Solution

Any chemically and physically homogeneous mixture of two or more substances is said to be a solution. It is possible to have solutions of solids in liquids, liquids in liquids, gases in liquids, solids in solids, etc.

Depending upon the size of the dispersed particles we recognize true solutions, colloidal solutions, and suspensions.

If sugar is dissolved in water, it is supposed that the ultimate sugar particles of molecular dimensions and that a true solution is formed. On the other hand if very fine sand is mixed with water, a suspension of comparatively large particles, each consisting of many molecules is obtained. Between these two extremes lie colloidal solutions.

From the pharmaceutical stand- point solutions of solids in liquids are of the greatest importance and many quantitative data are available on the properties of such solutions.

When an excess of a solid is brought into contact with liquid molecules of the former are removed from its surface until equilibrium is established between the molecules leaving the solid and those returning to it. The resulting solution is said to be saturated at the temperature of the experiment.

The extent of solubility of different substances varies from almost imperceptible amounts to relatively large quantities but for any given solute the solubility has a constant value at constant temperature.

Under certain conditions it is possible to prepare a solution containing a larger amount of solute than is necessary to form a saturated solution. This may occur when a solution is saturated at one temperature, the excess of solid solute removed, and the solution cooled. The solute present in solution, even though it may be less soluble at lower temperature, does not always separate from the solution and a supersaturated solution is produced.

ex. I. Match the English equivalent with the Russian one:

a) the extent of solubility

b)on the other hand

c) quantitative data

d) ultimate sugar particle

e) a suspension of large particle

g) an excess of a solid solute

f) solutions of solids in liquids

1. элементарная частица сахара

2. взвесь больших частичек

3. степень растворимости

4. с другой стороны

5. количественные данные

6. растворы твердых частиц в жидкостях

7. избыток твердого растворимого вещества

ex. II. Complete the gaps with the conjunctions:

provided- при условии

if- если

even though-даже если

1. ... a liquid contains free acids or alkali, a double filter should be used.

2. ... solutions of the silver salts are exposed to the light, precipitation will take place.

3.... the pharmacist is filling a prescription calling for a dozen or more powders, he assumes a serious responsibility in the identification of the material and in the accurate weighing.

4. You will certainly obtain a colloidal solution under existing conditions ... you know its properties.

5. Technical reasons will not influence ... it is possible to prepare a solution containing a large amount of solute under existing conditions.

6. The solid particles of the separating liquids are completely separated ... we use strainers instead of good paper filters.

7. However more satisfactory results could be obtained... the release rate was somewhat decreased.

8. Therefore in vivo results should be similar to those in vitro, ... that the assumptions made previously are valid.

ex. III. Define whether the following statements are true or false.

1. Solution is a homogeneous mixture of two or more substances.

a) True.

b) False.

2. From the pharmaceutical stand – point solutions of solids in liquids are of great importance but we know a little about the properties of such solutions.

a) True.

b) False.

3. Under certain conditions it is possible to prepare a solution containing a larger amount of solute than it is necessary to form a saturated solution.

a) True.

b) False

ex. IV. Choose the right answer.

1. Are paper filters the most useful of all for the pharmaceutist?

a) Yes, they are.

b) Yes, it is.

c) No, they don’t.

2. Is the paper specially prepared used for filtration?

a) Yes, it does.

b) No, it isn’t.

c) Yes, it is.

3. Can we prepare solutions in laboratory?

a) Yes, we do.

b) Yes, we can.

c) No, we don’t.

4. Do we recognize three kinds of solutions?

a) Yes, it is.

b) No, we don’t.

c) Yes, we do.

5. Is it possible to obtain a solution only by dissolving solids in liquids?

a) Yes, it is.

b) No, it doesn’t.

c) Yes, we are.

6. Is much known about the formation of colloidal solutions?

a) Yes, it is.

b) Yes, it does.

c) No , we don’t.

Study “Participle and its constructions” in the book “English Grammer for pharmaceutical students” and do grammer exercises.

ex.I. Underline the correct Participle form.

1. Paper filters are employed in all the operations (required, requiring) filtration.

2. The paper (used, using) for this purpose is specially prepared and is called filter paper.

3. A solution (contained, containing) a larger amount of solute than is necessary to form a saturated solution may be prepared under certain conditions.

4. The substance (occured, occuring) on the earth and in the sun and stars, is the first element of the Periodic Table.

5. Ointment bases (contained, containing) animal fats, vegetable oils or hydrocarbons are known as oleaginous basis.

6. The juices so (obtained, obtaining) may then be evaporated.

ex. II. Choose the correct Participle form:

1. Предметы, изучаемые в вузе, очень разнообразны.

a)being studied

b) studying

c) studied

2.Химик, делающий опыт, высоко квалифицированный специалист.

a) being made

b) making

c) made

3. Больной, которого сейчас осматривают, жалуется на сильную боль в желудке.

a) being examined

b) examining

c) examined

ex. III. Find the sentences with Absolute Participial Construction.

1. The boiling point of water falls out of the series being much higher than it should be.

2. No natural process takes place without water, being the formation of a new mineral, or a highly complicated biological reaction taking place in the organism of a plant or an animal.

3. Oxygen contained in water is a mixture of three isotopes: oxygen 16, oxygen 17, oxygen18, the first being the most common.

4. Three osotopes of hydrogen have been found by scientists, each of them being able to combine with oxygen.

5. Having only five hundred micrograms of plutonium scientists succeeded in studying the principle properties of this element.

Test your grammer.

Test 1. Tag- questions.

1. He can play golf well,...?

a) doesn’t he?

b) can he?

c) can’t he?

2. You are the new secretary, ...?

a) aren’t you?

b) are you?

c) don’t you?

3. Mr. Evans is speaking over the phone, ...?

a) is he?

b) isn’t he?

c) doesn’t he?

4. I’m busy, ...?

a) aren’t I?

b) don’t I ?

c) am not I ?

5. You like black coffee, ...?

a) aren’t you?

b) don’t you ?

c) do you ?

6. You aren’t well enough. You should stay with either me or your son, ...?

a) should you ?

b) shouldn’t you ?

c) are you ?

7. I’m not ill, ... ?

a) are I ?

b) am I ?

c) do you ?

8. It’s a nice day, ...?

a) does it ?

b) is it ?

c) isn’t it ?

9. There isn’t a cloud in the sky, ...?

a) is it ?

b) does it ?

c) is there ?

10. We haven’t got much time, ...?

a) do we ?

b) don’t we ?

c) haven’t we ?

11. Sam doesn’t work hard, ...?

a) is he ?

b) does he ?

c) isn’t he ?

12. There are a lot of photos in the album, ...?

a) aren’t they?

b) aren’t there?

c) are there?

13. There was nobody there, .../

a) was there/

b) wasn’t there?

c) were there?

14. Your son didn’t help you much, ...?

a) did he?

b) had he?

15. They sent a letter the day before yesterday, ...?

a) did they?

b) hadn’t they?

c) didn’t they?

16. My dad hasn’t read the newspaper, ...?

a) hasn’t he?

b) has he?

c) did he?

17. There will be a nice film on TV tonight, ...?

a) won’t there?

b) will it?

c) will there?

18. Neither your parents nor mine can lend us some money, ...?

a) can they?

b) can’t they?

c) do they?

19. He never uses his car except when it’s necessary, ...?

a) doesn’t he ?

b) does he?

c) isn’t it?

20. There’s little point in doing anything about it, ...?

a) is it?

b) isn’t there?

c) is there?

Test 2. Plural or Singular.

1. My hair ... clean.

a) is

b) are

2. Can I borrow your scissors? Mine ... not sharp enough.

a) is

b) are

3. Bad news (not/make) people happy.

a) don’t make

b) doesn’t make

4. There ... hair in my soup.

a) is a

b) is

c) are

5. I don’t want ... or help.

a) advices

b) an advice

c) advice

6. I’ve seen some comedies this month. Each ... funnier than the last.

a) was

b) were

7. We’d like three ... eggs.

a) dozen of

b) dozen

c) dozens

8. Knowledge ... power.

a) is

b) are

9. Everybody ... ready.

a) is

b) are

10. I need my glasses. Where ... these glasses?

a) is

b) are

11. In summer we eat a lot of ...

a) fruit

b) fruits

12. There ... a lot of sheep in the field.

a) is

b) are

13. The police ... to interview Fred about the accident.

a) wants

b) want

14. Money ... not everything.

a) is

b) are

15. Last Saturday we went fishing, but we didn’t catch many...

a) fish

b) fishes

16. Mathematics ... an exact science.

a) is

b) are

17. The sunlit ... look wonderful.

a) rooves

b) roofs

18. It costs four ... dollars.

a) hundred

b) hundreds

19. Julia’s clothes ... in her wardrobe.

a) is

b) are

20. Our team ... playing well.

a) is

b) are

21. Our team ... the best.

a) is

b)are

22.The United States ... a violent history.

a) have

b) has

23. ...are made of bronze.

a) pence

b) pennies

Keys

Test 1 Test 2

1.c 1. a 21. a

2. a 2. b 22. b

3. b 3. b 23.b

4. b 4. a

5. a 5. c

6. b 6. a

7. b 7. b

8. c 8.a

9. c 9.a

10. a 10. b

11. b 11. a

12. b 12. b

13. a 13. b

14. a 14. a

15. c 15. a

16. b 16. a

17.a 17.b

18 a 18. a

19. b 19. b

20. c 20. b