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Properties of acids and bases determined through indicators
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Untuk Kegunaan Pemeriksa
Bahagian Soalan Markah
Penuh
Markah
Diperoleh
1 11
2 9
3 10
4 10
5 10
A
6 10
7 20
B
8 20
9 20
C
10 20
Jumlah
Nama : ……………………………………………... Kelas : …...……
SEKTOR SEKOLAH BERASRAMA PENUH
KEMENTERIAN PELAJARAN MALAYSIA
_______________________________________________
PEPERIKSAAN AKHIR TAHUN TINGKATAN 4
2006
KIMIA
KERTAS 2
Dua jam Tiga Puluh Minit
JANGAN BUKA KERTAS SOALAN INI SEHINGGA DIBERITAHU
1. Tuliskan nama dan tingkatan pada
ruang yang disediakan.
2. Calon dikehendaki membaca
maklumat di halaman 2.
Kertas soalan ini mengandungi 24 halaman bercetak
4541/2
Kimia
Kertas 2
Nov
2006
2½ Jam
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INFORMATION FOR CANDIDATES
1. This question paper consists of three sections: Section A, Section B and Section C.
2. Answer all questions in Section A. Write your answers for Section A in the spaces
provided in the question paper.
3. Answer one question from Section B and one question from Section C.
Write your answers for Section B and Sectioin C on the lined pages at the end of the
question paper. Answer questions in Section B and Section C in detail. You may use
questions, diagrams, tables, graphs and other suitable methods to explain your answer.
4. Show your working. It may help you to get marks.
5. If you wish to cancel any answer, neatly cross out the answer.
6. The diagrams in the question are not drawn to scale unless stated.
7. Marks allocated for each question or part question are shown in brackets.
8. The time suggested to answer Section A is 90 minutes, Section B is 30 minutes and
Section C is 30 minutes.
9. You may use a non-programmable scientific calculator.
10. Hand in this question paper at the end of the examination.
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Section A
[60 marks]
Answer all questions in this section.
The time suggested to complete Section A is 90 minutes.
1 Figure 1 shows part of the Periodic Table of the Elements. A, B, C, D, E, F, G and H
do not represent the actual symbol of the elements.
A F
B D E G
C H
FIGURE 1
Using the letters in the Periodic Table of the Elements in Figure 1, answer the
following questions.
(a) Choose two elements which are metals and are placed in the same group.
………………………………………………………………………………….
[1 mark]
(b) Write the electron arrangement for an atom of element F.
………………………………………………………………………………….
[1 mark]
(c) Write the formula for the ion formed from an atom of element D.
………………………………………………………………………………….
[1 mark]
(d) (i) State an element which has a special characteristic that is can form coloured
compound.
……………………………………………………………………………
[1 mark]
(ii) State another special characteristic for the element that is stated in (d)(i).
……………………………………………………………………………
[1 mark]
(e) State one element that forms acidic oxide.
………………………………………………………………………………….
[1 mark]
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(f) Arrange A, B, D, E, F and G according to the increase in size of the atoms.
………………………………………………………………………………….
[1 mark]
(g) Element A can react with water.
(i) Write the chemical equation for the reaction between A and water.
………………………………………………………………………………
[1 mark]
(ii) When a red litmus paper is put into the solution in (g)(i), the red litmus paper
turns blue. Based on the observation, state the property of the solution
formed.
………………………………………………………………………………
[1 mark]
(h) Element H is less reactive than element E. Explain why.
…………………………………………………………………………………...
…………………………………………………………………………………...
…………………………………………………………………………………...
…………………………………………………………………………………...
…………………………………………………………………………………...
[2 marks]
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2 Figure 2 shows the structural formula of compound X.
FIGURE 2
(a) What is the meaning of molecular formula?
…..…………………………………………………………………………….
………………………………………………………………………………….
[1 mark]
(b) Write the molecular formula of compound X.
………………………………………………………………………………….
[1 mark]
(c) Can compound X conduct electricity? State a reason for your answer.
………………………………………………………………………………….
………………………………………………………………………………….
[2 marks]
C
C
C C
C
O
H
OH
CH2OH
H
H
H OH
OH
H
OH
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(d) Compound Y contains 52.2% of carbon, 13.0% of hydrogen and 34.8% of
oxygen by mass.
Given that the relative atomic mass of H=1, C=12, O=16.
(i) Find the empirical formula of compound Y.
[3 marks]
(ii) If the molar mass of compound Y is 46 gmol-1
, find its molecular formula.
[2 marks]
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3 (a) Figure 3 shows the flow chart for the industrial manufacture of sulphuric acid.
FIGURE 3
Based on Figure 3, answer the following questions.
(i) Name the process of manufacturing sulphuric acid.
…………………………………………………………………………………….
[1 mark]
(ii) Describe how sulphur dioxide gas can be produced at stage I .
…………………………………………………………………………………….
[1 mark]
(iii) Name catalyst X in stage II.
………………………………………………………………………………….
[1 mark]
(iv) Write the chemical equation for the reaction that takes place at stage II.
………………………………………………………………………………….
[1 mark]
(v) At stage III, sulphur trioxide is dissolved in concentrated sulphuric acid to
produce oleum. Write the chemical formula of oleum.
……………………………………………………………………………………
[1 mark]
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(b) Brass is an example of alloy.
(i) Name the main element which is added to copper to form brass.
.……………………………………………………………………………………
[1 mark]
(ii) Draw the arrangement of atoms in pure copper and brass.
Pure copper Brass
[2 marks]
(iii) Brass is harder than copper. Explain why.
…………………………………………………………………………………...
…………………………………………………………………………………...
…………………………………………………………………………………...
…………………………………………………………………………………...
…………………………………………………………………………………...
[2 marks ]
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4 An activity is carried out in the laboratory to determine the end point of the reaction
between 25.0 cm3
of potassium hydroxide solution and 1.0 moldm-3
of sulphuric acid.
Phenolphthalein is used in the titration to detect the end point of the reaction.
Figure 4 shows the set-up of apparatus for the titration.
FIGURE 4
The volume of sulphuric acid added and the changes of the colour of potassium
hydroxide solution are shown in the Table 4 below.
TABLE 4
(a) Name the chemical reaction between potassium hydroxide solution and
sulphuric acid.
………………………………………………………………………………
[1 mark]
(b) Write a chemical equation for the reaction.
……………………………………………………………………………...
[1 mark]
Volume
of
sulphuric
acid
(cm3
)
4.50 4.60 4.70 4.80 4.90 5.00 5.10 5.20 5.30 5.40
Colour of
potassium
hydroxide
solution
Pink Pink Pink Pink Pink
Colour-
less
Colour-
less
Colour-
less
Colour-
less
Colour-
less
Sulphuric acid
1.0 moldm-3
25.0 cm3
of potassium
hydroxide solution and a
few drops of
phenolphthalein
White tile
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(c) Write the formula of ions which are present in the conical flask when the
volume of sulphuric acid added is:
(i) 4.50 cm3
………………………………………………………………………………
(ii) 5.30 cm3
………………………………………………………………………………
[2 marks]
(d) How much sulphuric acid is required to neutralise 25.0 cm3
of potassium
hydroxide solution?
……………………………………………………………………………..........
[1 mark]
(e) Calculate the molarity of potassium hydroxide used in the above activity.
[3 marks]
(f) If sulphuric acid is replaced with nitric acid with the same molarity, predict
the volume of nitric acid require to neutralise 25.0 cm3
of the potassium
hydroxide solution. Explain why.
……………………………………………………………………………..........
……………………………………………………………………………..........
……………………………………………………………………………..........
[2 mark]
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5 Figure 5 shows the set-up of apparatus to investigate the electrolysis of
0.0001 moldm-3
sodium chloride solution.
FIGURE 5
(a) Name all the anions present in the solution.
………………………………………………………………………………………
[1 mark]
(b) What is the energy change that occurs in the electrolysis process?
………………………………………………………………………………………
[1 mark]
(c) (i) Name the gas collected in the test tube at electrode X.
………………………………………………………………………………………
[1 mark ]
(ii) Write the half equation for the reaction at electrode X.
………………………………………………………………………………………
[1 mark]
(iii) Explain how to confirm the gas produced at electrode X.
………………………………………………………………………………………
………………………………………………………………………………………
………………………………………………………………………………………
[2 marks]
Dilute sodium
chloride solution
0.0001 moldm-3
sodium chloride
solution
Carbon
electrode Y
Carbon
electrode X
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(d) What ion is discharged at electrode Y? Explain your answer.
.……………………………………………………………………………………...
.……………………………………………………………………………………...
………………………………………………………………………………………
[2 marks ]
(e) The volume of gas collected at electrode Y is 30 cm3
.
Given that Avogadro number is 6.02 1023
mol-1
and 1 mol of gas occupies a
volume of 24 dm3
mol-1
at room condition.
(i) Calculate the number of mole of the gas produced.
[1 mark]
(ii) What is the number of gas molecules collected?
[1 mark]
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6 Figure 6 shows four test tubes contain dry glacial ethanoic acid, aqueous solution of
ethanoic acid, dilute hydrochloric acid and aqueous solution of X.
P Q R S
FIGURE 6
(a) (i) State the colour change of the litmus paper in test tubes Q and R.
................................................................................................................................
[1 mark]
(ii) Write the formula of ion which caused the colour change of the litmus
paper.
................................................................................................................................
[1 mark]
(b) Is there any changes of colour of the litmus paper in test tube P? Explain why.
.....................................................................................................................................
.....................................................................................................................................
[2 marks]
(c) Table 6 shows the pH value of aqueous solution of ethanoic acid and dilute
hydrochloric acid of the same molarity.
Type of acid aqueous solution of
ethanoic acid
dilute hydrochloric
acid
Molarity 0.1 moldm-3
0.1 moldm-3
pH value 1.0 2.9
TABLE 6
Explain why the pH value of aqueous solution of ethanoic acid is higher than the
pH value of dilute hydrochloric acid.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
[2 marks]
Aqueous
solution
of X
Blue
litmus
paper
Dilute
hydrochloric
acid
0.1 moldm-3
Blue
litmus
paper
Dry glacial
ethanoic
acid
Blue
litmus
paper
Aqueous
solution of
ethanoic acid
0.1 moldm-3
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(d) Calcium carbonate powder is added into test tube R. Write the chemical equation
for the reaction that takes place.
....................................................................................................................................
[1 mark]
(e) Aqueous solution of X is an acidic solution. As a chemistry student, describe
briefly how you are able to prove that X is an acidic solution. You are not allow to
use litmus paper, pH meter or any indicators.
Procedure:
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
[2 marks]
Observation:
....................................................................................................................................
....................................................................................................................................
[1 mark]
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Section B
[20 marks]
Answer any one question.
The time suggested to answer this section is 30 minutes.
7 (a) What is meant by “melting point”?
During the melting of naphthalene, the temperature remains constant even though heat
is applied. Explain why.
[4 marks]
(b)
Describe the change of the kinetic energy, arrangement and the forces of attraction
between the particles at the following states:
before condensation
during condensation
after condensation
[10 marks]
(c) Figure 7 shows the electron arrangement of ion Y3+
.
FIGURE 7
(i) Calculate the nucleon number of atom Y. [2 marks]
(ii) Y reacts with oxygen to form oxide Y, with the formula Y2O3.
The chemical equation for reaction Y with oxygen is show as:
4Y + 3O2 2Y2O3.
Given that the relative atomic mass of Y = 27 and O = 16.
Calculate the mass of oxide Y, Y2O3 formed when 10.8 g Y is completely burnt in
oxygen.
[4 marks]
Condensation is the process where a gas changes to its
liquid state at a certain temperature and pressure when
it is cooled.
14 n
e
e
e
e
e
e
e e
e e
3+
n neutron
e electron
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8 (a) Helium, He4
2 exists as a monoatomic gas whereas chlorine, Cl35
17 exists as a diatomic
gas. Explain why. [4 marks]
(b) Table 8.1 shows the proton number of magnesium, chlorine and carbon.
TABLE 8.1
(i) Carbon reacts with chlorine to form a compound.
What type of compound formed?
Draw the electron arrangement to show the chemical bond in the compound.
[3 marks]
(ii) Describe how ionic bond is formed between magnesium and chlorine atoms.
[7 marks]
(c) Figure 8 shows the set-up of apparatus to investigate the electrical conductivity of
solid and solution of sodium chloride, NaCl.
FIGURE 8
Table 8.2 shows the result of the two experiments.
TABLE 8.2
(i) Compare the electrical conductivity of solid and solution of sodium chloride,
NaCl. Explain why the results of Experiment I and II are different. [4 marks]
(ii) Calculate the mass of sodium chloride, NaCl in 50 cm3
of 0.2 moldm-3
sodium
chloride solution.
Given that the molar mass of NaCl = 58.5 gmol1
[2 marks]
Element Magnesium Chlorine Carbon
Proton
number
12 17 6
Experiment I II
Compound Sodium chloride Sodium chloride
State of compound Solid Aqueous
Observation Bulb does not light up Bulb lights up
Bulb
Electrode
carbon
Sodium
chloride
Electrode
carbon
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Section C
[20 marks]
Answer any one question.
The time suggested to answer this section is 30 minutes.
9 (a) Reactive metal can be extracted from its ore by electrolysis. Aluminium is a reactive
metal. State how aluminium can be extracted from its ore, which contains aluminium
oxide.
[4 marks]
(b) Daniell cell is an example of a voltaic cell. In this cell, zinc and copper are used as
electrodes. Explain how a Daniell cell can produce electric current.
Use a labelled diagram to explain your answer.
[6 marks]
(c) A student intends to electroplate an iron spoon with a suitable metal.
Design a laboratory experiment to electroplate the iron spoon.
Your answer should consist of the following:
Chemicals required
Procedure of the experiment
Diagram showing the set-up apparatus
Half equations involved in the reaction
Observations
[10 marks]
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Cation Anion test
10 (a) An insoluble salt can be prepared by the precipitation reaction.
Give an example of an insoluble salt and suggest two solutions to prepare the insoluble
salt.
Write the ionic equation to represent the precipitation reaction.
[4 marks]
(b) Figure 10 shows an incomplete flow chart of cation and anion tests for salt X.
FIGURE 10
Use the reagents listed below to confirm that salt solution of X contains Zn2+
ions and
SO4
2-
ions.
[6 marks]
(c) Copper(II) sulphate is a soluble salt. Describe how to prepare a dry sample of
copper(II) sulphate in the laboratory.
Your answer should consist of the following:
Chemicals required
Procedure of the preparation
Chemical equation involved in the reaction
[10 marks]
END OF QUESTION PAPER
SO4
2-
Zn2+
REAGENTS
Sodium hydroxide solution
Ammonia solution
Hydrochloric acid
Barium chloride solution
Salt solution
of X
26. 2
Marking Scheme Paper 2
Section A
Question
Number
Explanation Mark
1(a) A,B 1
(b) 2.8 1
(c) D3+
1
(d)(i) C 1
(ii) Form complex ions // Act as catalysts // Exhibit different oxidation
numbers
1
(e) E // H 1
(f) F, A, G, E, D, B 1
(g)(i) 2A + 2H2O 2AOH + H2 1
(ii) alkaline 1
(h) 1. Atom E has a smaller size
2. The attraction forces between nucleus and electrons are stronger
OR
1. Atom H has a bigger size
2. The attraction forces between nucleus and electrons are weaker.
1
1
2
1
1
Total 11
27. 3
Question
Number
Explanation Mark
2 (a) Formula that gives the actual number of atoms of each element that
are present in one molecule of the compound
1
(b) C6H12O6 1
(c) 1. No
2. Exits as molecules
1
1 2
(d) (i) C H O
1. Mole 52.2/ 12 13.0 /1 34.8/16
4.35 13.0 2.175
2. Ratio 2 6 1
3. Empirical formula = C2H6O
1
1
1 3
(ii) [2(12) + 6(1) + (16)]n = 46
n = 1
Molecular formula = C2H6O
1
1 2
Total 9
Question
Number
Explanation Mark
3(a)(i) Contact Process 1
(ii) Sulphur react with oxygen 1
(iii) Vanadium (V) oxide 1
(iv) 2 SO2 + O2 2SO3 1
(v) H2S2O7 1
(b)(i) Tin 1
(ii)
1
1
2
(iii) 1. Tin atoms with different size disturb the orderly arrangement
of copper atoms.
2. Tin atoms prevent the layer of copper atoms from sliding.
1
1 2
Total 10
Tin atom
Copper
atomsPure copper Brass
28. 4
Question
Number
Explanation Mark
4(a) Neutralization 1
(b) H2SO4 + 2KOH K2SO4 + H2O 1
(c)(i) K+
, OH-
, SO4
2-
1
(ii) K+
, SO4
2-
, H+
1
(d) 5.0 cm3
1
(e) 1. MaVa = a
MbVb b
2. 1.0 (5.0) = 1
Mb (25) 2
3. Mb = 2(1.0)(5.0) = 0.4 mol dm-3
25
1
1
1 3
(f) 1. 10.0 cm3
2. nitric acid is monoprotic acid / sulphuric acid is diprotic acid
1
1 2
Total 10
Question
Number
Explanation Mark
5(a) Chloride, hydroxide 1
(b) Electrical energy to chemical energy 1
(c)(i) Hydrogen 1
(ii) 2H+
+ 2e H2 1
(iii) 1. Lower a lighted wooden splinter
2. A “pop” sound is heard
1
1 2
(d) 1. Hydroxide ions // OH-
2. The concentration of hydroxide ions is higher
1
1 2
(e)(i) 30 / 0.03 / 0.00125
24000 24
1
(ii) 0.00125 x 6.02 x 1023
/ 7.525 x 1020
1
Total 10
29. 5
Question
Number
Explanation Mark
6(a) (i) Blue to red 1
(ii) H+
1
(b) 1. No
2. No water / H+
ions
1
1 2
(c) 1. Ethanoic acid is weak acid, hydrochloric acid is strong acid
2. The concentration of H+
ions in ethanoic acid is lower / The
concentration of H+
ions in hydrochloric acid is higher.
1
1 2
(d) CaCO3 + 2HCl CaCl2 + CO2 + H2O 1
(e) 1. [ Material : name of reactive metal / name of carbonate salt]
2. [To test gas produced]
3. [Observation]
Example 1
Procedure:
1. Magnesium ribbon is added into the aqueous solution X
2. Lower a lighted wooden splinter
Observation:
A “pop” sound is heard
Example 2
Procedure:
1. Calcium carbonate is added into the aqueous solution X
2. Passing the gas through lime water
Observation:
Lime water turns milky
1
1 2
1
1
1 2
1
1
1 2
1
Total 10
30. 6
Section B
Question
Number
Explanation Mark
7 (a) Melting point is the temperature at which a solid changes into a
liquid at a particular pressure.
Because the energy absorbed by the naphthalene is used to overcome
the forces of attraction between the molecules of naphthalene.
1
1
1
1 4
7(b) Before condensation
The kinetic energy is high
The particles are very far apart from each other
The attraction forces between particles are very weak.
During condensation
The kinetic energy decreases
The particles begin to move closer toward one another
/ the distance between the particles decrease
The attraction forces between particles become stronger.
After condensation
The kinetic energy is low
The particles are packed closely together in an orderly manner
The attraction forces between particles are strong.
1
1
1
1
1
1
1
1
1+1
1 10
7(c)(i) Proton number = 13
Nucleon number = 14 + 13 = 27
1
1 2
7(c)(ii)
Number of moles of Y =
27
8.10
= 0.4
Number of moles of Y2O3 = 0.4 ÷ 2 = 0.2
Relative formulas mass of Y2O3 = 2(27) + 3(16) = 102
Mass of Y2O3 = 0.2 102 = 20.4 g
1
1
1
1 4
Total 20
31. 7
Question
Number
Explanation Mark
8 (a) Helium atom has two electrons in its valence shell / helium atom
has achieved a duplet electron arrangement.
Helium atom will not gain, lose nor share electrons with other atoms.
Chlorine atom has an electron arrangement of 2. 8. 7, needs one
electron to achieve the octet electron arrangement.
Thus, two chlorine atoms share one pair of electrons so that both
atoms can achieve the octet electron arrangement.
1
1
1
1 4
8(b)(i) Covalent compound 1
1 + 1
3
8(b)(ii) A magnesium atom with an electron arrangement of 2.8.2 //
donates 2 valence electron to achieve the stable / octet electron
arrangement // 2. 8.
A positive magnesium ion, Mg2+
is formed.
Two chlorine atoms, each with an electron arrangement of 2.8.7
accepts 1 electron to achieve the stable octet electron arrangement//
2. 8. 8.
A negative chloride ion, Cl
is formed.
Mg2+
and Cl
ions are attracted to each other by a strong
electrostatic force.
1
1
1
1
1
1
1 7
8(c)(i) Solid sodium chloride cannot conduct electricity, sodium chloride
aqueous solution can conduct electricity.
In solid state, sodium ions and chloride ions are held together by
strong electrostatic forces // are fixed in their position
and cannot move freely.
In aqueous state, sodium ions and chloride ions are free to move.
This enables ions to be discharge at anode and cathode.
1
1
1
1 4
8(c)(ii) Number of moles of NaCl = 0.2 0.05 = 0.01
Mass of 0.01 mole of NaCl = 0.01 58.5 = 0.585 g
1
1 2
Total 20
C ClCl
Cl
Cl
32. 8
Section C
Question
Number
Explanation Mark
9 (a) Cryolite is added to aluminium oxide to lower its melting point.
Molten aluminium oxide is electrolysed using carbon electrodes.
Aluminium ions are discharged at cathode. // Al3+
+ 3e Al
Oxide ions are discharged at anode.// 2O2
O2 + 4e
1
1
1
1 4
9(b)
Zinc is more electropositive than copper.
Zinc atom releases electrons to form zinc ions, Zn2+
in zinc sulphate
solution.
//Zn(s) Zn2+
(aq) + 2e
The electrons flow from zinc electrode to copper electrode through
external circuit.
At the copper electrode, the electrons are accepted by the copper(II)
ions, Cu2+
to form copper atoms.
//Cu2+
(aq) + 2e Cu(s)
1+1
1
1
1
1 6
Zinc plate
Copper plate
Copper (II) sulphate solution
(1.0 moldm-3
)
Zinc sulphate solution
(1.0 moldm-3
) Salt bridge
33. 9
9(c) Silver can be used to electroplate the iron key.
The electrolyte is silver nitrate solution, [0.5 moldm-3
].
[or other suitable metal and electrolyte]
The silver electrode is connected to positive terminal of battery // act
as anode.
The iron spoon is connected to negative terminal of battery // act as
cathode.
The switch is turned on.
Anode
Half equation : Ag(s) Ag+
(aq) + e
Observation : Silver electrode becomes thinner.
Cathode
Half equation : Ag+
(aq) + e Ag(s)
Observation : A thin layer of shiny grey solid is deposited on the
iron spoon.
1
1
1
1
1+1
1
1
1
1
1 [11]
Max. 10
Total 20
Iron spoon
Silver
Silver nitrate solution,
0.5 moldm
-3
34. 10
Question
Number
Explanation Mark
10 (a) [Name any insoluble salt]
[Name any two suitable solution]
[Write correct ionic equation]
Example:
Lead(II) sulphate
Lead(II) nitrate solution and sodium sulphate solution
Pb2+
+ SO4
2
PbSO4
1
1+1
1 4
10(b) Test for Zn2+
ion
Procedure I:
A few drops of sodium hydroxide solution are added into the
salt solution of X until in excess.
Observation :
White precipitate dissolved in excess sodium hydroxide
solution to produce a colourless solution.
Procedure II:
A few drops of ammonia solution are added into the salt solution
of X until in excess.
Observation :
White precipitate dissolved in excess ammonia solution to
produce a colourless solution.
Inference:
Zn2+
ion is present
Test for SO4
2+
ion
5 cm3
of hydrochloric acid is added into the salt solution of X
follow by 2 cm3
of barium chloride solution.
Observation:
White precipitate is formed.
Inference:
SO4
2+
ion is present.
1
1
1
1
1
1 6
35. 11
10(c) Chemicals :
sulphuric acid and copper(II) oxide / copper(II) carbonate
50 cm3
of 1.0 moldm-3
sulphuric acid is pour into a beaker and
warmed carefully
Copper(II) oxide powder is added a little at a time into the acid
using spatula.
The mixture is stir well with a glass rod.
Copper(II) oxide powder is added continuously until some of it
no longer dissolves.
The mixture is filtered to remove the excess copper(II) oxide.
The filtrate is pour into an evaporating dish and heated gently to
produce a saturated solution / heated until the filtrate is
evaporated to about 1/3 of its original volume.
The saturated solution is then allowed to cool to room
temperature for crystallisation to occur.
The copper(II) sulphate crystals are filtered and dry by pressing
them between a few pieces of filter paper.
H2SO4 + CuO CuSO4 + H2O
1
1
1
1
1
1
1
1
1
1 [10]
Total 20
END OF MARKING SCHEME OF PAPER 2
