手七十七國民華中
育数
開港日十三月十年辰戊曆夏
會獲我的理想說繕,再
將將爲加拿大成商赴武 特利用世界皮草展, 匯集世界優質皮草的蒙 據主機指出, 姓高品質的皮草時裝。 的該項展覽會,展示海 明年五月三至六自製辦
報日僑華
四期星 八月二十(八八九一)年七十七國民華中
(14)
龍星校長球隊
本港 新聞,
申請,並促黎本地皮草
·受廠商參加兩項民衆的 ”貿易發展現已接
一理會,預計將吸引凤大,
於十二月二日(展期六 。 像阳光,設立开蹈 中大部份來自美國 龍星放長李冢雨預算來年紀五歲的,其八三三四三三三科股整, 有關在可致電:j
遠征濠江友賽 及及業務及裝製;
龍先生(特爾皮芭 及章榮先生(
港
圖:龍星校長球 上連兩項於明年舉際
聯絡。
長李
致逸朗
世人,一 分之後梅勝 將以「班之利,以慰 停換人者再,惟元老隊 我分占世扳平,雙方生 寶刀未老,沉着惡戰,
清明傥,就星各将先聲 首場比賽擔下于六 亦於百忙中到当行。 一行就醫領除力培湘議員 控置、黨國明、蔡旻生 陳伯成、及籃球名將上 輝、吳樹紀、黃廣求、 潘至强、謝金、吳樹 强、沛忠、黃國、
偉、紫篦康、敎練煜尚 星点蹺計有:綠長瑞 西抵澳門1入球 龍號。
龍星校長球隊敬
瑞米,主除擁有數名 萬事發蘭桂坊音樂節
役球員,年輕力壯,惟
礼榘校長近日熱於提速 十六日舉行亮燈儀式
,而能領先,上除不敢
,合作純熟,勇徒,
變色
直奔馬劻區,並汴土一時將由多位社會ㄉ習人的歡樂時 但任於稍後給裎4襖,則於十六晚舉行,屆時,一次過慢每多的不 潘树*未能简睽出登·聚行。流重的症楊儀式,本港的清空戰气友,
因而提高,而整個人╋上初感,世界
住西兵遭判、张岩走 旋樂, 管當......午, 進正事長現,實蕘近 THE BLOCK 上送阿楠美日大廈管 禄合龍星此点证澳OCK AROUND1 一及MY STORE使
TATEMY
投籃、「大師」歌线设西的主開發麻、酒、舌蘭桂等 ,若將丘空容以身擦k 五盱衡賀安二時在地上,以變被撞特設計
生之大坦沙灣
太古汽水銷量
【兆武》香港貿易
貿易發展局組 參加國際皮草展
陶檣頏除裼此限
再度創新高峯
全亞洲最大霓虹招牌
燉管代設團,分别 發展品將引造兩副本港
設於灣仔添維港特色
明年在港潮行的科際畫ia
散供成立行業联助的推示一词口可樂」在香港 銷量,更邊地了百分之 大眾特利润府行的过路高跟煜維多利亞海港的向佔本港汽水市馬達 越兩項展墅均爲货另一特色,更進一步通 份之多,應 已許立在灣仔海傍,示,該公司的飲間,一
組織的本裾代云團在 一貿易發展局繼令年
,將再度組織一個代表一個或 際支革展戴上下进行
二十七日舉行的吼一 加於卯年四月二十四至
二十家公司悞, 一該代公剛倒,山約
製品與半製成品,苯 一、獸皮、化學藥品・皮的話係積。 品,包括生產機器,該一领併太古汽水有閣公司 相比,銷往高達後書的
多雄系列皮革微有对炎「ED可樂」;以及, 這算,一可喜可樂」與 道可口可辭」在港特約蟻最接近的可樂對手
將推出全新裝璜的葉酸 十以上。「腿叵先生 ,正好配合太港市場即 【水總消耗佔百分之五 新鸯蛀招舯的落戒 迎的品,佔每年全 「可口可樂」商標古汽水廠就下赜主要的 產品,亦是木地受歌
四米,龔示了由著名商更加常。 虹招牌,商小米,個让一飮品市场的領導地位, 中華海景酒店萡部的第一在治,分該公司在木地 這個位於港島灣任司歷年來最高的市場佔
市場悠然的禎導地位。一,爲太子汽水有園公
製用品、鞋服及配俺紵
鬥:位於灣亍海傍的巨型「可口可樂」
虹学誌。
蒙特利科國際支 登 著今年出湖參予加拿大 貿易發嬖帶亦將
CHERS
teach
Biology & Junior Form
) in january, 1989.
Mathematics & Social
) in February, 1989..
Cs & Englist(CM)
cancy.
cation & Junior Form
-}-{temporary}
89 tc July, 1989.
in writing to the
..Stephen's College,
g Kong.
1989 中學會考預習專欄
明德出版社 MILL & DALE PRESS
路德會
12
2. Inelastic, f.e. Ea
<1.
5. Perfectly inelastic, 1.e. E = 0.
F
57
361
55
$4-
ELASTICITY
AND
TOTAL REVENUE There is a close relationship between elasticity
demand and total revenue(TP). If the demand is elastic; .1 price reduction will bring more. revenue. If it is inelastic, a price reduction will bring less revenue. The total revenue will reach its maximum at the point where is unitary elastic.
Fig. Use
11.7 as
The examplc.
findings are as follows:
勤
TR
$6 0
>
Economics (11)
服務處
上程度,路懂會計
下 ,有兩年以上駕駛小
近照寄九龍何文田忠 事主任救。
ELASTICITY OF DEMAND
急聘幼師
Alain Li
。 1
2
4
2
6 7
Fig. 1.1
Iake Fig. 1.1 as an example. When the price falls by one dollar, ie, from S弘 to $3. the quantity demanded increases by one unit, i.e, from 2 to 3, The percentage change in price is 25%, i.e. $1
x 100%, and the percentage change in
50%. the quantity demanded is
Fig. 11.3
3. Unitary elastic, e. Ed
17
1.0.
$5
Thus the elasticity of demand is 2. Z.
50%
i.e.
TYPES OF CLASTICITY OF There are 5 types of
y
$4
園聘幼師及助教多 全日半日均可,助 ,有意請於辦公時 560781
會計員
口聘LCC初級
打字,
The Law of Demand states that 你吧 Quantity demanded changes in response to a
The price change.
degree of responsiveness of the quantity demanded to a change in the price of the good is': called 'price elasticity of demand or simply 'elasticity of demand'.
Generally, the calculation of the elasticity of demand is as follows:
percentage chang
Elasticity the quantity der
of Demand
or in symbols:
1. Batic,i.e. Ej
232727洽
交急聘
以上程度,任教中四至
科,葵涌區工作。 1,中五程度,葵涌區工
履歷到葵涌石交徑5號 ~200999)或青山道339 厦3字樓(3-611819)
行補習社
誠聘
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職均可,可在彩虹 工作,有意請電 1968 ?
兒中心
、青衣區資助機構招 員,具經驗者優先, 具履歷、相片寄元朗 大會堂4樓收或電 9006 ·
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意請電
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percentage change
price
$2
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1989 中學會考預習專推 明德出版社
MILL & DALE PRESS
Chemistry (11)
R. Chu
Chemical properties of dry HC1 gas
5.
Dry HC1 gas is covalent and not very reactive.
5.1 It forms white dense fuses with amomia gas. The fumes consist of solid ammonium chloride.
HC1(g) + RH2(g) →→→ NH2C}(s)
5.2 It gives a white precipitate of silver chloride on passing into
acidified silver nitrate solution.
HCl(g)+AgNDg{eq}~ AgCl{s)+HINOg (aq}
the
5.3 Metals above
hydrogen
in
Activity Series, when heated in HC1 gas, can displace hydrogen gas from it.
2.g. 2Na + 2HC→2NaC! +
Fe + 2HClay FeCl2 + H2
(N.B. If the metal has more than one oxidation state, the chloride with the metal being in its lowest oxidation state is obtained.)
6. Chemical properties of aqueous HC1
solution
共圖
1:.4
4. Perfectly elastic,
$7
15
14.
$3
?
$3
门
1
7 等
手 6
Fig. 11.2
www.
24C) + {0}-> H_O + Cly Oxidising agents commonly used are: KMnOg: Mnny, Pb30 n PbO (Llse last three requires heating).
The preparation of chlorides
Chlorides Method 1 Method 2 Hothod 3
K
Metat
Metal oxides/
hydroxides/
> caronnat占9
JEE ACT
KONG
6.1 The solution of HCI gas is prepared by dissolving the gas from the
generator directly in water.
An
inverted funnel is used in order to
prevent the sucking back because HO is very soluble in water.
The Fla of
beaker
funnel is just belo, The water surface.
water
6.2 Dilute
hydrochloric acid is
acid, typical
having all general properties of an acid.
the
6.3 Concentrated hydrochioric acid is acidic but also readily oxidized to chlorine
ē strong cxidizing
acent.
Q
3 C
}
Fig.11.5
(b) Solids X, Y and Z are three sodium
halides.
FEST
OBSERVATION
The solution turns
1. Pass chlor!re you
into Aqueous solution) prowns
13 Y.
.Add ac Fd! (led silver nitrate solution to
Aqueous Y.
Add cóne. H2SO, to solid Z.
. Add cont. 50 to
selld X.
(1) Write
A yellow precipilate
is ostafred,
Misty Whire tunes are
Reoul sh-brow vapour is seen.
G PUBLIC
The chlorides of the underlinec metals are very deliquescent and readily hydrolysed by water. Thus, special arrangements of the
have apparatus
to 照
in made preparing these chlorides 品 anhydrous pure form, .9. FeCl3.
Iron fllings
Soda Ime
(for removing excess Cty and proventing moisture in air trom entering into the receiver)
Slack crysta:s of anhydrous rect
the
3) would thes, protipijatan obtained in to dissolve in
excess ¿queous armonia.
(3) Name the reddish-brown
observed in IV. Write an ecuation of the reaction.
(4) What is the anion contained in Z?
Question 5.2
In the experiment below the gas X, formed by the action of concentrated hydrochloric acid On potassium permanganate crystals, was passed over some iron filings at red-hot. After a while, a black solid Y was collected at the place as shown.
Glass
Heat
Receiver (far collecting hely sublimate)
“
Question 6.1 (a) The
give
Some
below table information about four clements in Group 7 of the periodic Table.
Element Atomic Melting
number paint(*C)
日
Bolling
point (*C)
Fluorino
-229
-128
Chlorine 1/
Bromine 35 Tudine
53
-34.7
-7.3
113
193
(1) Referring 話 their electronic configurations, explain why they fall within the same family.
(2) They
consist of diatomic molecules. Draw the electronic structure of such a molecule, using the outermost shell only.
and boiling a (3) The melting points
the points of
elegents down the group. Explain the trend briefly.
of the (4) Which one
four would react with hydrogen gas least readily.
Iron
things
Solid Y
x
Da crystals
Water Conc. H250
Soda Ime
Poat
(a) Identify and name the substances
X and Y.
(b) Krize the equations
the
formation of X and Y respectively. (c) State the purposes of passing X successively through (1) water and (2)concentrated sulphuric acid.
(d) What is sodalime?
State TWO functions of socalize in the above experiment. (e) would there be any reaction if the tror in the above experiment, is substituted. in turn, by
(1) couper powder,
(2) carbon powder?
If there is a reaction, write an cquation of the reaction. If there
is NO reaction, state so.
D
Fig.11.6
Generally, when comparing 2 demand curves of different steepness, it can be said that the steever one is less clastic than the gentler one. Strictly speaking, the elasticity is different at different points of a straighting cemand curve oven though all These points of the demand curve have the same degree of steepress.
See #ig. 11.7
$6
45
Fig.
In Fig. 11.7 at
the demand curve,
1.
$5 1 15 到
$4 2 起 >
$1
3 99
點
50
FACTORS AFFECTING ELASTICITY OF DEMAND
There are 5 factors affecting the clasticity of demand:
1. Availability of substitutes
If there are many substitutes for a good, the demand for the good will be elastic.
Degree of necessity
If a particular good is a necessity for living, the demand for it will be inelastic.
3. Consumers' habit
If it is the consumers' habit to consume ત particular good, the comand for the good will inelastic.
If
4. Proportion of income spent-
a particular the spending on good is only a small proportion
է
IS
5.
Ahove the mid-paint, the elasticity is greater than 1. And below the nid-point, the elasticity is less tnan 1.
Question 6.3 Ju the experiment below the gas A formed by the action g-consentrated sulphuric acid 01 sado hloride crystals was passed over anton wire at red-hos. A solid Babtained and a colourless gasa was collected, which could form. an explature with
Sodium chloride
Eristels
Hear
Ald B
Sas D
Haver
name the substances (a) (dentify and
A, B and D) respectively. (b) Give En equation of the formation
cf A.
(c) krize an equation of the reaction
between A and the hot iron wire.
(d) Why was, solid B collected at the place as shown, but NOT near or on the hot iron wire.
(e) How could you avoid too much of cas A being unreacted after passing over the 'ron wire?
(f) Would there be any gas collected
in the test-tube if the iron wire in the above experiment is replace, in turn, by
(1) zinc powder,
(2) copper coil?
If there is a reaction, give an equation of the reaction, if there is NO reaction, cxplain briefly.
Solution to Q. f.1
(a)
(1) Their atoms have the same number of
electrons in the outermost shell.
(2) The electronic structure of
halogen moleccio is:
a
(3) The molecular size increases down
the group.
the thus increasing intermolecular forces. Since the molecules are more strongly attracted together down the group, increase in the 30. there is an m.o.'s and D.p.'s down the group.
of the
consumers' income, demand for it will be inelastic.
Number of uses
If a particula" good can be used for many different purposes, the demand for it will be elastic. When its price falls, more people will use it for other purposes.
(4) Iodine is the least reactive. (b)
(1) C1
Clp(g)+?{{aq).
(1)→ly{dq]+20¥ ̄{aq)
(2) "he precipitate is silver chloride. It is insoluble in aqueous ammonis solution.
(3) It is bromine vavour,
(#250-a&r—430, +Br
• 2H2D+Br2+2$02
(OR 38,50+38 BAHS04+2H2D÷2502
(4) The chloride ion (C17).
Solution to Q.6.2
(a) X is chlorine gas.
Y is iron(UE) chloride.
{b} 2KMn0-16HC1→→→ 2KC} +2MmU? ¿+5011⁄2
2Fe+301
2FeC!,
3
15
+3H_0
好
LO
Gry
the
{c}{1} Water
to dissolve hydrogen chlorida gas. (2) Conc. 15504 15 chlorine gas.
(d) Sodalime is
mixture of solid sodium hydroxide and calcium oxide. It is used to react with the excess
Cl2 gas and to prevent the moisture
in
apparatus.
from eaterring
(e) (1) Yes: Cu+C'2-> CuCl 2
(2) No reaction.
Solution to 0.6.3
(a) A is hydrogen chloride. Bis ror(1) chloride, D is hydrogen gas.
(b) NaCl+Fq30g-
(c)2HCl-7e --→ Felig+Hy
+ HCT
into
the
(d) Lt is because Front) chloride sublimes readily when heated, so, it is collected on the cooler part of the combustion tube.
(e) This can be achieved by controlling the rate of adding conc. H2504 to the NaCl crystals, thiis producing gas A at a reasonable slow rato.
(f) (1)Yes; zinc reacts with gas A to
give hydrogen gas too. Zn+2HC1ZnCl2 #2
(2) No: because copper, being lower in position than hydrogen in the Activity Series, carmut displace hydrogen from hydrogen chloride,