1989-12-15 — Page 13

(13)育教 刊畫日八十月一十年巳己曆更

#1815

五期星

日五十月二十(九八九一)年八十七國民華中

轎訊電 日

•

對秀麗氣質。 大型序幕巡禮由什位佳麗穿着清代宮庭華跟亮和,表現各精

燦爛笑容獎」。 獎- 除冠、亞、季軍外,莖特彩增設之一最具東方魅力獎」及「最具 十二月十七日舉行之「一九八九國際華裔小姐競選 共設五項大

,傳達中西合璧,協調和諧調。 張姿風節,望將穿著現代裝,加上有打中國民族風味的精

唐代輕冲服飾,發揮小魘古典美態性感的一面。 在一個以西樂錄影帶形式拍攝·中樂罐底的環節中,非醃將穿彩

國際華裔小姐後日競選

3=EUC12KTEYZE

態美外,仍不失其女一面· -

滿東方魅力的動感服飾,令各佳麗在台上演出時,除-

分發揮其動

埃德蒙頓

梁寶珊

布里斯班 ̇朱惠芬

香港 陳法蓉

維多利亞 魏志紅

澳門畢美娜

新加坡 陳娟娟

三藩市

李榮晶

黑斯斯 李麗蓮

溫華 蘭

芝加哥 袁華

墨爾本-吳筱捷

大溪地 江嘉敏

助,才取出她的「眼中針」。 WET BETABLE JERKI<**

:造成疏失。 是在睜一隻眼閉一隻眼的情况下動刀,」 金小姐動手術時,他自己的岩服不適,他 李姓醫生一狀,這名粗心的醫生坦哦, 他磨析的金小姐,今天向檢方些了. 【建鐡涵。

度,都應該要倣「發開 ,不論求學及懷人的 最後他勉勵各同學

* E***

红蛋

香港-湛江

CA334

CA 334

蒙特利爾 李美蘭

1990 中學會考預習專欄

明德出版社

MILL & DALE PRESS

2HG07-

1

Oxidising agents, commonly used are: Krog, and Fajn, and Ably (the last three requires heating).

Cortonatos.

dil HCI

約翰內斯堡 劉秀嫦~

iv. Which one of the four elements would react with hydrogen gas least readily.

(b) Solids X, Y and Z are Bree scdium

halides.

TasI

Pass chlór ne gas intu aqueous

solution of Y.

Ado eightled-sian nitrate solution to aqüébus 7. A... 1. And conc. H2 50

OBSERVATION

The solution turrs brown.

一讀城:邱明珠

Question. 6.3

※卡爾加里區婉瑜~

(b)

In the experiment below the gas a formed by the action concentrated sulphuric acid or. sodium chloride. crystals was passed over an iron wire at red-hot. A solid B was obtained and a colourless as B was collected, which could form an explosive mixture with air.o

--COAC. FSC

yellow preci stand.

Iron Saila 8

tu

Misty White tunes arci

soun.

Gas A wire

Reddish-brown vapour

7.

The preparation of chlorides

Chlorides

Method 1 Mathad 2

Method

Chemistry (11)

K

Ka

Relat ecides/ hydroxices?

Ca

Metal

M

4

R. Chu

dil HC1

Metal

path FeCl2

solid X.

Heat

only)

Ay

* Feci

By Frecipita- only)

Crilor the

(feci

༣

i.

Writo an ionic equation of the reaction in Test 1.

Sodium chloride

crystals

solid Z. Aúd conc, H250, 10

1. (12(9)+21" (aq)

·西雅圖范瑜姆·

-12(aq) +201"(aq)

11. The precipitate is silver chloride. It is insoluble in aqueous ammonia solution.

iii. It is bromine vapour,

H2504+2Her

(OR 3H250+3B"

H5Q+HBr 2H50+Br2+250

- NaHSO4+21120+2502

iv. The chloride ion (017).

+Br2}

TEL: 5:8

707

TEL: 22.

訂位查

5.

Chemical properties of dry HCl gas

Dry H01. gas is covalent and not vory mactive.

5. It as white dense fumes with AVE AS. ine fures consist of salad renorium hloride.

5.2

2

a white precipitate of ver chloride on passing INDO artin and silver nitrate solution.

→ AGC1(S) +HWQgian)

5.3 Metals

above hydrogen in the Activity Series, wher heated in HC1 es, en displace hydrogen gas from

11..

2.1. Zha + 2h01 - PNECT -

IN.B. I the metal has more than Que puidation state, the chloride with the metal being in its lowest oxidation state is obtained.)

The chlorides of the underlined metals are very deliquescent and readily hydrolysed by water. Thus, special arrangements of the apparatus have to be made in preparing these. chlorides TA antycrous pure form, e.g. FeCl3.

tran

1ilings

Sada me

(for removing excess. Cly and preventing moisture in air Tron entering Into the receiver

Black crystals of anhydrous

Glass

YOU!

deat

Receiver (or collering Deol, sublimate)

Sono

6. Chemical properties of aqueous #1

solution

6.1 The solution of C gas is prepared by dissolving the à5 from the grator directly water. An invorted funnel is used in order to prevent the sucking back because HOT 15 dry soluble in water.

Question 6.1

(a) The table below give

information about our elements in Group 7 of the Periodic Table.

Element

.Deaker

וּ :

fre rim at

tunnel is just below the water surface.

water

Atomic Helti

304|Eng.

number polat (C)

Fluerine

g

-220

point (°C)

--- ਜਸ

Cltior ina

17

-34.5

urgring

Jedine

35

-7.

ーケン

53

115

123

i.

Referring

to

their electronic configurations, explain way they fall within the same family.

diatomic consist of molecules." Craw the electronic structure of such a molecule, using the oule most shell only.

ii, they all

typical acid, having all

if i u 15 3

the

6.2 Dilute hydrochloric

general properties of an acid.

6.3 Concentrated hydrochloric acid is

acidic but also readily oxidized to

chlorine by agent.

ڈیا

strang oxidizing

iii. The melting points and boiling points of the elements increase down the group. Explain the trend briefly.

ii. Would the precipitate obtained in Test be able to dissolve in excess aqueous ammonia.

H

ini, hame the reddish-brown vapour Write an equation

observed in IV.

of the reaction.

iv. What is the anion contained in Z?

Question 6.2

in the experiment below the gas X, formed by the action of concentrated

acid. hydrochloric

on potassium permanganate crystals, was passed over sone iron filings at red-hot. After a while, a black solid Y was collected at the place as shown.

iron

Conc. C

Gas X

filings Salid Y

MA

deter

Conc. 1504

rystals

>leat

Sode time

(a) Identify and name the substances X

and Y.

(b) Write

the equations af the farination of X and Y respectively. (e) Stare the purposes of passing X Successively through (1) water and (ii) concentrated sulphuric acid.

(d) What is sodaline?

State TWO functions of the sodalime

in the above experiment.

Water

(a) Identify and name the substances A,

8 and respectively.

(b) Give an equation of the formation

of A.

(c) Write an equation of the reaction between A and the hot iron wire.

(d) Why was solid 8 collected at the place as shown, but NOT near or un the hot iron wire.

(e) How could you avoid too much of gas A being unreacted after passing over the iron wire?

(f) Would there be any gas collected in the test-tube if the iron wire in the above experiment is replace, in tura, by

i. zinc powder, if. copper coil?

If there is a reaction, give an equation of the reaction. if there

is NO reaction, explain briefly.

Solution to 0.6.1

(a)

1. Their atoms have the same number of

electrons in the outermost snell.

ii. The electronic structure

halogen molecule is:

of

a

со

(e) Would there be any reaction of the iii. The molecular size increases down

iron in the above experiment is substituted, in turn, by

1.

copper powder,

ii. carbon powner?

If there is a reaction, write an

equation of the reaction. If there

is NO reaction, state so.

the group, thus increasing the intermolecular forces. Since the molecules are nore strongly attracted together down the group. 50. there is an increase in the m.p.'s and b.p.'s down the group.

iv. Iodine is the least reactive.

Solution to 0.6.2

(a) X is chlorine gas.

Y is iron(II) chloride.

(b) 2KMnO4-16HCF-2KC1+2XnC12+501 + BHD 2FeCl3

2Fe+3012

(c)

i.

Water is to dissolve the hydrogen chloride gas.

11. Conc. H2504 is to dry the chlorine.

gás.

(d) Sodalime is J mixture of solid sodium hydroxide and calcium oxide. It is used to react with the excess Cl2 gas and to prevent the moisture from entering into the

-in air

apparatus.

(e) i.

Yes; Cu+C2

CUC) 2

ii. NO reaction.

Solution to Q.6.3

(a) A is nydrogen chioride. B is iron(1) chloride. D is hydrogen gas.

(b) NaG1+H2SO4°

(c) 2HC1+Fe

NaHSO+HC1

-FeCl2+H2

(d) It is because iron(11) 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. 2504 to the NaCl crystals, thus producing yas A at a reasonable slow rate.

(f)

i. Yes; zinc reacts with gas A to give

hydrogen gas too.

Zn+2HC1

ZnCl2 + H2

if. No; because copper, being lower in position than hydrogen in the Activity Series, cannot displace hydrogen from hydrogen chloride.