1972-11-09 — Page 22

莫二第張六第日四初月十年子壬發

1973英文中學會考試題預習專欄

化學科

Chemistry (3

Solutions for laat wear

Part

T. D

2. E

51

MHKO

1106-00

(=)

3

B

42

Part II

1. Law of multiple proportions-

When two elements combine. to form more than one compound the weights of one element which unite with identical weights o the other are in the ratio of whole numbers, usually small.

In the first compound:

36.32 gm. of oxyzen combined with 63.65 gm. of nitrogen.

ร

gm. of oxygen combined with 63.65

= 1.75 gm. of nitrogen.

In the second compound: 53.32 gm. of oxygen combined with 46.68 of nitrogen.

46.68

of oxygen combined with = 0.87 gm. of nitrogen

In the third compound:

74.06 gm. of oxygen combined with 25.94 gm of nitrogen

1 gm. of oxygen combined with.

25.94 22-06

= 0.35 தூம் of nitrogen. 74 Thus, the ratio of weights of nitrogen which combined with

2. of oxygen =1.75 0.87 0.35

or 10:5:2

Which is a simple ratio, 2. From (1) 5.85 gm. of sodium

chloride contained 2.30 gm. of sodium,

100 gm. of sodium chloride contained 2.

230 x 100 gm of

sodium.

ave. 39.31 gm. of sodium and

60.69 zu. of chloride;

From (11) 7.6j gm. of sodium chloride contain 3 gm. of sodium.

100 gm of sodium chlorid. contain

x 100 gm. O

sodium.

7-63

1.6. 39.31 gu. of sodium and

- 60.69 gm. of chloride. Thus the composition of sodium 1 constant as required by the law,

Diffusion and Brownian movement.

Diffusion of gases: If a light

gas is brought into contact witu a heavier gas, the two gases. mix together despite the differ -ence in their densities.

frahan's law of diffusion: The

relative rates at which two gases diffuse are inversely proportional to the square roots of their densities. That is,

WAH KIU YAT P

Brownian movement in liquids

郭日僑

When very tiny particles of

matter are suspended in a liquid,

雞玉

the particles engage in ceaseless activity. Each particle moves

first one way and the another in a ranion or disorganized va

Lever roally getting anywhere, out always on the move,

The Gram-atom, the gram-formule

and mole.

The atomic weight of an element in grammes 13 called a

grar-atom of the element. Thus a gram-atom of oxygen is 16 gm. of oxygen..

The gram-formula weight 0. an ionic compound can also be expresse in grammes, giving us

gramme-forula of the compound Thus for potassium chloride;

ca 35.5

Formule Weight: 74.5

A mole is the molecular

weight or the formula weight of a substance express in grammes.

1 gm-mole of sulphur dioxide. weighs 64 gms. Avogadro's Number:

1 gm-mole of any substance

contains the same number of mole- cules. This number is called

Avogadro's number and has be found: experimentally to be 6.02 102

Thus, Number of molecules in a gram molecule of nitrogen.

28

wty (in gms, of the nit molecule

28 x=wt. (in gms. of hydrogen atom

6.02

1023.

Exercise:

Part I

1. 100 cm3 of hydrogen and 100

of a gas A diffuse through a porous plug in 10 seconds and 50 seconds at the same condit- ions, the molecular weight of A is therefore

A 5

C. 50 100

5. 25

"

one mole of chlorine weighs

35.5 gms B. 2 x 35.5 g.

x

0.6.02 1023 m.

D.

x

6.02 x 1023

2 x 6.02 x 1023

The foumula N, may be used for

Element

gm - atom of nitrogen

molecule of nitrogen formula of nitrogen

gm

14 gm of nitrogen

6.02 x 1023 atoms oi nitrogen

Atomic valency weight

Calcium

40.08

Jarbon

12.00

NO. OT

atoms: in

gm-aton: 6.02 x

Molecular weight of gas 1 Molecular weight of ens 2:

Example ! The rate of diffusion

esrbon dioxide and ozone are approximately as 2.9:2.71. IẾ the molecular weight of carbon lioxide is 44, what is the nolecular weight of ozone. rate or Aiffusion o carbon dioxide anul

its vapour deng-ty

rate of diffusion on ozone and D' = its vapour density

X should be A. 6.02 x 10 B. 6.02 x 1023 702x1023 C. 6.02 x 1023 D. 6.02 x 1023.

5.6.02 s 1023

The gran formula weight should be used instead of molecular weight for

A. Chlorine

Then

D

Mole

25.2

Lar weight x 2 = 5014

ozone

B. Ether

C. Sodium-

OF 002

D. Acetic acid E. Nitric acid

121.00

12.00 40

100 cc. of hydrogen are confin -ed in a duffusion tube exposed to air. When change of volume, ceases, What volume of air will have enter -ed the tube?

·四期星

日九月一十年二七九一座公钅一十六國民皆中

津貼小學校長會

週六敎育研討會

「巴和沙撈越——的人文 的成員———用來韮沙、

.同時舉行會到大會討論修

學校校長戊有永峰大 小堅校委會 倻使解會,到四時卅分有平行就 港弑香港一時半完畢後,茶舞小啓 陈煜洲食啖都市,思維及中國中之工作,介紹 破一:强調新嘉坡城 ANERTYO

LIKO ZOUKEN

,高板金主任政嗓志,此片在泰风的人, 「校內次試分數隣整」,湘主任两级似,會特酸、怪族等料加工製造的,光反时偷到」,「光 日前所發出之涌5第一,又昨日該會主席周她的貨物薄運站,勾線一數,一直對

18-FERRER FL

方

*理法述在介

•ME BEREMON

「無際械之資醮」

折射之直驗」,「光的

「R下午三時強調的四 一事務之所館參加。號有阿難選商討六,指州觀争,此烹大地一 薛俊海主持,並作息;果出例證,若十二:此案與多方肉弹| 金工:「H」 演講。恶各軍貼小黑份,分转展出席之校長,餘地介杯於离的地理、一分將解介绍一鼬工」的 校長偕同類與教區及到,屆時升畫國各校長。 基本技術和工作醤程。

玫噍中心EW究會之便,將有储、情

·麥行研討會, 高轵波· 擬越太湖六舉行會員。 3 七一,假油露地東。對東流,是大金鶵整內容之若一對。其中德角的唾佛寺,速度之實驗」、「長铑 同郷疗方本泉星校物院干嵗點,所會信實、面发价低及水上市寫實驍心,「就吐之宜

組

視聽教育組續增

扎下的指影

·

各學科膠券多套

介人把各都市 一及冻統的功能,包骨」心型砂微法」的工作形 体災及性糾台(第一般和解説明「引方鉄

的破壞以及在戰火發覺。精液」和「草砂造型」 SIZKREER (FRESEOR HITARENJE

(30) FEKİR.

E

cos ezik. 余片操作

!實膠各黻!

ARTESEN BRUNENSE 1858 #NEW-52166 · 955FXFSK (E12)] •85 LEVEKRITIE

此等限僻片節闢如下:

ENTREE JOURNEY BONES EISE (SER 「女南亞——教國,生殖溫綿的功褚及一、有異的介四名博彩接(

HERAKENDER TESK

RM42

$<**** BERKEERS.COKER

MESECEAN PORTER 295.1

感焌銅人投,品

#

1973中學入學試

試題預習專欄

「京南——馬來:傳粉

花粉

育载僑载

鮮甜

esting boiled eggs,

R. of S. at T. with)

PQR

7.□□□□□

for Q. to R.

by)}

智慧出版社主

英文科(三)

They will leave Hong Kong.

tomorrow

England

ANSWERS, TO PREVIOUS EXERCISES

SECTION A: I,

SECTION B:

some

the

SECTION (multiple choice)

the

Choose the correct aNSKAT. Draw a firm line across the correct box. Examples My brother is good

arithme tio,

B. with

D. for 3. from)

·Most children are fond

A B C D E

00900

from D. at

chocolate: for)

A B C D E 1.00000

After leaving the cinema, they talked

the runny film.

Dabout.

00000

getting dark now, please switch

the light.

D. For by)

DE

□□□□□

4. Mrs. Chan was very pleased

servant.

his

(A of 3. for G. up. D. with E. at,

00000

Good pupils like getti

to morning

A

□□□□□

Please look 14

e dictionar

RS T

□□□□

The host divided the cake

equal parts.

1000

P.to into B. between S, in (T among)

9. bbbbb

10. He is not interested

(P. At 0 to R. for S.

P Q R S

□□□□?

SECTION – B

Ir. Underline the suitable Preposition in

the brackets:-

John often plays football (to,

with, of, by) his friend,

The nurse da looking (to, after up) the patients

He often plays a trick (at,

on, in) his friend.

MIt is very kind (to, at,

of you to come," Uncle said David

The poor man was in need (to,

for, from, on) money.

6. The train arrived (to,

the station late last ni

night.

The policeman asked the women (in, at, to, for, by) the front of the queue.

It has not rained(for, since, in,

at last mont

9. Mr. Brown suffered a lot (of, from,

on, over, with) his stomach-aobe.

The scenery (or, at, Wi

Hong Kong is beautiful.

III. Fill in the blanks with suitab)

Prepositions:-

14the farmer worked hard from morning

night.

2. It is

the law to spit in public places.

3. That rich nan Barried

"daughters.

Peter Ng is weak

Biras

together.

English

the same feathers 1100k:

John Ma parked his car

8 lorry

Will you share your fort

your three sons?" the lawyer asked.

The fire is now

Wing On has not yet.

his illness.

10, I shall take

it is very

gon cro1.

coat because