».
Берцелиус ввел современные символы для химических элементов.
Некоторые элементы могут существовать в двух различных формах в одном и том же физическом состоянии. 4. И озон, и молекулярный кислород содержат только атомы кислорода. 5. Реакции озона совер шенно отличны от реакций кислорода. 6. У озона— три атома кисло рода, а у молекулярного кислорода— два. 7. Чтобы избежать путани цы, молекулы газа записываются как 0 2 N2 и т. д. 8. Красный фосфор стабилен на воздухе при температуре 240°С. 9. Белый фосфор, напри мер, воспламеняется на воздухе при комнатной температуре.
Ex. 12. Make up questions to the italicized parts of the sentences.
1. The symbols began as a simple shorthand for referring to the names of the elements (3). 2. Ozone will immediately oxidize metallic silver (3). 3. There is no way of discovering how many atoms arc combined together in any solid (2).
Ex. 13. Answer the following questions:
1. What were the symbols introduced for? 2. Who introduced the symbols for chcmical elements and when did he do it? 3. What significance
did symbols acquire? 4. What is the difference in writing allotropic modifications of elements?
Do'stlaringiz bilan baham: |
