1973-02-15 — Page 30

1978

真二張八第日三十月正年丑発夏

WAH KIU YAT PO

報日橋罩

四期星

日五十月二年三七九一腊公年二十六國民華中育教備審

1913英文中學會考試題預習專欄:

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直英文書院主編

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化學科

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Chemistry (17)

Solution of last week Part

Part

(a)

6600.00

Carbon dioxide was made in the laboratory by the action of dilute hydrochloric acid on marble with the apparatus as shown above. Dilute hydrochloric acid was poured down the thistle funnel on to the marble in the flask. Effervscence occured immedi -ately and carbon dioxide was liberated.

CaCO3

201

The gas was passed through sodium bicarbonate solution in the first wash bottle, (to remove suspended hydrochloric acid), dried by passing it through con- centrated sulphuric acid in the second wash bottle and collected by down-ward delivery.

The high density or the gas was demonstrated by pour- ing it into a gas-jar which a candle was burning. The candle was soon extinguished, showing carbon dioxide, to be deng than a

(11)

Carbon dioxide does not support burning. This property 19 illustrated by lowering a burning taper into a jar of the gas. It is extinguished at once and the gas does not main. Carbon dioxide io slight -ly acidic. This is illustrat-

ed by puttive piece of

Litmus paper into a jar of the tas. It turns claret.

Carbon dioxide has reaction with lime water, forming calcium carbonate. This is well illustrat- ed by passing the gas into lime water. A white ppt. is formed. 302 + Ca(OH)2 →→ CaCO2 + H2O

(iii)

A strip of burning magnesi um is lowered. into a jar of carbon dioxide. It continues to burn for some times with a

spluttering flame because burn -ing magnesium is hot enough to decompose carbon dioxide. The magnesium burns in the oxygen liberated to magnesium oxide..

2Mg + CO2

2Mg0+ 0.

Black specks or carbon can be seen on the side of the jar. This experiment clearly shows that the gas containa carbon and oxygen.

(b) Four commercial uses of

carbon dioxide.

in fire extinguishers, cause the gas is heavy and will not support burning. (ii) used as a refrigerating

agent in the form of dry ice. (iii) in aking aerated water. (iv) in the Solvay process to

manufacture washing soda. (e) The apparatus just before the reaction takes place is shown below:

weight of carbonate used =76.33.

-67.93

93 = 8.4 gm.

eight of carbon dioxide evolved

76-33 14.95 -1.38 sm.

Whence percentage of carbon ide in the carbonate

(a)

x 1000

dio

16.4%

Dip a glass red into lime water and then withdraw it so that a clear drop hangs from its end. If this is Lowered into a gas jar full of carbon dioxide, the drop acquires a milky appearance If it is lowered into a gas jar of carbon monoxide, there is no visible change. place a light taper into a gas jar full of carbon di- oxide does not burn or sup- port. combustion. But if the lighted taper is introduc ed into a jar of carbon mon- oxide the taper is exting- dished, but the gas burns with a bright blue flame. (iii) Introduce a few drops of

(b)

blue litmus solution into a jar of carbon dioxide is an acidic oxide. But Carbon monoxide has no effect on the litmus solution.

Carbon dioxide is removed. by passing the gas through godium hydroxide solution, because it can react with: sodium hydroxide to form

sodium caroonate while the carbon monoxide remains unchanged.

Sulpur

Occurence

Native Sulphur occurs as the element in the volcanic regions of Sicily and America. Sulphides These are compounds of sulphur and metals, e galena, iron pyrites, Zind blende and cinnabar.

Sulphates Elg. gypsum, anny- drite, Glanber's salt and 3psum sait.

4. Other sources From netural gas and patroleum and from crude coal-gas:

ALLOTTOPIc forms of sulpur:

· Sulphur exists in a large number of allotropic foms; 1) amonphous ---- plastic sulphur ii) Crystalline ---- Rhombic and pris- matic sulphur; iii) Liquid forms of sulphur, and iv) gaseous sulphur

Sg. S2 and S.

Rhombic sulphur-Shake some powder sulphur with carbon ci- sulphide, filter it into a dry beaker. Fasten a filter paper OVEĽ the beaker aside, the carbon di- sulphide will slowly evapomte, depositing crystals of sulphur, which because of the slow evapor ation, will be large enough for their shape to be seen. The variet -ly of sulphur as called rhombic sulphur or octanedral orx sulphur. 2. Prismatic sulphur

place powdered sulphur in a crucible. Heat it and stir, until it melts. Then allow the sulphur to cool. After a time, a solid crust will

begin to form on the surface, pierce it at two points with glass rod and rapidly pour out the liquid sulphur from inside. With a pen-knife, out through the solid crust all the way round the crucible near the rim, and lift it out. Underneath will be seen long "needle-shaped" crystals of sulphur known, as Monoclinic sulph- ur or prismatic sulphur or 6 sulphur.

Rhombic

above 95°C below 9000

a

Monoc linac

This temperature of 4590. 13 known as the transicion point between the two forms, and a mix

文中學會考試題預習專欄 英文科 (十七) 徐有祿。

English (17)

Answers to last week's questions

on Comprehension are set out below:

(1) The Hong Kong Child Labour

Law sets the minimum age limi at 14.

(2) "Infringement" means doing

something against", (3) The Labour Department intro-

duced a new method enabling the Department's inspectors to verify the age of workers by visiting their homes.

(4) It means the factories had been found guilty in Court and had to pay sums of money as punishment

(5) concertrated (6) drive

{(7) "Census" is a government

undertaking once in every ten years nomally to find out the density of population, the birth rate, the death rate the education and the occup- ations, etc. of its people. (8) the year 1971.

(9) Success was based on the

Labour Department's campaign, which yielded a detection rate of 70 per cent for 1971 and 90 per cent for last year. (10) 600000 workers were checked.

The following is a Translat- 1on in English for last week's

în Chinese: passage

The area of Hong Kong is very small. It is less than 400 square miles, including the New Territor- ies. It has no famour maintains or rivers which cause people to ling- er to the extent of forgetting to

go home. Yet whenever there is holiday, providing the weather is fine and that the sun is shinn- ing, crowds of people are found. visiting the places far away from the city. Young and old, they gather together in friendly groups to go to the open spaces to exer- cise their tired bodies and to breathe the fresh air. They do not have any special love for the scenery. They are doing it to get away from their everyday routine.

Translation from English to Chinese is just as important as Translation from Chinese to English. The following passage in English should give the candidates good practice to do translation from English to Chinese.

Sales of Brandy during the Chinese New Year holidays were up 30 per cent this year over- last year,

The growth rate or brandy. sales in Hong Kong has consistent- ly been on the uptrend since 1967. Among European liquors imported to Hong Kong, brandy held 62.5 per cent share of the market in 1972, 57.2 per cent in 1971 and 54 per cent in 1970.

While the volume or imports of liquorin general has slowed lown, brandy is holding its own.

However, the consumption or brand; is levelling off, as there is a growing tendency among the younger Chinese towards white liquor-gin, vodka, white rum.

Brandy is still considered a prestige drink and a great portion of the consumption here is not attributable to regular drinking as much as to socials- banquets, weddings- -and during Festivals,

ture of the two 19 in equilibrium only at this temperature. 3. Plastic sulphur -Heat some powdered sulphur until it is boiling rapidly. Then pour the boiling sulphur in a than continu- ous stream intc a beaker of cold- water. It forms long, elastic, light-yellow ribbons of "plastic sulphur

4. Amorphous Sulphur

This 19 a non-crystalline variety of sul-

1973 中學入學試

試題預習專欄

英文科

智慧出板社生糲

(十七)

SECTION A: I

ZERS TO PREVIOUS EX CISES

A

SECTION B CIT

6. Q 108

birioe 2. as long as wherever

"aoon as

so that

SECTION A (multiple choice) Choose the beat answer. Draw a

Line across the correct box.

is the bicycle over there?” "It's mine.” (A. What B. which C. Whom D. whose

E. Who)

A B C D E

ᄆᄆᄆᄆᄆ

ala Tom see the analo the road-side", (A. When B. Where

B. What)

Hor

On

A B C D E

DOOOD

is-Tony Lau's father?". "Bo*a

·waiter"

(A. Whòn? 5. Who

E. Where

is Mr. Lung's

Peak Street..

Ther D. or

A. B. G

ress??

(A. What B. Where C. Thioù D. HOW

3. Why

ABCD 3

00000

...can you swin?" "About fifty yards (A. How long B. How far C. How much

D. How many B. How often)

B C D E

(□□□□□

6. The building where we live consists

ten storeys.

(P. with Q. of R. on S. for 2. DYJ

ΠΕ

7. Henry hurt himself when he jumped

the train. (P. out Q.

A man

3. for by)

□□□□□

white beard came here,

in Qu by E. on S. with 1. of)

Q

met my old friend yesterd

(P. in Q by

T. 46)

10. The hungry boy ate.

□□□□□

chance

with 5.

Q R S T

ᄆᄆᄆᄆᄆ

all the food.

a out B. on S. off I. over]

SECTION B

□□□□□

II, Ada NOT to each of the following sentend

Example: I have been to Macao.

I have not been to lisczo- There is some soup in the bowl..

You ought to wake him up.

She needs to take a rest

111 they some again?

Tell her to wait here.

phur, which is orten almost white. It is usually produced by Chemical, action between materials in aqueous solution, as:

2H 3 + 50,

Properties

2120 +35

It is a yellow bolid, which

is insoluble in water, but soluble

in carbon disulphide or hot ben-

zane. It is a poor conductor of

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