English for chemists

Section I
Ex. 1. Practise your reading.
Liquid solutions provide an extremely convenient means of bringing together carefully measured amounts of reagents and of allowing them to icact in a controlled manner.
Ex. 2. State what parts of speech the following words belong to:
press, pressing, pressure, compress, compressible, incompressible, compression
Ex. 3. Define the meanings of the word respect in the following sentences:
1. Wc respect our supervisor very much. 2. In this respect the tw substanccs arc alike. 3. Everybody has great respect to our lecturer in

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general chcmistry. 4. Selenium resembles sulphur in many respects. 5. My opinion is in no respect different from the author’s. 6. With respect to their properties, halogens arc of particular interest.
Ex. 4. Analyse the following sentence:
The most important problem of chcmistry is that of explaining the behaviour of substanccs.
Text 26 A
Liquids and Solutions
Solids and gases represent the extreme states of behaviour of molcculcs. The liquid state can be thought of as an intermediate condition in which some of the properties found in cither solids or gases arc displayed. Liquids, like gases arc isotropic and flow readily under applied stress, but like solids, they arc dense, relatively incompressible, and have properties that arc largely determined by the nature and strength of intcrmolccular forces. With rcspect to molccular order, liquids arc substanccs considered to be intermediate between solids and gases. The fact that liquids arc isotropic tells us immediately that they do not have the extended latticc structure and long-range order of solids. Yet, the density of a liquid is generally only 10% less than that of its solid phase; this must mean that the molccules in a liquid arc packcd together with some regularity, and do not exhibit the complete chaos associated with molcculcs in the gas phase.
One of the most important properties of liquids is their ability of acting as solvents. In the first place, liquid solutions provide an extremely convenient means of bringing together carefully measured amounts of reagents and of allowing them to react in a controlled manner. Sccond, the nature of the reactions which proceed and the speed at which they occur can be greatly influenced by the properties of the liquid solvent medium. Finally, the physical properties of solutions are interesting and important, because they can be used to determine molccular weights of dissolved substances and to study the nature and strength of forces between solvent and solute molcculcs.
One of the most engaging and absorbing features of the study of chcmistry is the attempt to explain the behaviour of bulk matter in terms of molccular properties. Therefore, it is important to outline a molccular picture which will help us to understand and relate phenomena associated with the liquid state.
Words and Word-Combinations to Be Memorized
ability, absorb, bulk, complete, convenient, display, engage, generally, intermediate, intcrmolccular, lattice, a means, outline, reagent, range, with respect to, solute, strength

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\ Ex. 5. Give the Russian equivalents for the following:
I think of, display some properties, dense, intcrmolccular forces, with respect to, immediately, the lattice structure, the long-range order, mean, be packed together, provide a means of, carefully measured, procccd, flnsUly, because, the behaviour of bulk matter, outline a picture, be associated with, the strength of forces
Ex. 6. Give the English equivalents for the following:
поведение молекул, жидкое состояние, либо... либо..., главным образом, порядок расположения молекул, занимать промежуточное положение между, на 10% меньше (больше), плотность жидкости, способность действовать в качестве растворителя, протекать с опре­ деленной скоростью, оказывать большое влияние, физические свой­ ства растворов, определить атомный вес, растворенное вещество, растворитель, растворимое вещество
Ex. 7. Fill in the blanks with articles where ncccssary.

1	liquid state can be thought of as intermediate condition between
... solids and gases. 2		.... properties of liquids arc determined by ...	na­
ture and strength o f ...		intcrmolccular forces. 3— density o f ... liquid is

generally only 10% less than that o f ... solid. 4. Their ability of acting as

... solvents is one o f	... most important properties o f ...		liquids. 5. It is
important to outline ...	molccular picture o f...	liquid state.

Ex. 8. Give synonyms for the following:

think of, display, under stress, largely, immediately, little, allow, influence, feature, explain
Ex. 9. Give antonyms for the following:
incompressible, extend, long-range, less, convenient, be influenced by, most important
Ex. 10. Translate the sentences into Russian.

1. 
   One should follow the proceeding reaction very carefully.
   

2. 
   Selenium, an element belonging to the sulphur group, is as much non-metal as metal. 3. Many factors mentioned determine the reaction rate.
   

4. 
   There is a striking resemblance between some elements. 5. St. Petersburg University has its own publishing house. 6. The boiling point of water is accepted to be 100°C. 7. Some objections were found to the Arrhenius theory long believed to be true. 8. The most striking thing about hydrogen is its extreme lightness. 9. An acid is defined as a compound or an ion capable of liberating a proton. 10. Two or more atoms having identical nuclear charges but different numbers of Acutrons are said to be isotopes. 11. Ores containing as little as 2 per cent or even less of copper or nickel arc worth mining. 12. Bond formation involving
   

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elements toward the middle of the periodic tabic occurs by the proccss of clcctron sharing. 13. There arc a number of different procedures being used in qualitative analysis. 14. The calculation of hydrogen ion concentration in a solution containing a weak clcctrolytc is a difficult one for the average student first facing this problem. 15. Sulphur dioxide is more than twicc as heavy as air and is one of the most easily liquefied gases known. 16. The term “heat” of combustion refers to the amount of heat liberated per mole of the substancc burned. 17. Many industrial processes depend for their succcss upon the solubilities of the compounds formed. 18. The system of chcmical symbols now used was proposed by the Swedish chcmist Berzelius in 1818.19. Fluorine, though for a long time known to exist, was not isolated until 1886. 20. There has been, sincc earliest times, an atomic hypothesis thought to be implied by the diffusion and the compressibility of gases on the one hand and by the symmetry of crystalline solids on the other. 21. The question of the composition of air long supposed to be one of the elements was solved only in the 18th ccntury. 22. Dangerous bactcria in drinking water may be killed by small amounts of chlorinc. 23. An clement is represented by certain letters for ease in writing. This symbol stands for one atom of the element. 24. There arc numerous methods for demonstrating the spectra of many of the elements. 25. In qualitative analysis there is usually greater difficulty in diagnosing the cations present than in recognizing the anions. 26. In English, wc have the practicc of naming chcmical elements in Greek and Latin. 27. As a rule, there arc several ways of preparing an element. 28. Mercury has the property, unusual for a metal, of being a liquid at room temperature. 29. The phenomena likely to arise during the experiment must also be taken into account. 30. The amount of the pure metal ccrtain to be obtained for the ore can be calculated in the following way.
Ex. 11. Translate the sentences into English without using a dictionary.
1. Жидкое состояние, которое, как обычно думают, является про­ межуточным, проявляет некоторые свойства и твердых всщсств, и газов. 2. Подобно твердым веществам, жидкости являются плотны­ ми. 3. Плотность жидкости, как обычно считают, только на 10% мень­ ше плотности твердого вещества. 4. Способность быть растворите­ лем — одно из основных свойств любой жидкости. 5. Представить себе молекулярное строение жидкости — одно из важнейших усло­ вий понимания природы се свойств.
Ex. 12. Answer the following questions:
1. What arc the main states of matter? 2. What factors determine the properties of liquids? 3. Is there any diffcrcncc in the density of solids, liquids and gases? 4. Why arc liquids usually thought of as solvents? 5. How can one understand the phenomena associated with the liquid state?

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^ Scction II
I Упр. 1. Назовите значения следующих интернациональных слов:
' kinctic, analyse, constantly, collision, observation, botanist, diameter, external, convection, manifestation, thermal, suspend, dctcct, individually, csscncc, execute, energy
Упр. 2. Проверьте, помпнте ли вы значения следу ющих слов; если нет, обратитесь к словарю:
substantial, motion, single, neighbour, reveal, tiny, incessant, random, cause, intrinsic, wealth, experience, surround, instant, displace, average
Text 26 В
Прочтите текст про себя (контрольное время чтения— 3,5 минуты).
A Kinetic Theory of Liquids
In a liquid, molcculcs arc close to each other, and consequently the forces exerted on one moleculc by its neighbours are substantial. Thus, the problem of analysing the motion of a single molccule is exceedingly difllcult, for cach is constantly in “collision”, subject to the forces for as many as twelve nearest neighbours. What then can wc say about molccular motion in liquids? One of the most revealing observations in this respect was made by the botanist Robert Brown in 1827. Brown discovered that very tiny particles (10“* cm diameter) suspended in a liquid undergo inccssant randomly directed motion. These motions occur without any apparent external cause such as stirring or convcction, and arc evidently associated with an intrinsic property of all liquids. A wealth of experimental observation has confirmed the idea of this Brownian motion being a direct manifestation of the thermal motion of molcculcs. When it is suspended in a liquid, a very small particle constantly experiences collisions with all the molcculcs surrounding it. If the particle is small enough, so few molcculcs will be able to collide with it, that at any particular instant the number striking it from one side may be different from the number striking it from the other sides; consequently, the particlc will be displaced. Subsequently, another unbalance of collisional forces may occur, this time displacing the particlc in a different direction. The great majority of these displacements arc so small that they cannot be detected individually, but the motion which is observed is a result of many of the smaller random displacements. In csscncc, a Brownian particlc is a “molccule” thought to be large enough to be observable, but small enough to cxccutc observable random thermal motion.

Analysis of the motion of Brownian particles shows that their average kinetic energy is J/, kT. Sincc cach particlc is to be considered as one of the molcculcs of the liquid wc can concludc that tlic average kinetic energy of a molcculc in a liquid is also V, kT — exactly the same as the kinetic energy of a gaseous molcculc at tlic same temperature.

Упр. 3. Передайте основное содержание текста в исскольких пред­ ложениях.
Упр. 4. Какое слово в тексте означает «подвергаться воздействию»?
Упр. 5. Найдите в тексте ответы на следующие вопросы:
1. Почему трудно проследить движение одной молекулы жидко­ сти? 2. Как в общем можно охарактеризовать движение молекул жид­ кости? 3. Как выглядит взаимодействие молекул в жидкости? 4. Как определяется средняя кинетическая энергия молекул жидкости?
Упр. б. Закончите следующие предложения:
1. The molecules in a liquid arc... 2. To analyse the motion of a single molcculc is difficult bccausc ... 3. Brown discovered ... 4. Brownian motion is caused ... 5. The average kinetic energy of a molcculc in a liquid is ...