English for chemists

Lesson 16
ГРАММАТИКА: Инфинитив и инфинитивный оборот в функции подле­ жащего.
Section I
Ex. 1. Practise your pronunciation.

1. 
   molecule ['-molikju:!], peculiar [pi'kjurlio], rearrangement [,п:э‘гет-d3mont], neutral ['nju:trolj, other [*лдэ], exemplify [ig'zasmphfai], chlorine [*kb:ri:n], compound ['kompaond], existence [ig'ztstsns], exhibit [ig'zibit], sample [sa:mpl], diatomic [.daio'tomik]
   

2. 
   thc^'modcmNchcmist, the^‘smallest\particle, intoj^'chemicalj«\action, thcu'other\elemcnts, in^'which^'thcyNbcar, ofu thcir^,'own\kind, by^the^'water
   

Nmolccule, are^of imSportancc
\ c) 'Chemical 'unions | are of 'two 'gencralNtypcs.
Ex. 2. Pay attention to the structure of the following words. Translate them into Russian.

1. 
   reread, rewrite, reappear, recombine, replace, reproduce, redistribute, rearrange, remake
   

2. 
   colour, neighbour, behaviour, favour, vapour
   
3. 
   friendship, leadership, relationship, hardship, professorship
   

Ex. 3. Define the meanings of the word kind in the following sentences:

Д. I’m sure, the professor will help you, he is very kind. 2. What kind of substance is it? 3. Compound molecules arc composed of two or more kinds of atoms. 4. What kind of man is he? 5. Be so kind as to shut the door. 6. There arc different kinds of animals on the earth. 7. Everybody knows that your mother is very kind. 8 .1 don’t like stories of this kind.
9.1 hear he is good at mathematics.— Nothing of the kind, he always asks to help him with the problems.
Ill

Ex. 4. Find the predicate and the subject in the following sentences:

1. To the modem chemist, the atom is the smallest particle of an element that can enter into a chcmical reaction. 2. To think of a molcculc is to think of the atoms which it contains and their proportion. 3. In compounds, molecules of two or more kinds of atoms bccomc bonded together. 4. For the reaction to start, two conditions must be met.
Text 16 A
Molecules
To the modem chcmist, the atom is the smallest particle of an element that can enter into a chcmical reaction. Thus, cach element has atoms that arc peculiar to itself and different from those of cach of the other elements. Chcmical reactions occur when atoms of different kinds unite to form groups in which they bear definite relationships to cach other or when these groups undergo disruption or rearrangement. Chcmical unions arc of two general types.
In one type of union, atoms bccomc bonded together to form definite aggregates that exist as independent, electrically neutral particles and arc known as molecules (Latin “little mass”). Some elements have atoms that unite with others of their own kind to form molecules. These arc known as elemental molecules and arc exemplified by the chlorinc molcculc which is made up of two chlorinc atoms. Compound molcculcs arc composed of two or more kinds of atoms and arc exemplified by the water molcculc, which contains two atoms of hydrogen and one of oxygen.
To give a short definition of a molcculc is not to give a more or less full account of properties.

Molcculcs arc regarded as the smallest particles or elementary substanccs that can have independent existence. They account for the chcmical properties and at least some of the physical properties of the substancc they constitute. A single molcculc docs not exhibit in full the physical properties commonly associated with its particular variety of matter. These properties arise both within the molcculc itself and within the aggregates of like molcculcs that constitute a sample of the given substancc. The density of water depends not only on the mass and volume of indivilual molcculcs but also on the manner in which the molcculcs arc packed together. Sincc the chcmist works with the aggregates, their properties arc of great practical importance.

A molcculc of a compound contains, of necessity, at least two di ffcrent atoms. An element molcculc may contain only one atom, or it may contain two or more. Helium has monoatomic molcculcs; chlorinc and hydrogen cach exist as diatomic molcculcs; and sulphur molcculcs contain eight atoms. During reactions the atoms of elemental molcculcs usually arc separated and individually redistributed in new combinations.

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Words and Word-Combinations to Be Memorized
arise, be made up of, be of importance, both... and, commonly, constitute, definition, density, depend (on), distribute, cach other, helium, independent, at least, manner, more, neutral, pack, particular, rearrangement, relationship, sample, those, type, union, within
Ex. 5. Give the Russian equivalents for the following:
enter into a chcmical reaction, be different from cach other, occur, definite relationships, undergo rearrangement, chcmical unions, bccomc bonded together, form definite aggregates, be exemplified by, give a full account of, account for chcmical properties, a single molcculc, exhibit a property, arise within the molcculc itself, density, depend on the mass, pack the molcculcs together, be of great practical importance, contain two or more atoms, exist as diatomic molcculcs
Ex. 6. Give the English equivalents for the following:
каждый элемент, вступать в химическую реакцию, отличаться от, электрически нейтральный, молекула хлора, состоять из, слож­ ная молекула, молекула соединения, состоять из нескольких видов атомов, молекула воды, краткое определение, более или мснсс пол­ ный, по крайней мере, некоторые из свойств, отдельная молекула, в самой молекуле, образец данного вещества, плотность (удельный вес) вещества, зависеть от, иметь практическое значение, одноатом­ ная молекула
Ex. 7. Fill in the blanks with prepositions where necessary.
1. The smallest particle of an clement that can enter ... a chcmical reaction is an atom. 2. The lecture has already begun, don’t enter ... the classroom, please. 3. Elements differ... cach other. 4. Atoms ... different kinds can unite and form a molcculc ... a compound. 5. Elemental molcculcs arc composed ... the atoms ... the same kind. 6. Chlorinc molcculc is made... two chlorinc atoms. 7. This definition docs not give a full account... the properties of a molcculc. 8. The density... a substancc can be easily calculated, it depends ... its mass and volume.
Ex. 8. Translate the sentences into Russian, paying attention to different functions of since.
1. Wc call the atomic hypothesis a theory, since it has been verified by further discoveries. 2. Bohr’s atomic theory has been known since 1913. 3. Chemistry has changcd greatly since 1869 when the periodic law was published. 4. The periodic system has long since served as the greatest contribution to science. 5. Since the combustion of many non-metals yielded products which rcactcd with water and gave acidic

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solutions, Lavoisier named the ncwly-discovcrcd gas oxygen (“acid former"). 6. Ever since Lavoisier in 1792 demonstrated that diamond and graphite are allotropic forms of carbon, man has been interested in converting carbon into diamond. 7. They left St. Petersburg in 1996, they haven’t been there since then.
Ex. 9. Translate the scntcnccs into Russian.
1. To analyse a substance means to define its components. 2. To have a laboratory practice work is very useful for students of chcmistry.

3. 
   To know the atomic structure is to understand this phenomenon.
   
4. 
   To give a short definition of a molecule is not so very easy. 5. For uranium minerals to be used in industry is not a usual thing. 6. For atoms to have the same chcmical properties is to be the atoms of one clement. 7. To make accurate measurements requires great carc. 8. To start a reaction is one thing, but to keep it going on is another. 9. For molecules to have the same composition implies the existence of the same structure. 10. To think about ordinary conditions of a reaction means to think about room temperature and 1-atm pressure. 11. To speak about the properties of halogens is first of all to mention their extraordinary activity. 12. For compounds to be bonded by a covalent bond implies having one or more shared electron pairs. 13. To compare the size of molecules is rather difficult. 14. To imagine a molecule of water means to imagine a certain combination of hydrogen and oxygen atoms. 1 S. To obtain a spectrum is to pass a beam of white light through a spectrograph. 16. To say that the density of a substance depends only on its mass and volume is to lose sight of the manner in which the molecules are packed together.
   

Ex. 10. Translate the sentences into English.

1. Атомы каждого элемента отличаются от атомов других эле­ ментов. 2. Химическая реакция происходит, когда атомы взаимо­ действуют друг с другом и образуют новые комбинации. 3. Молеку­ лы, как известно, электрически нейтральны. 4. Молекулы соединений состоят из двух или более видов атомов. 5. Дать определение моле­ кулы — значит сказать о ее составе и свойствах. 6. То, что соедине­ ния имеют одинаковые физические свойства, не означает, что их химические свойства тоже одинаковы. 7. Молекула элемента может состоять из одного, двух и более одинаковых атомов.
Ex. 11. Answer the following questions:
1. What is a chcmical reaction? 2. What types of chcmical unions do you know? 3. What is an elemental moleculc? 4. What is a compound molecule? S. What determines the properties of a moleculc? 6. What composition an elemental moleculc may have? 7. What is the difference between an atom and an elemental moleculc?

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Scction II
Упр. 1. Назовите значения следующих интернациональных слов:
composition, identical, ozone, sort, dimethyl, amine, gas, clcctricity, covalcnt, ocean, ordinary, illuminate, optical, microscopc, vision, especially
Упр. 2. Определите значения выделенных слов по контексту.
1. The boiling point of water is 100°C. 2. The original temperature of the solid was 23°C, then it was heated to 100°C. 3. When a thing is not visible by man’s eye optical instruments should be used. 4. It is not possible to see atoms with the most powerful microscopc. 5. Some substanccs fail to react at room temperature. 6. It is claimed that an electron microscope is a very useful instrument for molecular investigations.
Слова к тексту:
size — размер; per — на, в; melt — плавиться; tiny — крошечный; meaningful — имеющий смысл; dye — окрашивать; throw — бросать; at random — наугад; exceedingly — чрезвычайно; directly — прямо, непос­ редственно; reveal — обнаружить; resolve— физ. разрешать
Text 16 В
Прочтите текст про себя (контрольное время чтения— 4,5 минуты).
M olecular Composition and Size
Molecules are chemical units composed of one or more atoms. The simplest molecules contain one atom cach; for example, helium atoms (one atom per molcculc) arc identical with helium molcculcs. Oxygen tonoleculcs (0 2) are composed of two atoms, and ozone (03) of three. Molecules may contain several different sorts of atoms. Water (H20) contains two different kinds, hydrogen and oxygen, and dimethyl amine ((CHj^NH) has three kinds. Molecules of many common gases (hydrogen Нг, oxygen Ог, nitrogen N2, and chlorinc Cl2) consist of two atoms cach.
Not all molecules are molecular in structure. Some are atomic and many are ionic. Molecular substances are characterized by low boiling points and poor conductivity of clcctricity when dissolved or melted. Gases are generally molecular, and so are many liquids, and some solids. All compounds of hydrogen and поп-metallic oxides arc molecular. These compounds arc considered to be bonded by a force callcd a covalcnt bond (or bonds) which consists of one or more shared electron pairs.
The size of molecules, especially of the smaller ones, is so tiny that to make a meaningful comparison is rather difficult. Let us assume that the water molcculcs in a cup of water arc dyed so that they can be identified. If this cup had been thrown into the ocean 2,000 years ago, these molecules would have become distributed evenly in all bodies of water on the earth.
US

A cup of water taken at random from your nearest supply, would give you at least one hundred of the original dyed molcculcs. The exceedingly large number of molcculcs of water in a cup is, of coursc, directly related to the fact that each molecule is exceedingly small. Molcculcs arc too small to be visible in ordinary light. The most powerful and best illuminated optical microscope has failed to reveal molcculcs by direct vision, although it is claimcd that they have been resolved in the electron microscope.

Упр. 3. Передайте основное содержание текста в нескольких пред­ ложениях.
Упр. 4. Составьте план текста.
Упр. 5. Прочтите предложения и скажите, соответствуют ли они содержанию текста. Если нет, исправьте их.
1. Molcculcs usually contain several different kinds of atoms. 2. The water moleculc is composed of two different sorts of atoms. 3. Molcculcs of all gases consist of two atoms. 4. Molcculcs may be molecular, atomic or ionic in structure. 5. There is no difficulty in comparing molcculcs by their size. 6. Molcculcs are too small and cannot be seen by ordinary means. 7. The electron microscopc is the most powerful instrument that is used for molecular investigations.
Ex. 6. Найдите в тексте и переведите на русский язык предложения, где идет речь о молекулах, состоящих из разнородных атомов, а также предложения, в которых дается характеристика таких молекул.