1978-05-22 — Page 26

華僑日報 All

-DE

日二廿月五年八七九一腊公年七十六國民華中育教化交

閉手大學 好

華僑文化

台美旗仁佛學院除長谌業老師 - 昨(十一)晚七時半,在九雅山林道紗被林素食店 一,將參加

道源法師昨講戒殺放生 各界善信仕女參聽者衆 隨堂派送戒殺放生文及素食小册

女王

岡之酒 月滿

戒親

生,大

衰语童四次生展

·王葉袖大法師之戒殺城生文,及果通師所求之「爲什麽案食有益」說小册,均在會場 就會计五日在油麻地亞科大烖粘學行之故生籌款法事,於跳解戒殺放生交後,得以印證,

連日參觀者衆 昨晚圓滿閉幕

臺語會第四次腰,宗十九日開幕以來,愛

BRINN

།། ༄་ ̇立要吾門,汝其一片心,年前舍教弟子

波且天生就額,智慧過人。平歲就在 淳有禮,和鎮可說,好本力行,这師本 .。余虧季之除,傷客不已--浩其含人就

-望風貓啦?我箎兩行淚,今拼永存師生 梁徒棠日昨因患塌血管病,不治,

·選音重忍啦·悲慎購物,忘傳衣砵

EZE-EKKN - SEGEES

果: 輓梁耀棠賢徒 邵鐵鴻

(B

迷你

香珠本

(#ID

什詠.

HE

SER·SEKAKES

STIER-CEERDE

林金:

-如何老傘多來售,不積高苗種基制。

可笑荒散盛名。我來高負善耕作。

《·其四

(##).

*踏翠今來少客

·盆花映日午風濕,摻外江出家

1 RESKVZ - MEMELE

明珠社佛史專修班

·梦魂不織滄桑换i尙到家製本。

·浪跡天涯數十年。海心日日逐飛出。

本週日高永霄主講

(廿八》早十時,由高永霄導師講「唐代佛

KETED-ERGES +E (ESR) A

九醛新界各大音樂社團教授樂,澳門。有情義派途。微址:九龍窩打老谮十一號

再二第張七第 日六十月四年午戊

WAH KIU YAT PO

報日僑華

***

域川看惟

Fill

,幹向余願執弟子蟾·余感其離,乃送

; 會幾何時,奈何梁徒剛年逾不惑,令人 其志;而余亦竊喜衣体可傳,樂藝有出

讀禮運大同篇書感

(*):

· 周蓋伯

龍而已! +91-KK-BROWN ( ལལ་བ་བ་ཅ

在女兒昨報》 由台般譽返港之凌票超氏之近

FRE 母湯文武,禮義以爲能。

·文化都大興,共拘嚐技力 西融重商周,郅足矜式

湖古五千年,中華始建國。

KERUZ - HERIK-

·打醋孔家店-旗嫌從斯域 0 BROKE- BREEG-

百家學說中,家乐昌盛。 二千五百年,長期受崇敬。 薏五四日,在溯忽升。

幸而生孔子,天縱之將聖。 PREKE HESEN 齊風孝道,槍不施仁致。

閉繫計如契界怪壞

21.1

登法

(REZALETTEKH )

-

澤注

南川安

隆有位

八所川

TESTERNE

方通澤

所余股

達台躬

RISESJOVKLKIV(+26

【現我出香港酒店)

出版消息

題桫習,每本四元,*

用等三章;遷附有害 在甲子數字計算機上的

,分算術,鎘世代及

店有售。

各大州店有 :

·由天地術有限公司出

Z-EVDETUR-

:「世界與中融」

化學科建議答案

曾益之澤

(iii) The oil bath will pro-

vide a uniform heating; besides, butan-I-ol is highly inflammable,

(iv) The concentrated sulph-

uric acid acts as a dehydrating agent. The water is used to.

Suggested Solutions to KCEE 1978

Chemistry

(v)

Paper I

dissolve the unreacted

butan-1-ol vapour.

(vi)

The bromine solution is decolorized,

(b) (1)

CH, CH2CH=CH2 + BE2

CHCH CHCH B

(a) (1)

Gas X is hydrogen.

doride.

(11) acl+50

(1) It is to prevent "sucking

back" because hydrogen chloride is very soluble in both water and toluene.

(iv) than hydrogen chloride dissolves in witër, it ionizes to form Hydronium: Jons, and chloride

2 ?c1, which can jong, conduct electricity; but hydrogen chloride does not ionize in toluene and remains as covalent mole- cites which cannot con- duct electricity. There are present in the aqueous solution of the

) (i)

(b)

hydronium ions, J,07, :

which are risponsible for

its acide properties;

hut, there is no such

40 ion in ethylbenzene. adition.

White precipitate of ammonium chloride is ob tained because ammonius chloride, being ionic in nature, does not dissolve in the covalent solvent, methylbenzene.

The yield of hydrogen. decreases, as the forward. reaction is exothermic, (ii) No; increasing the tempe erature has no effect or the equilibrium position because the total er

of moles of viseous re- actats ad that of Cas- eous products are equal. (iii) The excess steam will shift to equilibrium position to the right, so, the field of hydro- ven incras B.

(iv) The catalyst can speed,

up the attainment of the equilibrium. The cata- lyst will have no effect. on the equilibrium posi- tion because it speeds up the forward and the backward reactions to the extent.

(0) (1)

Ilo. of carbon atoms in 1g of isotopes is

2 x 10-23

x1022

Avogadro's number

C

=no. of Catoms in

12 € of

22 12 x 5 x 10° 6 x 1023

(11) No. of oxygen molecules in. 150 cm of oxygen is

150 24000 X (6 x 1023) |

- 3.75 x 1021

(iii) hass of water - 150 s

no. of water molecules

in 150 g of water is

150

x (6 x 1023)

18

ཧ་ ཏ་ ཚ

24

(a)

Gas Xis it--ene.

IL-C-C-G-C-0

#

Br

(vii) The apparatus as shown

in the following diagram is used. The wet gas X is passed through the anhydrous claciun chio- ride as the drying agent.

(b)(1)

wet gas X dried gás X

drying agent

(1) A could be sulphur

dioxide.

(2) A could be ethene(or

any gaseous alkene). CH2=CH2 + H20 + (0)

H-C-O-H

OH OH

(ii): (1) They are the sulphite

and the carbonate ions.

(2) Dilute nitric acid is added to the precipi- tate; it will not dissolve if it is barium sulphate.

(c) (1) In the or

conversion of nit- rogen to nitrogen dioxide, nitrogen monoxide is sim- ply mixed with oxygen or air at ordinary conditions.

In the conversion of sul- phur dioxide to sulphur trioxide, sulphur dioxide is mixed with oxygen or air and the mixture is then passed over a heated catalyst such as platinum / or vanadium(V)oxide.

(11) The oxidation number of s

in sulphur dioxide and sulphur trioxide are +4. and respectively.

(a) (1) P is the positive pole. (11) At the electrode Fi

+ 2e

It is an oxidation reaction.

(111) Oxygen gas is collected

over electrode. C ̈and hydrogen over electrode

D.

(iv) Amount of electricity

passed is

2 x (3 x 60 + 13)

2x 195

386 coulombs

According to the equation

amount of“X deposited...

I no. of faradays

used

386

96500

0.002 moles

of inetal X is

0.127

0,002

", relative atomic mass

63.5

re-

When the current is versed, the metal X ori-. ginally deposited on B- dissolves and gas bubbles of oxygen will be seen around B which is now an anode when all the metal

(11)

X deposited has dissolved.

Y belongs to group 4 and Z to group 6.

The order is: IH XHZH2

YH has no lone pair but

four bond pairs; as the repulsion among then is the same, so, the molecule is tetr- ahedral in shape. Xiz has one lone pair of

electrons and three bond pairs; since lone-pair bond-pair repulsion is greater than bond-pair bond- pair repulsion, so, the angle between two bond pairs gets smaller.

ZH, has two lone paire

and two bond pairs; owing to the larger lone-pair bond-pair repulsion, the angle, between the bond pairs get even smaller.

(iii) It is because that in...

the liquid state, their molecules are held tow gether by weak inter- molecular force (or van der waal a force), so, they have low boiling points..

(iv) The structure of the

compound is:

(v) XE3

dolution

fades. (iii) Reddish-brown funes of nitrogen dioxide would be observed.

2Zn(NO3)2

22n0 + 4NO

+

nation of bromine.

colour

is due to the for-

*2*201

012

+ 2Br From the above, it is seen that chlorine is a stroyero-dising agent.

(a) (1) 20

(iv) Since zine hydroxide is

amphoteric, so, it can react with excess sodium hydroxide to form soluble sodium zincate. White gelatinous precip– itate of zino hydroxide is seen first and this precipitate will dissolve when an excess - armonia solution is added.

3

If lead compounds are used, the paint will turn dark readily because of the formation of black lead(II)sulphide by hyd- rogen sulphide present in the polluted air. How- ever, if zinc oxide ie used in the paint, the paint will stay white as the zinc sulphide formed is also white in colour

(b) (1) (1) The suitalbe raw mat-

erial for manufacture of chlorine is rook salt or sea water. (2) The suitalbe raw mat

erial for the manu- facture of oxygen is air or water.

(11) (1) process involves the

electrolysis of molten or aqueous solution of: sodium chloride using carbon electrodes.

(2) The process involves the fraction distillation of liquid air (or elect- rolysis of water).

(111) Chlorine

The molten or concent- Tated sodium chloride. solution is electrolysed using carbon electrodea. At the anode, the chiro- ride ions give up elect- rons and are discharged as chlorine gas,

201

The 3-D structure of Xias

ΟΙ

+

W

(vi) The 3-D arrangement of

the atoms in the hydride of phosphorus is:

(c) (1)

(vii) There are three lone

pairs in each molecules.

(a) (i)

A is zinc powder;

B is zinc nitrate;

C is zinc oxide;

D is copper powder.

(ii) The zinc powder dissolves

and the blue coloration of copper(II)sulphate

Oxygen

C12

The air, from which carbon dioxide and water vapour as well as other Ampurities have been re- moved, is liquefied at first. The liquid sir is then subjected to fractional distillation and nitrogen would comes. off first and oxygen 18. left behind.

or

The water, acidifièd with sone dilute sulph- uric acid, is electro lysed. At the anode, the hydroxide iona, OR, are oxidised and liber- ated as oxygen gas.

The descending order. 18:

(11) The halogens have the

same number of electrons. in the outermost shell- of thier atoms, so, they have similar chemical

roperties.

(ii) When 1otassium chloride

in rdded into the aqueous

rquine, there is no

How- obeervalle change. ever, when potassium bro die is added to the aqueous chlorine, orange or reddish-brown colour will be observed. The

+ 2Na

2011(OH) Ona + H

'2'x

(11) No. of moles of hydrogen

31

rated is.

0.05 ioles

According to the equati

no. of Holes of A

2

ho, of moles of

= 2 x 0.05

I 1920s

the formula maen of

6.0

(111) Ferula loss of A

= (1245)+(1242)x+16+1

=252 + 14X

60

1450 - 32:- 22

Tence, te formula of

((17) 3 de rojanoic acid (ör.

propionic acid).. sodium propanoate (or sodium prop- 1onate).

C is

CIL OTI, CII, OII+ 2(0)

CILCH COOH + HO

+ Naon

(vi) The acidified potassiui

dic rolete solution vorld turn from orange

to redn.

(vii) The indicator employed

as pheroli hthalein. At the end-point, it. Lurus Trou colourless to nik or vice versa.

(viii)According to the equat-

iosa in (v), T

(b) (1)

T

no, o oles of sodium hydroxide required

no of poles or B fomed

no. of moles of A used,

0.1 moles

volume of Kaolt neeued

0.1

0.2

0.5 dra

The yellow deposit is sulphur particle. The white ash is magnesium oxide. (11) 2Ng+802 - 20g0+5 (111) The apparatus used is:

deflagrating

spook

ges-jar

magnesium

sulphur

dioxide

(iv) The white precipitate 18)

barium sulphate.

(v). In the expericent I,

sulphur dioxide is re- duced as the oxidation number of sul hur atomi decreases from +4 (in 50) to 0 (in solid 8). In the experiment 11, sulphur dioxide is oxi- dized as tue oxidation number of 3-atom increaes from +4 (in 50g) to re (in alpiate fống).

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