1973-11-26 — Page 16

報日僑

-期星

日六廿月一十年三七九一曆公年二十六園民華中 育教儷華

「名如后;朱玉珊、陳 「師生共六十五人,劳 「 那明 - 張低,胡文 C英中B),

ER-BAK USE KES) ENRE 陳劍沓 蔡寶玲、陳照,全美女甲冠軍黃瑞和,

• · HR· · SSE KINK4) · KNEE 玉泰、謝啓點、楣餐、冠軍减少体(中班)。

· ÉRE · BUZELEZEEN( 丽好,第疮涼,岑人兒 錦標急英中四野社,全

一阵•莫運查、李明微,含有四百二十 張儀、何景輝,林学施:四項破大食紀錄,十][ ,對文體,黃家酸,林一項平大會紀錄,全場總 - 媒坭勝、陳金衡、李、十萬,競賽結果,有十 若萍郭文・天瑞(英中五山・男丙

遄·李康•陳文·丁一人,兩組共六百一十九 良镳。楊志鏋,黃統遭人,運項目,共有五 故意萍,李否題、杜人一女她動員有一百九十七 葉翠芬,解馬大。这一日運動大會參加之男運 閻國良·需針泉,危為一始在雄壯校歌券中完谰 華、吳甌國、黃燦鈞,一閉幕。據大食統計;是 華、梁楹斯·皮新林一獎,頒發完畢,大會 芻嫩培 - 高橋標、蔡貴,校長甄体光分別主持 芬、范紹治,危滿強、閉幕机。由校戴佩裤埣 師生輸血。此次瘀血者影開始,立即熱烈展開 | ESKRA - ESC 競賽,直至下午四時全、

「倍,找危救急,快來 於昨日上午灣出基本人立蓋,何孫康拍攝政 【翡,砌丽蘼能可貴。石該會長及該校校李 負多名。前赴該校含客,她全校同事,按由

當局以該校學生熱心社,將國後式正式開始,黃 三义之申請捐血,越會列激操過司令台後,開 HERÈDEKCE

「名學府,該校師生恩啊 動,乃集协向該會作第一長燈大會主湍鍾偉光主

|敎會香港區會培英中學,一連兩天,假座九龍仔 瓯香港紅十字會捐血站 兼大會會長黃石歡,校 ,係不倦祆史悠久之翼溫動場舉行,開幕式及

·一兆玩心中華基督,第七屆全校凱動大會, 「禮,由該校校監督 持,當運動員資

三度集體捐血

培英中學師生

|共事務秘書胡錦才、出版事務陳炳死。八背 宗教事務秘書李!國際事務於習葉涼,公 「長潘麗。常為秘書夾扣,財務秘書李特明。 【友共聚一堂,氣氛快,該會基国新戲如下: 會,日昨下午二時在會所舉行交接典禮,嘉賓會 會長李志強,內務副會長文均,外務副會

〔等凯)香港天主浟大專聯會第十三屆幹事

天主教大專聯會

六十五人响應運動

十三屆幹事接任

【英等。該校師生素受

英,陳發爾·蒍民

| 客錦瑛,李女富,吳育

#HER-INH:

何榮,黃天賜!

D

KEBACKZ

|崇正中學

精神·殊堪科式。並

「血之,其捨己禇入之一

亶澳州間,而有串體料育刊在第

校正

六特訊】洪正中學。

按運大會 留意

真六育

意請張刊尙

讀第在有

者四第教

PERAREC

·上運動大會,假荃灣楬

HRIG-BL103

·該股本屆大會成

六特茶灣官立

K+15

學中業工立官灣荃

紀|創|大陸

錄新會運

獎頒持主芳浦陳

四十七,七秒成統,亦為難得。 "

|燃辻僅以11十分之後動倒杠吐而榮登查座。 官立中分別奪得男,女子組冠軍,而男子組之

·敦請荃灣鄉事委員會主席嬴流芳先生主

冠軍之爭奪,亦甚,積分此上彼落 結果 : 至於邀請接力賽,元朗鄉局中學及何交田

闷友,李沃荣;潘柏雅及馬俱等亦建殊動。總 民及四百公尺餘,此外。李文立,用盜、伍

「先生及黑區界育會主席成先生等數十

特别掂與會嘉賓計有新界區高级教育官梁发随

樊下百公尺,11百公尺

·及跳盡之新接,女子甲 祖賢亦起新一百公

·一秒及十三舆十时 蔡世囅以十四·一秒,

新祀錄,三三項不大會紙

:其中尤以女予丙梃

A A

くく!

900

(1974中學會考試題預習專欄

POJEM EL...

化學科(課程乙)三 王兆女

CHEMISTRY (3)

„Suggested answers for Last

From (1) 5.85 mm of nodu

chloride contained .30

nod um

100 g of godium chlorile

conta mod

01258 1:00 pm of sedius

1.e. 39,2)

60.69

From (11)

sodium and

17.6 chloride.

gn of sodium

chloride contain 3 m of sedium

100 gm of sodium chloride.

contain

n-3x 100 mm of sidium

e. 39.31. gn of sodium and

60.69 m of chloride,

Thus the ammonition of is constant in required law.

dium

the

In the first oxide 12.36 en of carbon combine with. 57.1 gm of

oxygen.

In the second oxide 1.363 m of carbon combine with 3.637 cm of. oxygen, 1.c. 12.86 m of carbon combine with 114.3 g of oxygen. The values 57.14 and 11.3, being In the ratio of 1:2, 4Ilustrate the law. An alternative, methor carrying out the calculation, is as follows;

L

In me mole of the first oxide. 42.86

128-atome of carbon combine

57.14

X

42.86

with

of oxygen.

In one mole of second oxide

g-atom of carbon combines with 3.637

-atom of oxygen.

Im-atom of carbon combined with 3.637

of oxygen

Again the ratio 1:2 3a obtained to 11lustrate the L

Rate of diffusion of methane-

≈ 120 cm3/40 seconds

3cm2/aocond

By Grahaa. Jogi

Rate of diffusion of methane

Rata of diffúsion of hydrogen bromdalla

Density of hydrogen bromide

Dezrity of methane

“Molecular. wb. bf hydrogen braaide

Molecular weight of methane

-81.

Rate of diffusion of Kür.

Rate of diffusion of HBr --- ca

30cm of hydrogen bromide would diffuse in 30 3 22.5 seconds

D. Atom and molecule

An atom is the smallest particle

of an element, which can take part in a chemical change. The atomi

The atomic went of an element is the ratio of the weight of its aton to one-twelfth of the weight: of an atom of carbon

Atomic weight -

weight of. l'aton of

2X weight of 1 atom of cart

A Molécule is the smallest manticle of an d'ement or compound which can exist in a free state The Molecular weight of an element. or compound is the number of times one molecule of its as heavy as one-twelfth of an atom of carbon..

Molecular weight

M

weight of 1 molecule of substance. x weight of 1 atan of carbon

Determination of atomic weights

Dulong and Petit's Law:.

For slid elamonts, the product of atomic weight and specifi hent is equal to

6.4 Atomic weight

mpler

1,6 mm of drob dishlaced 668 co Hy measured at 10°C and 755 mH Tte specific heat is 0.112, what is its atomic weight?

Vel of Hat S.TIP:

760

11.2 litres H2 at S.T.P.

Hence

1

GE.W. of iron

640 cc H (ST.P.) = 1.6cm Fe 200 cc (S.T.P.)

11200

-64:0

31.6 g of iron

21 en of iron

the E.. of iron 28.

6.11

ht. 10-11

atomic ut

Valency

the accurate atomic weight'

onuivalent weight x valency

5610

Istory

Irates are atons which contain the same nugber of protina but deffaring na bers of neutrons. They have (ontooss of hydrogen ocented) the same chemical

parties but differing atomic; weights

35 37 Example: Chlori

Formulae

CI

The Empirical Formula of a substance is the one which shows the simplest ratio of the numbers of different atoms in the moleale Several substances may have the sare empirico farmla,

The molecular formula is the one which shows the actual numbers of each kind of ato in the molecule

Molecular Formula - (F-nirical

Formula) x. n where n is a whole winter

Enirical

formula

CH

Molecula form

Example: A compound of carbon

and hydrogen has the following percentare commosition: C÷375% 0-50% H=12.5% What is its empirical formula z

$ cormound Atomic' V. Ratin of atoms

37.5 12: 37:

50 16.

12.5

Reduce tr whole moj bije Alviding by the sallest

Ernirical formula - CH

PTRE

Example: A compound as the nercentage commisition by weleht 0: #NO,TH-6,67 :0=53:33: Its vanour density to 300 What 1 te molecutr formylo 2.

Mol. wt. = 2x V. 230 -6 Determinat "on of the lemntricat formlo

Rotor tams

COMP12 3.33 Dividing = H=6.67+1 = 6.67 hy 0-53.33+16= 3.333-33-

h_Ta

the Banirigal formula - CH2O

A substance of this camosition would have a 4^u =(10+2+16) = 30

The actual ol. wt. = 60

molecular formula

6. Throato", the

and 4-16

xenotrical

armula

Phr atomic weight

gram-aton In train is called

elemort. Shut. Pram-aton oxygen in 16 **. as oxygen.

Praca weight of an commoung, can also be öxpress. ༡༩༥༣དཀ༠་

Thus for

A mole is the molecular weight. the formula velucht of ay subht gy-ress in iraquer, te.Al

1 pa-mole of sulamur dinkide.

Avarodrom Himber:

1 -- 01 of any substance con- tain the same number of molècules Thân' midber is called Avogadro's number and has be found experi méntally to be 6.02 x 10'

Thus, rugher of 4-lecules in a ad moleend of nitrogen:

28.

6.02

the nitrogen molecul 22

tom

H. Chemical tuuations,

Anouation is: a representation of a pherical change On the Teft are placed the formulae of those subataroos bout t change (ie. the reactants) and on the right, the formula of the neodiicts.. Since a chemical change obeys. the law of Connervation of Nann," there

must be the

anne

her

and kind

of ators in both sides, to the equation wint Whalance", Bamnler 1.26 of black cooner oxid are commletely reduced by hydrogen to cooner, What we' ghts of copper and water are formed ?

79.5

Cu + H2O 63.5 R 18 79.5 W CHO forms 63,5 Chand

For water

100 x 1623.

and

alo. 1.02 m conher and water are formed.

Example: What volume of carbon. diovide measured at 27 Card: 75 en He can be obtained, from 10." of Cu(OH^chco, 12.

343 cm x 22.41 At

10. 1

x 4.8 1 a+ S.T.P.

1-48 3:0 343

X

273

and 75 cm le

1457 litres

Questions for this reek:

20 ml of yous hydrocarbon X mero exninded with 120 ml of oxygen. After the explosion the Fatuma of sores rentiniam was 90 mly and this. Incrons id to 50 el trant at with caustic sotarh. Calculate the lecular formula of%

2. (a) mineral contains 14.7% Ca

and 67.6% #; the remainder is cxen Find its formulal:

(b) When inches um 15 hotted in måtromen St. Torre an-nesium nitride. the latter can hund erasts, vilir water to fh anmacium hydroxide. and lo amonia, teine the equations for these two reactions näé ch'eu- Tate: (1) the volume of nitrogen.. anantared at 1730 and 750 4, which would be herdel to react with 1.2 6 s of -razesiuri, and G-1) the volume

of 4mania, at the same to merature: and resure, which would he obtain. ed from the maconsïum nitride so obtained.

(0) han 1, 193 • af chloride nË The Aldolved in water and

gchan of milvän nitrate eelution, 2.151 or silver dioride wore nrecipitated. Deduce the coustion for the reaction bete on the titanium Chloride and "lven instratë.

1874中學會考試題預習專欄

NOVADA A MIL

地理科(課程乙)

Geography Revision (2)

Tropical Cyclone

RE

Its origin and development:

Cyclones sometimes do arise in the tropics and have similar. clockwise and anti-clockwise circulations as that of temperate cyclones. Owing to the absence, at the equator, of the deflecting force due to the earth's rotation, tropical cyclones never develop on the equator, but usually between 100 and 200 N and S.

in the summor season, when the sea surface around the tropics. become intensely heated, warm and humid air starts to rise, cuol and condense, then produce clouds and heavy rainfall. Surrounding air is immediately attracted to rush cyclonically clockwise or anticlockwise into this lowi pressure centre. These ground winds never succeed to reach the very central point of the low pressure for they soon become warm and humid and upthrusts. rapid -ly in spiral paths. On reaching the tropopause. i.e. the upper limit of the lower atmospheric layer, they are forced into. anticyclonic paths before they sink onto the ground. Some of the cold air may find its way down through the space enclosed by the spiral winds. Therefore, an 'eye' is formed which denoted such region of cold descending. air and calm condition. Surround- ing the eye' is a circular

vortex! where the spiral ascend- ́ing-air.currents condense and produce very dense cumulo-nimbus clouds which cause thunderstorms and heavy rainfall. (see Fig. 1)

However, convection of warm humid air is not the only explan- ation for the origin of tropical cyclones. Very often, a tropical- dyclone is likely to develop out

of the convergence of a tropical continental and two opposing tropical maritime air masses. (see Fig. 2)

On weather charts, a tropical cyclone is presented as a series. of circular isobars which decrease in mb. towards the eye Winds are inblown, clockwise or anti- clockwise according to hemispherea and increase in speed towards the. centre. (see Fig. 3) -

Tropical cyclones migrate. westwards over oceanic surfaces, usually follow a hyperbolic curve around the western fringes of one. of the sub-tropical high pressure and often finish by entering the westerly wind belt. (see Fig. 4).

If a tropical cyclone passes onshore, leaving the ocean source of humid air, its intensity is rapidly reduced and assisted by frictional effects of the irrequl ar land surface it is soon die- integrated.

Weather on the passage of a" tr cal cyclonea:-

Ahead at X, outside the cyclone, there is dead calm with heat and great humidity. Low swells appear at the sea surface. As the vortex (Y) approaches X, there is a distinct lowering of air pressure and an onset of squally weather. Clouds are thickening; winds become violent reaching speeds of 150m.ph.; thunderstorm, lightning and heavy rain occur at the same time and visibility becomes very poor. The sea surface is very rough. Within the eye (2) pressure remains very low, clouds thin out. There is light or no rain and no wind, This period of calm is followed by the vislence on the other side of the vortex but here wind direction is, the reverse of that at Y. Gradually pressure rises as the storm passes away. (see Fig. 1)

Compare and contrast of Tropical Cyclones (TC) and Temperate Depressions (TD):-

(A) Similarities

1. Both have a low pressure.

centre.

Both have "eyclonic winds, in similar anticlockwise and clockwise directions for respective hemispheres. Both are oceanic in origin.

(B) Differences

TC develops out of convection of air, or tropical convergen- de of air masses TD develops as

a result of temperate convergence of air

. ៣២ រៀន

TC is origined usually between

·10°, and :20° N & S

TD around 45 & S

TC has no fronts but an eye and a vortex.

TD is marked by distinct waTai and cold fronts and sectors.

On weathes charts TC is represented by circular isobars

TD is marked by oval ise bars

TC can generally extend up to 400 miles in diameter.

up to 1000 miles in diameter

TD

6. Around the central 'calm' of a TC, there is a vortex with thick clouds, thunderstorm and gusty winds Temperature is at the centre highest. Even in the warm sector of the TD, there is unstable rising air. Along the fronts fog and less heavy rain occur.

Temperature is higher in the warm than in the cold sector.

7. TC dies because of loss of

humidity supply from the sea and friction of surface relief TD dies. because of occlusion- of warm and cold fronts i.e. the uplift of warm air from the ground.

8. Te brings more destructive

effects on the affected areas. PD usually bring rain to the lans affected.

TC may be known as hurricane (Carribean, areas), typhoon (S.E.Asia); cyclone (Indian Ocean & East African coast) and Willy Willis (East Australian coast)." Tiso low as depression or extratropical cyclone.

CZANES

C Gerus.

N-SC. Nimbe Ürdies

Care-Stratus 1: 10-20 m2, 1---

EYE

VORTEX.

Fig 1 Structure of a Tropical Cylone

Gusty hind

Very Rough

3 = fit; ml:

TROPUPAUSE

cout, des

-cending -

Calm

Justy Whats

Very Rough/Low:

VORTEX

St - Stratus

Cu-Nb "Cumulo-N-mbut

Brical

(off lardy

EQUATOR

"NE, trades

-Inter-tropical

Front

trades

Tropical Maritime Clu 502 A Triple Peint on the Intertepuul

-X is likely to be the point of origin of a

Fry 3 A tropical Cyclone.

•Weather Chart

5 Bye

- trough line (Low Person).

494 990 are Ribars in inity bars

ivinit aeries (in Krits)

One of the hyperbehe. paths of tropical cyclones

the Pacihe Sab Tropical Hon Fressure. the tropical cyclone

H.P

L.P

→ path of the cyclone

Tropical Cyclone Region