4. Answer the questions to the text:

1) What is a centrifuge?

2) What was the first successful centrifuge used for?

3) How can separations be speeded up enormously in centrifugal equipment?

4) In what way is centrifugal force is generated?

5) What does rotating a cylinder at high speed induce?

6) What is the design of a sedimenting centrifuge?

7) What is the principle of action of a filtering centrifuge?

8) What are the advantages of batch machines?

9) What factors are important when determining separation capabilities, and whether a batch or continuous centrifuge is the best option?

10) What are the advantages of centrifugal processing compared with other methods of liquid-solid separation?

5. Change the following sentences according to the model:

Model A:	If this mixture is placed in a test tube, it will glow dull red.
B:	If this mixture were placed in a test tube in two hours, it would glow dull red. C: If this mixture had been placed in a test tube two hours ago, it would have glowed dull red.

1. If metals are heated, oxides will be formed.

2. If any liquid is in a vessel, it will take the shape of the vessel containing it.

3. If some air is allowed to mix with hydrogen, the reaction will take place with a characteristic sound.

6. Translate into Ukrainian paying attention to the word “since”:

1. Since diamond is the hardest substance known, it must be polished with diamond dust.

2. Many years have passed since Mendeleyev made his great discovery.

3. This method of mixing has been used since the days of World War II.

4. This process was developed twenty years ago, since then it has been used in many countries.

5. Carbon is one of the most important and interesting elements, since its compounds are widely distributed in nature and play such an important part in daily life.

7. Say if the following statements are true or false. If the statement is false

and explain why:

1) A motor puts an object in rotation around a fixed axis, applying force perpendicular to the axis.
2) Centripetal acceleration is used to separate substances of greater and lesser density.
3) The ultracentrifuge, devised in the 1883 by the Swedish chemist Theodor Svedberg, found wide application in scientific research.
4) A mechanical method of separating immiscible liquids or solids from liquids by the application of gravity force.
5) Tensile stress in the cylinder wall limits the centrifugal force which can be generated in a unit of a given size and material of construction.
6) There are two major types of centrifuges: sedimenters and filters.
7) A filtering centrifuge contains a solid-wall cylinder or cone rotating about a horizontal or vertical axis.
8) In filtering centrifuge the filtration rate increases with the centrifugal force and with the permeability of the solid cake.
9) If the material to be processed has low residual impurities and a high washing requirement, the greater flexibility of the batch process allows the necessary adjustments.
10) Centrifugal processing provides a number of unique advantages.