XIII. Read some statements on the fundamental discoveries in chemistry. Find some additional and more detailed information about these scientists and their discoveries.

* Robert Boyle was the first who studied quantitatively the relationship between the volume of a gas and the external pressure upon it.

* A. Lavoisier introduced the concept of chemical elements.

* A. Avogadro introduced the concept of molecules. He stated that equal volumes of gases under the same conditions of temperature and pressure contain the same number of molecules.

* F. A. Kekule and A. M. Butlerov introduced the structural theory of organic chemistry.

* In 1869 D. I. Mendeleyev discovered regularities in the properties of elements.

* N. Bohr developed theory of the hydrogen atom.

* In 1934 the Curies announced the preparation of artificially radioactive elements.

* Marie Curie discovered the two new elements – radium and polonium.

Branches of chemistry

1. Study the list of topical vocabulary to avoid the difficulties in understanding the text in exercise III. Consult the dictionary to pronounce the words correctly.

artificial – искусственный

branch – раздел

be connected with – быть связанным с

consider – рассматривать

constituent – составная часть, компонент

deal with – иметь дело с, касаться

deposition – осаждение

fundamentals – основы

law – закон

measurement – измерение

point out – указывать

possess – обладать

practice – заниматься, практиковать

qualitative – качественный

quantitative – количественный

treat of – трактовать, говориться

unite – объединять

utility – полезность

vital – жизненно важный, существенный

II. Translate the following words and constructions into Russian. Try to memorize them. Make up sentences using these words.

In order to, to be due to, in part, particularly, since, whereby, directly.

III. Read and translate the text, say what its main points are. Study the vocabulary notes after the text.

BRANCHES OF CHEMISTRY

Chemistry is defined as the study of matter and its transformations. Chemists study substances in order to learn as much as they can about their properties and reactions that change them into other substances. They discover many laws, investigate many important phenomena, create many artificial substances with valuable properties. This knowledge is growing fast and becoming broad and more detailed. So, the necessity to unite similar scientific facts and divide chemistry into some separate fields appeared.

There are more than thirty branches of chemistry. Some of them are: organic and inorganic chemistry, analytical chemistry, physical chemistry, biochemistry, nuclear chemistry, colloidal chemistry, electrochemistry etc.

The birth of biochemistry, for example, is due to the close link of chemistry and biology.

Inorganic chemistry studies substances which cannot be got from living organisms. Inorganic chemistry explains and develops the Mendeleyev’s Periodic Law stating: «The properties of the elements are periodic functions of their atomic numbers (positive charges of their nuclei)». Inorganic chemistry is concerned with the combinations of atoms and the causes of their combination, the formation of molecules and ionic crystals from atoms. Besides, it considers the relationship of the properties of substances and their atomic and molecular structure.

Organic chemistry treats of substances which are composed in part of carbon, and many of which are associated with living bodies, plants and animals. The separation of organic chemistry as a branch takes place in science because there are more compounds of carbon than compounds of all the other elements put together¹. So, organic chemistry is a very large branch of chemistry.

Analytical chemistry is concerned with the identification, separation and quantitative measurement of the composition of different substances. Practicing analytical chemistry means dealing with different analytical methodologies applied to solving scientific problems. Chemical analysis – qualitative and quantitative – has helped chemists to discover many elements existing on Earth, to account scrupulously its reserves of chemical elements. Chemical analysis has enabled them to identify the constituents of chemical compounds, both simple and complex. Chemistry owes much to analysis its becoming a science. So, it is usual to believe² that to be a good chemist it is necessary to be a good analytical chemist first.

Physical chemistry deals with those data of chemistry which are closely linked with physics. Physical chemistry includes many principles of both chemistry and physics. The knowledge of physical chemistry is particularly important to all branches of chemistry, since its fundamental laws are the basis all these branches are established upon.

Electrochemistry is believed to be a branch of physical chemistry. It studies the relation between electrical energy and chemical change. Electrochemistry develops the scientific fundamentals of electrolysis, electrosynthesis, corrosion protection of metals, creation of chemical electric current sources etc. Electrolysis is the process whereby electrical energy causes a chemical change in the conducting medium (which is usually a solution or a molten substance). This process is generally used as a method of deposition of metals from a solution.

Photochemistry considers reactions caused by the effect of light. The most important natural photochemical process is photosynthesis. One of the first laws in photochemistry formulated in 1818 is that only light which is absorbed is photochemically effective. Later the new laws in photochemistry were developed by A. Einstein.

Nuclear chemistry covers the study of atomic nuclei transformations and the structure of atomic electron shells. Nuclear chemistry is directly connected with nuclear physics, radiochemistry and physical chemistry. Some dictionaries point out that the term nuclear chemistry is often used in the same sense as radiochemistry.

The division of chemistry into some branches or, in other words, the integration of chemistry with other fields of science causes the technological progress. It helps to create substances that are not found in nature but possess important properties of great utility and vital for the wellbeing of mankind. This produces the improvement in the standard of living.

Vocabulary notes:

¹ put together – взятые вместе

² it is usual to believe – принято считать

IV. Translate the following words, define the part of speech they belong to. Find their synonyms in the text Branches of Chemistry.

To deal with, consider, to be connected with, to divide, important.

V. Find all the international words in the text. Say what Russian words help to guess the meaning of these words. Make up sentences using some of these international words.

VI. Read the following English word combinations taken from the text Branches of Chemistry. Choose their Russian equivalents.

associated with living bodies	применяемый для решения научных задач
atomic electron shells	превращения атомных ядер
to owe much to smth	позволять выявить компоненты химических соединений
the effect of light	база, на которой основываются все разделы химии
conducting medium	электронные оболочки атомов
atomic nuclei transformations	разрабатывать научные основы
to develop scientific fundamentals	связанный с живыми организмами
to enable to identify the constituents of chemical compounds	воздействие света
the basis all branches of chemistry are established upon	быть многим обязанным чему-либо
applied to solving scientific problems	проводящая среда