Химия CHROMATOGRAPHY AND ION EXCHANGE TECHNIQUE просмотров - 213
Answer the questions
lack - відсутність, недолік
cause– примушувати, викликати
negative - негативний
completeness - завершеність
neutral - нейтральний
partial - частковий
exert – впливати, викликати
positive - позитивний
ionization - іонізація
weaken - послаблювати
1. What are ions?
2. What process do we call ionization?
3. Can electrolytes conduct electricity?
4. What do we call non-electrolytes?
5. What compounds have molecules with unsymmetrical electrical field?
6. What are electrovalent compounds composed of?
2. Translate word-combinations:
to carry an electric charge; neutral atoms; its ability to carry on the experiment; conductors of electricity; covalent compounds; polar covalent compounds; weakening their bonds and causing dissociation
3. Translate word-combinations:
кислоти; проводити дослідження; розчинені у воді; електричний заряд; нейтральні атоми та молекули; сильні електроліти; частковий позитивний заряд.
4. Translate the following sentences:
1. The material was by no means perfect, and the results obtained were rather irregular. 2. Speeds are obtained partly by electrical means. 3. This device is used as a means of regulating the amount of gas. 4. It is a means for producing a chemical reaction. 5. Practically this means that you made a mixture of these gases. 6. The mean atmospheric pressure, however, has been fixed at 760 mm, and is often simply called "atmosphere". 7. Deformation means change of form. 8. I shall do it by all means. 9. Radio signal is transmitted by means of radio waves. 10. He has to finish this experiment by the end of the year by all means. 11. In the first year we are taught chemistry, structure of matter, higher mathematics, etc. We are also given laboratory works to do. 12. The delegates were shown new types of devices which are produced at our plant. 13. All the instruments were looked at with great interest. 14. At this chemical plant the huge automatic unit was opera- ted by only a few men. 15. Great attention is paid to the development of science and technology in this country. 16. His scientific paper will be discussed at the conference. 17. All the data will be analyzed by the experimenter himself.
Chromatography is a method of chemical analysis based upon the selective absorption and partial fractionation of various substances by certain suitable materials. The method is simple and requires a minimum of special equipment. The technique consists of pouring a solution through a column containing a suitable adsorbing material. A selective developing agent is then passed through the column and the different substances in the solution are spread down the column into layers visibly separated from one another, provided the substances are colored. In the case of colorless substances, the layers of the different substances may be located by the use of ultra-violet light or by chemical tests.
This method was first described by the Russian botanist Tswett, in 1906. Tswett was engaged in the extraction and purifictaion of plant pigments.
Methods of chromatography have been applied to the separation of the rare earths and a number of procedures, based on chromatography techniques, have been developed for the separation of the inorganic cations and anions.
Answer the questions EXERCISES VOCABULARY bond– зв’язок lack - відсутність, недолік cause– примушувати, викликати negative - негативний completeness - завершеність neutral - нейтральний conduct- проводити partial - частковий exert – впливати, викликати positive - позитивний ionization - іонізація weaken -... [читать подробенее]