Pay attention to the pronunciation of the following words.

[o] v o lume, m o lecule, s o lid, qu a ntity

[ei] sh a pe, st a te, obt ai n

[e] r e lative, poss e ss, ess e ntial

Pay attention to the stress in the following words. Pronounce them.

ֽextra´ordinary	´molecule
´temperature	´ vaporize

Read the text and fulfil the exercises.

BASIC STATES OF MATTER

That matter may exist in three physical states (solid, liquid, and gas) is common knowledge. It is usually possible to change matter from one state to the other by changing its temperature. For instance, a piece of ice is called a solid: it may melt and form liquid: as it evaporate s, liquid water changes into vapour, i.e. into gaseous state.

Many kinds of matter, like water, can be obtain ed in each of the three states; for some, however, extraordinary means have to be used in order to produce one, or even two of the states; and for others, only two states are known or can be produced.

Common salt, for example, exists normally as a solid; at temperature of several hundred degree s, it can be liquefied; and at still higher temperature it is converted into vapour. Carbon, a solid under normal conditions, can be vaporized, but it has never been liquefied.

Solid s have both a definite volume, but they take the shape of their containers. Gases have neither a definite shape nor a definite volume. A chemist must have a thorough knowledge of the states of matter and of physical laws that govern the behaviour of matter in various states.

That all matter is compose d of molecules is known to everybody. The question which must be answered, then, is: if all matter is compose d of molecule s, what is the essential difference between the states of matter? The answer to this question is that the essential difference between these states is the relative quantities of energy molecule s possess in different states.

4. Look through the text again and find the sentences where the author describes:

1) the facts that are well-known;

2) examples of matter changes;

3) the necessity for a specialist to know matter transformations;

4) a question on the matter composition and the answer to it.

Find English equivalents to the given Russian words, word combinations and chemical terms.

1. общеизвестно 2. обычно 3. существовать 4. чрезвычайные средства 5. таять/плавиться 6. градусы 7. определенный 8. состоять из 9. относительное количество 10. преобразовываться

11. получить 12. произвести 13. форма 14. твердое тело 15. испаряться 16. объем 17. тщательный/глубокий 18. аналогично 19. выпариваться 20. углерод

6. Match the Russian words, word combinations and chemical terms from Ex.5 with their English equivalents.

a) to obtain b) common knowledge c) definite d) relative quantity e) still f) to melt g) to exist h) volume i) to evaporate j) to produce k) thorough

l) like m) usually n) carbon o) to be composed of p) extraordinary means q) to vaporize r) degrees s) to convert t) solid u) shape

Answer the following questions to the text using the dictionary.

1. How is it usually possible to change matter from one state to the other?

2. Can all kinds of matter be obtained in each of the three states?

3. What do solids have?

4. What characterizes gases?

5. Why should a chemist know the states of matter?

6. What other substances besides water can be obtained in the three states?

Lesson IV

WHY IS WATER SO IMPORTANT?

Lead-in

What comes to your mind if you see or hear the word “water”?

Complete the following chart with your ideas and share the information with your fellow students.

Vocabulary

1) steam	- пар
2) surface	- поверхность
3) ice	- лед
4) change of state	- изменение состояния
5) heating	- нагревание
6) point of view	- точка зрения
7) chemical reaction	- химическая реакция
8) decomposition	- разложение, распад, деструкция
9) fundamental	- основной, базисный
10) importance	- важность, значение
11) physical change	- изменение физических свойств
12) compound	- соединение
13) electric current	- электрический ток
14) hydrogen	- водород
15) oxygen	- кислород

Pay attention to the pronunciation of the following words.

[i:] st ea m, h ea ting, t ea cher, ea sy

[Λ] s u bstance, f u ndamental, c u rrent