A. Read the text thoroughly with a dictionary and answer the following questions

1. What sugars does the author mean?

2. Why are carbon compounds so important?

3. What was the source of organic chemicals in the past?

4. What chemical did Wohler prepare in the laboratory?

5. What else can Wohler be credited with?

6. What do you know about petroleum?

7. It’s written in the text: “Nowadays, however, we use the term “organic compounds” to mean carbon compounds, there being some exceptions to the rule”. What are the exceptions?

B. Find in the text English equivalents to the given Russian words, word combinations and chemical terms.

nouns: исключение, образование, правило, причина, сырье

verbs: означать, рассматривать(считать), узнать, преобразовывать, соединять(ся), разделить, производить

adjectives and prepositions: внутри, некоторым образом, просто, непосредственно, слишком много

word combinations: нельзя не удивиться, можно сказать, в настоящее время

chemical terms: сахар, этиловый спирт, метан, мочевина, углерод, цепочка атомов, углеводород

c. Fill in the gaps in the sentences with the following words: organic, living, branch, cleavage, carbon, organism, properties, chain

1. Organic chemistry is the………….of chemistry dealing with compounds containing carbon-carbon bonds.

2. Every living…………., irrespective of plants and animals are composed of organic compounds.

3. …………..chemistry reactions are different from inorganic chemistry reactions.

4. …………….can form a long chain due to its catenation ability.

5. The root word of organic chemistry, 'Organic' means that the compounds were synthesized from………… organisms in the past.

6. All the organic compounds with same functional group have same chemical……… which make the study of organic chemistry much easier.

7. The organic chemistry reactions involve the………. of the covalent bonds and forming of new bonds.

8. The physical properties may differ with the number and nature of carbon…........

III. Reading 2

Read the text and divide it into logical parts and entitle them.

Carbon

Carbon is to be ranked along with hydrogen and oxygen as one of the most important of all the elements to man. Carbon occurs in nature as a free element and in many compounds. It constitutes only about 0.03 percent of the Earth’s crust, but this relatively small amount of the 300,000 or more compounds of the element which exists naturally or which have been prepared. It is proved that this number is approximately ten times the number of compounds of all the elements put together. For a long time it was believed that these compounds might have never been produced except with the aid of organic life, in other words, by living plants and animals. For this reason they were called organic compounds. It is known that carbon occurs in two crystalline forms which differ strikingly by their properties. 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. It is the crystal structure, as determined by X-rays, which gives an explanation of this contrast of properties. The four valence electrons of each carbon atom enable it, by sharing electrons with four of its neighbours, to be linked with them in a covalent union. It may be shown by X-rays examination that in the diamond the four nearest neighbours of each carbon atom are symmetrically arranged about it in space. All atoms in a diamond are thus firmly linked together, hence the whole crystal acts as a giant molecule. Thus we account for the extreme hardness of the diamond, its high melting point, and its failure to dissolve in any solvent. On the other hand, it is found that graphite possesses parallel planes of atoms, and each is at a considerable distance from its neighbours. Each carbon atom in graphite has three nearest neighbours and they all are present in its own plane. Only three of the four valence electrons of each atom are needed for furnishing bonds with these nearest neighbours and the fourth is available for producing a bond with a neighbouring plane. A certain portion of the electrons in graphite are relatively free to move as it is true of metals. Hence, graphite is a conductor of electricity.