I. Speaking: Chemical Elements. Properties of Substances

Exercise 1. Test yourself: do you remember these words? Read, pay attention to their translation.

Change: change of color; chemical changes; physical changes. We can change the color of metals.

Produce: the factory produces various materials; production of materials; this medicine was produced in 1929.

Consider: they considered themselves very important; they consider him a famous scientist; we must consider his youth; she is considered a very clever girl.

Rain: It rains today; when it rains, I usually stay at home; there was a heavy rain last night.

Establish: our college was established in 1928; there are many higher educational establishments in our city; it is established that the substance dissolves slowly.

Leaf (pi. leaves): Leaves of trees are green in summer; the last leaf falls to the ground; leaves fall in autumn.

Exercise 2. Read the following words of Latin or Greek origin. Pay attention to their spelling and pronunciation.

Periodic [piari'Ddik], hydrogen ['haidracbjan], carbon [^-ka:ban], nitrogen ['naitracfjan], iodine ['aiadi:n], concentration [,krjnsant'reijh], ion [aian], oxygen ['oksicfjan], phosphorus ['fbsfaras], chlorine ['klt>ri:n], potassium [pa'taesjem], calcium ['kaelsiam], human ['hju:man], total ['tautl], evolution [,i:va lojan], constituent [kan'stitjuanf], sodium ['saudjam], protein ['prautim], bicarbonate [bai'ka:banit], ammonium [a'maunjem], phosphate ['fosfeit], sulphate ['sAlfeit], diet ['daiaf], dioxide [dai'Dksaid], metal ['metl], molecular [mau'lekjula], molecule ['mt)likju:l], organic [a:'gaenik], lithium [liOiam], magnesium [ma;g'ni:zjam], bromine ['braumkn], liquid [Tikwid], component [kam'paunant], mixture ['mikstfa], practical ['praktikal], chromatography [,kroma'rogran], caustic soda ['ka:stik'sauda], sulphur ['sAlfa].

Exercise 3. Read and learn the following words: a) names of chemical elements or their combinations:

lead [led] свинець fluorine ['floari:n] фтор

diamond ['daiamand] алмаз; діамант fluoride ['floaraid] фторид

copper ['кора] мідь gold ['gauld] золото

iron [aian] залізо silver ['silva] срібло

solid ['snlid] тверда речовина bone - кістка tissue - тканина

light - легкий

transparent [traens'paearanf] прозорий

rapid - швидкий

affect - впливати

separate - відділяти

sample ['sasmpl] зразок; проба

detect - відкривати, знаходити, виявити

b) names of substances:

sugar ['Juga] цукор sand [saend] пісок dust [dAst] пил

c) names of physical properties:

sense [sens] відчуття; відчувати taste [teist] смак odor ['auda] запах break [breik] ламати freeze [fri:z] замерзати deform - деформувати density f'densiti] питома вага soft - м'який

Exercise 4. Fill in the blanks with the verbs affect, occur, separate, remove, detect.

1. Oxygen and nitrogen widely ... in nature. 2. High temperature and pressure ... sometimes the composition of a compound. 3. It is necessary to ... impurities before the beginning of the experiment. 4. Water can be ... by means of distillation. 5. Chlorine is a greenish yellow gas which is not difficult... by its odor.

Exercise 5. Answer the questions.

1. Is fluorine a gas? 2. Does lead deform under the action of high temperatures? 3. Does diamond deform under the action of high temperatures? 4. Does the human body contain inorganic substances? 5. Is oxygen present in the human body? 6. Does water constitute 45 to 75 % of the total weight of the human body? 7. Is calcium contained in bones? 8. Are there important inorganic constituents in the human body in addition to water? 9. Is carbon the most common element of living matter? 10. Do most of inorganic elements occur in living matter? 11. Is chlorine a greenish yellow gas? 12. Does sodium conduct electricity? 13. Is sodium a very reactive substance? 14. Is the river water a mixture of substances? 15. Is distilled water a pure substance?

Exercise 6. Read the sentences, name the tense and voice of the verbs.

1. Water freezes at the temperature of 0°C. 2. It is considered that life developed in the water of the Earth. 3. One half of the body weight is due to carbon. 4. Physical changes do not mean a change in the composition of a substance. 5. Some elements easily conduct electricity. 6. Many drugs affect living cells and are considered a strong poison. 7. Tea and coffee are characterized by different taste and odor. 8. Water is a colorless, odorless and transparent liquid with a boiling point of 100°C. 9. It is difficult to separate and detect constituents of drugs.

Exercise 7. Name the chemical elements in English.

Fe, Cu, O, Na, K, HC1, S, H₂S0₄, CI, C, Ca, F, PI, N, 1, H,0.

Exercise 8. Read the text and translate it.

Symbols in chemistry stand for the elements. For example, H, O, N, CI, K, S stand for the elements hydrogen, oxygen, nitrogen, chlorine, potassium, sodium respectively. The chemical symbol stands only for one atom of the element. The atom is the smallest particle of the element that can enter into chemical combinations. Atoms can combine and form molecules. For example, two atoms of hydrogen will form a molecule of hydrogen.

When different atoms combine as in the case of water (H,0) or sulphuric acid (H₂S0₄), the formulas say what atoms and how many of them are present. For example, H₂S0₄ molecules consist of two hydrogen atoms, one sulphur atom and four oxygen atoms.

Exercise 9. Match the nouns to the verbs.

solidify	detection
suspend	characteristics
characterize	suspension
locate	separation
deform	occurrence
take	deformation
consider	identification
identify	intake
establish	consideration
occur	establishment
separate	location
detect	solid

Exercise 10. Read the description of some chemical elements. What elements are spoken about? Use their names instead of blanks.

1. ... occurs naturally both free and combined in the form of sulphates of calcium, barium, magnesium, and sulphides of zink, iron, copper, and mercury. One of the most abundant minerals containing ... is iron pyrites. In volcanic regions, for example, in Italy, North America, ... is found in free state associated with native sulphate and carbonate. ... occurs in group VI of the Periodic Classification, which includes oxygen, sulphur, selenium, tellurium, together with the metals of the A subgroup. ... and oxygen are in many ways similar.

2. Of the three elements - iron, cobalt, and nickel - which are included in group VII of the Periodic Classification, ... finds important uses in medicine. ... is not generally met in the free state but its combinations are widely distributed. ... forms two series of salts. Solutions of ... salts are usually very pale green.

3. ... is a colorless liquid having a characteristic alcoholic odor. The boiling point is 66"C. It mixes in all proportions with water and with ethyl alcohol and burns with a pale blue flame, forming water and carbon dioxide. Chemically it is very reactive. ... is neutral to litmus, but reacts with concentrated acids. With acetic acid it gives methyl acetate. It reacts readily with phosphorus trior pentachloride with the formation of methyl chloride.

Exercise 11. Complete the sentences using the following word combinations.

1. Sugar and salt have ... . 2. Breaking, freezing, melting, boiling and deforming of a substance are considered .... 3. The reaction of sodium with chlorine is a typical... .4. Filtration can be used to separate the iron powder from the ... . 5. Most of nitrogen, sulphur and iodine and heavy metals are present or combined with ... 6. Life is dependent upon great amounts of ... .7. Toxic substances can be classified into several categories according to ... .

(sulfur solution, chemical reaction, organic molecules, many different elements, effects on the body, different tastes, physical changes)

Exercise 12. Communicative situations.

1. Tell English tourists about Dmitriy Mendeleev.

2. Tell about the Periodic Classification of the Chemical Elements.

3. Characterize some of the chemical elements according to the plan:

1. Physical properties of the chemical elements (odor, taste, color).

2. Physical and chemical changes.

3. Properties of some chemical elements.

4. Chemical elements of living matter and their amount.

5. Water, its composition.

6. Purification of substances.

7. Methods of purification.