19. Characterize aluminium using your words and word-combinations written out.

20. Complete the sentences. Choose the answer a, b, or c which you think fits best. Conductivity

It will be interesting to note that an iron wire of the same _1_ as a copper one has a greater resistance. _2_ the same conditions the copper wire allows more current flowing _3_ the iron wire. Copper has a greater conductivity. Conductivity means the _4_ of carrying the current. The _5_ of conductivity is the Siemens or the mho. The unit of resistance is the Ohm.

In 1826 Ohm found a simple _6_ between resistance, current and voltage. He also observed that if the voltage remains the _7_, the greater the resistance, the smaller the current is. So, it has been stated that the current that flows in a circuit is directly proportioned to the voltage and _8_ proportioned to the resistance.

1	A) long	B) longevity	C) length
2	A) at	B) under	C) in
3	A) than	B) then	C) that
4	A) feature	B) characteristics	C) ability
5	A) unit	B) measure	C) property
6	A) relation	B) correlation	C) relationship
7	A) some	B) same	C) simaltenious
8	A) inversely	B) conversely	C) indirectly

UNIT III MIXTURES AND COMPOUNDS

Grammar: Passive Voice

Comparative Constructions

Text: Mixtures and Compounds

1. Translate and memorize the following words.

divide into	mean	collaborate
fall into	result	excess
make up	obtain	prominent
break down	constitute	remarkable
possess	ignite	magnitude
separate	detect	residue
spark	yield	rate

2. Define the parts of speech and translate:

constitute – constituent; continue – continuation – continual; ignite – ignition; mix – mixing – mixed – mixer; obtain – obtainable; follow – follower – following – followed; separate – separation – separable.

3. Find the pairs of synonyms.

to compose, to have, to make, up, to fall into, to constitute, to be divided into, to possess, to combine, to get, to return, to obtain, to separate, to come back.

4. Translate into Russian. Pay attention to "the more... The better"

1. The more we study matter, the better we know it. 2. The more he experimented, the better he understood the laws of nature. 3. The less you study, the less you know. 4. The more experiments you make, the better experimenter you become. 5. The stronger the acid, the greater is the tendency to lose protons. 6. The stronger the magnification, the greater is the possibility to detect whether the body is homogeneous. 7. The faster an object moves, the greater is the air resistance. 8. The lower the atomic weight or atomic number of the inert gas, the lower are its boiling and melting points. 9. The larger the diameter, the smaller is the resistance and hence, the more current will flow through it. 10. The greater the number of free electrons in a substance, the better that substance is a conductor of electricity.

As chemists you’ll easily memorize and transform the universal formula of the Passive Voice formation: be + Participle II.

Study and remember the following chart:

1. This book is translated into many languages.

2. This analysis was examined by our students.

3. The new laboratory will be built next year.

4. Many new houses are being built in our town.

5. When I came to this town our Institute was being built.

6. It has already been used.

7. The innovation had been tried before they came.

8. The synthesis will have been finished by 3 a.m. tomorrow.