Примечания к тексту

1. are not those of water – не являются свойствами воды

2. set of properties – ряд свойств

Запомните следующие слова и словосочетания:

admixture, amount, ash, boiling point, brittle, case, clouded, contain, distinguish, enumerate, feldspar, hardness, heavy, homogeneous, heterogeneous, melting point, mica, mixture, odour, property, pure, retain, sample, set, soluble, specific gravity, substance, transparent, varying, volatility

Упражнения

1. Найдите в тексте придаточные предложения: определительные и обстоятельства времени, цели, условия и следствия.

2. Дайте анализ следующего предложения:

Analytical chemistry has for its aim the determination of the constituents of which a substance or a mixture is composed by methods which are qualitative when the identification is to be carried out or quantitative when the quantity or proportion is determined.

3. А) Определите типы придаточных предложений, обращая внимание на союзы. Б) Переведите предложения на русский язык:

1. Any element when it combines with oxygen forms an oxide. 2. The methods of determination of specific gravity are well known to everybody as they are used on a large scale. 3. That oxygen can be liquefied only under high pressure was proved by experiments. 4. The process oxygen takes part in is known as oxidation. 5. In order to learn the properties of a substance we must have it in its pure form. 6. Oxygen has been known since the 18^th century. 7. Oxygen can be liquefied provided that pressure is sufficiently high. 8. If sugar and water are mixed, crystals of sugar disappear, but those crystals form again as water evaporates. 9. Whether water or other liquid is used as a solvent depends on many factors.

4. Напишите глаголы, от которых образованы данные существительные:

production, mixture, activity, difference, existence, application

5. Сгруппируйте антонимы, переведите их на русский язык:

similar, heterogeneous, soluble, different, transparent, colorless, pure, heavy, easily, hard, homogeneous, insoluble

6. Заполните пропуски следующими словами и словосочетаниями и переведите предложения на русский язык:

one must, foreign, in order to, properties, turns brown, easily, pure

1. Substances are distinguished by their … . 2. Sugar is … soluble in water. 3. Sugar … when it is heated. 4. … learn the properties of a substance … have it in its … form. 5. Small admixtures of … substances change the properties of a substance.

7. Выберите правильный вариант перевода:

1.	примесь	а)	brittle
2.	углерод	б)	enumerate
3.	образец	в)	distinguish
4.	полевой шпат	г)	transparent
5.	постороннее вещество	д)	specific gravity
6.	неоднородный	е)	property
7.	свойство	ж)	heterogeneous
8.	удельный вес	з)	foreign substance
9.	прозрачный	и)	feldspar
10.	различать	к)	sample
11.	перечислять	л)	carbon
12.	хрупкий	м)	admixture

8. Прочитайте следующие числа:

3.725, 13.819, 12/16, 3/125, ¼, ½, 0.115, 0.003, 5², 3³

9. Ответьте на следующие вопросы:

1. What are the properties substances are distinguished by? 2. Is sugar easily soluble in water? 3. What colour is sugar? 4. Is sugar lighter or heavier than water? 5. What taste has sugar? 6. What is its specific gravity? 7. In what form must one have a substance in order to learn its properties? 8. What may change the properties of a substance? 9. What happens if a drop of milk is added to a glass of water? 10. What substances does granite consist of?

10. Проделайте парную работу на перевод с русского языка на английский:

А	B
Все окружающие нас предметы состоят из веществ. (All objects surrounding us consist of substances.)	All …
They …	Они состоят из одинаковых молекул. (They consist of similar molecules.)
Гранит состоит из нескольких веществ. (Granite consists of several substances.)
Therefore …	Поэтому гранит состоит из разных молекул. (Therefore granite consists of different molecules.)
Химия изучает вещества и их состав. (Chemistry studies substances and their composition.)	Chemistry …
It …	Она также изучает процессы и законы, по которым происходит изменение их состава. (It also studies processes and laws according to which the change of their composition takes place.)

11. Прочитайте текст 5 В, не пользуясь словарем:

TEXT 5 B

Physical and Chemical Properties of Substances

Properties. Bodies are composed of materials such as wood, steel, cement, stone, silver, gold, lead, iron, etc. These materials may be either homogeneous or heterogeneous. A substance is defined¹ as a variety of matter which has definite properties and definite composition. All samples of a substance possess the same properties and have the same composition, regardless of their source². Every substance therefore possesses specific physical properties, such as colour, odour, density, hardness, melting point, and boiling point.

Every substance also possesses definite chemical properties; these concern its transformations³ into other substances, and especially, the different kinds of substances into which it can be transformed. Water is an example of a substance; one sample of water is like all others and there is only one set of properties by which all samples of water can be described and identified.