English for chemists

Lesson 35
ГРАММАТИКА: Предложения с парным союзом the... //ic... . Двойное отрицание.
Scction 1
Ex. 1. Practise your reading.
When a solid is heated to incandcsccncc, it emits more or less continuous spectrum.
Ex. 2. State what parts of speech the following words belong to:
continue, continual, continually, continuation, continuity, continuous, continuously, continuousncss, continuum
Ex. 3. Define the meanings of the word like and its derivatives in the following sentences:
1. Do you like classical music? 2. Would you like to go to the theatre today? 3 . 1 should like to discuss this problem now but wc arc short of time. 4. It’s likely that the reaction will start after some heating. 5. The chcmical formulas of these salts arc alike: LiCl, NaCI, ctc. 6. Oxygen can be made commercially, just like hydrogen, by the clcctrolysis of water. 7. Unlike oxygen, ozone has 3 atoms in a moleculc. 8. The reaction will most likely take place with great evolution of heat and light. 9. Every laboratory must have glasses, tubes, beakers, bottles and the like.
10. Elements of the same group have like properties. 11. It is not at all likely that this assumption will comc true. 12. The relationship discovered is unlikely to hold at low pressures.
Ex. 4. Analyse the following sentences:
1. It is unlikely that the error will be great. 2. It is not unlikely that the error will be great. 3. The sooner you get acquainted with the equipment, the better.
Text 35 A
Investigations of Spectra
The more profound is the investigation of the structure of atoms and molcculcs, the more problems arise. It was not long ago that consideration

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of the extra-nuclear clcctrons was restricted to an indication that their number must equal the atomic number of the element, and to a mention of the fact that they form a relatively open structure about the ccntral nucleus. The question of their arrangement must now be discussed in detail, and in this conncction valuable information has been obtained from an examination of both optical and X-ray spcctra, the former term being used to describe spcctra in the ultraviolet, visible and infra-red regions.
When a solid is heated to incandcsccncc, it emits a more or less continuous spcctrum, but gases and vapours under the same conditions, when examined spectroscopically, show a scries often very complicated, of distinct lines or bands occupying definite positions, that is, with definite wave lengths. The more information conccming the composition of various spcctra was obtained, the clcarcr it bccamc that the line spcctra arc produced by atoms and so arc not unfrcqucntly referred to as atomic spcctra, whereas the so-called band spcctra, which can, in fact, often be resolved into large number of closely spaced lines, arc obtained from molcculcs.
A line spcctrum is the one formed when radiation from an incandcsccnt gas is passed through a slit and then dispersed. The lines arc produced by energy changes when clcctrons pass from high energy quantum levels to low energy quantum levels. The clcctrons arc cxcitcd from low to high levels by the input of energy into the gas — usually in a discharge tube under a high voltage.
In a molccular spcctrum, a scries of fairly broad bands is formed. These bands arc sharp at one edge but dying away on the other. They arise from the complex energy changes possible in a molcculc. Under high resolution, the band is shown to be made up of many lines sharper and clcarcr together at the head of the band but more diffuse away from the head of the band. It seems not at all unlikely that the more complcx the molcculc, the more complicated the spcctrum is.
It is from atomic spcctra in particular that information conccming the cxtra-nuclcar clcctrons has been obtained.
Words and Word-Combinations to Be Memorized
band, complicated, concerning, on/under condition, conncction, in conncction with, diffusion, disperse, edge, emit, examination, cxcite, extra, in fact, the fact that, head, incandcsccnt, infrared, investigate, length, most likely, not likely, nuclear, optical, in particular, pass, radiation, radiate, slit, spectroscopy, the... the..., unlikely, voltage
Ex. 5. Give the Russian equivalents for the following:
a profound investigation, restrict consideration to, mention the fact, in this conncction, examine a spcctrum, heat to incandesccncc, examine spectroscopically, a distinct line, resolve into a number of lines, pass from one level to another, cxcitc clcctrons, by the input of energy, in a discharge

8 Степаном ₂₂₅

tube, a scries of bands, arise from energy changes, under high resolution, information conccming extra-nuclear electrons
Ex. 6. Give the English equivalents for the following:
равняться атомному номеру элемента, относительно открытая структура, расположение электронов, оптический спсктр, в инфра­ красной области, испускать непрерывный спсктр, при тех же услови­ ях, занимать определенные положения, длина волны, получать ин­ формацию, линейный спсктр, близко расположенные друг к другу линии, раскаленный газ, пропускать через щель, высокое напряже­ ние, на одном конце, в частности
Ex. 7. Fill in the blanks with articles where ncccssary.

1 more is known about...		spcctra,... more questions arise. 2. When
... solid is heated to ...	incandcsccncc, it emits			... spectrum. 3. ...	line
spcctra arc produced by ...	atoms. 4....		electrons arc excited in ... discharge
tube under... high voltage. S		information conccming... extra-nuclear
electrons has been obtained particularly from ...				atomic spcctra.

Ex. 8. Give synonyms for the following:

examination, be limited to, question, important, evolve, a number of, dear, actually, get, give, likely, complcx
Ex. 9. Give antonyms for the following:
disappear, rcccntly, closed, different, indefinite, small, low, simple
Ex. 10. Translate the sentences into Russian.
1. It is not unusual to consider elements from the point of view of their properties. 2. Not unfrcqucntly water itself acts as a catalyst in many reactions. 3. The higher the temperature, the greater is the viscosity of gases. 4. The greater the number of carbon atoms in a given structure, the more ways there arc for arranging them. 5. The smaller the chargcs carried
by the ions of a crystal and the larger the ionic radii, the weaker the forces that bind the ions to one another within the crystal, and the more readily the crystal structure is broken down. 6. It is not improbable that the results of their work will be similar to ours. 7. Vaporization proceeds faster, the higher is the temperature, pressure being constant. 8.1Ъс results will be in closer agreement, the more strictly the instruction is followed. 9. The accuracy of weighing is not inconsiderably influenced by the sensitivity of the balance used. 10. Under these conditions concentration is higher, the higher the temperature. 11. The harder you study, the better you master the subject. 12. The reaction is more efficient, the purer the chemicals. 13. The smaller the number of the element, the lighter it is. 14. The greater the quantity of heat possessed by the body, the greater is its hotness. 1 5. The earlier the history of chcmistry, the more striking it is. 16. Not unfrcqucntly the word has several meanings, c. g., the word “theory". 17. It seemed not

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improbable that some elements occur as a mixture of isotopes in nature. 18. It is not at all unlikely that new elements will be discovered. 19. The properties of the element are not inconsiderably influenced by their atomic number. 20. The atomic weights of elements are not uncommonly revised after thorough studies in laboratories.
Ex. 11. Translate the scntcnccs into English without using a dictionary.
1. Существует множество методов изучения структуры атомов и молекул. 2. Ценную информацию в этой связи можно получить из исследования спектров. 3. Ученые различают спектры атомов и мо­ лекул. 4. Атомы дают линейные спектры. 5. Молекулярные спектры называют полосатыми.
Ex. 12. Answer the following questions:

1. 
   What information can one obtain from an examination of spcctra?
   

2. 
   What kinds of spcctra arc known? 3. When docs a solid emit a spcctrum? 4. Under what condition docs a gas emit a spcctrum? 5. What spcctrum is callcd linear? 6. What is the difference between linear and band spcctra?