1989-01-05 — Page 29

華僑日報 All

(29)

日八廿月一十年辰戊夏

1989 中學會考預習專欄:

MARKET

明德出版社

MILL & DALE PRESS

Economics (15)

Alain Li

There are 2 broad types of market:

perfect competition; and (2) imperfect competition.

Perfect Competition

Perfect. competition nas the following characteristics:

1989 中學會考預習專欄

明連出版社

(1) Large number of buyers and sellers

There are many buyers and sellers. Thus, the volume of transactions handled by each is so small that nobody can individually influence the price.

(2) Homogeneous product.

The product. for transaction homogeneous,

(3) Free entry

Everyone can enter or leave the market freely..

14). Perfect information

Everyone has perfect informationi about the market.

a close example to perfect competition

is the stock exchange.

Imperfect Competition

Imperfect competition can "be" Furblier subdivided into 3 types of market:

A. Monopoly

has

the

Monopoly characteristics:

(b) with other reducing, agents, coric.

•HNO3 is reducve: ráinly to

brone gas and 20.

·C + 4HNO-Z CO2 + ANO12 + 2H2?

6N02

報日僑

(1) Only one seller

(3) Economic advantage

There is only ore seller and so he can influence price..

(2) No close substitute

There is no other product that can replace the product sold by the monopolist.

(3) No free entry

Nobody else can enter the same industry.

Amoriopoly may exist owing, various reasons:

(1) Legal status-

to

It may be established by law. This is called franchishised Monopoly 壁断

(2) Natural advantage

arise because of the. It may natural advantages enjoyed by a the firm Firm for example, -controls the only source of raw

materials:

Question 8.1

In the experiment below, a colourless liquid X and a colpurless ges Y were obtained on passing the gas W over some. Icad(11) oxide, at red-st.

Deying agent

Lead 11.25 --.

tum sulphan

Caldice hydroxy

四期星 日五月一九八九一)年八十七國民華中

If there is a firm outstandingly more efficient than the rest,

the other firms may be driven out of the industry..

(4) Market size

It the market size is so small that it cannot accommodate acther company, it is called natural monopoly.

An example of monopoly, is the Town.

H. Monopolistic Competition

Monopolistic competition has the following characteristics:

The

(1) Large number of sellers

There are many sellers. volume of transaction handled by each is very small.

(2) Differentiated product.

The products sold by the.. firms are not exactly the same. They Thus ·the differentiated. sellers has some influence on tne price charged for their

are

The following cbservation was recorded.

I. 30. orvatuls

11 KNO, crystals

and cours

14,50

ITE. A

crystals+

Observation

Solic meted.

the glowing splint was re-

Indled

Pale-brown funes were seen. The plowing splint was re-. kadled

Darse brown fumes were seen. The glowing splint) was extinguished.

products.

(3) Free Entry

Everyone can freely enter the industry.

An exemple of

monopolistic

competition is grocery stores.

has the

c. Oligopoly 01 gopoly characteristics:

(1). Small number of firms

following

There are only few firms. Thus each of them must consider the

others' reaction, before they do anything.

(2) Homogenepus'. or slightly

differentiated products

The products may be homogeneous or slightly differentiated..

(3) Difficult Entry

Cutsiders cannot easily join the industry.

An example of oligopoly is the oil companies.

(2) M(Pb0) = 223 gmo]

「百八十三手,一月份十點一三道仙,成八

濟經

日八廿月一十年屋

價造糖】

跌下幅:

共白全,淡平况市

◎手九十一百

一九日增加三百九十九

-包十四奂的

K

.期貨交易所發

昨日收市價群:

三月份十形五英仙,共成一百三,五月份

十點六「美仙,共成三十五手,七月份十大 九

的十九上四芡

本港外幣行情

JANA » • REALITARIANS 外嘴

7.6

1780.60 781.10 780.40

2770,40

1780

781

NA 14.22 14, 28

1 655.20 G56,70

20

·美膠! #

HARX

EXTENS

14 128 80

44512

. 390.80

BRE

THA

*2*11

SE

441.50. 443 519.80521.30 130. 30 202.30

1 678.90

1773 497.80 19 629,70

440. 25.20

17.70

E 289

6.00%

630, 90

$99.00

431 20

27, 70

40. 20

290, 50

*

****

馬來西亞元

*

M 402.10

433.90.

2NH-

+ 3P003Pb + Ng

1mal

3820

****

29.70

.31.70

PER

SE

41

51

短萬 109

113

ECU.

每個

(3x223)g 24 dm3 36 cm3 (Pb0) reacted = {3x223)×200

9. 18

9.195

港幣兌人民幣一

47:72

47.19

港巂街數

100, 4

+0.

MILL & DALE PRESS

港元外幣存款利率收市

(q) (1)NO reaction; because

WH does

1989

4.8

東亞銀行提

駕稱贊位

一個月

二個月

Chemistry (15)

not reduce Znu.

6:00%

R- Chủ

pale-

yellow.

preem

(a) Identify and name the substances. W,

X and Y.

- copper turnings

IV. POU

Solid melted, Brown fumas were

[2]Yes, there is a reaction.

Copper(II). oxide turns black to reddish-brown, because copper is formed.

8. 1875

from

英 元

9

8,50

9, 0625

12, 4375

12. 50

ZNO

4, 125

4.185

Chemical Properties of NO

51 HND is readily decomposed, when

neated of exposed to light

Warm turpentine

(b) White an equation of the formation

of gas H.

(c) tead() turned from opa

yellow first to reddish brown, and

insy grey.

(1)her is the

obtained?

seen.

2NH3

+ зCuO →→→→300+ 3H20 + N2

The glowing splint was rem

Solution to Q.8.2

NZ 西德馬克 WAR

14.125

14:375

4.875

4.875

9.75

9: 875.

sal 10

(a) Mate

(2) Write

an equation of

the

glowing and. IV,

ase that re-kind és the

in experiments

(a) It acts as a catalyst..

oxide (b) Nitrogen

紅西蘭元

12. 375

12.75

arid water.

E.C.U.

7.325

7. 125.

vapour.

brown gast

dissolves in the acid and makes

MNC is monobasic, so,

eries of

reaction

Nitrates

(c) The

nitrogen! IV)

one

nitrates.

NO2 and

of the

and Wh

進湧資外

升挺匯

惠受亦

̇線短元澳好

●可則美 八〇五轉

亦場国八再䱵元,大至,輕

HANN, KERALA, GUXWEUPEBEONETU

·女林墨影响而可怕,最低跌成。 大多交易員仍在度假未跡。部份投資人士園,

黃金的穷我才作打算,成交合約隔二站 - 望態度邊厚,不願入市,以便幾則今年初

九米〇升,市菜

而低挫

外睌

手做內

場收市竞

11-

OHEK

̇市 宜甦 接而對

行的重貼現利息即 特爽升 5. 發呆盘,但因澳元的批升而將紐元亦拖两 CMPC - INEXHSELO · KIC<0M004% PEREZO - KITANOSAKCE - KEFK@O KUK ELZE 咸U瓴四日電;铅西蘭外匯市場新年低蘭改首日復市,紐元全自交、【通下降了一張E膩,尾市市場傳出十三 美國正要向地中海的清息也吸引了 鵜 可再試新低點,大溪南就有可船报至,大的收市價下幾點加息。而蟻(遠 二 年八〇一二三四,三五之間上落。中間 元做價發威,尾市的價整也彌補不了且而, 成交爾第一個LO 外悉商又稱:是在官方拍商的國庫分利品卡升,台市宮洌韩機組、元在外圍外匯市場的共知,以安府對 外出市,因新年假期就係,是日才向復正 五收市回跌一,八〇日圓。 美元開市報兌一二三九八日陶,全日在 美元的部份買盤,可彤,美國當局稱是 美元走势。是日有投機性的估售,而機構查 * v覑採取觀望態度。等侯美國週五公佈十二月 外匯商稱:美元目该主要是反映籍絲團

苟失業率。

it yellow in colour.

5.2 Dilute PNO, is a strong, moncrasic

acid. I

useal exhibits the properties of acids. However, its reactions with metals are different from those of othe typical acids much as dit HCl, dil H2504, etc. because dit HNO is an oxidising acid.

Only very dilute. HMO, behaves as a normal acid when reacted with Mg and Ca..

e.g. Mg+2HWG→

5.3 Both dilute HNO3 and concentrated

6.1 A

6.2 All nitrates are soluble.

6.3 A nitrates are thermally vestablet

and decaaposed on heating. The ease of décomposition increases down the Acties.

Nitrates of Products of

Heating metal

Κ.

Na

Ca

MJ

as strong oxidising

AL

Metal oxide

Zn

agents. (cxf. Conc.

1504) because

Fe

the nitrate for (NOT) in an acidic medium is an electron acceptor.

PE.

Conc. NU

ND12"{aq)+(aq) +e→→ N£2 (s) + H2(8)

(+5)-

0.N. decreases.

Dilute or moderately conc HNG? NO2"(aq)+4t*{aq)+3e→→ NO(g) +2H20(2),

· ( + 5) - ·

6. decreases(+2)

N.B. The reduction of HNO3 is in fact very complicated.. Sometimes ND, Ng and even NH3. are obtained,

depending on the strength of the reducing agents, the temperature and the concentration of HNO, etc.

3

(a) HNO3;

dilute

concentrated, reacts with metals both above and below hydrogen the Activity Series. Brown gas of NO, are seen.

AND

Metal

HND

or:

Metal oxide (oxidation) +NO2 &H2O neutralization Metal nitrate

Melul -

HNC Metal nitrate

e_g_ Cu+4FNQz→QU¡¥3)2+2H2C+2ND2

conc

blue

3Cu+ShkQ3Cu(NO3)2+420 20

dil. or moderately

cons

N.D. A on Fe are rendered passive

when added to HNO because the

metal oxide layer. formed on the

Surface be the metal prevents

Turther attack of conc(NO3.

效廣法刊明香三一本 刊告律登合港月九報 物之性有指政

有質關定府日叁在

لمبارا

-Metal

AC

an

N.B. Thus,

important method of preparing a metal oxides is by beating its niureles strongly.

6.4

Test for nitrates

(a) If a brown gas is perated when a solid is heated with a little of conc. H250 and copper turnings, then the solid-isa nitrate.

In

+2120(1) +2NU_(5)

(b) tix the unknown solution with freshly-prepared iron(11) -sulphate a test-tube. Add conc. H2504 slowly so the mixture down the side of the test-tube so as to form a Tower layer. If a brown ring 5 formed between the conc. 2504 layer and the aqueous layer, then the unknown solution consists of NO ions.

-

brown riig

Conc. H250

(d) What property of gas Wis indicated

in the above experiment? -

(e) Name a suitable drying agent "fon.

995 ม.

(f) it was fourid that 36 cm3 of dry gas Y measured at 25°C and atm of pressure, was collected at the end of the experiment...

11) What was the volumes of gas W reacted, measured at 25°C and 1 atn. of pressure?

(2) What was the mass of lead(11) oxide-peacted?

(g) Would there be any reaction if lead(11) oxide is replaced, in

turn, by

(1) Znic(11) oxide,

(2) Capper(II) oxide.

If NO state so.

If there is a reaction, describes Briefly your observation and write an equation of the reaction.

Question 8.2

In the experiment below oxygen gas is bubaled through Some concentrated

cueous amonia solution above which a hot platinum spiral is banged from a glass rod.

Oxygen

g35

the

Platinum spice!

→Concentrated

aquedur annia solution

cortaining a few drops of 11

solution

function of the

(a) that

Platinum spiral? (b) Name the substances formed at the

platinum spiral

Write an equation of the reaction. (c) A-brown gas is seen near around the

it? platinum spiral. What is Write an equation of its formation; (d) The platinum spiral needs to be

heatce initially only. Once the. reaction is started, no more keating of the spiral is necessary. Explain why this is so.

(e) The litmus tunds from blue to red.

during the reaction.

Explain briefly the changes observed.

Question 8.3

In the experiment below - Substance X was heated strongly in a.. Pyrex test- tube and a glowing splint was placed in the position d's, shown.

-hisat

(b). Write an equation of

in 1.

(c) What is the brown gas?. (d) Write the equations

reactions in 41, 4 respectively.

(e). Which of to two nitrates, KNO," and Pb(NO3)2 is more stable towards heati heating? Explain your answer.

Question 8.4

The schematic diagram below shows the Haber Process by which antoniais. manufactured on large scale..

Converter devitel

privracíed N2 and l

racyclus

(a) State ONE possible source Ao

nitrogen and name the process which it is obtained from source.

(b) Stute, ONE possible source of hydrogen and have the process by which is obtained from its

*(c) The converter is packed with a

Suggest atalyst.

મુ suitable catalyst of the reaction.

(d) Suggest TWO suitable methods to

remove ammonia from the device Y.

(e) Nitrogen gas react with - hydrogen.

gas to form, aumenta according to the ruvarsible equation below.

N2 {g} + 3H12 (g) → 2 NHz(9); AH=-93kJmal ̃!-

(i) is the yield of ammonia b -Increased by using a high or low

temperature?

Is the yield of ammonia be increased, by using a high or low. pressure?

(1) In practic, it is not desirable to use a too. high "pressure ani a too low temperature

in the converter.

Explain briefly your answer in each

case.

Solution to Q.$.1

(a) M is ammonia.

X. is water.

Y is hitrogen.

(c) (1) The grey solid is Tead.

(21 2NH2+3PbQ →→3Pb+34, O-N2

(d) The reducing property of gas Wis

indicated..

(e) Calcium oxide (quicklime).

\(f) (1) ZNK + 3P303Pb

N

To

1.e.2vol.

"Ivol.

2 cm

36 cal

vol of

reacted

36x2

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廣告部電話:5 4908847

·必讀

·學生·

ANH3 + 502 →→→→→4NO + 6H20

axide.

brown gas

2N0 + 0 2NO

the reaction occurring at the Spira exothermic. The heat evolved can manitain the spiral at

high temperature.

(e) Ammonia solution, is, alkaline, so.

it turns litmus blue. During the reaction, ammonia is reacted while nitrogen(IV) "oxide is": forded. Nitrogell(TV) oxide is then? dissolved in water to give an acidic solution which thus turbs 1ftmus red.

·Solution Q.8.3

(b) ZKMC3

gas.

(c) Mitrogen (IV) oxide.

11 KNO + H2SO4

AHNO ̄ ̄ 2H,0 + 4NU

ID: KNO3 + HSDKHSU + HNO3.

Cu+4HNO3 →→→Cu(NO3]2+2NO, +2H20 IV: 2Pb(NO3)22PbQ+4NO2+I2

(e) (NO3 is more. stable because it is

decomposed, on heating, to KNO (potassium nitrite) only, not to its oxide.

Solution to Q.8.4 (a) Air.

N2 is obtained from liquid air by fractional distillation.

(b) Water/Natural gas/Petroleum.

industry.IN

H2 is obtained from water by electrolysis.

(c) Iron powder (with a small andunt of.

(d) it is either condensed to liquid Mi3 by cooling or dissolved in water to form aqueous NH2 solution. (e) (1) The yield is increased by using

a low temperature, fam Since the forward reaction is exothermic,

So, lowering the

temperature will shift the equilibrium to the right, thus giving more NH

(11) The yield is increased by

csing a high pressure.

Since the number of moles of gaseous reactants is greater than that of products, so, an increase. in

will shift pressure equilibrium to the right, yielding more

the

thuis.

(ii) It is rather difficult and

net economical to build a converter

to withstand too large a pressure.

The reaction is too slow at too low

@pressure. As a consequence, an optimal pressure (200 atm.) and

temperature (450°-500°C) is are employed...

全經包專新歷六一創

憍濟羅刊聞史月九刊

稱報萬豐翔悠五二在 許導有富貴久日五於

“比上週 物桑市道艇氣氛搏盡,不過加息後的一次,產生證太壓力了,所以未來利率走勢,台校 升至十一氬二五水平,令到過去一個月來,一定巳不算低,若利率再升,對物坻市道粱會 率再升半厘而爲十二厘,而樓宇按揭利率亦 未對物業市道造成沉重打,問題是現時利 . . supdate...............優惠利 率,仍無處於不接受水平的,故此利率達升 ,距离地成績衷現對來,發展商一般仍對

八八年中小和住宅市场表現過動,主要是市,預賞祔對機價計算,現時一般物業投資回報 。從市場反映出,市民對一些有色好交通糊一工短缺,工人收入上升推動下,樓價再有一 的 新市橫碼表好感,除了受新市鎮各項設施,成左右升路是鎖中样之佐計了。《江亮》 復律在低水平等有利因素,沒有助市各殿莉·現象,只要八九年本港經濟體特話選,在勢

·民一般的收入增加,就棄案底及上半年利率率仍有百分之六左右,顯示出也仍無高 “因”王毛物、受加息: 明現左右物業市道的。 ! . 擕a黹稍問行葚科總锉理綦买柆指出,今年物業組售價 戍者以上之开航。從 蟲持平穩,價格仍可以乱和上升,後市-

滿信心,故此物業界人士普温仍如珠

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