Read, translate and define what parts of speech the words, their derivatives and related words belong to. Consult the dictionary, write out the meanings that are new for you.

Valence – valency – valent – trivalent – quadrivalent; form – formula – formulae – formulate; denote – denotative – denotation, denotement; substitute – substitution – substituent; consider – consideration – considerable; similar – similarity – similarly; violate – violation; destroy – destruct – destruction – destructive; homolog – homologous – homologue – homology; saturate – saturated – unsaturated – saturation; specific – specifically – specification – specificity – specified – specify; add – addition – additional – additive.

Find the right statement.

1) Structural formulae …

a) show the arrangement of the atoms in space;

b) show the arrangement of the atoms in a molecule;

c) cannot be written in a shortened form.

2) The reason for the diversity of organic compounds is …

a) the destruction of the molecules;

b) the rapid advance of organic chemistry;

c) the ability of the carbon atoms to form chains.

3) Paraffins …

a) mean “little affinity”;

b) are called unsaturated hydrocarbons;

c) do not form the homologues series.

Translate the following sentences in writing. Make up your own sentences with the parts in italics; use the words from the exercises 1, 2, 3.

1) Let us consider the first of the Butlerov’s theoryprinciples as applied to hydrocarbons.

2) It iseasy to see that this must be the case.

3) If we were to assume, for instance, that any two of the hydrogen atoms were connected with each other, this would mean they had exhausted their valences and could not link up with other atoms.

4) What accounts for the constant increment in the composition of hydrocarbon molecules?

5) This is due to the fact that in the transition from one member of the series to the next the chain of atoms is each time extended by a CH₂ link.

6) Itshould be born in mind that structural formulae only show the order in which the atoms are connected, but do not show the arrangement of the atoms in space.

7) Therefore, no matter how we write the formula of propane, it will still be one and the same substance, since the order in which the atoms are connected has not changed.

Look through the text. Find the sentences with the Adverbial Clauses of Condition and analyse them. Translate the sentences into Russian.

Read the text and answer the following questions.

1) What substances are called homologues?

2) What is the general formula of the hydrocarbons of the methane homologous series?

3) Why are methane and its homologues called saturated hydrocarbons?

4) How do the physical properties of the substances in the homologous series of saturated hydrocarbons change? Give examples.

5) Which homologue of methane has a density approximately equal to that of air?

Find suitable definition for each of the terms given.

a) Butane; b) chemical bond; c) chlorine; d) homologue; e) methane; f) paraffin(e).

1. A liquid mixture consisting mainly of alkane hydrocarbons with boiling points in the range 150°-300 °C, used as an aircraft fuel, in domestic heaters (домашний обогреватель), and as a solvent (растворитель).

2. A colourless odourless flammable gas, the simplest alkane and the main constituent of natural gas: used as a fuel. Formula: CH₄.

3. A toxic pungent (ядовитый) greenish-yellow gas of the halogen group; occurs only in the combined state, mainly in common salt: used in the manufacture of many organic chemicals, in water purification, and as a disinfectant (дезинфектант) and bleaching agent (отбеливатель). Symbol: Cl; atomic no.: 17; atomic wt.: 35.4527; valency: 1, 3, 5, or 7; density: 3.214 kg/m3; relative density: 1.56; melting pt.: -101.03 °C; boiling pt.: -33.9 °C.

4. Any homologous compound.

5. A colourless flammable gaseous alkane that exists in two isomeric forms, both of which occur in natural gas. The stable isomer, n-butane, is used mainly in the manufacture of rubber and fuels. Formula: C₄H₁₀.

6. A mutual attraction between two atoms resulting from a redistribution of their outer electrons.

Translate the following sentences into Russian.

Этан представляет собой химическое соединение с формулой C₂H_6.. Это единственный двууглеродный алкан, то есть алифатический углеводород. При стандартных температуре и давлении этан – газ без цвета и запаха. В промышленном масштабе этан выделяют из природного газа и получают как попутный продукт нефтепереработки.

Cегодня этан – важное нефтехимическое сырье (feedstock); он отделяется от других компонентов природного газа на большинстве хорошо разработанных месторождений. Этан также может быть выделен из нефтяного (попутного) газа (petroleum gas), смеси газообразных углеводородов, которая возникает в виде попутного продукта нефтепереработки. Этан используется как катализатор для ускорения (to boost up) реакции; и в производстве этилена посредством парового (термического) крекинга.

Make a short report on Butlerov’s theory.

11. Do you think whether it is important for you as a specialist to know Butlerov’s theory? Give your arguments.
TEXT 5. CHARACTERISTICS OF ORGANIC SUBSTANCES

Organic compounds are generally covalently bonded. This allows for unique structures such as long carbon chains and rings. The reason carbon is excellent at forming unique structures and that there are so many carbon compounds is that carbon atoms form very stable covalent bonds with one another (catenation). In contrast to inorganic materials, organic compounds typically melt, boil, sublimate, or decompose below 300 °C. Neutral organic compounds tend to be less soluble in water compared to many inorganic salts, with the exception of certain compounds such as ionic organic compounds and low molecular weight alcohols and carboxylic acids where hydrogen bonding occurs.

Organic compounds tend to dissolve in organic solvents which are either pure substances like ether or ethyl alcohol, or mixtures, such as the paraffinic solvents such as the various petroleum ethers and white spirits, or the range of pure or mixed aromatic solvents obtained from petroleum or tar fractions by physical separation or by chemical conversion. Solubility in the different solvents depends upon the solvent type and on the functional groups if present. Solutions are studied by the science of physical chemistry. Like inorganic salts, organic compounds may also form crystals.

A unique property of carbon in organic compounds is that its valency does not always have to be taken up by atoms of other elements, and when it is not, a condition termed unsaturation results. In such cases we talk about carbon double bonds or triple bonds. Double bonds alternating with single in a chain are called conjugated double bonds. An aromatic structure is a special case in which the conjugated chain is a closed ring.

Tasks on the text

Memorize the following words and word combinations.

1. unique[jH`nJk] – уникальный 2. catenation [,kxtI`neISn] – сочленение, соединение 3. in contrast to – в отличие от 4. to sublimate [`sAblI,meIt] – сублимировать, возгонять, очищать 5. soluble [`sPljub(q)l] – растворимый 6. compared to – по сравнению с 7. with the exception of – за исключением 8. carboxylic [,kRbPk`sIlIk] acid – карбоновая кислота 9. to dissolve [dI`zPlv] – растворять(ся), разлагать 10. solvent – растворитель

11. ether [`JTq] – простой эфирwhite spirit – уайт спирит, нефтяной скипидар 12. tar [tR] – смола 13. solution[sP`lHS(qn)] – раствор, растворение 14. unsaturation[An,sxtSq`reISqn] – ненасыщенность 15. triple [trIpl] – тройной; утроенный 16. conjugated [kPnGu,geItId] double bond – сопряженная двойная связь 17. to alternate[`O:ltqneIt] – сменять друг друга; чередоваться, колебаться

Choose the Russian equivalents from the right column.

1) double bond; 2) covalently bonded; 3) closed ring; 4) conjugated chain; 5) occur; 6) alcohol; 7) aromatic structure; 8) stable covalent bond.

a) замкнутое кольцо; b) случаться, иметь место; c) ароматическая структура; d) устойчивая ковалентная связь; e) двойная связь; f) спирт; g) сопряженная цепь; h) ковалентно-связанный.

Choose the English equivalents from the right column.

1) распадаться; 2) чистый или смешанный; 3) смесь; 4) молекулярный вес; 5) превращение; 6) растворимость; 7) отделение; 8) диапазон, пределы амплитуда, ряд.

a) conversion; b) solubility; c) separation; d) mixture; e) pure or mixed; f) range; g) decompose; h) molecular weight.

Read, translate and define what parts of speech the words, their derivatives and related words belong to. Consult the dictionary, write out the meanings and transcription to the words that are new for you.

Alternate – alternately – alternation – alternating – alternative – alternatively – alternativeness; converse – conversion – convert – converted; dissolvable – dissolvability – dissolve – dissolved – dissolver; mix – mixable – mixture; pure – pureness – purification – purify – purity; separate– separately– separation – separator.