Give your answer to the following question; add other characteristics of the element

Which metal is the best conductor of heat and electricity? Its conductivity is a standard, which means that all other metals are compared to it when it comes to measuring their conductivity of heat and. electricity. Another thing about it is that it reflects 95% of all the light reaching it, which makes it the whitest and brightest of all metals. It was the rarest and most precious metal for ancient Egyptians. It is five hundred times more expensive than iron, fifty times more expensive than copper, but is only worth one-fiftieth as much as platinum and one-twentieth as much as gold.

5. Translate the following sentences into English:

1. У своїй статті Менделєєв писав, що він відкрив періодичний закон.

2. Стародавні греки вважали (вірили), що речовина складається з нескінченно (infinitely) малих часток.

3. Аристотель (Aristotle) думав, що його теорія узгоджуватиметься з його загальними поглядами (general views) на природу.

4. Уже в 1789 році Лавуазьє доповів Французькій академії наук, що вода – це сполука кисню та водню.

5. У той час Прістлі не розумів, що його відкриття дуже важливе.

6. Кавендіш (Cavendish) відкрив, що вода складається з певного відсотка (proportion) кисню та водню.

7. Автори твердо переконані, що їхня робота може вплинути на розвиток хімії.

8. Ми повинні провести новий дослід, тому що необхідно (it is necessary) отримати ці речовини.

9. Ми не знали, що повинні були обрати хід реакції.

10. Доповідач (speaker) повідомив, що повинен закінчити нову серію () експериментів.

11. Якоб Берцеліус (Jacob Berzelius) почав свої дослідження після того, як дізнався про атомістичну теорію Дальтона (Dalton).

12. Авогадро (Avogadro) розробив нову гіпотезу до того, як були класифіковані елементи.

13. Крукс (Crookes) зміг описати декілька характеристик променів (rays).

14. Бор (Bohr) був упевнений, що теорію світла, розроблену Планком (Planc) і Ейнштейном (Einstein), можна застосувати до атома.

TEXT 9

WATER

Learn the new vocabulary:

compound	сполука, сполучення
fraction	частка
minute droplets	дрібні краплини
solvent	розчинник
composition of water	склад води
to be stated	бути доведеним / установленим
pure / impure	чистий / нечистий
to purify	очищувати
odourless	без запаху
to freeze	замерзати
to boil	кипіти
pressure	тиск
major constituent	основна складова частина

1. Read and translate the text:

Water is hydrogen oxide, a compound of hydrogen and oxygen. It can be made if hydrogen or a hydrogen-containing substance is burnt in air or oxygen.

Most of the world's water is liquid, but an important fraction is solid as ice and snow.

Many mineral substances contain water of crystallization (e. g., copper sulphate) and in the atmosphere there are millions of tons of water vapor. Clouds consist of minute droplets of water or crystals of ice.

Water dissolves a very large number of substances and is the most important solvent. It does not dissolve greasy, fatty substances or most plastics.

After they had found the composition of water, the scientists could investigate its properties. It was stated that ordinary water is impure it usually contains dissolved salts and dissolved gases, and sometimes organic matter.

For chemical work water is to be purified by distillation. Pure water is colorless, tasteless, and odorless. Rain water formed by condensation of water in the air is nearly pure water, which contains only small proportions of the dust and of dissolved gases.

After the examination of the water properties the chemists found that physical properties of water can be used to define many physical constants.

The freezing point of water (saturated with air at 1-atm pressure) is taken at 0 С and the boiling point of water at 1 atm is taken as 100°С

The unit of volume in the metric system is chosen so that 1 ml of water at 3.98°С (the temperature of its maximum density) weighs 1,000 g/cm.

So water is one of the most important of all chemical substances. It is a major constituent of living matter and of the environment in which we live.

2. Read and translate the following words both as nouns and verbs:

change, state, water, mark, influence, increase, decrease, experiment, experience, comment, matter.

3. Give Ukrainian equivalents to the following words, word combinations and chemical terms:

Nouns: 1.condition, 2.current, 3.hydrogen oxide, 4.importance, 5.point of view, 6.quarter, 7.surface, 8.vapour.

Verbs: 9.burn, 10.cool, 11.cover, 12.heat.

Adjectives: 13.artificial, 14.dangerous, 15.marked, 16.strict.

Adverbs: 17.commonly, 18.exactly, 19.in this way.

Conjunctions: 20.either … or …

4. Match the words of ex. 3 with their synonyms given below:

a) to warm up k) water

b) usually l) viewpoint

c) stream m) synthetic

d) steam n) to fire

e) to chill o) rigorous

f) hazardous p) to hide

g) the 4th part of a whole q) significance

h) noted r) the outer part

i) state s) precisely

j) thus

5. Match antonyms in A and B:

А                           В

1. the commonest    a) impossible

2. like                      b) the most unusual

3. simple                  c) old

4. usually                d) common

5. new                e) few

6. single                    f) exceptionally

7. many                   g) to lose

8. decomposition     h) natural

9. to obtain               i) unlike

10.possible               j) integration

11.easy                    k) complicated

12.dangerous            1) secure

13.artificial             m) lenient

14.strict                   n) difficult

6. Change the given sentences into indirect speech:

1.The author writes: "Three-quarters of the Earth is covered in water."

2.The writer asks: "Is it possible to make water from its elements?"

3.The scientists stated: "The radiation from thorium nitrate is unsteady."

4.Rutherford remarked: "It's really very fine to see the things one has seen in imagination visibly demonstrated."

5.He said: "I have already drawn your attention to the social implications of the release of atomic energy."

6.Pauling often repeated: "I keep on the outlook for aspects that I don't understand."

7.The scholars usually asked: "What causes electrons to change orbits?"

8.They also asked: "Is the electron a wave or a particle?"

TEXT 10

ATMOSPHERE

Learn the new vocabulary:

layer	шар
to cover	покривати, укривати
blanket	ковдра
thin stuff	тонка матерія, тонкий
to hardly know	погано знати
at the bottom	на дні
to climb / climber	підніматися, залазити / альпініст
sea level	рівень моря
exactly	точно, правильно
deep	глибокий
to mix together	змішуватися
spontaneously	спонтанно, довільно, стихійно
to escape the Earth	полишати Землю, відриватися від Землі
single substance	однорідна речовина
gradually	поступово
plenty of ways	багато способів
to put it another way	іншими словами
apart from	окрім
amount	кількість, об’єм
density	густина
to contaminate	забруднювати, псувати
light bulb	електрична лампочка

1. Read and translate the text:

The layer covering the Earth like a blanket is called the atmosphere. It is made of very thin stuff called air. Air is so thin you hardly know it's there. But it's all around us.Really, we live at the bottom of a very deep "ocean of air".

Air gets thinner and thinner as you go up. There's enough air to breathe at the top of Mt. Everest (five miles above sea level), but getting there is hard work! Most climbers have used breathing apparatus on their way up. By the time you get to 50 miles above sea level, there's practically no air left. The air doesn't stop suddenly, however, so it's impossible to say exactly how deep the atmosphere is.

Air is not a single substance. It's made of a number of gases all mixed together. It's impossible to stop gases mixing together. They mix together spontaneously. So a gas that escapes from the Earth becomes a part of the atmosphere. Scientists believe that the atmosphere has changed a very great deal since the Earth was first formed. At first, the atmosphere may have been made up of gases like ammonia, methane, carbon dioxide and water vapor. Later, the first early forms of life developed and gradually more and more oxygen was added to the atmosphere. Nowadays the main gases in the air are oxygen and nitrogen.

You can easily perform experiments in the laboratory to find out about the air, for example, to prove that it's a mixture rather than a single substance, or find out how much oxygen there is in it. These experiments usually involve getting the oxygen to combine with another substance. In other words, to get rid of the oxygen altogether a chemical reaction is used.

There are plenty of ways to do this because oxygen is a very reactive gas. For instance, burning and rusting are two kinds of chemical change that use up oxygen.

The main gas left after removing oxygen is nitrogen. In fact, nearly all of the remainder (about four-fifths) is nitrogen. To put it another way, 78 percent of the air is nitrogen.

Apart from oxygen and nitrogen, there are only small amounts of other gases in the air. One of them is carbon dioxide. Another of the minor constituents of the air is water vapor. Ordinary air always contains some of it. The best way to show that there is water vapor in the air in the laboratory is to condense the water. This can be done by cooling the air. Altogether there's not much of either water vapor or carbon dioxide in the air, both of them are very important.

So far we've mentioned oxygen, nitrogen, carbon dioxide and water vapor. Are these the only gases in the air? The answer is "no", but it's hard to prove.

Evidence for other gases in the air came towards the end of the 19th century (a long time after oxygen and nitrogen had been sorted out). The work leading to their discovery was an investigation into the density of nitrogen.

Unlike oxygen, nitrogen is very unreactive. So it's difficult to do experiments to remove nitrogen from the air. But it's quite easy to take the oxygen, carbon dioxide and water vapor out of the air practically leaving nitrogen alone. This nitrogen might be called "atmospheric nitrogen".

The main gas that "contaminates" the atmospheric nitrogen is argon. Being a very inert gas, it's used for filling electric light bulbs.

2. Give the answers to these questions using the text and your knowledge of chemistry:

1.Air is not a chemical compound, is it?

2.Is air the same as atmosphere?

3.Can any chemical formula exactly show the proportions of oxygen and nitrogen?

4.What is the nearest simple formula of air?

5.Why can’t you know that the air is around us?

6.Why isn’t it possible to stop gases mixing together?

7.What was the atmosphere made up at first?

8.What are the main gases in the atmosphere nowadays?

9.What can you say about carbon dioxide and its importance?

10.How can you show that there is water vapour in the air?