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particular solvent at
... given temperature is its concentration in ...
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saturated solution. 4. It is
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difficult to overemphasize... importance o f ...
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conccpt o f
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... solubility to
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... chcmistry. 5. Wc shall first analyse
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... case of...
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ideal solution.
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Ex. 8. Give synonyms for the following:
capacity, limit, place, principally, be accompanied by, because, toward, consequently
Ex. 9. Give antonyms for the following:
constant, saturated, at first, always, easy, decrease, near, minimum, seldom, limited
Ex. 10. Translate the scntcnccs into Russian.
1. The capacity of a solvent to dissolve a given solute is often limited though there arc many pairs of substanccs which can be mixed in any proportions. 2. In order to control our environment, the first purpose of science must be to study and understand it. 3. To answer the question “What arc the uses of sulphuric acid?” fully, one would need to write a book. 4. The alkali metals arc usually stored in oil so as to cxcludc air. 5. In order for two molcculcs to react with each other, they must, first of all, be in the prcsencc of each other. 6. For hydrogen to be obtained from water, electrolysis may be used. 7. Sodium is a white metal soft enough to be easily cut with a knife and light enough to float on water. 8. The minerals in which aluminium occurs, arc too numerous to recite. 9. The vapour pressure of many pure liquids or solids is very low, in fact, so low as to be immeasurable by direct means. 10. The catalytic substancc can be recovered unchanged after the reaction is completed. 11. As the temperature is raised, the rate of evaporation increases. 12. Oncc the validity of a hypothesis has been tested by all possible experiments and is found to be in harmony with all the facts, it assumes the status of a theory. 13. Whenever a chcmical reaction occurs, an energy changc takes place. 14. Liquid bromine should be kept in well-stopped bottles, as this clement is poisonous. 15. The discovery of silicon was an important event in chcmistiy, for the properties of the clement were found to be very close to those predicted by D. I. Mendeleyev on the basis of his periodic law. 16. Where the current enters or leaves the liquid, there are evidences of chcmical action having taken placc. 17. If sulphur trioxidc is thrown into water, it will dissolve with the evolution of much heat. 18. If there were no order in the way in which atoms of different elements combine to form the molcculcs and crystals of compounds, it would be ncccssary for us to memorize one by one the formulas of thousands of substanccs. 19. If wc had chosen the second oxide, the valcncc of sulphur and, therefore, its equivalent weight
would have been different. 20. With a few exceptions the molten metals arc completely soluble in one another, so that it is possible to make solutions of all concentrations. 21. True salts are always ionic, whether they arc in solution or in their crystalline forms. 22. Fluorine and hydrogen combinc violently even in the dark, provided a trace of moisture is present.
Strange as it may seem, the reaction may procccd both ways.
Important as the problem of solubility may be, wc shall not consider it now. 25. Let us consider any factors lest anything may be omitted.
Unless the clcctron microscopc had been used, it would not have been possible to obtain these results. 27. Were the parameters maintained, the reaction would go to completion. 28. Physics and chcmistry arc so closely related that textbooks of these two subjects contain much in common.
Many oxides arc found to combinc with acids to form salts and water.
Carbon monoxide cannot properly be described as cither a basic or an acidic oxide, inasmuch as it docs not react with water.
Ex. 11. Translate the sentences into English without using a dictionary.
1. Различные вещества обладают различно» способностью раство ряться в данном растворителе. 2. Растворимость вещества — это его концентрация, характерная для состояния равновесия между раство римым веществом н раствором. 3. Понятие растворимости представ ляет собой основу для многочисленных лабораторных и промышлен ных процессов. 4. Растворимость зависит как от природы самих растворителя и растворяемого вещества, так и от условий процесса.
Два жидких компонента идеального раствора могут смешиваться
любой пропорции.
Ex. 12. Answer the following questions:
1. In what way can the capacity of a solvent to dissolve a given solute be characterized? 2. What state is regarded as equilibrium between the
solute and solution? 3. What is usually callcd the solubility of a substancc in a particular solvent? 4. What is the importance of the conccpt of solubility? 5. What is an ideal solution?
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