XIII. Translate the following word-combinations into Russian.

a science of substances, a great and complex subject, at an ordinary temperature, may become liquids, at very high temperatures, two great classes, consist of, may be metallic and non-metallic

XIV. Translate the following word-combinations into English.

наука о веществах, разлагаемый, может быть разделен, при обычной температуре, в трех состояниях, твердые вещества, до соответствующей температуры, состоять из двух и более различных веществ, азот и углерод, превращаться

XV. Read the text and translate it. Do the tasks below.

 

Chemistry

Chemistry is a science of substances, their structure, their properties and the reactions that change them into other substances. Chemistry is a great and complex subject.

Substances may exist in any of the three states. They may exist as solids, liquids or gases. Sulphur, iron and silver are solids at an ordinary temperature, bromine and mercury are liquids in the same conditions and oxygen and hydrogen are gases. But solid substances may become liquids if we heat them to a proper temperature. Liquids turn into gases at very high temperatures.

Elements and Compounds. All substances can be divided into two great classes, namely, elements and compounds.

An element is an undecomposable substance, all compounds are substances, which consist of two or more different substances, and so they can be decomposed into two or more simple substances. Water can be decomposed into oxygen and hydrogen.

Elements may be metallic and non-metallic. Nitrogen and carbon are non-metals, but lead and tin are metals.                           

 

XVI. Fill in the gaps with the proper words.

1. Do you know chemical …. of Hydrogen?

2. Iron and silver are …

3. Hydrogen is a …..

4. Elements are …. Substances.

5. Mercury is ….

 

(gas, properties, metal, elements, undecomposable)

 

XVII. Fill in the gaps with prepositions.

1. Chemistry is the science which deals …. substances, their structure and their properties.

2. The scientific foundation … chemistry began to appear in the 18^th century.

3. Water can be decomposed … oxygen and hydrogen.

4. Now there are more than 30 different branches … chemistry.

5. Sulphur, iron, and silver are solids … an ordinary temperature.

 

XVIII. Complete the sentences.

1. Chemistry is the science of substances, their structure, …

2. Liquids turn into gases ….

3. Sulphur, iron and silver are solid…

4. All substances can be divided …

5. All compounds are substances which consist of …

6. Water can be decomposed …

XIX. Translate the sentences into English.

1. Элементы следует разделить на 2 больших класса.

2. Серу, железо, серебро следует отнести к твердым веществам.

3. Бром и ртуть следует считать жидкими веществами

4. Вам следует нагреть твердые вещества до определенной температуры, чтобы получить их в жидком состоянии.

 

XX. Tick the sentences that are true and change the ones that are false.

1. Chemistry is a science of substances, their properties and the reactions.

2. All substances can be divided into three great classes.

3. Elements may be only non-metallic.

4. Sulphur, iron and silver are liquids.

5. Water can be decomposed into oxygen and hydrogen.

 

XXI. Answer the questions.

1. What is Chemistry?

2. Which states do substances exist in?

3. Is iron a liquid or a solid element?

4. May solid substances become liquids?

5. Which groups are all elements divided into? 

XXII. Make up a plan of retelling.

XXIII. Retell the text.

XXIV. Make up a dialogue according to the topics.

1. Chemistry

2. Elements and compounds.

 

Lesson III

Hydrogen

Word formation: Suffixes of nouns - ion, - tion

Grammar: Degrees of comparison of the adjectives and the adverbs

Text:  Hydrogen

Assignments to do:

Remember:

Suffixes -ion, - tion form the nouns from the verbs:

to prepare – готовить; preparation- подготовка;to translate – переводить; translation – перевод.