1980-05-01 — Page 23

*有教僑藏頁三張六第

日七十月三年申庚瑟夏

WAH KIU YAT PO

報日僑華

四期星

1980

of the circle ABQ- To prove: (a) PB ~ PO

26.

中學會考試題預習專欄

(b) CP produced

bisects BQ ut right angle

數學(廿七)

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Mathematics (27)

C. P. Man

Mill & Dale Press Ltd

Solution to Exercise 11

Section B

J

+3) lies on

ax

Proof:

(a) [ACB

LAPB

('s in the same seg)

LACH 2/AQB

(centre double the O

[APB = /POB + /PB0

(ext of 7

2/AQB

(PQB

ཟ

POB

PBQ

PO PB (sides

opp eu (8)

CQ - CH (radii)

CP is the L bisector of BQ

(1 bisector locus)

(2,-5) and (5,-2) lie on the curve

To prove BE BC - 2AE

6/2

31/6

-4x1x3

AB- AB

Given: BAC 90

Proof: Draw AD ↓ BC

(2)

AD AB

– 90° (given) BC (const)

Co-ordinates of the points where the graph cuta the x-axis are (3+/6, 0) and (3-/6, 0)

The additional linear graph

5

DE

heot30°

-HD-BC

(mean proportional) AB - AE (given) ADAD (common)

A ABD = A ACD (R.H,S)

BD DE

AB2

BE BC

ie. 2AB

BE BC

BE BC

15, Coat price for each bicycle

$18750 250

875

The fixed selling price for each bicycle

875 × (1+305)

- 697.5

Total sale for the first 230 bicycles

- 8180x97.5+50x97.5x(1–3)

$21450

Sales for the rest bicycle

-$(75-10)x20

$1300

Gain % on the whole. tramanetion.

2145041300–18750-

18750

Let r be the radius of

the circle.

hant30)

c53 8.

tan/FAC

FAC

beat 300

(b) AF = hooaac1).

BF hoosec30

68/AFB

LAFB

kensoc30°

hcosec19

100tan19 G'

HC

100cas538

·60 ́m

AB

Volume of the solid

4x60x34.64x80

83136 cu.m.

XOY - X- 48

Area of AXOY

**r sin(1-20),

ir2sin26°

Area of sector AUX-

Area of semi-circle ABC

coas

1980

in20

中學會考試題預習專欄

When dilute hydrochloric

acid is added to the

solution of a colourless:

solid X, white precipitate

is observed whi cli disappears on heating. Which of the following

substances is most most probably the solid... X? A. lead(11)nitrate B. silver nitratë C. lead(TI)chloride D. potassium sulphate E calcium carbonate

Which of the following" netals will NOT liberate hydrogen gas from hot caustic soda (cone, sodium hydroxide)?

A. magnesium

Tead

aluminium tiny

Then hydrogen sulphide gas is passed into an aqueous solution of iron(III) chloride, which of the following substances are present in the products 2

(1) iron(III)chloride (2) sulphur

(3) hydrochloric acid (4) iron(II) sulphide (1) and (2) only only (2) and (4)

c. (3) and (4) only

(1), (2) and (3) only E. (2), (3) and (4) only

29. Which of the following

statements

is/are Cop Sution:

A. It can form ions with.

valencies +2 and +3.

B. It occurs naturally

combined only with oxygen EARN

C. It can be used as a

catalyst for certain processes,

D. Many of its compounds

are coloured.

E.

It is the main component of the alloy, steel.

30. The oxidation number of x

2- in the species X207

A. 3

B.4

0.5

D. 6

31. Which of the following solutions is the WORST conductor of electricity?

A

molar hydrochloric acid

B. molar ethanoic acid

molar ammonia solution De impure water.

molar sugar solution

electrolysis of kated water using

electrodes, the mtio of hydrogen to oxygen liberated by

Which of the following

factors will influence the selective diacharge of an ion at an electrode during electrolysis?:

(1) The nature of the

electrode used.

(2) The quantity of

electricity passed. (3) The temperature of

the electrolyte.

(4) The concentration

of the i008. concerned,

and

only

(2 and (3) only

c. (2) and (4) only

化

(#)

D. (3) and (4)

E. (1) and

only only

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Chemistry (30)

Reginald W. Chu

Mill & Dale Press Ltd

日一月五年〇八九一腊公年九十六國民额中

(1) The reaction at

the cathode can" be represented by the following ionic equation:

Na

+

Chlorine gas is liberated at the anode

(3) The resulting

solution of the electrolysis is alkaline

The substancè o liberated at the cathode and anode respectively are in the molar ratio 1:1

All B. (2), (3) and (4) only C. (2) and (4) only D. (2) and (3) only E. (2) only

35. Which of the following statements about a homologous series in general is INCOPRECT?: A. All the members have

the sune empirical farmula

36

B. All the members have general molecular formula DA

Each member differs from the next by A methylene unit, -CBg- in their molecular formula:

The boiling pointa increases gradually as the number of carbon". atoms increases The molecular weight increases regularly

by

When ethene is passed

the aqueous breuine

VPN the chief

obtained has a tructural formula of

13

Br

но

F

་

CIE FICII F-O-K

------- ----

OH H

Br.

37. In the diffused sunlight,

mothane reacts with chlorine to give a mixture of producta. Which of the following substances may be present in the mixture

(1) CHI2G1

(2) CIL Clą

(3) CHC),

(4)

8, (2)

and

only

4) onl

c. (1). (§) and (4) unly and (3) only D. (2),

E. ALL

38. In the experiment as shown

helow, the bulb does NOT light up when the key O̟ is switched on. Which of the following conclusion is. most likely?

bulb

key Q

bettery

carbo

Fiquid

hydrogen

chloride

electrodes

39. When a mixture consisting

ne mele of ethyl of ere ethanoate and one mole of water is allowed to stand for a long time, the

ethanol, ethanoic acid,

väter, and ethyl ethanoate C. ethanol and ethanoie

acid only

D. ethanol; wüter and ethyl

ethanoate only

E. ethanoic acid, water and

ethylethanoate only

40. CH COOL + Cl2

light

CH2C) COOH + H¢1

he reaction represe

by the above cquation is known as

A substitution

B.adition

C. hydrolysis

D. esterification

E. neutralization

41. Which of the following

statements about carbon droxide and sulphur dioxide is INCORRECT? A. Both are soluble in

water to give a weak dibasic acid.

Both are colourless, odourless gases. Both give white precipitate on passing "into aqueous barium chloride solution.

D. Both can oxidize a burning magnesium. E. Both do not support

the combustion of candle.

+ X(aq) —► Y(aq) +Z(k) w(s). Which of the following. may affect the rate of the reaction represented by the the equation above?

(1) Concentration of X (2) State of

subdivision of W (3) Temperature (1) only

B. (2

only

(1) and (2) only D. (2) and (3) only (2) and (3)

(g)

3H (

2NH2(g) → heat

In the above reaction which of the following conditions will produce the Highest yield of ammonia?

A. High pressure and

low temperature D. High pressure and

high temperature C. Low preasure and high temperature D. Low pressure and

low temperature

E Normal pressure

When ordinary goap in

med into a hard water,

a "scum" is formed. The

scum" mainly consists of (1) calcium stearate

(calciur

octadecanoate). (2) magnesium atenrate

(magnesium octadecanoate)

8

calcium carbonate calcium sulphate only B. (2) only

BAN 1.

C.(1) and (2) only

D. (1), (2) and (3) only E.. (1), (2) and (4) only

45. Whi

of the following. reagents ia/are usually stored in brown bottles?

(1) Bq0g -

(2)

(3)

(4) conc. H,SO

A. All

B. (1), (2) and (3) only G. (1) and (2) only D. (2) and (3)

only

E. (3) only

ANSWERS:

26 A 31 E 36.

27: A

32 C

37 E

42 E

28 E

33 E

38 B

43

substances then present in

the mixture, are

29 B

34 B

39 B

A. ethyl ethanoate and

water only.

30 D

35 A 40 A

45 B

經包

羅刊開史

稱報萬豐翔悠 許導有富實久

Given: Circle ABPC passes

through the centre, C.

不隨禮柯多新彩無報請選 另報拜式采顆色任販就道 收附出印多雜8歡訂近閱 當送版刷誌僑迎閱向户

When a 5M solution.

andium chloride is

electrolysed wit, ?

carbon

electrodes, which of the following results is/are

true?

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