有四第張六第
日二十月二十年午丙歷夏
英文中學會考試題預習 專欄
物理科
(十四)
梁海明
PHYSICS (14) H.M.Leung
Solution.
E
BRUKKORKERS
「香港」,由前香港大學列校長赖德爵士主
WAH KIU YAT PO
EKBERBER. J. LETHBRIDGE.
三月三十日,「中國人之家庭」,香
SMYLYH
ENDACOTTHE
BRYDSHE D
|套瞉委员會高級建築師堂先生主講。 本清言:「攤到爾),由屋宇,隨之人士而戰,仍由任教,管致還說,農 二月十[]日:「徒件問題」,由徒置一生。文速成班以商科僳程,各科均價 |校及孔年博士親自 歷屆畢業生成織均甚
夯孤額招收新生及、沈记、商信托等 會考均瀧,二月份辦文簿記、會、打字 進語文專修科,以及英
抽
疯仍 然 自由
班及
當電蟈
法
#J • HEERUFALHE
SPEISEKHE 三月十六日,「在英國人未到達之
前
各國留學或就業。 之法國教師讓授法師 三月九日,「未有漢人到遠之前的下一按釋,中級以上各班佳,近又有畢,生多, 會話,留法者酸授) 則聘請富有敦學經歷人前在加拿大及陳州
對區聯絡員,中文大學潤師史米啊) W
(25 (a)
Refractive index:"The" value or the constant
gini/sint wheme 1 is the angle of incidence and
is the refractive angle for à ray passing
from air into a particular medium is called
the refractive inder of the medium.
Critical angle: When light passes from a denser medium to a less dense medium, the an-
gle of refraction is greater than the angle of incidence. If the angle of incidence is such that the angle of refraction is 90°, then we call such an angle of incidence the critical angle.
.
Relation between refractive index and crit- ical angles
U the the re ga
Let C be the critical angle.
fractive andex tron glass to air. U
..
to glass.
from air
&
MADET
保該意觀英
郁
Then sinG
sin90
but
g a
en-『,
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日一月二年七六九一股公年六十五國民革中
作爲香港人、應知香港事,
中大校外部設
香港介紹課程
十長分
講中賴 大德 僅及爵 能港士 容大
高助
·級理
講輔 師政
參、司 加高、
級統
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受等司
報主
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置
共處
C特阴姒作爲香在人,憑知香港事,
四月二十日-「香港人對戰爭的經歷
| 香港中文大隔校外進修部,協助本港市」,仍由德僻主主講。 民多瓟香港一般形,將辦一項具有 四月十七日:「同時代的香港JCC
CONTEMPORARY HONGKONG)
BEHE...
一據悉,並攻魔配已定名念,「香港及當月四日:「今日咎圈之居民」,由
RJ (HONG KONG AND ITS P
一担任主講,其中包括有香港大學前校長
成有,大人圖的全四
心瘋
著
GREGAZ ZAKARANDE ( D CH28EMERS BRACE OF FERER HAINE INE
1. C. BARTY) •
三
期望.11次大國前後的歷史等。至有關民衆方面 「此,英入宋到逹之前的香港懾史,香黹在
EDECEKKERTRENERE
STARKAREJ SEK-WHER
香港法文專校設
[ 法文會考補習班
考指
考法文科考試: 指導學生參加英中會
上建地點舉行。在將各大滯題列下“: THE CHINNERY' S W ORLDJENEKEKRE G.B. DE_ROW -
二下午七時起,在石岩大會堂八拔北演講室、 離開路,以後逢星期四下午七降至八時,在一萬木港學生參加英中 秘,除法文科外,另 KXEATENTELK - RELE 會考法文科考試。該設有日文、德文、四
薪,居雋顯,邊村居民生活情形等等 ,將包括有香港之一般社會狀况,人口之 此項四座,現定本月十六日(黾期四|艾科學校近年璒酸 谆。該校位於尖沙咀 【文會考補習班,揖 加連威老道十二號二 〔韓餅(香港法文文法、翻譯及寫作
(b) 1-60°
U-4/3
san
gîn 2
- san ? - 160°
0.6495
40 30
(0) By measurement.
angle of tot
otal
deviation 60.
incidin
26 (a) refractive index
Real depth
Apparent, dep
Apparent debth
(b)
M
60%
refleted ray
+12%
The Object 18 iz om. directly under water.
It appears to be larger than the object afaelf
for the apparent depth 10 shorter than the real depth. That is to say, the object seëna to be nearer than it actually 18.
Let u be one refractive indet, x cm, bề distance of the bubble from the first face
then-u...
(1)-(2)
real depth. apparent depth
12)
16 • 22 (0) As shown in the diagram ABC is a right-angled" isosceles A prism with AB as the hypotenuse If the incident ray is per- pendicular to AB, then we can turn the ray of light through 180 and at the same time invert the ray of light. The reason for this is that the total reflection occurs when
the angle of incidence exceeda
42 The Tay 19 turned through 90
15 cm
英文中學
考試題預習專欄
化學科
(十四
CHEMISTRY (14)
·王錦釗·
2.(a)
cent
common
1.Hydrogen chloride is prepared by the action of
ated sulphuric acid on sodim chloride. Som salt is put into a flask fitted with a thistle funnel and delivery-tube. When concentrated sulphuric acid is poured down the thistle, effervescence takes place, and we misty fumes of moist, hydrogen chloride are evolved. The gas 19 dried by passing it through concentrated sulphuric acid and it is then cullected by downward- delivery
OKON
each time,
being reflected twice is turned through 180.
Topics for revision this week:
1. Converging and diverging lenses.
Magnifying glase. camera. projection-Lantern,
Questiona
27. (a) An inverted image 8 cm. hign is formed 10 cm.,
away from a convex lens. If the object 3 m high, find graphically (1) the focal length of the lens, and (ii) the position of the object. Where must an object be placed in relation to a convex leng so that the mage may be ()unk upright, (ii)diminished; (iii) virtual, (iv) inverted and magnified (v) the same size as the object? beton FF
at ZF.
(c) Find where a pin must be placed so that its
image formed by a concave lens of focal length 20 cm. may be one half as high as the pin. 28,(a) Describe the optical system of the project-
ion lantern and explain “he purpose of each lena
(b) Describe a simple photographic camera with
a single movable lens and explain how it works. [C] A long-sighted person is able to read a
book at distances down to 25 on by means of convex lenses of focal length 27.5 cm. What is his nearest point of distinot vision when he is not wearing spectacles?
ENT
SULPHURIL
HEH T
GENTLY
NaHSO;
RCI
Samt, ENTRA. TEL
SULPHURIC
R
(«)Pass dry, tyarogen chloride gas over red now con
filings in a combustion tube The fron will dis place
he hydrogen from the gas which
läplacement of water
acted
PI
2HC13
hydrogen chloride
Fect
ferrous chloride
be coll
The gas that 18 colected can be shown to be ngaro gen for it will burn in air with a blue flame, and when it is mixture with sit. and then ignited the
tologixture with alt. and ixture
6)That hydrogen chloride is very soluble in water can
be illustrated,
ted by the "fountain experiment". A round bottomed flask fitted with a rubber stopper and two glass tubes (one ending in a jet) is filled with hydrogen chloride and clips are fitted over the rubber tubing at the ends of the glass tubes as shown in the diagram
J A
BLUE
The flask is then inverted over a trough of water. A little water is introduced into the flask through the shorter tube and the clip is replaced over the rubber tubing. When the clip at the en
end of the longer tube is released, water will rush up
the longer tube and comes out of the jet like a foun- tain Te)Hydrochloric acid will reduce lead dioxide to lean
chloride, pour concentrated hydrochloric acid on to brown lead dioxide. Effervescence takes place and chlorine gas is evolved. A white residue, lead chloride, which is insoluble in cold water, but.... soluble in hot water remains. The acid has reduced- the lead dioxide to lead chloride:
Pb0> Lead dioxidé
1* PbCl + Cl2 • ZH20
Lead M chloride
(d)Mydrochloric acid may de identified by means of its reaction with ammonia Dip a clear glass rod into bottle of ammonia solution and put the wet rend.
of the tubé at the mouth or a Deaker containing
Dense white fumes of ammonium hydrochloric acid. chloride will be formed round the end of the rod
NH3801 » NH, GI
Hydrogen chloride is a covalent compound. Its solution in toluene shows the properties of a covalent compound but its solution in waterianows the properties of in electrovalent compound..
Solution of hydrogen chloride
in water thydrochloric acid)
Solution of
hydrogen
chloride in
dry toluene Duct elect
Conduc Does not con-
for of
electri
citv
Action with ammonia
city
AMRONLUM
chloride 19
formed as a
white precie pitate as 12
is insoluble in
Coluene,
Little or no
action takes
Act10 with.
carbon-
place.
stes
Act ion No reaction
with
metals
Extremely good conductor in dilute solution. Electrolysis Lakes place with the evolution of hydrogen at the cathode, and chlorine at the anode. Ammonium chloride is also
but the ions formed formed, remain in solution, and clear colourless bakut” résults.
NH; HCT - NH C2
Effervescence takes place gas evolved being carbon dio xide
Effervescence occurs, with the evolution of hydrogen. Za + 2H Zn + H2
(b)Hydrogen chloride is a covalent o compound, that 19, th
elements hydrogen and chlorine share electrons so as
to establish the inert gas electronic arrangement Each
PRO COM contributes one election to the shared pazra
thus setting up what is known as a covalent link. Hydrogen chloride exists as molecules, and ions are not produced..
When hydrogen chloride dissolves in dry toluene the covaleat link is undisturbed and no ions are formed. Hence the solution of hydrogen chloride in dry toluene.
ibits all the properties of a covalent compound. But when hydrogen chloride dissolves in water, hydrolysis takes place, the covalent link between the hydrogen atom and the chlorine atom in each molecule 18 broken, and ions are formed.
H30 nydroxonium
ion
C12 Chlorine
The dissociation into ions is almost complete, and result, the solution of hydrogen chloride in water exhibits all the properties of an electrovalent. compound..
Q.5 Three ways in which hydrochloric acid resembles the
other common bench mineral acids are:-
1 It will react with a base to form a salt and water
only
HCI + NaOH
NACI ...H2O
(acid) (base) (salt) (water)
It will react with metals, more electropositive than hydrogen, to yield hydrogen.
eg 2HC1
- MgCl2 *
It will react vigorously with carbonatea in the cold, effervesence, occurs and carbon dioxide is evolved
CaCl2 + CO2
*g CaCO, * 2H01
Questions for next week Q.1.(a)Describe briefly the preparation of dry chlorine in
the laboratory starting from common salt, 11lustra ting your description with diagrams. Give equations (b)What is the simplest way of preparing chlorine in
the laboratory without the necessity of using heat? Write the equation for the reaction. (a)Describe one method for the industrial production of
chlorine,
[d)You are given several jars of chiorine. Describe a series of teata showing the chief properties of chlorine. In each case state the purpose of the explain the chemical reaction which occurs, and describe what would be observed during the teat Q.2(a) What percentage of manganese dioxide is present
0.5 gu. of à mixture of this substance with potassiu chlorate, if 90 cic. of oxygen at 16°C and 750 produced by heating the mixture?..
(b) If the resulting mixture in (a) is heated with con-
centrated sulphuric acid, what volume of chlorine would you obtain at 16°C and 250 mm. pressure?