I.4. Определите функцию каждого из выделенных слов в предложении и назовите часть речи, к которой они относятся (глагол или существительное).
1. Carbon forms extensive covalent bonds not only with other elements but also with itself.
2. Minerals are available in tablet, capsule, powder, and liquid forms.
3. The body needs vitamin B2 for proper circulation and healthy skin.
4. Oral contraceptives may increase the needs for folic acid.
5. The largest amounts of vitamin B12 are found in cheese, eggs, liver, milk and seafood.
6. A daily dosage of vitamin A for good health amounts to 10,000 IU.
7. Acne is a sign of various hormonal changes that take place at puberty.
8. During a chemical reaction a substance changes its chemical structure and composition.
I.5. Подчеркните сказуемое в каждом предложении и назовите его видо-временную форму в активе или пассиве по следующему образцу.
Inorganic chemistry deals with the compounds of all the chemical elements except carbon. (deals – Present Simple Active)
1. In October 1807 the English chemist Sir Humphrey Davy isolated potassium and then sodium.
2. Industrial chemistry deals with making in vast quantities the chemicals required by modern industry.
3. Physical chemistry is concerned with those parts of chemistry which are closely linked with physics.
4. Pharmacy is the branch of chemistry which is carried out in a drugstore.
5. Analytical chemistry deals with the content of materials and is divided into two subjects: quantitative analysis and qualitative analysis.
6. Quantitative analysis examines the amounts of different elements within a compound.
7. Biochemistry involves the study of compounds and chemical reactions occurring in living organisms.
8. The study of the inside of the atom revolutionized chemistry and physics in the 20th century.
9. Some substances react so rapidly and violently that only careful monitoring of the conditions will lead to the desired effect.
10. Frequently, heating will increase the rate of a reaction.
I.5. Прослушайте небольшой текст и скажите, о чем в нем говорится.
II. Работа с текстом.
II.1. Ознакомьтесь со словами к тексту А:
| the universe [ju:nI΄ v@:s] | вселенная |
| state [steIt] | состояние |
| property [΄ prOp@tI] | свойство |
| size [΄saIz] | размер |
| atom [΄eIt@m] | атом |
| electron [I΄ lektrOn] | электрон |
| charge [΄ tSA:dZ] | заряд |
| nucleus [΄ nju:klI@s] (pl nuclei) | ядро |
| valence[΄ veIl@ns] | валентность |
| way [΄ weI] | способ, образ действия (то, как что-то делается) |
| bond, bonding[΄ bOndIÎ] | связь |
| ion [΄ aI@n] | ион |
| total [΄ tout@l] | общий |
| diverse [daI΄ v@:s] | разнообразный |
| atomic[@΄ tOmIk] | атомный |
| ionic [aI΄ OnIk] | ионный |
| complete [k@m΄ pli:t] | полный |
| abundant[@΄ bönd@nt] | распространенный, обильный |
| the melting point | точка плавления |
| the boiling point | точка кипения |
| to decompose [dI:k@m΄ pouz] | разлагать на составные части |
| to constitute [΄kOnstItju:t] | составлять, входить в состав |
| to occur [@΄ k@:] | встречаться |
| to account (for)[@΄ kaunt] | насчитывать (ся) |
| to indicate[IndI΄ keIt] | указывать |
| to determine[dI΄ t@:mIn] | определять |
| to move [΄ mu:v] | двигаться, перемещаться |
| to hold [΄ hould] (held, held) | удерживать |
| to gain [΄ geIn] | приобретать, принимать |
| to lose [΄ lu:z] (lost, lost) | терять, отдавать |
| to transfer [tr{ns΄ f@:] | перемещать |
| to arrange [@΄ reIndZ] | размещать, располагать |
| obviously [΄ ObvI@slI] | очевидно |
| accordingly [@΄ kO:dIÎlI] | соответственно |
| extremely [Iks΄ tri:mlI] | чрезвычайно, крайне |
| according to [@΄ kO:dIÎt@] | согласно, в соответствии с |
II.2. Прочтите следующие вопросы и пометьте те из них, на которые вы можете ответить. Назовите номера вопросов, на которые вы затрудняетесь ответить.
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1. What does all matter basically consist of?
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2. What is a chemical element?
3. Can you name the most abundant elements in nature?
4. What is the total number of elements known today?
5. What do the properties of the chemical elements depend on?
6. What does the atomic number of an element indicate?
7. How is the ability of an atom to combine with another atom called?
8. How are the atoms held together?
9. What kinds of bonding do you know?
10. What is the Periodic Table of elements?
II.3. Прочтите текст А и найдите в нем ответы на «трудные» вопросы. Назовите номера вопросов в предыдущем упражнении, на которые вы ответили неправильно.
Text A
Chemical elements
A chemical element is any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Chemical elements constitute the fundamental materials of which all matter consists. Of all the known elements, 90 occur in nature either chemically free or in combination with other elements.
About one-third of the elements found in nature occur in a chemically free state on Earth. These elements, which obviously are not very active chemically, include nitrogen, gold, platinum, copper, and the noble gases. The five most abundant elements in the Earth’s crust are oxygen (466,000 parts per 1,000,000, or 46.6 percent), silicon (27.7 percent), aluminum (8.1 percent), iron (5 percent), and calcium (3.6 percent). Hydrogen is by far the most abundant element in the universe, accounting for more than 90 percent of the total number of atoms and for about three-fourths of the mass. Helium is next in abundance, constituting about 7 percent of the number of atoms and nearly one-fourth of the total mass.
The properties of the elements are to a large degree attributable to the electronic structure and size of their atoms. Accordingly, they are extremely diverse. Helium, for example, has the lowest-known melting point (-271.4 0C at 29.6 atmospheric pressure) and boiling point (-268.98 0C) of any of the elements, while tungsten has the highest-known melting point (3,370 0C) and boiling point (5,900 0C).
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The atomic number of an element indicates the number of protons (positively charged particles) in the nucleus of a given atom. It is also the number of electrons (negatively charged particles) in the atom that determines the chemical properties of the element. Each electron moves in an atomic orbit (equivalent to a particular energy level) around the nucleus.
The ability of an atom to combine chemically with another atom is called its valence. The valence of an element is the number of electrons it needs to gain or lose in order to make it stable. Atoms require a total of eight electrons in the outermost energy level to be stable in the case of the lightest atoms (hydrogen and helium) the number is two.
The way in which atoms are held together is known as bonding. The covalent bond is a type of chemical bond in which atoms are held together by shared pairs of electrons which move around both atoms. The electrovalent (or ionic) bond is another kind of chemical bond between atoms. Here, electrons are transferred from one atom to another forming ions. This produces electrostatic attraction; in other words, the attraction between opposite charges holds the ions together.
As the list of different elements grew in the 19th century–by 1860 over 80 were known – chemists attempted to group them together and to classify them according to their behavior. In 1869 the Russian chemist Dmitri Ivanovich Mendeleyev made a complete table by arranging the elements in order of their atomic weights in rows so that elements with similar properties appeared in columns.
The Periodic Table produced by Mendeleyev was refined by further research into the structure of atoms. At present there are 110 known chemical elements. (The discovery of element 110, reported in 1987 by Soviet scientists, remains unconfirmed, however, and is still considered extremely tentative).
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