progressive - degressive

To derive from

To divide into

To occur

To include

To describe

To identify

to invent

to distinguish

to separate

to apply

to depend on

to consist of

Ex. 3. Read and translate:

carbon dioxide, formulation, carbon monoxide, carbonate, conductor, formulism, to melt, covalent bonds, derivative, derivation, atomic number, atomic mass, division, reactivity, radioactivity, chemical equation, description, descriptive, ionic bonds.

Ex. 4. Use the prefix “de-“ to form new words:

Eg. compose – decompose

progressive - degressive

to generate, to mobilize, to calcify, to carbonize, to centralize, to code, to increase, to induce, formation, hydration, gradation, proficit, induction, effective.

Ex. 5. Mind the pronunciation of the following elements, write their chemical symbols:

Boron, manganese, nitrogen, potassium (kalium), hydrogen, bromine, calcium, sulfur (sulphur), sodium, chromium, carbon, mercury, selenium, lead, neptunium, helium, beryllium, neon, plutonium, palladium, platinum, oxygen, iron, copper, magnesium, lithium, zinc, zirconium, chlorine, radium, silver, aluminium, gold, iodine, tin.

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Ag, Al, Au, B, Be, Br, C, Ca, Cl, Cr, Cu, Fe, H, Hg, He, I, K, Li, Mg, Mn, N, Na, Ne, Np, O, Pb, Pd, Pt, Pu, Ra, S, Se, Sn, Zn, Zr.

Ex. 6. Divide the elements above into two groups: metals – non-metals. Comment on their physical and chemical properties.

Ex. 7. Read and translate the following text:

A chemical symbol is an abbreviation or a short representation of the name of a chemical element, generally derived from its Latin or Greek name. That is why chemical symbols may not be similar to their English equivalents (e.g., Na is used for sodium (Latin natrium) and Au is used for gold (Latin aurum). All natural elements have symbols consisting of one or two letters; some man-made elements have symbols of three letters.

Chemical symbols are listed in the periodic table of Mendeleev. Each element has its atomic number, atomic mass and period number. According to it, all elements are divided into groups or families, for example alkali metals, transition metals, halogen gases, inert gases. Each chemical element possesses physical and chemical properties. Physical properties include: density, boiling point, melting point, conductivity, heat capacity. Chemical properties include valence, reactivity, radioactivity. Chemical symbols are used in chemical equations to describe the process of a chemical reaction.

A chemical formula is a combination of chemical symbols of elements that constitute a particular chemical compound. A chemical formula also describes how a chemical reaction occurs. It identifies each constituent element of a compound and indicates the number of atoms of each element. For example a simple molecule of methane, consisting of one carbon atom and four hydrogen atoms, has the chemical formula: CH₄ and glucose with six carbon atoms, twelve hydrogen atoms and six oxygen atoms has the chemical formula: C₆H₁₂O_6. The system for writing chemical formulas was invented by Swedish chemist Jons Jakob Berzelius in the 19^th century.

Ex. 8. Choose the best answer to the question according to the text:

1. What is a chemical symbol?

- derivation from Latin or Greek

- initial letters of the name of a chemical element

- name of a chemical element represented in short

2. Natrium and sodium…

- are two different elements

- are two English synonims

- both represent one and the same element

3. Periodic table of Mendeleev…

- is a list of chemical symbols

- helps to determine atomic number, atomic mass and period number of an element

- is structural division into groups or families

4. Physical properties of an element do not usually include:

- heat capacity

- reactivity

- conductivity

5. A chemical formula is used…

- to identify each constituent element of a compound

- as a combination of chemical symbols of elements

- by Swedish chemist Jons Jakob Berzelius

Ex. 9. Answer the questions:

1. Why do people use chemical symbols?

2. Who invented the periodic table?

3. What physical properties do you know?

4. What does a chemical formula describe?

5. Who was Jons Jakob Berzelius?

Ex. 10. Divide the following elements into two groups: Latin – English.

Translate them.

Nitrogen, platinum, calcium, tin, potassium, hydrogen, sulfur, sodium, carbon, gold, aluminium, mercury, selenium, lead, neptunium, oxygen, helium, iodine, zinc, beryllium, neon, chlorine, silver, plutonium, iron, copper, lithium, zirconium.

Ex. 11. Read and translate the following chemical symbols:

Na, Fe, Be, Cl, Ag, Zn, K, Pt, He, Mg, Mn, Al, S, Au, B, H, Cu, Br, C, Hg, I, Ca, Li, N, O, Sn.

Ex. 12. Read and translate the following text:

A chemical compound is a substance consisting of two or more different elements chemically bonded together.The atoms in the molecule of a compound can be held together by no bonds, covalent bonds or ionic bonds. For example H₂O is held together by polar covalent bonds. Sodium chloride (NaCl) is an example of an ionic compound. Compounds have different physical and chemical properties from their constituent elements. This is the one principal criterion for distinguishing a compound from a mixture of elements or substances: properties of a mixture are generally similar or related to the properties of its constituents. Another criterion is that the constituents of a mixture can usually be separated by simple, mechanical means such as filtering, those of a compound are often very hard to separate. Furthermore, when a compound is formed from its constituents, a chemical change takes place through chemical reactions. Mixtures can be made only by mechanical means. Compounds may have several possible phases. All compounds can exist as solids, at least at low enough temperatures. Molecular compounds may also exist as liquids, gases, and, in some cases, even plasmas. All compounds decompose upon applying heat. The temperature at which such fragmentation occurs is often called the decomposition temperature. Decomposition temperatures depend on the rate of heating. At sufficiently high temperatures, all compounds, either after they have decomposed somehow or in the act of decomposing, fragment into smaller compounds or to individual atoms.

Ex. 13. Say wether the following statements are true or false:

1. A chemical compound is a mixture of elements or substances.

2. H₂O is an example of an ionic compound.

3. Compounds have similar physical and chemical properties with their constituent elements.

4. There is only one principal criterion for distinguishing a compound from a mixture of elements or substances.

5. Constituents of a compound usually can not be separated by simple, mechanical means such as filtering.

6. Mixtures can be made only chemical reactions.

7. All compounds can exist as liquids, gases, and plasmas.

8. Decomposition temperature is the temperature at which fragmentation of a compound occurs.

Ex. 14. Answer the following questions:

1. What is a chemical compound?

2. What types of bonds do you know?

3. What are criteria for distinguishing a compound from a mixture of elements or substances?

4. What is the difference between compounds and mixtures?

5. What is “decomposition temperarure”?

Ex. 15. Find in the text the words which mean the following:

“connection”, “link”, “cohesion”

“to differentiate”

“part of a whole”, “component”

“to isolate”, “to divide”

“to make up”, “to create”

“particular characteristic”

“state”, “condition”

“to fragment”, to breake into smaller parts”

“method”, “way”

Ex. 16. Read the text and fill in the gaps according to the sense:

Elements form ………. to become more stable. They become stable when they have the maximum number ……… possible electrons in their energy level, which is normally two or eight valence electrons. This is the reason why some gases do not frequently ………..: they already ………… eight valence electrons (the exception being helium, which ………… only two valence electrons to achieve stability).

Ex. 17. Describe the following chemical formulae according to the plan:

- constituent elements

- number of atoms

- chemical bonds

NH_3, H₂SO_4, HCl, C₂H₅OH, HNO_3, NaNO_3, H₂CO_3, CaCl_2, C₆H_6, CaCO_3, H₃PO_4, C₆H₅OH, FeSO_4, KOH, NH₄Cl, Al₂O_3, Ca(OH)_2, AgNO_3, C₆H₁₂O_6, CuSO_4, H₂SO₃

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фенол, оксид алюминия, оксид железа, хлористый аммоний, этиловый спирт, сернистая кислота, фосфорная кислота, угольная кислота, соляная кислота, азотная кислота, серная кислота, нитрат серебра, нитрат натрия, хлорид кальция, бензол, карбонат кальция, гидроксид калия, гидроксид кальция, глюкоза, сульфат меди, аммиак.

Ex. 18. Describe the physical and chemical properties of the compounds above. Write down chemical equations to show their formation and try to explain the process of chemical reactions.