English for chemists

One finds the reason for this similarity in the periodic table. 9. It takes

one much time to make all the calculations without a computer. 10. It is one of the simplest methods and it is often rccommcndcd to the students.

Ex. 9. Translate the sentences into Russian.

1. Everybody considers him to be an expert in his field. 2. Mendeleyev believed some elements to be missing in his periodic table and he even predicted their properties. 3. The teacher cxpcctcd us to finish the work at 5, but we couldn’t solve the problem. 4 . 1 suppose the paper to have been already typed. 5. They saw him pour the liquid into the test-tube and then heat the tube over the burner. 6. She heard somebody call her and went to the door. 7. Wc waited for the solution to boil. 8 .1 knew him to have passed the exam in mathematics successfully, that is why I asked him to help me. 9. Wc should cxpcct the atomic weight of sulphur to be greater than that of oxygen. 10. The ancicnt scientists believed earth, water, air and fire to be elements. 11. Dalton thought a water molecule to consist of one hydrogen and one oxygen atom. 12. Certain conditions must be observed to make nitrogen react with other elements. 13. Sometimes, the presence of the catalyst causcs the two dements to unite and form a compound. 14. Dr. N thought high stability of the compound to be due to the prcscncc of an admixture ions. 15. Let’s assume the volume of the gas to be equal to x. 16. He was made to stay in the

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laboratory and finish cleaning. 17. Pressure causes gas to comprcss.

18. 
    The obtained results led us to draw the following conclusion.
    
19. 
    Under ordinary conditions it is not always easy to get some elements to combine with other elements. 20. They were forced to use an old apparatus because the new one was out of order. 21. Qualitative analysis enables the composition of a sample to be determined. 22. Mendeleyev’s periodic table allows the suppositions about the atomic structure to be made. 23. Experiments sometimes permit some useful information about the chcmical bond to be obtained.
    

Ex. 10. Translate the scntcnccs into English.

1. Знание электронной структуры атомов позволяет определить xapaicTcp связи. 2. Ковалентность каждого атома в молекуле может быть в большей или меньшей степени связана с его положением в периодической таблице. 3. Существуют соединения, имеющие оди­ наковый состав, но разную структуру. 4. Один из примеров таких соединений — это этиловый спирт и димстиловый эфир, оба они могут быть написаны одной и той же формулой — С2Н«0.5. В моле­ кулах атомы удерживаются вместе посредством связей, одна из наи­ более распространенных связен — ковалентная, б. Эта связь очень интересна с точки зрения ее электронной структуры.
Ex. 11. Answer the following questions:
1. In what way is it possible to count the number of valcncc electrons in the molecule? 2. What rule helps us to determine the distribution of valcncc electrons in electron pairs? 3. What attracts the attention of the chemists as regards such compounds as ethyl alcohol and dimethyl ether? 4. What kind of bond is usually callcd a covalent bond? 5. What is the usual way of writing structural formulas of molcculcs?