負四第張七第 日十三月二十年愚丙瑟复 WAH KIU YAT PO
1977中學會考試題預習專欉
明德社主编
化學(十五)
朱宏林•
Chemistry (15).
Question 25
A series of chemical reactions
are summarized in the following: block diagram.
a colourless,
excess
cone H304
at 1800
at 250 c
propanal, CHỊCH CHO
a colourless, sour liquid B
Na metal
colourless crystals
+
soda lime
and heat
a colourless gas D
hydrogen gas
Identify and name the compo unds A, B, C, D and E.
b) There are two other compounde isomeric. to compound A. Write down their structures and nare them,
c) What reagent(s) would you use
to convert
i) propanal to B,
ii) A to B in one step? What is soda lime?
Why is concentrated sulphuric acid used in converting A to gas E?
f) Give the equations for the
reactions converting
1B to C. ii C to D.
iii) A to B.
What would be observed if gas E is mixed with bromine vapour! Give an equation for the reaction."
h) What is the role played by
copper in converting liquid A to propanal?
1) What would be obtained as the
main product(s) when a mixture of liquid A and liquid B is heated in the presence of a little of mineral acid? Give the equation for the reaction. Question 26
A. The methanol is prepared in
industry by the following reaction which is reversible:
00(8) + 212(6) — CH2OH (c) -9.2 kJ-equationTM
1
Is the backward reaction endothermic or exothermic? b) What is the energy change
in preparing 16 g methanol by the above reaction?
) Describe the effect on the
yield of methanol of
i) increased pressure; ii) increased temperature; iii) adding a catalyst;
iv) increased the pressure
of hydrogen gas only? a) What would be obtained if
phosphorus (V) chloride is added into some methanol in a dry test-tube? Name the products and give an equation for the reaction. B. The ester, CH,C000, can
react with water according to the following equation and the reaction is reversible:
COH * CH COOR
a) State the conditions under
which the above reaction. will proceed readily in a reversible way?
b) It is found that the forward reaction(4.e. hydrolysis) can be made almost 100% complete by adding causṭio soda solution into the re-
Explain action mixture. why this is so and name the products thus obtained. c) Write an equation for the
reaction between the ester, CH COOH, and caustic soda as mentioned in (b).
a) with reference to your an- swer to (c), write an equa
tion for the reaction bet tween the caustic soda' and CH2OOCR
CHOOCH
CH2OOCR
where R repre-
sents a large alkyl group. e) Name the products obtained
in (a). Which one is known more commonly as 'scap'?
地理科(十五)李婉備 ̇黎仲豪
GEOGRAPHY (15)
Answer: 21.
We can find from the dia- gran the size of the farm is about 56 aquare km. The fields are almost surrounded by dense forests. There are road systems and plenty of buildings with various func- tions scattered all over the farm. The fara in well plan- ned.
A. This kind of farming can be found in the tropical coastal regions such as Sri- lanka, Java, Malaysia, West Africa coast, Brazil and Cuba.
B. This kind of farming me- thod is known as plantation agriculture.
G. In plantation agricul- ture, it is usually one or two crops grown in the farm. The farm size is large of 4- 8 aquare km. The farm is cleared out from the dense forests because this planta- tion is usually established by the Europeans in the tro- pical coastal regions. Heavy _capital is required in ea-
tablishing this kind of far- ming so there is great need for investment. Only the European investors can help its development. The planta- tions are managed scientifi- cally by the exports and the. labourers who are the natives of the regions employed by the investors. The labourers and their dependants are provided with accommodation units and with other funda- mental facilities such as markets, schools, co-opera- tives and clinics. There are also workshops, scattered all over the farm. Farming mac- hinery is employed in this kind of farming. Laboratories: are being set up for reseac- hing and promoting farming method. Some factories are also established for packing and processing of the pro-
ducta. For the products are mainly for export and getting foreign exchange in return, transport systems are well built. Roads, railways, piers and warehouses are prepared for the transportation of products.
D. Since the method of plantation is so modernized and scientific that the practice of this kindof farming will bring good to those tropical regions. The plantation agriculture is in large scale production which produce unique crops to supply the international market. It can offer on- ployment to the local people and help to increase the people's living standard and help prosper the economy of the regions. There is high mechanization in this kind of agriculture therefore it is easily to improve the quality of the products high yield will be the re- sult of monoculture.
However, the European the owners were afraid of unrest and disturbances in these regions, they relied on the strong military force in order to control the lo- cal people. Thus, such act- ion will arouse colonialism "of these areas. Resourcès of these tropical areas will sooner or later be ex- ploited by these European . investors. Also monoculture nay weaken soil fertility and fertilisation is surely needed. Since the crops are mainly for export, any change in the demand of the International market will greatly affect the price of the crops. Price fluctu- ation is unavoidably and this will have great effect
報日僑
四期星
on the economic development of the region. The yield of such monoculture wil no matter depend on the climatic condition. Also unpredictable climatic con- dition will affect the yield of the arop and fai- lure comes.
The crops grown in plantation are rubber, tea, pineapple, coconut and oil- pala.Rubber is the crop planted in that farming
area.
F. In recent years, after the European plantation owners have left the coun- try, local management be- comes inefficient. The plan- tations either continued operation under government control or become divided into small holdings owned by the natice farmers. Diversification is encou- raged by planting other crops particularly food crops in fighting against the price fluctuation. Mono- culture no more existe in this kind of farming.
Question for Next Week:
22.
PLAN OF A FARM MAIN ROAD
(35).
(36)
(22)
(30)
(25)
(40)
MAN
ROAD
(38)
Pasture
Wheat
Homestead
Dams
(No. in brackets show arez in hectares)
Above shows a plan of a farm in the Murray-Darling Basin in Australia
a.
Give a reasoned account of the farming activities which are carried on in this farm.
What are the main charac- teristica found in this farm which cannot be found in an average farm in Hong Kong?
C. In a simple exreriment, a
student obtainoi the following. results:-
solution
Na2 CO2
KC1
NH C1
pil value
日七十月二年七七九一层公年六十六國民中育教僑錄
What acid is run into flask A? Why is potassium permanganate used?
o) What is the use of placing the - concentrated sulphuric acid in
bottle B?
a) Give the equation for the re- action taking place in tube C when chlorine is passed over the heated iron,
e) It is dangerous to allow ex- cess, chlorine to escape into the room.
1) Why is it dangerous to
allow any chlorine to escape in such way?
ii) How would you carry out the experiment to avoid such danger?
iii) low would you detect we
whether the excess chlo- rine was escaping?
f) Iron can form two kinds of
chlorides: iron(II)chloride and iron(II)chloride; why only iron(III)chloride is ob- tained in the above experiment?
e). If dry hydrogen-chloride, in- stead of chlorine, was passed over the heated iron, which iron chloride would be obtained? Explain your answer briefly.
h) Anhydrous iron(III)chloride is
a dark solid; but its aqueous solution is yellow in colour.
1) What is resposible for the
yellow coloration?
ii) Would you expect the pH
value of the yellow solut-
ion to be greater or smal- ler than 7? Explain your ariswer briefly.
iii)What would be observed if
an excess of sulphur di- oxide is passed into the yellow solution of iron (III)chloride?
0.5 mole of chlorine gas is passed over excess iron in the tube C.
1) What mass of iron would be
used if the chlorine react-
ed completely with iron?
ii) What mass of iron(TIF)
chloride would be formed?
物理 (十五)·魯榮家
PHYSICS (15)
Exercise 8
Answer ALL the questions: Relative density of mercury
13.6
Bensity of water = 1000kg m
the
1. (a) When a sample of enclo- sed moist gas is compressed at constant temperature. following relations between the pressure (P) and the yo- lume (v) of the gas are ob- tained :
P (in mm Hg)
>7.
Vin ca
7
35
200
70
100
<<7
(A)
70.
140
50
154
40
164
184
35 28
Try to give brief explanat- ion to the pH values observed.
Question 27
A sample of anhydrous iron(III) chloride is prepared in the exp- eriment illustrated in the foll- owing diagram,
potassium
permanganate
B
acid
heat sulphuric
concentrated
Это вварха
concentrated
acid
chloride (as dark
chlorine
fron
solid)
iron(III)
(1) For which of the given pressures does Boyes law *pply ?
(ii) What is the pressure or the moist gas, as indicated by (A) in the above figures ?
(iii) For which of the given pressure is the gas saturated with water vapour
(b) A cylindrical diving-be11 containing a barameter, sis filled with air at 720 mm Ng is lowered to the bottom of
a lake. If the reading of the barameter is then 900 mm Hg, the height of the bell in 2m.
(1) Find the length of the column of water entered into the bell.
(ii) Estimate the depth of
the lake.
(c) An air bubble occupies 9.12 x 10-6
At the
cu.a bottom of a pool. When it rises to the surface it is found to occupy 3.02x 10-6 m
to the The temperature of water in. the lake is not uniform and it is found that the temper- ature is inversely proportion- al to the depth. If the temp- erature gradient is 1'c/n, And the temperature at the surface is 27. What is the depth of the lake if the at- mospheric pressure is 750mmig.
2. (a) A convex lens is placed 0.1m in front of a convex mirror of focal length 0,25m, It found that when an object is placed 0.3 m in front of the lens, it coinsides with ita own inverted image formed by the mirror and the lena, Determine the focal length of the convex lens.
(b) If an object 40mm tall is
placed 0.24m infront of the convex lens mentioned above,
(i) find the position and size of the image.
(ii) If a plane mirror is placed 0.4 m behind the con- vex lens (ie, the convex lens is 0.24 m behind the, o object and 0.4m in front of the plane mirror). The plane is perpendicular to the axis of the lens. Determine the position and size of the image.
3. (a) The following values for u (noject distance. ) and v (image distance ) were obtained experimentally with a concave mirror.
in m
0.25 0.4 0.5 0.75|1.0 v in m 1 10.4103302731025
Plat the graphs of
[[(4) 1/u (b) uv
(u+v)
the
ench graph focal length of the mirror.
(b) The figures represents two probes "A and B of a rip- ple tank. A and B are 0.05 apart and one attached to the aane vibrating arm. Water wa- ves are set up simultaneously by the vibrating probes. The distance between adjacent wave crests in each wave tr- ain is 0.04m,'
(i) state the kind of inter- ference which will run at p if AP - 0,33m and BP = 0.37m (ii) A,B and 9 in the figure are collinear, State in terms of wave length the path diff erence at () between the two waves from A and B,
.A
0.05m
B.
· (c)As figurës shown, a metal black hangs freely in air äre end of a gonoseter wire. The resonating length is found to he 1 m when a tuning fork is inserted. The metal then hàngs completely submerged in, water the resonating length is re- duced by 0.1m. Determine the density of the meta)..
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