1974-12-20 — Page 19

育教經馬 頁三第張五第2日七初月一十年寅甲曆夏

育 教僑

華

1.575

中學會考專欄

堅道壽生編

化學科(六) ·陳湛杰

UHL.ISTRY (6)

SOLUTIONS FOR CHEMISTRY

Multicle Choice Questions.

1(C) strong heating of lead;

monoxide Pbo

2. (B) strong heating of mercury.

oxide in open air

3

(0) monoclinic sulphur 4.(E) orange to pale yellow

5.(D) sodium bieulphite. is foamed

Conventional Questions:

1. Oxides of metals and non-metals constitute an important class of compounis. They can be best:

classified on the basis of their renctions with acids and/or basesi The general types are:: basic oxide: acidic oxides, amphoteric oxides, peroxides, compound oxides, outra.

oxides.

(a) Basic

oxides-these are ones that interact with an acid to give gelta and water only Basie Öxide: are generally formed by combinatici of axygen with a metal, eng..

2Cu +..02 = :2000

CuO + H2SOq = CuSOq + H2O

Basic oxides of alkali metala undi ilkaline earths unite with water to form soluble hydroxides, which are also basic.

CHO + H2O =

Ca(OH)¿ +

=CaCl2 + 2H203

華(b). Acidic oxides-these are ones

that react with a base to give

salts. Oxides of non-metals are:

usually acidic, and may write with

water to form an acid.

+ H2CO + Ca(OH) = Ca003

Ban +90= = BaSOg + HAO幾 Na 0+ 150 Na2SO H2O,

(e) Compound oxides-theat may be regarded as formed by the combin

nation of two oxides of the game.

Thus red lead Pb04. element.

appears to be a compound of

litharge Pbo with lead dioxide Pbo, since it reacts with hot dil. nitdeucid to give a solution af lead nitrute and a precipitate of lead dioxide,

PkgOq+4HNO; 2Pb(NO3)2+PbUy +214_0 Similarly, Cerroso-ferric oxide. Fe3O4, can be regarded as a compound of ferrous and ferria.

(f) Neutral oxides-these are one! that do not react with an acid or a bao to give salts. Thus, carbon monoxide CO and nitrous oxide No aro, examples. M

In addition to the above types, some elemente combine with oxygen to a greater or smaller amount that is required by their normal

The former may be valencies. tamed as polyoxidesaid are, examplified by lead dioxide Pb0, and manganese dioxide MnO2, am ar.

apable of acting as oxidizing" agents in reactions. The latter may be termed as suboxides and are gully unstable, carbon suboxide | C;0u-being. the best known

example. 2. (4) Hirogen chloride gas

= Na Hão + 101

gif

(higher temperature required) (a) Mitric acid vapour, the vapour is coloured somewhat brown. due to decomposition of nitric to nitrogen dioxide and oxygen.

F NANO : + H=$0g = MASO + HNO MEHSO+Mar NA-504 + IND2

(higher temperature required) fol Carbon monoxide.

H.COJOH

H.Đo Of + Na Han

acid): 00 (conc. 1,50 as a dehydrating agent)

(d)Carbon monoxide and caroon.

dioxide

2H2O

Na

The higher oxides of some metals. are also acidic. Thus although chromic oxide Cr,o, is basic, chromium trioxide 3cro3 is acidic.

• CxO2 + 2NaOH = N=Cro + H20

(C) Amphoteric oxides these are. ōnes that have both acidic and basic properties. Thus aluminium oxide reacts with acids and baseg to give salts.

an acid)

H230, 25 a dehyd mating agant.). Concentrated sulphuric acid has oxidising properties, which increase in power as the concer tration of sulphur trioxide. Cine reases. Thus hot concentrated

will oxidise sulphur to acid

itself is also reduced to sulphur [dioxide::

S+ 2150 =

+ 2H 5 380 Sulphuriennad in the concane trated state has a great affinity

**A1203 + 311,304 = 412(SO4)3 + 3 sulphur diocide, whilst the adid

2NaOH: +A120g = 2NaA10g + H2O Other examples are zinc oxide źno, stannous oxide Snü, plumbous oxide

(d)

Peroxides-these are ones that yield: hydrogen peroxide on'

dilute

acid.

acidification with a

for water. Organic compounds that

contain the elemins

of

water

are

WAHKID YAT PO

easily dehydrated. For suger notion of concentrated acid will cause the formation of a spongy mags of carbon:

C1222011

= 120 + 141120 (removed by

cone H504)

報日僑

20 DEC 1974.

RITY HALL

五期星

日十二月二十年四七九一曆公年三十六國民華中

along CD

Forces Beting,

friet

(D)

At

= Amy?

simvị ngh

COE 379 120

Work (done

to move t

the movable

parta

Amy

Efficiency.

(B)

我

100%

Concentrated sulphuric acid-like" the dilute soid also possesses neidio properties. The acid, being.

ibasic will react with tubes in two stages, forming firstly an acid. salt, then with excess base to neutral salt::

Zno

Il280 4 = 250

QUESTIONS FOR THIS WEEK

The questions in this issue are. related to 2.1, (b) (iv) Nitrogen; 2.1. (b)(v) Phosphorus 2.1. (6) (vi) Carbon Study your notes and text book before attempting the questions Conventional 'Questions

1. How would you prepare nitric acid in the laboratory? Explain. why the acid no obtained is yellow- ̇ish: in colour Imlicate how tha

removed. colormtion heay: bai

Explain icarefully how it may be shown that

nitric acid contains hydrogen, nitrogen and oxygensit

How would you prepare a specimen of pure carbon monoxide? In what way and under what conditions will carbon monoxide react witli (1) sodium hydroxide, (ii) nickel, (zig) chloriney (iv

what evidence is the

.On

fo mnula Co assigned to the gas? 3. Compare the elements. nitrogen and phosphorus with respect to the fo110ving: (a) Relative, tendency to fom multiple bonds. Give examples (b). Relative covalent radius

(d) Relative electronegativity.

Tendency to form ionic compound Electronic configurations

(sings,p,d,f notations)

CO 75

中學會考專櫃

: 堅道書主編:

物理科(六)·陸禾娜。

PHYSICS (6):

Bolutions Tor Questions in-last

(a) Posation lat A

Jalong AB

at B

Condition of energy E migh

losing | F Increases

|E="0" mgh= 0.

2

2

along. BC

lar C

kou righ mgh: amu2+ ng(h-r"}

121.

11 ms

(e) Position A is above D.

Energy possessed by the gall at Disamvængh* (a) This will be converted into kinetic energy at B

Amy

2

Amy+ngh

mig(+ 1); =mg(5.05)...

If the ball reached the posit tion A, it must convärt part of its kinetic energy into

Therefore, on coming to A, mg: (5.05 - 3) jouled is still in: possession by the ball. It means, that the ballis still having a velocity of.

#my12 = mg(2.05).

-1/2 x 20.5. 6.4 m/g

Cdef.of friction= tan 20°=0.36

The effective component that. causes the block to slide dow

.the plane Wsin370

Priotion opposes. motion, f

*f = 0.36 { Normal force)

= 0.36(Wcos 379 Fsin379)

The component of a that xceps.

the block.moving without accel- eration F cos 379

As the block slides car. the

plain ciiform speed, the for-

der actig on it are in equili briny, that is,

Weil 779 Feos (37%

60.80, 36(0.8W+b6F) 0.8F269#4 0.288)

70.210.216)

(0-6-0-2881

1-016F0.3127)

0.312

10 kef

When the forte exerts a force in ncing the lack the plans With form spend, the fed tive doponents of forces arks-

i

Effort (kgf) --

really br ile

reneen:antine on the block to

close the motion,

Wein. 37 friction

in 37 0.36(0.87 0.6F)

0.8BEN+ 012167

Forca 4d cansus the notion,

Fud 37

Since th block is acving in wi

10.81 - 6.888W - 0.216F 0.584F 0.983 x 130.

0.58

100 = 152

4

話

Lead (kgf)

Load (kgf)

14

31.5 14

333.43 3.5

(a) Prom graph 1, positiin A, he

sffort of 2.3 gr can raise e load of 9.2 -

(b) on the Sure graph, position.","

The effort required to reice: Va load of 7 kef 18 2.25 ket. (c) Thenaid gmch euts the yuaxis

at where the load, being zero. the effort required is used to raise the lower black. It is 0.5 r pulley (d), on graph 7 (efficiency va load)

when the load is 13 kgf, efficiency is 86.6%..

(e) Wien the load is 3 kgf,

efficiency becores 50%

(f) By. Conservation of Emery,

Man(A):

the

(0)

(3)

Work done.

Work done Work

on the 1+ done

on the

Toad by over-

by effort

mechine

the meching comé

(C) and (T) are constant. Efficiency of a

machine

·TET + 1) = (D) 100% Tx 100%

Efficiency varies with (B).

The larger the load, the better the: efficiency -

Questions for thio week

1. (e) The diagram shows a simple,

:: barometer.

What dogs it meature?

ii. Which height does one

mecsure x, y, or

2

Why use mercy in it?.

V

9(give 4 important..

reusong)

ivi Does the temperature.of.

baronster make any difference to ite read- ing? Explain. briefly. v. If mercury were used. which was still damp. with water whould that meke any difference?.

(b) Normal barometric height= 0.75 metre of mercury; mercury is 136 times denarr thar natër; 1.3 cubic move of water weighs 1000 g: 1 cubic metre of air weighs 1.2 kg.

(a) If the atmosphere. consisted entirely of mercury, the pressure, at the bottom being the same "as- it is now, how high would this

mercury atomoaphore" be?!! (ii) How high would g waterratmci

atmosphere?

high, then, is an sir

(iv) in fact, atmosphere of ein extends much higher then the height calculated in (ini). Why is this?

E

Compare the lifting capability. of two identical balloons A and

filled.

d with hydrogen and halium respectively. Mass of hydrogen meeded for: filling = 50 KG.

Mass of ballcon Fabric = 20 kg• The ratio of the density of hydrogen, helium, and air÷12:14

3. An object of specific gravity.

0.75 was projected vertically into a pond of fresh water.. Just before it entered the water surface, ta speed was 10 /s, The object returned to the surface without sinking.

to the bottom Find the depth it sank and the time for the whole flight. (Take gas: 10m/s? and friction of water negligi- ble.)

·

上有些俗

魋地的袋

合在農

奘

週

1-5態動

華僑馬經

老吉主编

駒狀態綜述

手破崙虎驃達巔峰

勤得幸運王子不俗

昨颃早怫伢崽出

兩次,可望再次走得拼一告。

意週已當出相關

的二有好戰信見、

昨得摊街八

見的捧節經冷

,要態。力有 隙更·梅紫薇

亦。再良之再週要捧佳 宜生日發片 二盯場, 吳得 正鄲

欄猛,拒,,試鑒,前平拼合,見

該據饰 夠尺第下告承

佳跑全審與線少病何未細

士無或會肝檢种微酸

十崗罵警化,尿現 廠於 黑 四部

月公司有宜放,亦前部織血

,還受惠有一定作緣。一個留意蘭尼兩坐騎

今塲的頭馬對象。必

安培拍跳,得猲S 當出色,勇態畢、應

·第四維炸動得與 組,此豹变在太神了。 一地,有機會送側同類各 的冷馬,發逹匙湖南 其,是另一匹要在就 匹危險份子。華爾秣態

有敗珊。或際大獎,組 身黑無後更靚,是第一

一些少,稍爲輕鬆 「俗,但峯之仍有

第三組永勝狀態不 自重標 亦在抖濬好。 好。好愉快做湟多少, 且看何人紮妞,值得 「機會。隳夠保持佳,

感十足,是牛鈴份子, 放蜇健執極 - 亦有一定

機會仍高。故都颱風,

再廠智勇雙全。 當不俗,雖負磅蟻, 騫二組虎聯試來相

「有未足的感覺,故選

一合脚法,可入位證。 歡狀禭亦見不俗,此程 ,還有接近演出,滿堂神 ,馬亦快照,今秋路合

飛馬王于亦見試得不俗蕙的一點。

此有展

熊亦見足够,弱馬本

|四。倍盧行圈謢步,狀

一態,是最宜敲冷的一 【飛近期難操,今早如甩

到今

面利態街,地有作用

一見湖步,有方入圍。必

甲一席,演說家來 |菑鋼門後,亦可 入]] | 所見 : 已能留力,今仗

甲可以入圍。

黨狀鸡大勇,近期课 一今個顯可爲了,新玩 |出色,馬匹酒質甚高, 試六化郎,狀態相當

·第五組赤昨早洲

本

兰色狀

勇,昨雖未見出腻。

留意,盈前程馬 晟鼎奇試來不俗,不妨 合,三甲期,國會昨 在狀態中,今同路亦 邊試來相當不俗,馬領一

第六祖幸王于昨一

死戰週去駒神

出發昨告報屍驗

象迹毒被無實證

班老程山,这

莉

巧惑

健

神的出,後走勢不規

可粘予對手苋大威脅的,且得 ;照团縱然沒有十足把握威馬取勝,亦自必 可可,不過,今番狀態大勇而路程頗合 ,劃得雖底質包辦,在現時衆三班已無便宜, 飲恨而回,不過復勰所見,而泛鵞有進無退 路程太短 - 以致前段失地過多,才後上不及 -韆就懟之利,且能否再挺而同,一 梅分人而然,今番對手不多,而蘭尼又收系 而「得」上仗本有憶殺之極,無奈因,

, 又見有關冊之意,最近積極儷腦,狀態起一 班仍是半超級份予,最近整伏了一段時期 ↗程以少碎距鹇哦俔蘇格蘭榭,顯示出禁山仍 老而緻壑,尚未完全退化,故此在目前第二 「山」,自由頂旺國降落第二班後,因能在同 「山」與「得」,前者辛送千食 ;而後者則參戰千六公尺中距離。先燐一

而同的!且此霫對時演出如何。 在關尼上陣馬當中,筆者似乎勝好

,車馬雖然不多,但由於四四均具份量關係, 以如隔厖能全力以赴話,亦可以一閟氣 話雖如此,在明天八塲愛事中,謝尼朥下上, 磨而已 - 廚出之差,實不敢使人相兮的。但

·闢尼近期表現失常,影下上陣馬癒出必:

山

得勤

皆利年鬥兒童城

義勇軍挑戰杯賽

·蘭尼到時使出何插戰略,雪勸 華棹

*德城齡莉博乖

国五五九六

註老

馬敏

SRETIK

温

高

容如下: 雙區。報名馬十六閂,其中,兩佤後悔,

·義勞軍挑戰杯,由第五班馬跑二二三C

·兒童茲·

愛甜蜜

呂志

昇平

(*)

「易〔]

標期(小)

一二八占莊臣〔米】 180#)

饥

NO

甘保頓(柱)

魏傣榿宀布)

蘭尼(擞)

謝恩:(歐)

夏遊(米)

(

今早出埠見解,或者區還速「皆利年」-「兒童城」,「快業獵人」與後備禺「巧感」

義式櫻相當出色馬

條,是冷門不可不防。 的馬-昨早已見孫達 第七組快樂人的

捧場。煲是實而不

塲見態生時,不妨下

NE

過用

用,因而此夫如果地好,當然「皆利年「兒童城」小白兩均都 「方惑 JQIEC磅太假了一些,「快樂獵人」要爋地方能起作

一過,比任何人灣楚。

壞以偶繪馬,考得「皆利郃」在勁好一些,因爲 老敏

「與「兒童錢」间等也。

ZDENIYANG

花美烈羅巨型

露雅福拔

鳳

凱意

演主銜頜星巨大雨 献誕

聲都

無門羅傑滋費

萊積福

登克

傳小豆大

的以

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