1982-12-20 — Page 21

育教僑華 頁一第張六第日六初月一十年戌壬夏

1983

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Economics (13)

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K.K. Wong & L.T. Chan

MILL & DALE PRESS LTD.

MARKETS

1. Perfect Competition

Perfect competition exists in a theoretic-

al environment in

which the following

conditions are

fulfilled:

large number of. buyers and sellers →

With a large number of buyers and sellers the total transaction will be very great. This means that each of them cannot exert his personal influ- ence on the market price of the product by increasing, or

decreasing its output. Thus in perfect competition firms

must take the price

at which they are ta aell as fixed. and the deband for the product of an

individual firm is perfectly elastic. (b)homogeneous product

Under a perfectly competitive market situation, the product of any one seller must be identical with the product of any other seller. This means that buyera have no motive for preferring the product of one firm to another and

rn raised- price, its sales would fall to zero (e)free mobility of

il a firm

resources -.

This implies that each required factor of production must

be perfectly mobile.

(d)perfect knowledge of

the market -

All buyers and

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sellers must posse 88- full information of the commodity if the market is to be a

perfectly competitive one.

(e)free entry by new

firms

There should not be. any restriction for the entry of new

firms into the market.

II. Imperfect competition

In real life situation,

the conditions of perfect competition cannot always be met.

Whenever one or more

of the above require- ments are not satis- fied, the market is discribed as an imperfect one, Imperfect competition can be classified. into three types according to its degree of imp tion. They are: monopolistic compet tion, oligopoly and nonopoly. )monopolistic competition

· This has three

fundamental characteristics: )there is a suffi-

ciently large number of sellers so that each can act

independently of the other firms. (2)products from

various sellers are

differentiated. (3)market entry of new firms is relatively

easy....

In monopolistic competition, individual sellers can have influ- ence over the market price

This is because when there is a large number of their products or services, the product of one firm is not regarded as

perfect substitute of anether,

An example of monopo- listic competition is to be found in the retail: trade. The ease of entry in this business resulta in excess capacity and differentîntion may take the form of difference in location (for instance

one shop being more

ethanol.

(v)What would be the

mass of ethanol

distilled off,

assuming there is the

no loss during process?

9B8OD*✯✯ ✯✯H (7)Suggest a safty

Chenistry (13)

Reginald d

HILL & DALE PRESS LTD,

Question 19.

(a) a piece of sodium

metai which has been exposed to air for some while is

is covered with a white powder. Z. The whole specimen ie then added, to 40 g of pure ethanol and

Tear-

less gas X is obtained, measured ata.t.p. When the excess ethanol is distilled :offy" as

of the com, dand

Y is left As residue.

the

the names of gas X, and the solids and Y

respectively.

Explain the forma- tion of giving the appropriate

equations.". Write an equation

of the reaction between sodium and ethanol.

(iv) Calculate the masz

of sodium which is reacted with

precaution to

observe when dealing with boiling ethanol (ví}}The ethanol is

distilled at about 80°C while The solid Y is unaffected at this temperature, Basing on the above.

information, state

an essential difference in

atructure of the ethanol and the solid Y.

State the conditions under which each of the following pairs of substances can be made to react-

Sulphur dioxide and oxygen gases i) Ethanol and

ethanoic acid ii) Nitrogen and

hydrogen gases (iv) Iron filings and

water

v) sodium sulphite and dilute bydrochloric

Tubeà en case, name ta productís, and write an equation of the

estion 20

state the oxidation number of the elements underlined

in the following species:-

WAH KIU YAT PO

conveniently situated fer some people), the general attitude of the shop-

keeper, and the extent of the service" available.

Actually, there are various sources of differentiation such as actual physical differ- ence, location, service consideration, reliabi- lity, personal attitude etc. In addition, price may affect the choice of, products since many buyers prefer these sellers who offer a lower, price. Since differentia- tion of product is

by essentially created. branding and packaging, marketing activities play: a major role in mono- polistic competition in attracting customers to patronize a particular brand,

(b) sligopoly

This is a form of imperfect competi tion in which there. are only a few producers as compar- ed to perfect competition where there is a large- number of producers.

general feature eligopoly is that the price policy of

firm is influenced by that of its competitors. This can be subdivided inte perfect and imperfeet oligopol (1)perfect oligopoly In perfect oligopsly, the commodity is hone- géneous and consu→ era have no prefer- ence for the product of one firm as compared with another. A price cut by ne firm will

lead to similar price cuts by other producers, Hence the largest firm- will usually become

the price leader, (2)imperfect oligopoly

In this situation, -some degree of

differentiation exists between the products of differ- ent firms. Even a slight differentia- tion in the product

Mnoh

(iv) Cr2by

(vi) (7gC1g

(vii) Ca≥0,

Call

help of the equa

the following observatiñami (i) Bleaching

ions

a powder smells strongly of chlorine and gradually loses its bleaching power on expraise to air. (ii) A colourless

explosive gas. is evolved when zinc is added to dilute sulphuric acid. However, the evolution of the gay can be speeded up by adding. copper (II) sulphate into the mixture, A piece of blue litmus paper turns red when put into dilute sulphuric acid but becomes darkenet when put into concentrated sulphuric acid, (iv) noth glucose and.

sodium chloride. white powder.

報日僑華

will make one product not a

perfect substitute for another. Under these conditions, competition tends be very keen and many firma may employ masa: advertising or price-cutting strategies. (c)nonspoły

一期星

日十二月二十年二八九一曆公年一十七國民華中

Argument 15.Ang

附加數

(十三)

In the strictest meaning of the term, monopoly occurs only when there is one. producer of a commodity for which

there is no substitute,

Colten.

situation, « referred to as absolute monopoly. This is quite rare in real life to have only a single producer of a product and even rarer to have no ̈ substitute for the product at all. Thus the term monopoly is often used to describe forma

very imperfect competition as in the following situations: (1)when one firm or a

group of firm work- ing together. controla a large proportion of the total supply of a commodity, For.. instance, most of the world's supply of rubber comes- from Malaya. (2)when it is westeful

to duplicate a given service as in the case of public utilities.

(5)patent rights -

patent is a grant to the inventor of a new machine or idea, giving him 8 mono- poly of its use for a certain period.

prare monopoly

in the home market may be protected from foreigx competition by means of a tariff on imperts, thus giving rise to a menopoly situation.

However, an aqueous solution of glucose is a poor conductor. of electricity shile an aqueous solution of sodium -chloride conducts

electricity readily.

2.57 g of a compound

p of formula

50, 1,0

is completely dissolved in 23

of 2 M sodium hydroxide and tire resulting mixture can exactly neutral- ize 16 cm of 1. M hydrochloric acid, (1) Write the equations

of the reactions involved.

(ii) Calculate the value of X in the formula 30X0

Question 21%

(a) is abown in the

diagram below a zi rod is placed in 10M zinc sulphate

solution inside a porous pot. The pot with its content is then placed in a breaker containing copper plate agent enpper (11) sulphu solation. When the key is closed, a current is registered. by the ammeter.

Key

anmeter

coppet. plate

-zinc

IM

pot

CuSOA

IM

Zn804

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Additional Maths (13)

S.F. Ko

MILE & DALE PRESS LTD

Complex numbers, I Worked examples:

1. Expresa

1-co86–i sing in the form x+1Y.

Soluti

tion:-

(1-c080)-ising

(1-cose)—usine

(1=c080)+isinė

(1-co90)+isine

(1-cose)+isine

2

(1-cose) +910

1-cos0+isine

2-2co80

1-(1-sin^2)+

1(2singcosg)

2-2(1-28in

20ing(sing+icos)

4sin

icos

sing

- (1+icot)

ot

2. Find the modulus and

argument nử

Solution: -

The polar form of 4+41

4/2(cos45 +isi

- 4/2ci845

The polar form of 1+=

(cos30+isin30)

8300

11

1/2c1945

2/6cis(45 2bcis15

Inedulus -= 2/6

(i) Write ionic.

equations of the reactions at the zine rod and the copper plate respectively.

ould there be an electron flow from

Y to Y in the external circuit? Explain your

answer briefly'.

(iii) In what direction

would the..

sulphate fonë

pass through the purons pot?.

(iv) Vould there be any

change in the

colour of copper(11)

sulphate solution?

·(v) If the cooper plate changes its mass by 2g at the end of the experiment, what would be the corresponding change in the mas of the zine rödg (vi) State three changes

you would observe when the zone rod and 1 Mn50, solution are replaced by a

silver rod and Unser

nitrate solution. angpectivedes

(b) Several reactions

were carried out on an alkanol A

as shown in Marrom below.

Identify and name the substances W. X, Y and restertively,

3. Find the locus of the

point z such that

122+1

-x+iy intó

Solution: - Putting the equations

(2x+1)+12y|

√ ( 1−y)2+x Squaring hoth.

(2x+1)

4[1-2y+y=

Which is the requi. Jocus of z.

Exercise

Exp

as the following in the form a+bi

(a)

còse-isi në

1+cosu-i sinf

(c) 5+41.

Find the modulus and argument of the

following expr

(a)

11/3

11#3

(i+=+

-(c) cosf+isinë

Sisina

asions:

Find the locus of such that

}2+1

(b) |Z~1|+|2+1} = 4 (c)2]2-2|=|z-61}

(^)

Given that z=x-iy and fzfa), slow

that z 7×1, where 7 is the conjugate of

(b) If e, ∞ are also

compler numbers, and 67+140, using the result of (a), find the value of

according to the

TUPAC systeme,

alkene:

Na

A:

alkanoic acid.x

a white solid

Ichloro-alkane

(ii) State the

is

reagent (s) and conditions neces- sary for converting A. separately to W, Y and Zuive equations of each of the above conversions. iii) It compoun; w

heated alone under high pressures and in

the presence of

catalyst, a compound with a large relative molecular mass is obtained.

(1) What is the

compound formed? (2) Give an equation of its formntion

(iv) Give the name and

the structural formula of a

isomeric with

Compound. P which

(v)

compound Y.

Compound W can react with hydrogen:

chloride to give the compound P. Write an equation of the reaction.