Lesson 3
Ex. 1*. Read and translate the following words without a dictionary:
Graphite Molecule
Organic Geometrical
Carbon Figure
Crystalline Tetrahedron
E lectric ity Transparent
Ex. 2*. Say what part of speech the following words belong to: relatively, importance, organic, property, colourless, conductor, transparent, hardness, strikingly, hardest,
arrangement.
Ex. 3. Group up the following synonyms: free, high, soft, conbined, large, hard short, unknown, long, small, known.
Ex. 4*. Check up if you remembr the following words: relatively, naturally, approximately, except, in other words, for this reason, thus, on the contrary, that is why, thus, account for.
Ex. 5*. Refresh your grammar. Remember Subjective Infinitive Construction.
The molecule is considered to consist of more than one structural unit.
Carbon is known to occur in two crystalline forms.
This phenomenon is expected to occur at a very high temperature.
This device is known to work well.
This rule is believed to be good for all cases.
This value proves to be approximate.
The diamond was thought to dissolve in some solvents.
The experimental data proved to be very important.
Graphite is believed to be a good conductor of electricity.
Diamond is known to be the hardest of known substances.
Ex. 6. Read and translate the sentences. Remember the meaning of the word "number".
Number - число, номер; насчитывать, составлять
A number of- ряд, несколько
Quite a number of- много, целый ряд
A large (great) number of- много, большое количество
A fair number of- достаточное количество
The diameter of the Sun numbers 1,391,000 km, that is 19 times that of the Earth,
Organic chemists study a great number of organic substances.
The numbers of protons determines the atomic number.
This problem is discussed in quite a number of articles.
The number of scientists taking part in the conference was very great.
A number of scientists have adopted this resolation.
Experiments carried out by this group of chemists numbers hundreds.
Quite a number of reports deal with the polarization of light.
The number of scientists and medical men who lost their lives before it was found out how to protect oneself from radioactive rays numbers hundreds.
Ex. 7. Read and translate the text.
CARBON
Carbon is known to be ranked along with hydrogen and oxygen as one of the most important of all the elements to man.
Carbon occures in nature as a free element and in many compounds. It numbers only about 0.03 per cent of the Earth's crust but this relatively small amount of the element is of great importance. Its importance is indicated by the 300,000 or more compounds of the element which exist naturally or which have been prepared. This number proves to be approximately ten times the number of compounds of all the other elements put together.
For a long time these compounds were believed to be never produced except with the aid of organic life, in other words, by living plants and animals. For this reason they were called organic compouds.
Carbon is known to occur in two crystalline forms which differ strikingly in their properties- graphite and diamond. Graphite is black, soft, a good conductor of electricity. Diamond, on the contrary, is colourless and transparent, the hardest of known substances, a non-conductor of electricity.
The difference between them is due to dissimilar arrangement of the carbon atoms in their molecules. In diamond they occupy the peaks of a geometrical figure called tetrahedron and are bound very strongly. Thus we account for the extreme hardness of the diamond, its high melting point, and its failure to dissolve in any solvent.
In graphite, on the contrary, the carbon atoms are arranged in planes and bonds between the planes are weak. This is why graphite is so soft.
Ex.8. Translate the following English words: amount, approximately, animals, conductor, transparent, account for, hardness, dissolve, bonds, solvent.
Ex. 9. Give English equivalents to the following Russian words: кислород, водород, углерод, соединение, встречаться, отличаться, свойство, точка плавления, точка кипения, бесцветный.
Ex. 10. Agree or disagree with the statements.
Carbon occurs in nature only in many compounds.
Carbon members 3 per cent of the Earth's crust.
A number of carbon compounds is very large.
Carbon compounds can be produced only with the aid of organic life, that is plants and animals.
Carbon occurs in two crystalline forms.
Graphite is the hardest of known substances.
The difference between graphite and diamond is due to arrangement of the carbon atoms in their molecules.
Ex. 11. Characterize graphite and diamond.
Ex. 12. Speak on the following topics:
Occurance of carbon in nature.
Two forms of carbon.