育救僑器 頁一第張八第 日一十月四年午戊惠
中學會考化學(同等課程) 試卷一試題
Conc.
HYSO.
solid NaCl
water
H2SO1
WAH KIU YAT PO
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0
(1) Suggest an inorganic gas which could be A.
三期星
日七十月五年八七九一層公年七十六國民華中
(2) Suggest an organic gas which will give the same observation for Test 1.
Write an equation for the action of acidifled potassium permanganate solution on the organic g
(U) (1) Suggest two anlors in aqueous solution, other than the suphixta ion, which would give a
whito precipitate with badum nitrate solution.
(2)
What further test is required on the white precipitate in Test II to find out whether B. contains the sulphate lan
nitrogen monoxide and nitrogen dioxide, sulphur dioxide and sulphur trioxide,
(7 micks).
() 0
For each of the following pairs of oxides:
solid NaCl
[cong, H250,
-methylbenzene
(toluana)
give the conditions under which the lower oxide may be converted to the higher oxide.
(U) Swit the oxidation number of sulphur in the two sulphur oxides given in (1).
(6 marks)
switch
theostat
does NOT conduct electricity
battery
2M NaOH solution is added continuously to 20,0 cm3 of a HCI solution in än insulated calorimeter. The temperature of the mixture is plotted against the volume of NaOH solution added, as shown in the graph above.
(1)* Explain the temperature change, from A to ♬ on the graph.
(b) Write the bonde equation for the peutralization..
(L) What is the volume of 2M NaOH solution required to neutralize 20.0 cm of the HCI solution 7
(tv) What is the molinity of the HCl solution?
(v) Eaplain the drop in temperature from Ble C.
(v) in another experiment 0.5M NaOH solution is used instead of 2M NaOH solution to neutralize 20.0 cm of the same HCI salution. Explain whether there would be any difference in the amount of heat produced by this neutralization compared to that uing IM NaOH solution.
(9 . marks).
(b) The properties of iron and tin are investigated by two experiments, and the results given sa follows:
Experiment
Tin filings are put into an aqueout salution of rondIf) chloride,
Result
Na vluble change
Concentrated sulphuric acid is slowly added to solid sodium chloride. The colourless gas X formed is separately dissolved in water and in methylbenzena (toluens) using an inverted funnel as klown above.
Some properties of the resulting solutions are listed as follows:
Solation of rai X in water
conducts electricity
turns blue litmus paper red
Stale the name of gas X.
Solution of cas X in methylbenzeng
does NOT turn, blud Iltmus paper rød
(U) Write an equation for the teaction. between concentrered sulphuric acid and sodium chloride,
- (B) What is the purpose of using the inverted funnel 7
(iv) Why does a solution of gas X in water conduct electricity, whilst a solution of gas X in methylbenzene
does not 7
Explain why the aqueous solution of gas X is seldie, but the methylbenzene solution is not.
(v) What would be observed when dry unmonia gas is passed into the solution of gas X in methyl-
benzene? Explain your answET,
(0) Hydrogen can be manufactured by an industrial process which involves the following system in
equlitislum at demperature T.
HO (8) + CO (G) • CO (B) + Hy ($) ; GBH = 42 k3 mor
(1). what is to affect of increasing the temperature on the yield of hydrogen t
(11) · Explain whether increasing the pressure will give a better yield of hydrogen at temperķtum T.
(151). In this process, excess steam is used. Explain how the excess steam will affezi the yield of
hydrogen.
(iv) fron is used as a catalyst in this process. What is the purpose of using a catalyst 7
Explain what affect the catalyst will have on the equilibrium position.
03M XSD,
The diagram above Ulustrates the apparatus used for the electrolysis of two solution. Electrode is made of metal X. The formula of the sulphate of metal X is XSD.. Electrodes &, C and D'are all made of platinura. ♬ and 2 are the poles of the battery...
On completion of the circuit, metal X begins to deposit an electrode B, and gas bubbles begin to appear above Electrodes and D.
(i)
Which one of the poles and 2 is the positive pole.7
Write an lonte equation for the reaction occurring at alvetrods A.” What is this type of miction.
called-?
(i) What would be the gases collected in the tubes above (1) electrode C, (2) electrode § 7
After the passage of a surrent of 2 amperes for 3 minutes 13 seconds, 0.127 g of mial X in deposited on electrode B. Calculate the relativa atomic masa of meisl X. (i faraday 96500 coulombs)
The current
now reversed for 8 minutes. Describe briefly two observations that can be made at electrode during this period.
(8 marks)
.II
lipn fllings are put into an aqueous solution of tin(It).chloride.
A precipitate of tin la produced.
(1) Explain the results of these expeilments.
∵Iron cans, couied with uri, are ued in the caining industry as tin cana' for noring various foodstuffe.
Give two reasons why from cans are conted with to.
0.3M
H2SO
(iii) Explain what would happen if the outer surface of a tin can" is scratched exposing the lion.
Give tonic equations where appropriate.
(8 make)
A, B, C and D'ame four different synthetic polymers (plastica). Small pieces of these polymers wara heated, and the following observations made.
Synthetic Polymers
Behaviour on heating
Smoke
Smeli
softens and chart around the edger
no smoke
burning wool
does not melt
no smoke
softens and then chars
D
softens to form balls and chars on the bottom
some light smako
white fumes
fishy.
vinegar
-irritating
Calculate the number of atoms in 1 g of11C isotope. Class of one atom of 13C= 2 × 10**R Henco caiculate、n value for Avogadro's Number.
(1) A 150 cm3 naik ta filled with pure oxyaan, at room temperature and pure. How many oxygen molecules are there in the Mak: ? : (Assume the molar volume of a gas at this temperature and pressure = 24 dan")
*(10) · The sazna flask is then completely filled with water at room temperaturs. Calculate the number
of water molecules present. Olio of 1 cm3 of water, at this temperature = 3.0}
(7 ibuka)
"The 'structuses of die hydrides öf elements X, Y and Z are shown as follows:
人人
人
beat
̇aluminium axide
water
ions-pair of electrons
"bond in plane of paper
bond coming out of paper
"bond going behind" paper -
Which are thermoplastic polymers Explain your choice.
(4) Which polymer could be cellulose acetate ?
(i) The white fumes given out by heating D form dense white clouds on conter with ammonia
Suggest what may be and explain your answer.
(iv) Which one of these four polymers would be the best choice for making handles of kattles 7.
Give the name of a polymer suitable for this purpose.
(8 marks) The following chart represents a series of chemical reactions starting from A which is in ses,
A
(Cit+O)
boil with NaOH (14)
aqueous residizu containing B
acidify with dilute H2SO2, then dini
thes Birtu
distillate containing C
jam vapour of C over heated A1,Öy
The above apparatus was set up by a student for the preparation of an organic gan X. Butan-d-ol in tube 4 wai heated in an oll bath. The alcohol vapour was passed through tubes B and C containing hested aluminium oxide and water respectivaly.. A colourless que X was finally collected in the glass tyrings 2.
(1) State the name of gu X
(1) -- Using structural formulae, give the chemical equation for the conversion of buland-oi to gaa X.
(E) Why did the student prefer to use an oll bath to heat the butan-4-ol 7
(b) What was the purpose of using heated aluminium oxide in tube" ♬ j
(9) What was the purpose of using water in tube C?
(1) What would be obsrived when gue X was passed into a solution of bromina in tetrachloromathana
(carbon tetrachloride) ↑
Write an equation for the reaction.
(vii) Staring with the gas X collected in syringe D, describe briefly, with the help of a diagram, how this
gas could be dried and this collected.
(0) Camdering the number of bond. pales and/or lane pairs of elastrona, to which group of.
elements in the periodic table do siemente Y and Z belong respectively 75.
(U) - Assuming that X, Y and Z are in the same period of the periodio table, arrange the hydrides in the order in which the angle between the central atom and two adjacent bydrogen atoms decreases. Explain 'your answer.
(1) Explain why these hydrides have relatively low boiling points.
(iv). Using the dutarmon shell only, draw an disctronic structure of a compound which is formad by
combining dementi Y and 2.
((6) Write an equation to show the reaction between the hydride of X and X* (hydrogen ion),
-Using the symbole given stove, draw a 3-dimensional structure of the product,
(vi) Drawn diagram to show the 3-dimensional arrangement of the sioma in the hydride af
Phosphorus.
7
(61). How many lone palm of electrons does asch molecula of the hydrides of group VII elements
(14 marks)
residua
distillatz.containing
Đ (CHO)
Cath
(1) Give the names of A, B and C.- Write the structural formula for A.
(1) Draw a labelled diagram of the apparatus you would use to separate -C from B
(1) Why can be separated from ♬ by distilation 7.
(h) Give the name of the reagonil which can be used to convert C to E. What hobused when this
zeagent is added to C-T
(v) What is the product formed when Gla heated with acidified potassium permanganate solution 7
(vi) | Describe briefly how you would perform so experiment to combine C and D ́to for A.
(Diagram is not required) · Write a chemical equation for the insollen.
(b) Three different types of detergents can be represented as follows:
hydrocarbon chain
(15 marica)
(12 marks)
(1) A cludant perfonned testa on two chemical substance 4 andỡ, and made the following observation.
Tesi
Obrvation
Gis A‚wse pined into
an acidified potandum parmanganate solution.
Barium nitrate solution
was added to a solution. of A
The acidified potaalum permanganate solution
was decolourized.
A white precipitate was
formed.
J-000
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K 855027
各快湖
teciperatura
volums of NaOH solution (cm3) --
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|楼H四八九四年
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CO物業
palar end
W
^asoj Na* >50% N*
00
Which one of the above structures represents a 'soap' datergent ? From what type of raw -material can the 'saap' detergent be manúfactured 1
(2) With reference to the structure of these 'detergents, explain
(1) why they are miscible with water,''
(2) how they remove gressy stains from clothes.
(L) When a drop of pure water is placed on a certain piece of cloth, the water stays at a drop on the
surface of the cloth. However, when a little detergent is added to Explain these phenomena.
END OF PAPER
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