Revision exercises

Ex.1. Answer the following questions:

1.What is the phenomenon of isomerism? 2. How are isomers classified according to the order of atoms or their arrangement in space? 3. Describe the isomerism tree. 4. Characterize each type of isomerism. 5. When are isomers super imposable? 6. What discoveries were made by Woehler and Pasteur to prove isomerism? 7. Who introduced the term isomerism?

Ex.2. Match the words with their definitions:

1. occur	a. to cause (two or more people or things) stop being together, joined or connected
2. arrangement	b. to connect, to combine, to unite
3. introduce	c. the act or process of moving or turning around a central point
4. link	d. the amount of a substance that will dissolve in a given amount of another substance
5. separate	e. to cause something to begin to be used for the first time
6. solubility	f. to happen, to be found or met with
7. rotation	g. the way that things are organized for a particular purpose or activity

Ex.3. Say whether the following statements are true or false:

1.Topological isomers called topoisomers are generally large molecules that wind about and form different shaped knots or loops. 2. Geometric isomers are superimposable. 3. The central carbon atom, to which four different atoms or groups are attached, is called an asymmetrical carbon atom. 4. Chain isomerism occurs when the way carbon atoms are linked together is the same. 5.Two molecules that have the same molecular formula but differ in the way atoms are arranged are called asymmetrical molecules. 6.There are three types of structural isomerism: chain isomerism, positional isomerism and functional isomerism.

Ex.4. Insert the necessary word:

1. The roots of the word isomer are Greek—isos plus meros, or “equal parts.” 2. Stated colloquially, isomers are chemical … that have the same parts but are nonetheless not the same. 3. To make a crude analogy, two bracelets, each consisting of five red and five green beads, could be … in many different isomeric forms, depending on the order of the colours. 4. Each bracelet would have the same parts—that is, the five red and five green beads—but each … would be different. 5. One could also imagine … of those same beads in which pendant chains were attached to a bracelet in

a variety of ways. 6. One might imagine two bracelets of the same red-green order but with … chains attached in different orientations. 7. Such structures also would be analogous to isomers. 8. In a more subtle …, one’s hands can be seen as isomeric. 8. Each hand possesses the same kinds of fingers, but a right … can never be superimposed perfectly on a left hand; they are different. (identical, variation, hand, arranged, combinations, compounds, analogy).

Ex.5. Translate the following text: