17. Read the information about several cross-disciplinary and more specialized branches without a dictionary and decide what field of chemistry it is about.

1. Untill the end of the nineteenth century chemists said that elements couldn’t be converted into one another by any means. Then it was discovered that the certain phenomenon involves the spontaneous transmutation of elements. In 1919 the artificial conversion of nitrogen into carbon was carried out by Lord Rutherford. Progress in this field became very rapid after 1930. Now it has become a large and very important branch of science. Over four hundred radioactive isotopes have been made in the laboratory conditions, whereas only about three hundred stable isotopes have been detected in nature. The controlled release of nuclear energy made a great contribution to the development of both industry and overlapping sciences.

2. Many chemical reactions take place by the effect of light. A very important chemical reaction is known as the conversion of carbon dioxide and water into carbohydate and oxygen in the leaves of plants, where green substance chlorophyll serves as catalyst. The law discovered in 1818 states that only light which is absorbed is photochemically effective. Thus a coloured substance must be present in a system that shows photochemical reactivity with visible light. In some simple systems the absorption of one quantum of light causes the reaction of decomposition of one molecule.

3. It is the science involved with designing, synthesizing and developing pharmaceutical drugs. It involves the identification, synthesis and development of new chemical entities suitable for therapeutic use. It also includes the study of existing drugs, their biological properties, and their quantitative structure-activity relationships.

4. It is the study of chemistry via theoretical reasoning (usually within mathematics or physics). Since the end of the Second World War, the development of computers has allowed a systematic development of computational chemistry, which is the art of developing and applying computer programs for solving chemical problems. It has large overlap with condensed matter physics and molecular physics.

UNIT IV Chemistry as a Profession

Grammar: Review of the Simple Tense Forms

The use of either … or, neither … nor

Text: Chemistry as a Profession and as an Aid to Other Professions

1. Translate and memorize the following words.

collaborate	get thin	sluggish
overcome	get thick	sound
retain	make up	viscosity
improve	alleviate	lubricant

2. Read the following words and define the parts of speech. Mind

the stress:

collaborate – collaboration – collaborator; improve – improvement; viscosity – viscous; alleviate – alleviation; expected – unexpected; medicine – medical – medicinal; lubricate – lubricant – lubricants; appreciate – appreciation; present – to present.