1975-02-21 — Page 20

華僑日報 All

頁四第張五第日一十月正年卯乙

WAH KIU YAT PO

報日僑

·五期星

日一廿月二年五七九一瑟公年四十六國民華中

育教滴輕

開市價 最高價 最低價

·元位單) 日十二月二

进潤

計統合綜價市栗股所易交券證間四港香

城市價,攻市價收市價

)銀行類

恆生銀行

67.00

68.00 67.00 68.00

開市價最高價,最低價 收市價 我市價攻市價: (四)地查建築類

Tit

遠東

脫......名

協成行.

開市價 最高價 最低饑政市價 收市價 收市價

B

開市價 最高價 最低價 收市價 软市政排假

遠東

0.42

0.42

0.42.

2.50

2.60 2.35

2.60

2.55

2.50

匯豐銀行

14.50 15.40-

14.40 15.00 15.00

.15.00

海外信託

$1.821.83

1.80 1.82 1.80 1.82

友聯銀行:

3.00 3.00

3.00

·3.00 3.00

中(二)公用類

99

11.30 11.50

11.10

11.40 11.10 11.10

香港電燈

2.55

2.70

-2.55

2.60

HERES

7.50.

7.65

7.40

7.50

電話公司

7.908.10 7.90

2.525 2,65 7.55 7.90 8.05

7.65

長啓利輝嘉

劃江興百年地

與實品發英地公公

美愛棠

0.65

利興發膠

0.45 0.46

0.45

0.68 0.58 "0.66 0.68 0.58 2.80 2.90 2.50 2.85 2.85 2.80 0.75

0.75 0:75

萬邦投囊 萬澳

1.400 1.40

1.40

3.276 3.275

3.25

0.75

太古昌!

0.70

·0.72

2.50/ 2.50 2.50

2.50

0.48

太平地

0.55

0.56

.2.25

2.30 2.25

2.30 2.30.

0.43

0.45

0.43

0.45

伊人阻業

東方貨服

1.55

·1.56 1.65

1.55 1.55

2.30 1.55

2120

2.20 2.20

2.20

新海康(除息》:

信託公司A

1.45

8,10

新昌集團:

0.83 0.85 0.80

5.60 6.00 5.45 5.80 5.85 5.85

1.48

1.48 1.40

1.44. 1245

0.32

0.32

(九)投資類

0.82 0.83 0.83

制器

聯合企業

3.30 3.10

3.05 3.10 3.30 3.05

遠東發

0.40

0.40

國樂份

·油飄場小輪:

8.60 8.60

九龍巴士

3.053.175

8.60 2.95

3.128 3.10

8.60 *3.125

`和記地

2.90 3.00 2.80

3.00

PAYU B

0.75

0.75 0.75.

0.75

統一機解 金山地理

1.45 1.45 1:45 1.45 4.80 4.80 4:80

4.80.

5.30 5.75 5.25 5.70. 5,60 5.65

(三)工商企業類

保留到(除感)

1,13

1,131,08

1.13

1.11

6:20 6.20 6.20

·6.20

安臣

聯邦A

1.20

1.23 1.17 1.20. 1:20

1,23

AL

(五)會場類

利搜家海外

2.20

2.20

2.25

TERA

#BA

7.90 8.40 4.70

4.85

7.90 7.90 8.40 8.30 4.70

4.70 4.85

港太投資(暫停,

新鴻基

1.68 1.68

· 1.65.

.1.58

1.66

1.65

-7.45

8.00

8.00 8.00

金門打權

9.30

5.75 )

5.75 (新

9.80 9.00 9.50 9.50 ́9.60)

5.75

大變

鹽製

0.71

0.74

0.70

0.72

九龍倉:

安全健酒

9.50

·9.95

10.00 - 10.00.

5.75

4.10

(十)橡膠類 聯合橡膠

1.63

1.63

1.63 1.63

4:10

4.05

4.00

1.28 1.30 1.28

1.28

1.30

1.10

1.10 1,10

新世界:

1.10

1.22 181

̇橡膠借託

1.60

1.65 1.60

1,20

1,27 1.28 1.28

(六)酒店類

1.60

1,601,60

1,60

保利工程(暫伴牌)

獅酒店

0.72

0.72

0.70

FILM

(十一)其他

0.15

9.155 0.14

0.15 0:14

2.85

2.45 2.30 2.425

$2.40:

2.425

發明難

21.00

22.50. 20.80

22.20

-0.55

0.55

城市酒店

0.55

0.55 0.58

2.20

22.20

大昌地產:

.0.50 0.52

0.47

0.48

·0,50

0.50

海港公司

6.00

星馬級業

6.00

大酒店

5.35

5.35

6.65

6.70 6.65 6.70 6.70

大新公和、

0.81 0.82

0.80

0.80

5.35 5,40

0.81

上帝國

12.

永安人壽 紅寶石:

1.15 1.16 1.15

1.15

·2.80

屈臣氏

FSHA

̇何機企業

8.40 8.40% 8.40 8.40 2.85 2.70 2.80 1.75 1.75

1.60 1.75 2.775 3.05.

2.75 --2.975. 1.44 ·1,44. 1,44 0.56 0.57 0.55

建国營業

8.40

2.80 2.75 1.60

雏利醫藥

·美麗華 永燕

6.90

7.00

·大石業

0,28 0.28. 0.28

0.28

5.00

5.00

5.10

1.70

大生地産

0.95 0.97 0.92 0.94 0.94

百樂 0.97

BARK

10.2010 20

10.20

∙10.20

0.24

· 0.21

港機工程

20.00-20.00

20.00

20.00

3.00

2.976

明輝家長

(七)方

1.44

ME

0.50 0.50 0.50

·九龍交易所上市股

0.50

0156

0.55

0.57

0.60 0.62

0.58

0.60

0.62

0,60

・本古行 A

温州保險

0.80 .0.35

4.90 5.40 4.90 5.20 5.30

·0.80

5.30.

李光地藥

0.48

·0.48

0.43

0.48. -0.44

044:

南豐殺廠(除息2.1.83

(KB)

1.83

1.83

̇開市價

最高價

收市街

海港工程(除感)

南海納廞

保麗

10.85

志正國際

恰和實藥。

大元

利安

A

10.40

10.60 10.40

10.60

新興政長 光安

0.49

0.50

0.49

0.50

13.45

0.46 0:46 0.44 0.35

0.35 ·0,35

.0.46 0.35

0.44

會德砂廠 依時要夾 裕器製衣 謝聯實業 長江膜衣:

3.30 -3.50

3.30

永達利

0.20

0.20

-0.80- 0.80 0.80

0.80

1.55. 1.55 1.55

1.55

永鴻

1.51 1.51 1:51

1.51

ZABALZE

英型

HEPHAR

3.50 9.50 3:60

3.50

成交數:香港餘二千零八十五萬元 遼南周三千零四十八萬元

金銀為二千一百四十四萬元·九龍周二百七十四萬元

3. The volume v of water in the củy. when it is filled to a depth his

-of-

→ =

(37 h2 (3x-1)

L975

中學會考專櫃

書院主

化翮科(十五) 陳湛杰

CHRISTEY (#15)

Solutions for Chemistry (#14) Conventional Questions

1. Ultimately, all energy sources originate from the sun (e. solar energy). In the present techno- logical age t two broad classes of energy are available, namely fossil fuels and nuclear energy. Possil ~ fuels

include petroleum, ma

naturil gag. anthracite goal,

bituminous coal, lignite coal and oil shale. Nuclear energy includes fission and fusion processes. Other important sources gy include also solar

of

energy

energy for direct, heating and gooling and- -conversion to elec-

tricity,

hydro-electric power and

energy

datos fuel is one that can

produce energy

spontaneous

by.

nerzy either alone: (8.8. radioactive decay or

decomposition). Feaction with another substance (e.g."by combustion with oxygen).

In ordinary processes of combust

top, mention of the fuel sog.

rogenj

with

the

oxidant

oxygen) relɛases anergy of. fuels (o petroleum). may be con-

ery in the form of best.

With the invention internal combustion engine liquid

(0.5. 200 veniently, converted to mechanical

Instead energy. In the fuel call, of direct combustion, the fuel is ionized at an electrode, the electrons generated being trans- fored

to the oxidant so that the

of reaction

energy electric energy.

In industrial processes, the carbon containing substances are still the conventional type of fuele waad.

d. These may be either solid (eg, coal, ooke, charooal, wood); liquid (e.g. oil, petroleumy alcohol); or gaseous (e.g natural gas coal e

E59, water gad).

Coal is a typical fossil fuel formed by the

gradusl decay of cellulose and other constituents of vegetation and occurs naturally. Petroleum products are the most useful

OF

よっ

Alcohol-is

liquidical countries.

some use in

where

but

B

petrolóum are BURTOS carbohydrate crops grow rapidly -the alcohol baing obtainable through fermentation.

For many

Industrial and domestic purposes gaseous fuels are the most convenient to use as they can be

location and piped readily to any the combustion process doenot demand any complicated or bulky equipment; furthermore their combustions are much easier to control by varying the proportion of the fuel gas with that of air in the mixture.

Producer gan may be prepared by passing a stream of air over red- hot coke. Carbon dioxide is first

however, as there is excess

fored col it is reduced to carbon monoxide. The issuing gas is thus a mixture of nitrogen and carbon monoxide, so that one third of the mixture is inflammable. Air

* 4N20 200 + 4,0 As the overal process is exothermic it is unnecessary to supply heat to the coke during the process once the reaction has started. Producer gas is used in heating retorte where dos converted to 0041 gás, for. beating line-kilne, steel furnaces as well as glass furnaces.

Water gas is produced when stean is passed over red-hot ooke, it is

a mixture of carbon monoxide and hydrogen in equal volumes

+ 8,0. — CO + E2 water.

·838 18.

a more useful fuel than producer gas because both constituents can be burnt, thus contributing to a higher calorific value.

However,

the preparation reaction is endothermic so that temperature falls rapidly unless heat is supplied Usually producer gas ani water gas are generated alternately using the same apparatus, the dumtion of the two processes being so controlled that it is not nepsgeary to heat the coke.

Con3 gas de often manufactured comeroially by high temperature

destructive distillation.The coal is heated to a temperature of about [1000°C. by producer gas in large vertical retorte in the absence air. Thê volatile products are passed to a water main and then through

air-cooled am water-

cooled condensers to remove the tat Next, ammonia de removed from the gas by washing very

water scrubbers, to in

sulphide.

is removed by passing the gas over ferric oxide whenne

gulphide

is removed by

the

gas over by passing ferric oxide whence iron sulphide 18 formed. The purified coal gas may then be collected over water in large gas-holders and sent through

pipes to consumers as required,

2Industrial Preparation of Chlorine

A common and cheap natural source. of chlorine is sodium chloride.

Thus commercially uhlorine is often prepared by the electrolysis of brine. A convenient process used is that of the diaphram cell,

•Frine

diaphra

mesh

The anode is of carbon and the cathode is a mesh of steel. Two of the pruduota, sodium hydroxide and chlorine are kept apart by a porous diaphram separating the anode and cathede compartmente.

During electrolysis, the chloride ions are discharged in preference to the hydroxyl ions at the anode, and chlorine is evolved

2012.

At the cathode, hydrogen ions are discharged in preference, to the sodium iong, and hydrogen is evolved: # +0

He

2H H

Sodium hydroxide is formed in the region of the cathode, drips through the diaphram and cathade, and may be collected and concen- trated

Reactions of Chlorine

When chlorine gas le bubbled through potassium Iodide solution, the latter turns brown; immediately. When mora chlorine is passed, a black precipitate of iodine is

2KT 2K01 + L formed. 01

(b) When gue jars containing chlorine and ammonia are placed mouth to mouth, dense white fumes of ammonium chloride appear with loss of the yellowish green colour of chlorine. In the first step, summonis, is oxidized by chlorine to nitrogen, tha chlorine being reduced to hydrogen chloride.

3012

With excess chlorine, an explosive compound, nitrogen trichloride

will be formed.

NOL 3. (6) When chlorine is passed into purple litmus solution, the latter is first turned red and then bleach ed to a colourless solution. Chlorine dissolves in water foming a mixture of hydrochloric and hypochlorous acid that turn litmus red. Hypochlorous acid further bleaches red litmus to a colourless substance

012+ 220 HOD. + H010

HOLO HO2 + 0 for oxidation (d) With water, chlorine forma hydrochloric and hypochlorous acida On standing, the hypochlorous slowly decomposes to hydrochloric acid and oxygen 2010 — 2H01 +02

(e) When a mixture of equal volumes of chlorine and hydrogen are axposed to direct sunlight, the two gases will combine explosively to hydrogen chloride.

ZHOL

(f) When chlorine is passed over molten sulphur, a yellow liquid, disulphur dichloride

19 formed 28 +

3. By air pollution one means the difference between clean country. air and the sort of air that is found in built-up cities all over. the world. Clean

air contains of oxygen, 79% about

21% of

79% of nitro- gen and very small amounts of other gases, including carbon dioxide (0,03%). Even in nature, air is never found to be completely "clean". Buch gases as sulphur dioxide, hydrogen sulphide and darbon monoxide are continually

released into the air an be

by... | products of such natural oc- currences as volcanic activity, vegetation decay, and forest fires. In addition, tiny particles of solide or liquids are distributed throughout the air by wins, volcanic explosions and other (similar natural disturbances.

Added to these "natural pollutants

from, the are

substances resulting

It is activities of man.

estimated that at least 200 million tons.

sof man-made pollutante now enter the air each year in the United States This amounts to about 1 ton per a person

person

Five

- 5-6 lbs. per

of substances,

knowa

types primary pollutants,

3. account for more than 90% of the air pollution They re: carbon monoxide, nitrogen oxides, hydrocarbons, sulphur oxides and particulates. Two questions frequently asked are: (a) which type of source puts the largest amount of pollutant into the air? and (b) which single atmospheric pollutant is present in the largest amount? 1. Carbon Monoxide formed mainly from three processes (a) incomplete combustion of carbon or carbon-containing compounds.

This is

This occurs when available

oxygen is less than the amount required" for complete combustion to carbon dioxide 20 + 02 →→ 200

200+ 0.

2002 (b) high temperature reaction takes: place between 00, and carbon con- taining materials.

-200

This reaction take place readily at the elevated temperatures comm in many industrial devices such as blast furnaces.

(c) at high temperature, CO dissociates into CO and 0.

CO2 co+0 (1% at: 1745°0)

In a city the mejor source of carbon monoxide is from vehicles, each gallon of fuel burnt in e petrol engine yields about 3.1b of carbon monoxide. When idling, as in a traffic jam the exhaust gas can be as much as 10% 00. In Hong Kong, values of 75 parts per million (ppm) were found in Garden Road on May 7th, 1974 between 12.50 and 1.15 pm (30pm or above is: considered "unfavorable")..

2. Nitrogen Oxides Although other nitrogen oxides exist, nitric oxide and nitrogen dioxide are the ones primarily involved in air pollution. under urban atmospheric conditions..

lower oxide in much larger

NO, da emitted the atmosphere

The basic

of formation of NO and

FO involves the reaction of

nitrogen and oxygen of the air to

give NO and then further reaction:

of NO with more oxygen to give NO2. 2ND

+

200+02 21T02

As air is composed of nitrogen and oxygen,

at high temperatures (above 1210°C) significant amounts: of nitric oxide are formed. Such temperatures are commonly reached during many combustion processes involving air and formation of NO may be considered ae a side reaction.

3. Hydrocarbona The hydrocarbons moet important in air pollution are those that are gases at normal atmospherio temperatures or those that are highly volatile at such

tures. Most of these

and have relatively simple

An

structures containing 12 or less carbon atome per molecule. The number of hydrocarbons involved in air pollution is fairly large. A analysis of urban air has resulted

identification of 56 differ- In 1965 a series of 200, samples of air was taken in the Los Angeles area and analyzed.

the nine most abundant ones were found to be met

n-butane 1-pen

in the iden ent hydrocarbon compounds.

toluene,

ethane, banzene, -pentane, propane

and ethylene. These originate from untumt or partielly - burat fuel. Some of these are cancer-inducing The "tars" da sigarette smoke are. high in hydrocarbons,

Pollution from 4. Sulphur Oxides sulphur oxides conaieta primarily of sulphur dioxide and sulphur trioxide. The combustion of any

containing

Even

both sulphite axle) will formed in the largest à 01.

in

presence of excess, air.

The quantity of 80, produced la de- pendent on readtion conditione, especially temperature, A simpli- PIPA machentam, jo po Palinwo•—”

250 +02 250. These pollutanta come mainly from the burning of coal and heavy fuel oil, not from traffic, They are also important, from oil refineries. (It can be smelled easily in areas such as Hung Hom, particularly near the power station).

5. Particulates. Although the four previous pollutant types are all guaca, small solid particles and liquid droplets, collectively called particulates, are also

great numbers present in the air and at times they constitute a serious pollution

problem and

In Hong Kong, due to poor ad

poor adjustment

maintenence,black oily

of endieraton art a notable featur particles from diegel engines. Large amourit of particles could also be generat- ed. from rubbish incineraters if not

Silica dust are treated properly. produced from mines and quarries, and asbestos, used for insulation and fire-proofing are also possible Bouroes of particulates.

Questiona for Next Week -

1. Describe briefly the principles underlying the extraction of metals from their ores, Illustrate your answer with reference to the manufacture of iron and steel. 2. How is methyl alcohol obtained industrially? What are its uses? How would you identify a liquid reported to be methyl alcohol? How Would you detect the presence of ethyl alcohol. in a specimen of zethyl alcohol?

3. When two pure compounds x and y were mixed together and heated with conc. sulphuric acid, a

greenish- yellow gas was evolved. x was a

insoluble in water or

black not dissolved in hot ·

aliute

acid, evolving cone hydrochloric

same gas as when heated in the the same

experiment. y was a white

which turned to

previous ont solidanted. A

a

white mins

mags when solution of

y in hydrolare eoid: did

not

react with

hydrogen sulphide, however, it gave a white

cipitate with ammonium hydroxide

precipitate dissolving in

excess of the hydroxide. Then

WES

hydrogen

sulphide

paskeŭ through the remiting solution, a

What are the mture of x and y? Explain the above observations,

white precipitate was formed.

生會考專欄

數學科(十五)

ADDITIONAL MATHEMATICS (#15)

Solution to Exercise 14

1. The radical axis of the required: circle and the given circle (x2 + y2 -15x+5y= 0) is the tangent to the given circle at (1,2); its equatio 18 x+2y-+(x+1) + 2(x+1) = 0. 3.2. 13x-9y+50 The Line meets the circle in two coincident, pointe.

The circle 2-15x+5y+k(13x- 9y+5)=a touches the given oirole at (1,2),............

The required circle passeg through (0,2):

** 4 + 10 + k(−18+5)= '0

14 i.e.

K = 13 The required circle is (x2 + y2-15x+5y) + (13x-9y+5)

13x 61y

or 13{x2+y2)

2. Since O cannot appear as leading

digit, the first plane can be filled in 7 waya and then the remaining 4 places may be filled in 7,6,5,4 ways, 30 7x7x6x5x4- 5880 numbers can be formed. To form even numbers, we must put in

If

the last place one of 15. the digit ohosen is 0,

-the

other

the

of the

7 digits may be placed in four places preceding it in

4 ways. If the final digit

7,6,514

is not 0, it can be chosen in 3-

ways and then the first 4 digits. may he placed in 6,6,5,4 ways, since o cannot occupy the leading "positions. So, the total number of

even numbers is

7x6x5x+6x6x5x4x3

3000

• 4 = 77(6xn - 3n2 jah

Since

= 5, - 4 and h = 3

7724- =10.108 PA

The rate of the surface rising is 0.108cm/sec. when the depth of water in the cup is: 3cm.

4. In figure

AQAR and AQ is a tangent to the inscribed circle

RPQ=/AQR = 90°- A

and ZPOR = 90°- 3B QRP = 90° Since QR ZAR sing - 2(3-2) sing

QP = 2(8-0) Bing

Area of APOR

= 2(a−a)(s−c) sin

242

242

#(s-b) abc

3

abc (a+b+c);

Exercise 15

OR QP sin ROP sing cos

ab

Tác

"If Z=cos 6+ i sin ; and nis

2 an integer, express 4 - -- in term

of 0.

Find cose in terms of cosines of

e, and prove that cose + sine. = −(3 cos 4 € + 5).

2. Show that there are 126 ways in)

which 10 children can be divided into two groups of 5. Find the number of ways in which this can be done,

a) if the two youngest children

must be in the same group. b) if

**key must not be in the same group.conta 3. Find the equation.of the

circumcirohe and the co-ordinates of the oircumcentre of the triang whose vertices are (1,2), (-1,-4), (3,-5).

PASAU

新數學(十五)·謝國與

MODERN MAXHEMAI-JOS (#15) Coordinate Geometry 17

a. Pas quation of the cle whost adatra is (h, k) and whyse riius din (x-1)+(y−k)2 = X2 (1) b. Any of role is defined by sin equation of second degree de

(2)

c. The relationsp between: (1) and

(P) are:

‡√L® +E2-4F

a. Equation of medical ació de the

equation of common chori (or, ta:rent) of two given airdles

Equation of jadical axis! (DD)x+(E4−E2}¥ + (Fq−F2) = 0 e. Length of tangent from a point

P1(3) to a circle.

- d is given by ±2=(x, −1)2+(y+**2

20

t. Bytem of cacles

The equation of system of otavles from two given 'oiieles

[1 = x2+x2+D+X+E+F;

0

= 0

is given by x k (x2+ y2+Dgx+÷Egy+Fq) = 0

PERAMELES:-

Find the equation of the circle Lesing through the points

I1 (0-3) and (4,0) which hausts

centre on the Line xay = 0, Lat

the required rique bian be. (x-li)

Since

2

} ii) p?

and my line on the soc

The centre (h,k) lieg on, the stren lines; h+2k = (3) - SALVIDE (1), (2), (3) wo get h

129 th

required ogs: 5x+5y==34x+7

2. Find the equation of the cirlc Anducted in the triangle whose':

Sades are AB: 3x-47–19 ~~, G 4x+3+170

* B

~CA x+7

A3: 190

CA : L=0

30

Es eqt of angle bisector of A is AD:

3x-4x-19 x+7 we ge

2x−y+4=2 0

The eat of angle bisector of Las CB: 4x+3y-177x+

·3x+y+6 =

Now 2x-y+4=0

we get

3x+y+6=10 15x+10=0, (2)(-2)-y+4=0

The centre of duscribed címla (-2,0)

The radius is the perpendicula

distance from any of the Tines,

(-2,0) Taking the xide AB,

J 2(-2)-4 (0)-19- -5

lence the cat. of required circle 18 (x+2)2+y?= 5" or x2+y2+4x-21- Solution to exercise. 14%

1. Jet the eqt be x cos cin

150, p. -po

sin 150° - sin 30° = .cos 1500

B

bet AB: 2x+y= 12 BC; x-2y-4,

CA = ?x-y+4=0 Kalucing 3 lines sa pormal:

AB:

CAI

2x+y=120 BO x-2y-4

+5

-2x-y+4 - AB = JAC

=0

we got = 2 BC

-J5

So the centra (2,2)

JAB

from

AB

of circle will be

to centre.

•2(2)+(2)−−13

·Selebont Ex. 14.

(2)

3. Let the required equation of

line be 2x+y+1+%{x−2y+1) =.0 The slope of

le†.

Since the requima line is⠀ parallel to 23, their slopes are equal.

(2+k)x+(1-14)y+(1+k) = ?

-

-6-3-4-8

The required eqt of 3 ing is 4x-3y+3 O

Exercise 15

1. By considering the length of the common chord of the cirules (x-a)2+(y+b)2= ad

• (x-5)2+(x+1)2=c2 fixe she conliiton for tangency of these circles, 2. Find the aquation of direjo paosing through (5,-3) Bod.(0,6) with its centre on 2x-3y = 6. 3. Find the equation of the oirvie of the systn

>2+y2-4x+2y+k (x2+y2-2y-4)=0 whoée

centre is on the line 2x+4y=1.

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