Vocabulary

аccept - приймати attach - кріпити bitter - гіркий definition - визначення dissociate - дисоціювати extremely - дуже, надмірно litmus - лакмус loosely - вільно

turn - повертати widely - широко replaceable - замінний soapy - мильний somewhat - кілька, певним чином sour - кислий taste - смак

Exercises

1. Answer the following questions.

1. What are bases and acids?

2. What are the properties of acids and bases?

3. How can acids and bases be produced in the laboratory?

2. Complete the sentences (use the text).

1. We have (a wealth of) information about ... . 2. In water solution acids yield H+ ions which ... . 3. All water solutions of acids contain ... . 4. An acid can be produced by ... .

5. Some important acids are ... . 6. Most bases are ... . 7. Among the more important bases are ... . 8. All water solutions of bases have ... . 9. Bases may be made by ... .

3. Characterize acids and bases using the following plan.

1. Bases are chemical opposites of acids.

2. The properties of water solutions of bases.

3. The production of bases.

4. What do we call acids?

5. What are the properties of water solutions of acids due to?

6. What do all water solutions of acids contain?

7. How can an acid be produced?

8. What are bases?

9. What bases do you know?

10. What acids do you know?

11. How can bases be made?

4. Find the pairs of synonyms.

to change, as, to possess, probable, to have, possible, device, speed, to let, velocity, apparatus, to permit, because, to transform

5. Match English word combinations with their Ukrainian equivalents.

1. differ somewhat а. дещо відмінні

2. are loosely attached b. розчинна основа

3. by adding c. шляхом додавання

4. soluble base d. вільно з’єднані

6. Make up sentences.

1. An atom, which, carries, an ion, is, or, group of atoms, an electrical charge.

2. Compounds, consist, electrovalent, of particles, state, in, the ionic.

3. Compounds, exist, the form, in, of crystals, usually, electrovalent.

7. Give definitions to acids and bases using this phrase.

I've got some useful information about...

8. Read and translate the sentences. Pay attention to the meaning of the word term.

1. The proper use of chemical terms is essential for your report.

2. The word term may have tens of meanings.

3. These examples are presented in terms of organic chemistry.

4. Non-metallic oxides are termed acid anhydrides.

5. The second term begins in February.

6. Your terms are unacceptable for me.

METALS

Chemically, metals are defined as elements which form positive ions in solutions and whose soluble oxides are basic. If elements form negative ions in solution or are parts of negative ions and form soluble oxides which are acidic, we shall name them non-metals.

Some elements act as metals under certain conditions and as non-metals under other conditions. Such elements are classified as amphoteric. Another group consists of elements which do not combine with other elements under normal conditions. Until recently, it was believed that these elements could not enter into any chemical combination and they were called the inert elements. Chemists have produced compounds of some of these elements.

Metals are the chemical opposites of non-metals. Metals tend to lend electrons while non-metals tend to borrow or share electrons when they combine with each other to form salts. Metals and non-metals generally differ in physical properties. Metals are good conductors of electricity and heat, non-metals are generally non-conductors or very poor conductors. In the solid state metals have a characteristic luster which non-metals do not have. And in this state metals arc malleable, and ductile, non-metals being brittle, non-malleable and non-ductile. Non-metals generally include the following 22 elements: helium, neon, argon, krypton, xenon, radon, hydrogen, fluorine, chlorine, bromine, iodine, astatine, oxygen, sulphur, selenium, tellurium, nitrogen, phosphorus, arsenic, carbon, silicon, and boron, the remaining elements being generally classified as metals, hydrogen having a dual character and being generally included in both groups.