Chemical Compounds

Step I. Speculate on the following

Ø What’s a compound?

Ø Are there any kinds of chemical compounds? What kinds of chemical compounds do you know? Name them.

Ø What kind of chemical compound is extremely common on the Earth?

Step II. Find in the text sentences with the following word combinations and try to guess their meanings:

Ø decomposition temperature; general scientific usage; general term; molten salts; with exception of.

Step III. Match the following:

1. химическое соединение	a. decomposition
2. определять	b. refer to
3. разложение	c. chemical compound
4. раствор	d. determine
5. реакция нейтрализации	e. solution
6. относиться к чему-либо	f. neutralization reaction

Text

Chemical Compounds

A chemical compound is a chemical substance formed from two or more elements, with a fixed ratio determining the composition. A defining characteristic of a compound is that it has a chemical formula. Formulas describe the ratio of atoms in a substance, and the number of atoms in a single molecule of the substance. The formula does not indicate that a compound is composed of molecules; for example, sodium chloride (table salt, NaCl) is an ionic compound. Compounds may have a number of possible phases. Most compounds can exist as solids. All compounds can decompose to smaller compounds or individual atoms if one heats to a certain temperature (called the decomposition temperature).

There are the following types of compounds: acids, bases, ionic compounds, salts, oxides, organic compounds and so on.

An acid is typically a water-soluble, sour-tasting chemical compound. In common usage an acid is a species that, when dissolved in water, gives a solution with a pH of less than 7. In general scientific usage an acid is a molecule or ion that is able to give up a proton to a base, or accept an unshared pair of electrons from a base. An acid reacts with a base in a neutralization reaction to form a salt.

Bases and acids are referred to as opposites because the effect of an acid is to increase the hydronium ion concentration in water, whereas bases reduce this concentration.

An ionic compound is a chemical compound in which ions are held together in a lattice structure by ionic bonds. To form an ionic compound, there needs to be at least one metal and one non-metal. The metal element is usually the positive charge and the non-metal element is a negative charge. Some properties of ionic compounds are high melting and boiling points and good conductivity. Ionic compounds are solids at room temperature and will usually form crystals.

Salt is a general term used for ionic compounds composed of positively charged cations and negatively charged anions, so that the product is neutral and without a net charge. Solutions of salts in water are called electrolytes. Electrolytes as well as molten salts conduct electricity. Zwitterions are salts that contain an anionic center and a cationic center in the same molecule.

An oxide is a chemical compound of oxygen with other chemical elements. Oxides are extremely common in Earth's crust, and indeed in solid matter throughout the universe. Oxides are usually created through the process of oxidation. Generally, oxides are not conductive to electricity.

An organic compound refers to any member of a large class of chemical compounds whose molecules contain carbon, with exception of carbides, carbonates and carbon oxides. The study of organic compounds is termed organic chemistry.

Topical vocabulary

acid –кислота; base – основание; carbide ['kɑːbaɪd] – карбид; carbonate ['kɑːb(ə)neɪt] – карбонат; conductivity [ˌkɔndʌk'tɪvətɪ] – проводимость, conduct - проводить; decompose [ˌdiːkəm'pəuz] - разлагать (ся), распадаться; decomposition - разложение, распад; dissolve [dɪ'zɔlv] - растворять (ся); hydronium [haıʹdrəunıəm] – гидроксоний; lattice structure – решетчатая структура; molten salts – расплав солей; oxide ['ɔksaɪd] - оксид ; ratio ['reɪʃɪəu] –отношение, соотношение, пропорция; sodium chloride ['səudɪəm] ['klɔːraɪd] - хлорид натрия, поваренная соль; soluble ['sɔljəbl – растворимый; solution – раствор; sour ['sauə] – кислый; species ['spiːʃiːz] – вид, разновидность; Zwitterion [ʹtsvıtəraıən] - цвиттер-ион, амфотерный ион, амфион (биполярный ион)  (молекула, которая, являясь в целом электронейтральной, в своей структуре имеет части, несущие как отрицательный, так и положительный заряды).

Step IV. Find in the text English equivalents to the following Russian word combinations:

xимическое вещество, образованное из двух или более молекул; основная характеристика соединения; формулы изображают соотношение атомов в веществе; формула не показывает, что вещество состоит из молекул; растворимое в воде и кислое на вкус химическое соединение; раствор, ph которого ниже 7; химическое соединение, в котором ионы имеют решетчатую структуру; температура плавления; температура кипения; положительный и отрицательный заряды; хорошая проводимость; твердые вещества при комнатной температуре; положительно заряженные катионы; отрицательно заряженные анионы; без результирующего заряда; соли, содержащие катионный и анионный центры в одной молекуле; соединение кислорода с другими химическими элементами; земная кора; в процессе окисления; соединения, чьи молекулы содержат углерод.

Step V. Agree or disagree.

1. A chemical compound is a chemical substance formed from only one element.

2. A defining characteristic of a compound is that it has no a chemical formula.

3. Bases and acids are referred to a similar chemical compounds because the effect of an acid is to increase the hydronium ion concentration in water, whereas bases reduce this concentration.

4. To form an ionic compound, there needs to be at least one metal and one non-metal. The metal element is usually a negative charge and the non-metal element is a positive charge.

5. Ionic compounds are solids at room temperature and will usually form crystals.

6. Solutions of salts in water are called electrolytes and molten salts can conduct electricity.

7. Oxides are extremely common in Earth's crust, and indeed in solid matter throughout the universe.

8. Generally, oxides are conductive to electricity.

9. An organic compound is a chemical compounds whose molecules contain carbon.

10. The study of organic compounds is termed inorganic chemistry.

Step VI. What is this?

1. A chemical substance formed from two or more elements is _________________. 2. A representation of a substance using symbols for its constituent elements is _____________. 3. Water-soluble and sour-tasting chemical compound is _______________. 4. A product of neutralization reaction, when an acid reacts with base is _______________. 5. A chemical compound in which ions are held together in a lattice structure by ionic bonds is _____________. 6. A liquid or gel that contains ions and can be decomposed by electrolysis is ______________. 7. Salts including an anionic center and a cationic center in the same molecule are ________________. 8. A chemical compound containing two oxygen atoms per molecule is _____________. 9. A chemical compound containing one oxygen atom and one other element is________________. 10. Compounds whose molecules contain carbon are _____________. 11. A compound of chemical elements containing no carbon atoms are _______________.

Step VII. Answer the questions.

1. What is a chemical compound?

2. What describes formula?

3. Can compounds decompose to a smaller compounds or individual atoms?

4. What types of compounds do you know?

5. What is acid?

6. Are bases opposite to acids?

7. What is an ionic compound?

8. Ionic compounds are solids at room temperature, aren’t they?

9. What is an oxide?

10. What’s an organic compound?

11. What is the difference between an element and a compound?

Step VIII. Discuss with your partner the following statements.

1. Compounds may have several possible phases.

2. Physical forces rarely break down compounds completely.

3. Compounds have few or none of the physical or chemical traits of the original element.

Step IX. Choose any chemical compound and prepare a report.

Fun Time

Chemistry Quiz

1. Can an element be broken down into a simpler substance?

A. Yes

B. No

2. What is a compound?

A. A substance made up of one kind of mixture

B. A substance made up of one kind of element

C. A substance made up of two or more elements

3. Sea water, smog and brass are all examples of …?

A. Alloys

B. Ionic compounds

C. Mixtures

D. Covalent compounds.

4. The simplest unit of a compound is?

A. Neutron

B. Proton

C. Atom

D. Molecule

5. What is used to represent the number of atoms of each element in a compound?

A. Mass number

B. Valence number

C. Atomic number

D. Chemical formula

6. Sodium chloride is also known as

A. Baking soda

B. Table salt

C. Washing soda

D. Bleach

7. Which of the following is a compound?

A. Calcium

B. Oxygen

С. Water

D. Hydrogen

8. Are there more compounds than there are elements?

A. Yes

B. No