Unit III. Liquids

I. Language.

Exercise 1. Read and memorize the following words:

attraction –тяжiння

to break –ламати

to collide- стикатися

drop –крапля

to escape –утекти

eventually –у кiнцевому рахунку , зрештою

gain –одержувати , здобувати

lattice –решiтка , сiтка

to melt – розчинятися, плавитися

to overcome –побороти

to remain –залишатися

to spread out –простягатися

vigour –енергiя , сила

vinegar -оцет

Exercise 2. Guess the meaning of the following international words:

molecule , energy , container , crystal , perfume ,temperature ,process ,eucalyptus ,group .

Exercise 3 .Find the synonymic pairs.

essential ,universal , to cause , liquid, to deposit , fluid ,to make , general , principal , to precipitate .

Exercise 4. Form the antonomic pairs.

to cool , eventually ,to supply ,to attract , boiling point , to repell , to provide , at last , to heat , freezing point .

II.Reading.

Exercise 5. Read and translate the text A “ Liquids”.

Text a Liquids

As we heat the solid its molecules gain energy until they are able to break out of the lattice and the solid melts .The molecules have not yet enough energy to move very far apart when thev are free to move. When they do so, they often collide with the sides of the' container they are in, the liquid taking up the shape of the container? If not in a container the liquid spreads out on the surface - that is the substance has lost its definite shape. In a con­tainer, a liquid still has one surface open to the atmosphere as vapour. The molecules in a liquid as a whole have more energy than those in the crystal lattice, the force of attraction between the molecules being already less strong. It is probable that more of them will escape and thus liquids more than solids give off smell, e.g. perfumes, methylated spirit, eucalyptus oil, vinegar, etc.

A liquid being heated is provided still more energy and the molecules begin to move about with greater vigour. Thus, many molecules having more energy reach the surface of the liquid, they overcome the force of attraction and leave the liquid as vapour. When eventually all the molecules begin to behave in this manner the liquid boils and the temperature at which this process takes place is the boiling point of the liquid. The opposite process occurs if hot vapour is cooled. After having lost their energy the molecules begin to move shorter distances and more slowly, the attraction be­tween them growing stronger until a point is reached where they can no longer remain free. They move forming small groups and drops of liquid are formed. Condensation has taken place.

III.Language.

Exercise 6. Match the words in column A with their equivalents in column B.

A В

1. attraction 2.solid 3.vinegar 4.to melt 5.to escape 6.drop 7. smell 8.vigour 9.definite 10.methylated spirit

1.плавитися 2 . крапля 3.запах 4.тяжiння 5.сила 6.тверда речовина 7. певний 8. утекти 9.денатурат 10. оцет

Exercise 7. Read and translate the sentences paying special attention to the translation of the Participle I,II .Define their functions .

1. The molecules of the solids when heated break out of the lat­tice, the solid melting.

2. Gaining enough energy to move far apart, the molecules often collide with the sides of the container they are in.

3. The students investigating this phenomenon carry out the ex­periments in the laboratory of general chemistry.

4. Breaking out of the lattice the molecules of the solid gain enough energy, being free to move.

5. The experiment being carried out by the researcher deals with the liquid state of matter.

6. Having prepared everything for the experiment, they reviewed once more the theoretical back­ground for its fulfilment.

Exercise 8.Read and translate the sentences paying attention to the translation of the Participle Constructions .

1. Molecules are in constant motion, the motion becoming more rapid with the increase of temperature.

2. The temperature being raised, the kinetic energy is increased.

3. The evaporation increases with the temperature, other conditions being equal.

4. Water power being one of the best and cheapest ways of producing electricity, it is widely utilized to drive generators which provide electric current.

5. This material being used in electronics, its properties should be studied closely.

6. Non-metallic materials are of great importance, some of them being widely used in place of metals.

7. They have to compare their experiments, their results being different

8. The data having been obtained, we discussed the results at the confer­ence.

9. Water being heated, it boils at 100°C.

Exercise 9. Substitute Ukrainian words for English one given below:

1.The molecules have not yet enough energy to move н абагато окремо .

( side by side, far apart, closely )

2.The molecules in a liquid have more energy than those in the crystal решiтцi .

( gate , net , lattice )

3.Liquids more than solids виділяє smell e.g.perfumes , vinegar, etc.

( emit ,give off , escape)

4. A liquid яку нагрiвають is provided still more energy .

( being cooled , being frozen , being heated )

5.Many molecules overcome the force of тяжiння and leave the liquid as vapour .

( evaparation , attraction , hardness)

6.The temperature at which the molecules leave the surface is the точка кип iння .

( boiling point , melting point , freezing point )