11. Study the Figures 3.1–3.3 and name hydrocarbons having formulas c4h10, c10h8, c6h12, c4h8, c2h2.Practice their reading according to the patterns given.

    1. Ethylene has the formula C two H four with two carbon atoms joined by a double bond and four hydrogen atoms.

    2. Benzene is a single-ring compound characterized by three double bonds alternating with three single bonds between six carbon atoms.

12. Translate the following sentences into Russian.

1. Парафин или предельный углеводород – техническое название алкана, (общая формула C_nH_2n+2). Он обозначает неразветвленный или нормальный алкан, тогда как разветвленный (изомер) называется изоалкан или изопарафин.

2. Самая простая молекула парафина, метан, – газ. Более тяжелые углеводороды ряда, такие как октан C₈H₁₈ – жидкие при комнатной температуре.

3. Твердыми парафинами называют смесь алканов от C₂₀H₄₂ до C₄₀H₈₂. Они находятся в твердом состоянии при комнатной температуре, но принимают жидкую форму приблизительно после 37 °C (99 °F).

4. Нафталин – органическое соединение с формулой C₁₀H₈. Это простейший полициклический ароматический твердый углеводород сo специфичным запахом, белого цвета, имеющий структуру с конденсированными бензольными кольцами.

13. Explain the difference between alkanes (алканы), alkenes (алкены) and alkynes (алкины). They are pronounced as [ˈælkeınz], [ˈælkiːnz] and [ˈælkaınz] respectively.

14. Read the text and find out what other names are in use for paraffins, aromatics, naphthenes, alkenes, dienes and alkynes.

Iupac nomenclature of organic chemistry

The IUPAC nomenclature of organic chemistry is a systematic method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). Every possible organic compound should have a name from which an unambiguous structural formula can be drawn. The classifications for hydrocarbons defined by IUPAC nomenclature are as follows:

1. Saturated hydrocarbons (alkanes) are the simplest of the hydrocarbon species and are composed entirely of single bonds and are saturated with hydrogen; they are the basis of petroleum fuels and are either found as linear or branched species. The general formula for is C_nH_2n+2 (assuming non-cyclic structures).

2. Unsaturated hydrocarbons have one or more double or triple bonds between carbon atoms. Those with one double bond are called alkenes, with the formula C_nH_2n (assuming non-cyclic structures); those containing triple bonds are called alkynes, with general formula C_nH_2n-2.

3. Cycloalkanes are hydrocarbons containing one or more carbon rings to which hydrogen atoms are attached. The general formula for a saturated hydrocarbon containing one ring is C_nH_2n. The group is also known as naphthenes.

4. Aromatic hydrocarbons, or arenes, have at least one aromatic ring.

Notes on the text:

1. IUPAC – Международный союз теоретической и прикладной химии;

2. unambiguous [ˌʌnæm'bɪgjuəs] – точно выраженный;

3. linear ['lɪnɪə] – линейный;

4. assumе – допускать, принимать во внимание;

5. arenes [ˈæriːnz] – арены.