Text 1: The Measurements in Chemistry

In order to¹understand the quantitative relationships which exist between various kinds of matter, the chemist who is interested in matter and the changes which it undergoes, has to measure the quantities of matter with which he works, that is²since mass is the measure of the quantity of matter, he is to measure mass. The measuring device the chemist is to employ in this determination should be the balance.

Since for every chemical change there is always accompanying energy change which the chemist has to take into account³, the calorimeter and the thermometer have to be used.

The chemist usually employs graduated cylinders, burettes, pipettes and volumetric flasks for the measurements of volumes of liquids, and the gas burette for the measurement of volumes of gases.

The chemist employs the barometer if he has to measure the pressure.

The analytical chemist and the physical chemist employ such devices as calorimeters, polarimeters, refractometers and a number of electrical devices.

If the chemist is to examine very small samples of matter, he should use a microscope. The microscope is an instrument which by the combination of lenses permits man to see objects which are too small to be seen with a naked eye. It is an instrument which is useful in many sciences and which, although more frequently used in a qualitative way can also be used quantitatively.

¹in oder to – для того щоб

²that is (i.e.) – тобто

³to take into account – приймати до уваги

The Metric System

The fundamental unit of the metric system is the metre. The millimetre and centimetre are the units which the chemist uses very frequently in his work.

If one is to measure extremely short distances, the micron is to be used.

The unit of mass is the gram, milligram or the kilogram.

The unit of the heat measurement is the calorie.

Ex. 14. Answer the questions according to the model:

Model: What is the crucible used for?

It is used for heating.

1. What is the thermometer used for? 2. What is the balance used for? 3. What is the calorimeter used for? 4. What is the microscope used for?

Ex. 15. Answer the following questions.

1. What relationship exists between various kinds of matter? 2. What is the chemist to do if he wants to understand the quantitative relationships between various kinds of matter? 3. What does the chemist use balances for? 4. When does the chemist use a calorimeter and thermometer? 5. What is it necessary to use in order to measure volumes? 6. What devices do the analytical and physical chemists use? 7. What device does the chemist use if he wants to examine very small samples of matter? 8. What is the fundamental unit of the metric system? 9. When can the micron be used? 10. What is the unit of volume? 11. What is the unit of the heat measurement?

Ex. 16. Translate the following sentences, mind the verbs.

1. They had to use balances in their work. 2. He was to determine the relationships between these two substances. 3. You should take into account all the results of your first experimental work. 4. In order to determine the definite weight some of the samples have to be examined. 5. Students should know that barometers can be of two types, that is (i.e.) mercurial and aneroid. 6. The quantity of the sample is to be measured before the experiment. 7. Various instruments are to be employed if chemists want to get necessary results. 8. Some balances are much more sensitive than others and chemists should take this fact into account. 9. Students have to know the metric system. 10. When a chemist finishes his work he is to put the analytical balance into a special glass box. 11. For a number of reasons, mercury is to be used in barometers. 12. Everything has to be put in order when you finish your experiments in the laboratory. 13. The industry spread to areas where coal had to be used.

Ex. 17. Find the pairs of synonyms and remember them.

matter, various, main, quantity, often, different, use, amount, employ, frequently, substance, fundamental

Ex. 18. Open the brackets choosing a suitable word. Translate the sentences into Ukrainian.

1. (A balance, a calorimeter, a thermometer) is a device which determines the quantity, but not the quality of heat in a body. 2. If a chemist determines mass he is to employ (a flask, a thermometer, a balance). 3. (A calorimeter, a flask, a microscope) is used if a chemist must examine small samples of matter. 4. For the measurement of volumes of gases a chemist uses (burettes, pipettes, gas burettes). 5. The unit of (volume, mass) in the metric system is the gram. 6. On (the Centigrade scale, the Fahrenheit scale) the freezing point of water is 0° 7 If a chemist must measure extremely short distances (the centimeter the micron) is to be used.

Ex. 19. Choose the Ukrainian equivalents from the right column:

relationship	піддаватися
to take into account	приймати до уваги
determination	відношення, зв’язок
to undergo	вимірювання
flask	колба

Ex. 20. Read and render the text.

A thermometer is a device which is used to determine the temperature of a body. Two bodies of unequal size may have the same temperature; the bigger contains more heat, but the quality of the heat in each is the same. Thermometers take many forms, the commonest of which is the mercury-bulb variety.

There are two scales – Centigrate and Fahrenheit.

On the Fahrenheit scale the freezing point of water is marked as 32^° and boiling point of water as 212^°. On the Centigrade scale the freezing point of water is called 0^° and its boiling point 100^°. Thus, 130 divisions on the Fahrenheit scale are equal to 100 divisions on the Centigrade scale, and 1^°F=5/9^°C.

If the chemist wants to convert temperatures from one scale to the other, the following formulas are to be used:

С. = 5/9 (F —32) and F = 9/5 С.+ 32

Ex. 21. Translate the text and answer the questions that follow.