Water is the most abundant substance

The abundance of water in liquid, solid and gaseous state is a matter of common observation. Water is not only the most abundant compound, but it is also very important for life. To be sure life would be impossible without water.

For many purposes water must be pure. The purest natural water is rain. But we can't say that it is really pure. The same can be said about ground water. It contains a great deal of impurities which fail to settle. Dissolved substances do not settle and don't evaporate with water, and this makes their removal difficult. One of the most important problems is to obtain water sufficiently pure to meet our needs. The choice what process is to be used for purification of water depends upon the uses for which it is intended as well as the impurities it contains. Water used for steam boilers should be free from substances that cause corrosion and scale formation. Water for washing should not contain substances that react with soap. When water is to be used for drinking, it is necessary to kill the microbes it may contain. To achieve this, water which is to be purified is thoroughly filtered.

Another way to purify water is to boil it. None of these methods is fit for producing pure water in the chemical sense, because most of the soluble salts are unaffected by the treatment. To remove these and to prepare chemically pure water suitable for scientific use, we take advantage of the fact that water is usually changed to steam while most of the dissolved substances as have already been mentioned are not volatile. If we condense the steam, we are thus able to remove all the impurities except volatile ones. This process is called distillation. Distilled water has many uses, both in the laboratory and in industry, when even small quantities of impurities are undesirable.

Vocabulary

dissolve

purify

pure

ground

removal

scale

abundance

compound

volatile

a great deal

Answer the questions

1. What is water?

2. What is the purest natural water?

3. What makes the process of purification difficult?

4. What does the choice what process is to be used for purification of water depend upon? Enumerate these processes.

5. How do you understand ''pure water in the chemical sense''?

6. Can you explain what distillation is?

3. Make a report “Why is water so important?”

Future Continuous Tense

Future Continuous, иногда именуемое Future Progressive – это длительное (продолженное) будущее время английского глагола. Это время употребляется для обозначения действия или состояния, которое будет происходить в течение некоторого времени в будущем, иными словами, продлится некоторое время.

Обстоятельства времени, указывающие на время

Future Continuous Tense

Exercises

Ex. 1

Open the brackets using Future Continuous Tense

1. She (to sleep) at home the whole day tomorrow.

2.They (to stay) at a new hotel.

3.I (to live) in Kyiv for the next few weeks.

4. He (to write) a letter at that time.

5. You (to do) your home task all these days?

6. They (to enjoy) the sunshine on the beach?

7. Victor (to read) the whole night?

8. We (to have) coffee?

9. Tony (to have) a bath at this time?

10. Where you (to wait) for me?

11. Susan (to do) at nine o’clock tomorrow?

12. When he (to pass) his exam?

13. When she (to type) letters?

14. We (not to speak) at ten o’clock.

Ex. 2

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