1978-11-10 — Page 30

五期星

anhydrous

興二路版八第 日十初月十年年戉惠

WAH KIU YAT PO

郭日倫華

(4)

1979

Liquid X iu nuidified | potnasium dichromatej

中學會考試題預習專欄

(11) Liquid X is bromine

solution in wateri

90%

catalyst

(114)Liquid X in neutral

barlum chloride solution:

化明

Chemistry (5)

Question 7

In the experiment as shown *below, the gas 2 evolved on heating a mixture of copper turnings and concentrated. sul phuric acid is passes into a liquid X In the test tube B.

copper. turnings

(a) Give the chemical name of

5(b) Write an equation for the

formation of gas 3.

*(0) If the liquid X is the

distilled water, state the

ions that will be present

in the resulting solution,

~(d) Would the resulting salute

孟勋看白金精彩d in (e) hav

All greater or smaller than

(e) Describe what would observe

whan the following liquide are placed, in turn, in the

teat tuba

(iv) Liquid X is saturated. hydrogen sulphide anlutton,

Give the equations for the reactions (ii), (111) and (iv).

(f) What

to passed over heated lend(IV)oxide? -

∙Give an equation for the

reaction, if any.

(R) A white solid is obtained |

*n the reüidue in the tube A at the end of the exper-

(1) What is the white

aolid?

(11) The residue in then

poured into a beaker half-full of water with stirring. What would be s

then?

(h) Would there be

produced 17 copper is substituted, in turn, by

wine?

If there is a reaction,

reaction,

If there is no reaction, explain briefly.

Question:

The apparatus as shown in the following diagram is used to prepare sulphur trioxide in the laboratory,

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政暴

CONA

HWS0A

1

heat

receive

ice and:

water

sulphur trioxida

(a) Give the equation for the

formation of sulphur trinxide,

(1) Suggest a catalyst suitable for the above reaction, (0) Why are the gaseous react.

́anta passed through optom entrated sulphuric acid?

(d) What doen solid sulphur

look like?

(e) Why is a drying bulb with

anhydous calcium chloride attached to the receiver? (1) It is found that the

alyst needs to be heated. initially and once the reaction has started, no more heating is required. What does this tell you about the nature of the reaction?

does the catalyst 'need to be heated at all?

(h) What would be the volume

of sulphur dioxide, me ured at wit, pa, chauned In proparing 1,6 g of aulphur trioxide?

usually

(1) Sulphurie auld in

日十月一十年八七九一层公車七十六三路費中 目標育教

|(b) When anhydrous iron(II)au]-

phate fa heated strongly,

obtained by dissolving

sulphur trioxide in cone- entrated sulphuric acid

first, but netidirectly in

water, Why is this step

(3) Using balanced equation(s)

only, show the reaction(s): that would take place in wach of the following experimentsi-

(1) A mixture of andium chloride, manganese (IV)oxide and concent trated sulphuricaseid is heated.

(11) A mixture of potassium-

nitratu, and concentra» ted sulphurie sold is heated with sopper turningsầ

(a) 8.74 g of a mixture of

Cammonium sulphate and pota

assium sulphate are weighed out into a flank and 30 cm2 of 0.9M potassium hydroxide solution are added. The solution is boiled to

expel all the ammonia gus and the excess potassium hydroxide requires 12.5 om of sulphuric acid donatine ing 19,6 g of sulphurie. noid per cubic decimetre. (Abste

1-1,8-32,0-16,N=14) |

(1) Write the equations

for the reactions

(11) Caloulete the compos- Ition of the original

the reaction represented

hy the following equation will take place.

PepDy + 80g + 50g.

(1) The gaseous products

are then dissolved in some distilled water. give the name(s) for any fons, that would be formed in the sol- ution,

wation(e) for the formation. (11) Barium chloride solutes

ion is then added to the solution obtained in (11), white preci- pitate is observed

Nade the dompounds present in the preci pitate and give. ionin @qautions for their formatipila

(111)What happens if an

联

天幫離告-斯沙·

;四十包分,秀传

rochloric acid is. added to the precipitate abulis mixture is heated gently?

)11 3.04 g of anhydrous

iron(11)sulphate is. completely decomposed, calculate

(i) the volume of the

gaseous products that would be gb- tained at stip,;

(ii) zhe wasa of iron

(111)oxide that

would be obtained. .wt, Fe-56,8=32,

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