new elements. 5. It was not my tcachcr whom I addressed my question to.
6. It was in 1869 that Mendeleyev’s periodic system was published. 7. It is
horizontal rows of the periodic tabic which arc callcd periods. 8. Ozone
docs remove harmful ultraviolet radiation from sunlight. 9. It is not this
examination that is the most difficult this term. 10. It was not till late in the
19th ccntury that numerous household items began to be produced at factories.
11. These results do support the kinctic treatment of the behaviour ofparticlcs
in colloidal solutions. 12. It is only at ordinary temperature that the agreement
between the two methods is satisfactory. 13. It was not until the results
concerning solid solutions had been obtained that a general conclusion was
reached. 14. The reaction docs procccd slowly in most eases. IS. It was
evident that the resulting mixture did obey the mixture law. 16. The use of
deductivc methods shows that all these cases comc from one and the same
root. 17. It is not until a substancc undergoes distribution that it has the same
molecular weight in the two phases. 18. It is not until two picccs of zinc and
copper are brought into contact that they bccomc clcctrificd. 19. In the actual
case the density of the vapour docs alter with the height. 20. It was not until
oxygen was discovered that many processes could be understood.
Ex. 11.Translate the scntcnccs into English without using a dictionary.
1. Считается, что аналитическая химия— старейшая отрасль хи
мии. 2. Потребовалось много лет, чтобы показать, что теория фло
гистона неверна. 3. Развитие экспериментальных
методов внесло
большой вклад в исследование состава веществ. 4. Развитие промыш
ленности сыграло большую роль в разработке новых методов анали
тической химии. 5. Многие
операции, производившиеся ранее дома,
стали производиться в промышленных масштабах.
Ex. 12. Answer the following questions:
I .
Whose investigations helped to prove the fallacy o f the phlogiston
theory? 2. Why is Lavoisier callcd the “father” o f analytical chcmistry?
3. Why is analytical chcmistry regarded as the oldest branch o f chcmistry?
4. What problems engaged the interest o f most chcmists at that time?
5. Why did the development o f industry stimulate the development of
analytical chcmistry?
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