Lesson 8
Ex. 1*. Translate into Russian without a dictionary:
Salt
Conde
nsation
Microbe Corrosion
Really Filter
Process Fundamental
Natural Distillation
Ex. 2. Say what part of speech the following words belong to: sufficiently, de sirable. purification, easily, dissolved, really, soluble, substance, undesirable, in fluence, natural.
Ex. 3*. Translate the wordswith the same root:
Pure, perification, to purify, impure, impurity. Form, to form, formation. Soluble, insoluble, solution, to dissolve, solvent. Act. activity, to react, reaction.
Ex. 4*. Refresh your grammar:
water should be pure; water should not contain some substances; microbes should be killed; water should be free from some substances; water is to be used; water is to be purified; water is to be boiled; problems are to be discussed; we are to remove all impurities; life would be impossible; it would be wrong to consider; water would be pure; substances would react with soap
Ex. 5*. Check up if you remember the following words: thus, however,
point of view, both ... and, while, through, thoroughly, already, except,
a great deal of, to be sure, to meet one’s needs.
Ex. 6. Tranlate the sentences. Remember the meaning of the following words;
Since - с, с тех пор, так как
Fail + инфинитив - не
For (после запятой) * так как
As well as... - а также, так же как и ...
Nor- частица "не», прибавляется к глаголу
Aluminium as well as copper are the best conductors of electricity.
For many purposes steel is much better than iron, for steel has much greater strength and hardness.
The substance failed to oxidize even when exposed to the air.
Many thousands of years have passed since man began to use metals.
The selection of proper method of purification is an important factor, for the success of the work often depends on it.
The substances fail to dissolve.
Boiling as well as distillation are good methods for water purification.
Dissolved substances do not settle, nor do they evaporate with water.
Oxygen has been known since the 18th century.
We do not consider rain water free from impurities.
11 )Since the hydrogen ion is composed of one proton the term "hydrogen ion" and "proton" are synonymous.
Ex. 7. Read and translate the text. Be ready to speak on the following topics:
The importance of water.
Pure water in nature.
The usage of pure water.
Methods of water purification.
WATER PURIFICATION
The abundance of water in liquid, solid and gaseous state is a matter of common observation. Not only is water the most abundant compound, but it is also very important for life. To be sure life woued be impossible without water.
From the chemical point of view water has many points of interest, for it enters into chemical reactions which are of fundamental importance. Not only does water react with many substances, but it has also a marked influence upon many chemical reactions.
For many purposes it is desirable that water should be pure. The purest natural water is rain. It would be wrong, however, to consider it as being really pure. Nor is ground water pure. It contains a great deal of impurities which fail to settle. Dissolved substances do not settle, nor do they evaporate with water, what makes their removal difficult.
One of the most important problems is to obtain water sufficiently pure to meet our needs. *The choice as what process is to be used for purification of water depends upon the uses for which it is intended as well as imperities it contains. Water used for steam boilers should be free from substances that cause corrosion and scale formation. Water for washing should not contain substances that react with soap. When water is to be used for drinking, it is necessary that the microbes which it may contain should be killed. To achieve this, water which is to be purified is thoroughly filtered. Another way to purify water is to boil it.
None of these methods is fit for producing pure water in the chemical sense, since most of the soluble salts are unaffected by the treatment. To remove these and to prepare chemically pure water suitable for scientific use, we take advantage of the fact that water is easily changed to steam while most of the dissolved substances as already mentioned are not volatile. By condensing the steam, we are thus able to remove all the impurities except volatile ones. This process is called distillation. Distilled water has many uses, both in the laboratory and in industry, when even small quantities of impurities would be undesirable.
Ex. 8. Translate the following words and expressions: settle, purify, impurity, liquid, influence, treatment, volatile, abundance, evaporate, suitable, state.
Ex. 9. Give English equivalents to the following Russian words: соединение, чистый, соль, растворять, очистка, вещество, пар, химическая реакция, растворимые соли, растворенные вещества, использование, фильтровать.
Ex. 10. Aualize the sentence marked *
Ex. 11. Fill in the sentences the missing words: impurities,
washing, abundant, pure,life, filtering, microbes, free, distillation, corrosion,