Experiments in the Laboratory

7. Many experiments can be carried out in the laboratory of inorganic chemistry. Thus, if we want to obtain hydrogen chloride (HCl), which is often referred to as a hydrochloric acid gas, it is necessary to pour some sulphuric acid through a tube over the crystals of sodium chloride in a flask. The flask is to be heated. On warming the flask, the hydrogen chloride is expelled as a colourless gas with a suffocating odour. It produces heavy clouds of white fumes when it comes in contact with the moist air of the room. It is soluble and it cannot be collected over water as oxygen and hydrogen can. It is much heavier than the air and may be passed through a glass tube to the bottom of the bottle. If we dissolve some of the gas in water, the solution has a sour taste, reddens blue litmus, reacts with zink, etc.: it is hydrochloric acid. When all the sodium chloride originally presents in the flask has been transformed, the reaction is complete. The flask then contains the salt called sodium acid sulphate (NaHSO4) together with unchanged excess of sulphuric acid.

VII. Прочитайте текст и ответьте на вопросы к нему

1. What is a laboratory?

2. What are laboratories equipped with?

3. What laboratory equipment is mentioned?

4. How can you get a hydrochloric acid?

5. What experiments can be carried out in the laboratory (give some examples)?

6. What is every laboratory to be provided with?

VIII. На основе текста составьте тему “ Laboratory”

ВАРИАНТ V

I. Перепишите и переведите следующие предложения. Определите, какой частью речи являются все слова с окончанием -s и какую функцию это окончание выполняет, т. е. служит ли оно:

– показателем 3-го лица единственного числа глагола в Present Simple;

– признаком множественного числа имени существительного;

– показателем притяжательного падежа имени существительного

1. Chemical reactions are the processes that convert substances into other substances.

2. This scientist uses computers for many different purposes.

3. Mendeleev’s greatest discovery was the Periodic Law.

II. Перепишите и переведите следующие предложения, учитывай особенности перевода определений, выраженных именем существительным

1. These space flight requirements are very important.

2. The effect of laser radiation on various materials has considerable importance.

3. Engineers maintain the same temperature level during the experiment.

III. Перепишите следующие предложения, содержащие разные формы сравнения, и переведите их

1. Beryllium is the least active member of the group, and there is a regular increase in activity from metal to metal in the order of increased atomic numbers.

2. At that time he presented the more familiar form of the Periodic Table and although it differs somewhat from the one we use today.

3. The more heat is supplied to a liquid, the quicker it evaporates.

IV. Перепишите и переведите предложения, обращая внимание на неопределенные и отрицательные местоимения

1. There were some famous scientists at the conference.

2. They made no changes in the working plan.

3. Does he have any problems in this field of science?

V. Перепишите следующие предложения, определите в них видовременные формы глаголов и укажите их инфинитив; переведите предложения

1. The study of the universe will be of great practical use for the study of our own planet.

2. The workers installed new equipment in the chemical laboratory.

3. The manufacturer wants to reduce noise emission of the equipment.

VI. Прочитайте и устно переведите текст

Пояснения к тексту