真四第張五第日十初月二年卯乙歷

WAH KIU YAT PO

報日僑華

六期星

日二廿月三年五七九一曆公年四十六國民茝中育教濟經

Ž

2.15

3.85

3.85

開市價 最高價 最低價 攻市價 收市價 收市價 (一)銀行類 恆生銀行(除息)82.00 赠醫銀行 除各項14.40 海外𠌯托(除感)210 友聯銀行

(元位單) 日一廿月三

̇香港 遠東

計統合綜價市票股所易交證間四港香

金銀

82.50 82.00 --82.50 14.40 13.90 13.90

13.90

13.90

(四)地產建築類 摩創園憟藥

開市價 最高價 最低價 城市攻市似,收市價: 股名

香港遼東

金銀

浮市值较低贷

香港进璁:

· HOCTET CARRETH OR

金銀

#

過度:最高、最低衢·

·香港

·锡成行

-0.77"

0.78

0.72

0.76- 0.74

BERTY

會德想造AT 會懷性能曲:

2.75

0.27

2.10

2.15

3:80

3,80

20 2.15

長江實業

3,475 3.475

3.40 8.425

•HADE

3.45

3.375

太古昌

身德營業

利興發展

0.61

10.63

0.61

0.61

0.63

南太平地

0.93 -0.93 0.85

0.88

0.89.

0.88

̇鹗邦航櫫 維望配業

3.425

3,425 3.425

2.75 2.75

0.28 0,26 -0.27 0.20

3.425

收市 收市假收市

2.75

0.85

0.85

電(二)公用類

WER

0.56 0.56

0.56

0.56

妻年地產

3,00 3,00

14.00

14.10

13.80

14.00

14.00 13.80

3.00 3.00

-0.30 0,30

-0.30

BPEOR 東方貨 SINGE

2.60 2.60

2.45 ·2.60.

2.55

1.75

1.75

1.65 1.75 1.65

微地公司,

6.35 6.35

6.15 6.20

6.15

6.20

香港耀證 *

3,70

3,80

3.70

BE10.00

10.10

.10.00

10.10

3.70 :3.70 3.70

10.10.

̇個托公司 A

1,64

1.65

1.60.

1.65.

1.60

0.42

-0.42

0.42

(九)投資類

合和實業

1.09

1.12

1,06

1.10

1,06

聯合企業:

3.50

3.50

3.50

3.50

電話公司

12.50

12.70

12.40

12.50

12.60 12.50

新昌集

油蔴地小輪 10,60 10.60

10.20

10,60 10.20

10.30

和記地

3.50 3,50

3.45 3.45

H

遠東發展

0.70 0.703

0,70

DARO

1.65

1.66 1.65

1,65

統一機欄:

·九龍巴士

4.35.4.50

4.325

4.40

4,40

4.425

四海地

(三)工商企業類

眼邦A.

1.47 1.47

1,55 1.56 1.51 1.56 1.55:

金山地带

0.50

0.50

0.50

1.55

太平證券。 怡和豆

5.50

5.50 5.50

6.00 6.15 5.95 6.00

.6.05

5.95

1.44 1,44 1.44

安速區

太古廣鞯A.

9.40

晚道公司:

$5.95

0.50. 0.50 0.50 9.40 5.95 5.85

0.50

0.50

海南

(五)會塢類

9.25

9.40 9.25

新鴻

5.90

5,85

XX

金門打率 除名

11.30

1150

10.90

10.90 10.90 10.90.

BEREN

2.30 2.275

2.25 0.14 0.15 0.14 0.86

2,375 ·2.30

2.275

Yordante

9.90

10.20

9.70

9.75

9.80

0.15.

11.60

11,80

11.30

1.30 .11.30

0.87 0.83

0.84

0.83.

安全保险

-.0.52

0,52.

资州英

7.40

7.40

7.00

7.20: 7.20

5.20

5.10

嘉祐

5.10 5.10

KA 2.45 2.50 福太投(要停?............... 二(+)橡膠類 野合換(深

2.50

2.45

TUBATE (RE)

E

1.96

2.00

1.96

1:96

2.00

新世界

1.59

1.60

1.52

1.52

1.52

1.53

>

和糖

1.50. 1.50 1.48

150. 1.48

永安

2.35 2,40

2.35

2.85- 2.10.

保利工程(暫停牌---

酒店

(十一)其他

凱酒店

0,90

明理業

-0.90

2.525 2.65

2.45

2,475 2.45 2.475

BD

0.80 0.80 ..0.79

怡和

25.30

25.30

立與

3.90

強力酒 瑞限公司 先施公司 寶光製藥

24.40 3.90 3.90 7.50 7.50 7.50

24.40 24.40 24.40

大地

0.77

0.79 -0.75.. 0.76

3.90

大新公和

1.01

1,03

1.00 1.01

:0.76 1,00

城市酒店 海批公司 大酒店

18.50 18.70.

18.50

18.70

邵氏

4.30

4.30.

6.50 5.50

6.25

6.20

3.60 3.60 3.60 3.60

7.50

食生

永在人口

雞爐業 ®

10,47.

0.47

0.44.

10.50

10.50: 10:50

10,50

餘利滋業:

BEA

HA

3.45 3.50 3.35 3.40 2.40 2.45. 2,40 ·3:40 3:35 3.50 3.25 3.225 1.82. 1.82 1.76 1.80

3.40

·3.40

大生地:

1.26

1.23

1.25 1,25

10.44 .0.45

1:25

***

8.90 ··8,90

1:36. 1.36 1:36

8.50

紅蛋白

(除您

大慈祐榮

建屋饰,

2.45- 2.40

314253.25

七)紡織製衣類:

機器

1.80

0.60

0.60

0.65 ·0,62

13%

0.70 0.70 0.70 0.70

*X*.

0.72

0.64

0.72

0,68

www.

25.00 25.00 25.00: 九龍交易所上市股

0.64

太古行A

6.05 6.10 5,85 6.00 5.85

5.90

̇州保險

·玉光地查 海龍工程

0.58

0,56

0.58

0.56 0.57

新衣

HT

107

427719

海沙區

聯保

̇南旗

0.86

合和實業:

0.86 0.86

0.86

志正國際

بی

XX

食德雙秘們 依時我

莊上集團

利器

DA

13.10. 13.10 ∙13.10

13.10

ENZRE

-0.63.

0.63

-0.63

1.02 1.02 1.02

·0.96 0.06 0.96

1.02

.96

梅闐尼

兆安:

0.59.

0.59

0.59

代表

鍾承烛(除序) 信息: **

国安维

.0.411

0.41

.0.41

041

·保中國麗新永萬 永

.0.41-

0.41

0.41

0.30

0:30

0,30

0.30

2.50 2.50 2.50

-$3.79

2.35

2.225

2.225 2.35

*X98

生物科 乙)(十九)

放次數:香港發

3:60

百一十八萬元:遠東為二千六百二十五萬元 金银用一千五百六十二萬元,九跟爲二百零八萬元

be, no resultent magnetic field existing.

育教僑華

L975

中學會考專欄

生物科 甲)(十九)。槨剪翼·

湿好內容(0)消化的意義;(6人體

信濃

連想食物之密性試

神経札

B) } ENLAR, Los

B

可分頸验,胸、腰椎及苑

Akamki do ki

・地

2.號糖心频

模式生

**

·

BIOLOGY (#19)

Q.25. Some yellow phosphorus and a

potted plant were placed under a bel jar and kept in the dark for some time and the exposed

in, light. State the aim of this. experiment and explain olearly

what happens:- RA

a) in the dark b) in the light N. B. Before you begin to answer this, first you must know why. phosphorus was used. From know- ledge of Chemistry, you know that yellow phosphorus, smoulders in air. In doing so, the chemical effect of abouldering is similar to those of

active burning of phosphorus except for the time factor. During this

process, carbon dioxide in the air la increased and oxygen is used up. Knowing this, we realize the aim of the experiment must be to show carbon dioxide is needed for photo- Bynthesis.

at

Another hint that this experiment is associated with photosynthesis 18. the fact that the apparatus, the start of the experiment was kept in the dark for some time. As the only way we can prove

taken place is

enthesis

pho

has

to prove that at its end starch is formed.

To show that

190

же

BO, We

aust start off by having NO starch In the leaves of the potted plant. To do so. must dastarch the

this, plent

we knew: Le darried in the dark where by the starch made in the leaves are reconverted to glucose and translocated to other parts for use or storage. This is

en essential step in ALL experiment involving photosynthesis. Explanation:

of

In the dark, the oxygen in the air is used up as the phosphorus

Thus an increase in the volume

carbon dioxide

ide results. In the meantime, the starch in the Leaves of the potted pe This can

plent is translocated" elsewhere. be proved by picking a leaf from the plant and testing it for the presence of starch after it has

-beon kept in the dark for sometime

(Note: What is the Test for Starch?)

factors

b. In the light, since the fa

necessary for photosynthesis, namely carbon dioxide, sunlight ahlorophyll and water, are present the plant will carry out photoaya thesis and use up the carbon. dioxide in the jar and liberate more oxygen. The new supply of oxygen, will maintain the smoulder

ing phosphorus with a continuous supply of oxygen. Staron can be proved to be present when one, of the leaves is plucked and tested for the presence of starch. Thus, it is shown that carbon dioxide is needed for photosynthesis and this supply cones from the surrounding modium.

26. List-the elements that are

essential for growth.of plants. Describe an experiment to provв State that they are necessary. the source of each and how they are obtained by the plants. Explanation:

are necded for Certain elementa are life and no mal growth of plants. They are:-

(1) Nitrogen (ii) oxygen(iii)carbon dioxide (iv) potassium (v) calcium (vi) magnesium (vii) iron

(viii) phosphorus (ix) sulphur (x) hydrogen (xi) sodium (xii) chlorine

The experiment to prove that they are necessary is one known as "the culture experiment". (Daually the water culture experiment is the one carried out in school..

I am sure you are all quite familiar with it so. I shall only point out the precautions which must be consider ed when carrying out such an exper iment.

1. The botties uhould be covered

with thick light proof paper so ag to prevent microscopic algal plank from growing. in the battles and use up some of the salts in the. colution.

2. Air should be blown through the solution daily to provide oxygen for the roopiration of the roots. 3. The solutions should be *topped

up' whenever recessary so that

there would be a continuous supply of the right concentration of Balta.

4. Watch out for any fungal pr

bacterial growth which my rot the aten.

The substances taken into the plant afe carbon dioxide, water and mineral salts. Oxygen is also taken in during respiration.

Carbon.

daoxide and oxyger are oblɛ118d oy dirfuzajon rom the surrounding medium of either ant 3 water through the stomata and Iontiosis. Water enters by

via the

th root hair or and plants and

the under surface of leaves thrush and roots of water plants. Mineral. salts come in dissolved foam from the soil water or surrounding water by diffusion.

L975

4鬧會考專欄

WE EM

化學科(十九) 陳湛杰

CHEMISTRY (+19)

Solutions for Chemistry (#18)

abtain the first

1.a. Copper and zinc According to the activity series of metals ooppe is above hydrogen endine is below hydrogen.

Honce copper does not readily react with liluie

acids, #111 zing.

dissolve, readily displacing hydrogen substance

In order to copper), dilute sulphuric is added to the mixture of

a solution of zinc forming a metals, sulphata. The resulting mixture de filtered, leaving the copper metal as residue, which can then be wash- ea with 1. Vater and dried by heating.

Cu H, SO

3

4

no

zn+H50 2050 H

ion

(八)航業資

3.60 3.50 3.60

Thu

surface of the fince and the andium bromide is left behind. process of sublimation should be mpeated for a few more times to make dure that the majority of

The momida de removed.

la then dissolved in

sodiumy of hot water and

in

2 inimui cooled to obtain tlie erystaLach car: then be dried in a deasinator. 2. IN B. Although the study of xenon 18 not dimetly Indicated the

syllabus, however, using basic chemical principleckle) this

a question is very easy to

From the study of the period io table, xenon is known to be inert gas having an octet of alections in

in the ou

ahell. outermost Thus the elemental gas is expected to be monoatomic: (no covalent bond possible between the Xe stoms. Further more hydrogen fluoride gas is expected to have formula of ir (hydrogen one electron in shell fluorine: seven electron in volence shell. Helectron sharing - covalent bond to give stable octet of elections) Thus the equation for the reaction

4

valence

::

From the general gas equation (PV), since tempemture, and pressure are constant, we see that.

number as nole of gas: (2) volume (V).

One note of Xer rields one mole of Xe and four mold of HP. Hence 3-8 litre of Xef yields 3.5 litre of Xe and (4 x 348) 1532 bitre of P.

QUESTIONS FOR NEXT WEEK

1. A certain ergenic compound is found by analysis to contain 31.9%

to tetroxide is very empirical for

Find the

b. Oxygen and dinitrogen tetroxide – Although both oxygen and dinitrogen carbon and 5.30% hydrogen. Analysie tetroxide dissolve in water, they shows that the only other element have different absorption coeffici-present is chlorine.

The compound is mula. ents. soluble in

because in addit heated with eodium and the chlorine present in 1.50g of the compound- interaction there

converted to chloride ion. How is also chemical reaction. Dinit rogen tetroxide is a mixed acidi

many millilitre of 0.450M AgNO, 1s oxide which react with water giving on? Then a 1.50g sample of the

required to react with the chloride a mixture of nitrous and nitric

compound is converted to vapour it To obtain the first named my substance (1.8. oxygen), the mix- is found to occupy 410 ml at 100°C,

762

molecular Find the ture of gases in bubbled, through

mm Hg. water, whence most of the dinitro- gen tetroxide de removed. The oxygen gas obtained is passed through quidclime. This basic. oxide will readily remove any treat. of dinitrogen tetroxide and also dries the oxygen.

Ecli acid.

H2O + H2O ---> NO2 + HNO3

fo rupla of the compous listed below 2. The four substances

are either single elements or com pounds. From the given description.

identify of properties,"

and give fomula for aach of them. Vrate the equations for

CB reactione deв- cribed.

is a substance of white cubic

When it is dissolved. in arystals. water and silver nitrate solution

avory pale yellow precipi- tate is

20+20a0 Ca (NO,'), +Ça (NO, detained. This precipitate

H2O+020✈ Ca(OH)

G

c. Fitrogen and carbon dioxide. Both gases are not very soluble in water under ordinary temperature and pressure.

However, as nitrogenL is a nitral gas and carbon dioxido an acidic oxide the latter can be readily abac

aboorbod by a suitable

Jotain the firat

named substance (nitrogen), the ture is bubbled through sodium hydroxide solution and then concen- trated ciphuric acid. Pure dry nitrogen can be obtained by colloc tion over mercury in a undiometer

00 + NaOHN CO2 + 10: d. Como, nitric acid än conc. sulphuric acid - ceno. nitric acid is more volatile than sulphuric. acid, thus the mixture may be ee- parated by distillation. To obtain the first named substance (1.0.HND the mixture is put into a glass retort and heated carefully to about 83°C which is the boiling point of HNO. The nitric acid that distills over is condensed with a water condenser and collected.

e. Sodium carbonate and calcium carbonate - The carbonate salt of the alkali and alkaline earth metals are different in their golubilities in wat

water.

Calcium carbonate is only sparingly soluble even in hot water. Thus the mix- ture is digested with hot water,

in

and filtered in a fluted funnel to fanitato at

afficiant filtintión

The filtrate is then con- entrateåby partial evaporation of water. This saturated soltuion wil

will yield sodium carbonate

orystals upon cooling.

The mixture

is filtered and the sodium carbon- ate crystals are carefully dried in adessicator using F5 as the de- hydrating agent.

f. Sodium bromide and ammonium bromide A large number of ammonium- sal

Its are rolate, 1.0. it eublime when heated. This is true also with ammonium bromide. Thus to obtain godium bromide, the mix- ture is put in a avaporating dish covored with a funnel and strongly. heated. The ammonium bromide sub- limate is.collected on the inner

is insoluble in dilute nitric acid but somewhat soluble in ammonium hydroxide. When flame test is.

the substance, Lilac

2 applied to colour is observed.

B is a white powder, When heated, is evolved but the powder reverts to a White colour when cooled. The solution obtained by

the heated residue in produce

5.

dissoudrochloric acid

dilute

e white precipitate upon addition anmonium sulphide solution.

of

O is a green crystalline ponder. a pale Tjer aqueous solution gives a green precipitate when treated with

The sodium hydroxide,

precipitate

and gradually turna dark green, finally brown if shaken with air

1o Molecular miqueta 20 åY

alignment, with oneri ende on esch side

ear

5°:

of these The unpaired ioles of open ends introduce ménetis effacts and Tare pole strengthe

6 There is no remitant migielten on the other parts of s sffect on

the magnet.

7. Molecular magnets at the fren

ende repol one another he 007.08,

allocato com therefore, distance away from the ma♫

That is why

A Its gnetic length is shorter.

than its physical length..

(i) Magnetic saturation

When all the uolecular regnts:

the str0= are aliguda in parallel, gth of maretism comes to & de tuis- Lion, No more nolcular aget are. 25ft in a closed chain store. (1)

Demagnetigation by eating heating causes the molecular naguts to vibrate violently. Thu alignment of N-S is disturbed. Closed-chain arrangerent predomin ates and it is demagnetise2.

Macle

(iii) Baking

a zaghet is broken into two, each h postuses two free ends. The open-ards are the north and south poles. These two halves are themselves magnets.

(b) Roads A, B and o are put together. When released one

of them, say 6, falls. Es no attraction

fore exerts on it. Rod 0.18 a

a copper rod Set the two ramining rods in

Carrangement, If A is horizontal and B attracts A, then B is a magnet and A is au

ag

notised

However, if 3 doesn't ectract A then A is a magnet while B is an urmasastised rod.

(c) conventional currants flow Crow

a higher potential, positive. Av terminal or a battery, to a lower potential.

{i} The direction of current flori (on both coils

În markud in

the

current in.... coil 'make's

X

A a north pole and

3 a south

pole, while current in y

makes A a south and B.a' north pale. Since there are equal water of turas in both coils, the currant strength, as well as the magnetic pole strength produced by then bra equal, the North and South polar ities produced by coils x and y. Cancel each other at A and B. is no existing pole there. (ii) Connection. should be made

A

as showIL will be thu 'south pole, ani the northm (iv) The soft ring pro

vides a good

The solution with dilute hydrochlogetic path

acid and barium chloride

and, thus, ...

polution gives a white precipitate. fo ming a mag-

ric

D

is a substance of high density.netic shield. It does not react with dilute

sulphuric acid. However, it readil

in dilute nitric acid to dissolves yield a solution. This solution gives a black precipitate with. hydrogen sulphide, whilst with Bodium hydroxide a white precipi- tate is fomed which dissolves in excess hydroxide.

L975

中會考專櫃

物理科(十九)

PHYSICS (19)

·國永熾。

(a) Outline of Molecular Theory of

Magnetism

Molecules of magnetic substancer are themselves penianent magnets 2o When magnetised, these mole- cular magnets in alosed chuina.

3o Adjacent poles, Nani S, ngu-

trelise each other. The re wil

The soft iron

bar inside is not magnetised.

2(a)!

The re

By induction, negative ofarges are attracted to the near of the fith-ball and positive charges are repolled. away from the rou Since unike charges attract Bach other the 11ght path-bill ie attracted to the rod.

After boing in contact the negative charges are neutralised, l only positive charges remain in the path ba

Like charges repoll. The pith-ball is pushed away by the aharged rođ

(b) Charing a gold-leaf Electro- goope by inductive.

Σ

AMA

When a positively charged rou 15

brongis ner to the cap of e-gold- leof electmscove, the nejutive arges are induced axi or bound you the put while positivo induced Giorgos are repelled to the gold-

-Lear Dagen de the

theclectroscope by

Sarthed the touching the car tempo mrily with a finger hile the finger is still in touch with the can, the positive charges are neutralized by in-rusha electrons from the earth. The 2014-leaf collapses.- Nogative

larges are bourn in position by the inducing charge

On, removing the finger and then tro inducing rod, the electroope is negatively charged, (o)?

Charger reside on the ho120 conductor.

Quantion for next week.

1. The folowing readings were Taken for a torch bulb add *1-47, 0.25A-

"V(pod) in wallsec8a12025050310| I(current) in 405 010 015 02023 024 025 (4) Flot & graph of V(j-axis)

agranat (x-axis). What can you doduce from ite form?

(b) Or the same place of papar diaw La graph of V against I for á

2 ohms. What pid. Would

yer to será a current of

be

0.2A.

restough the bulb and the.

cris7n the

(c)

dend

271

.. would be:

be required to

current of 0.1 CA. Through two similar bulbs in series? What current would pass if a p.d. of 1.Cy were connected across thes two bulbs in series?

(d) that current would paso if

hulbe were connected in parallel across a pia, of 1,2V? What pid. would be needed to send (01404 through the two bulba in pallal? 2. (w) State Ohm's Law

(b) Derive a formula for the combi-

'mtion of two resistances in parallel..

~(6) On the same piece of graph.

paper, áis graphs or the p.. V. Baroda each of the metal wires H,

and R, against the current I. lizourh it.

R

p.d.inv

I For R. 0.3

2.0 3.0 4.0 0.5 0.75.1.0

1.3

in

1.0 1.5 2.0 2.5

For R2-0.5

(A) Tor R0.8.

16 2.4 3.2 4.0

(1) Whet conclusion can be made.

from these grupho?

(ii) What are the values of these

resistances?

(iii) rat

potential difference is needed, to send a current of 1.04 through the three wires in geries?

fat is their combined resistance?

(iv) What is the total current

passing when they are connect- ed in parallel across a p.d. of 1V?

What is their combined resistance?

(4) Calculate the e.m.f. of the

cell in the circuit below.

Also calculate the current flowing through the 4 john resistance

0.4A

(a) A H.K, advertiser claim

1222

that

a certain electrical device costs only $1.80 per day when awitched on all the time. If electrion energy in H.K. de nupplied at 30. cents per unit calculate the power of this device in watts. Assuming the using voltage to be 200 volts, calculate the resistan ce in ohma.

What would it cost per day if the meine voltage dropped by 204?

Page 20Page 21

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