CHEMISTRY
Mock Exam Paper
HONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION
CHEMISTRY PAPER 1
(MOCK EXAMINATION)
Time allowed: 2 hours 30 minutes
This paper must be answered in English
GENERAL INSTRUCTIONS
1.
There are TWO sections, A and B, in this Paper. You are advised to finish Section A in about 45
minutes.
2.
Section A consists of multiple-choice questions in this question paper, while Section B contains
conventional questions printed separately in Question-Answer Book B.
3.
Answers to Section A should be marked on the Multiple-choice Answer Sheet while answers to Section
B should be written in the spaces provided in Question-Answer Book B. The Answer Sheet for Section
A and the Question-Answer Book for Section B will be collected separately at the end of the
examination.
4.
A Periodic Table is printed on the back of Question-Answer Book B. Atomic numbers and relative
atomic masses of elements can be obtained from the Periodic Table.
INSTRUCTIONS FOR SECTION A (MULTIPLE-CHOICE QUESTIONS)
1.
Read carefully the instructions on the Answer Sheet. Write your name, class and class number in the
space provided.
2.
When told to open this book, you should check that all the questions are there. Look for the words
‘END OF SECTION A’ after the last question.
3.
All questions carry equal marks.
4.
ANSWER ALL QUESTIONS. You are advised to use an HB pencil to mark all the answers on the
Answer Sheet, so that wrong marks can be completely erased with a clean rubber. You must mark the
answers clearly; otherwise you will lose marks if the answers cannot be captured.
5.
You should mark only ONE answer for each question. If you mark more than one answer, you will
receive NO MARKS for that question.
6.
No marks will be deducted for wrong answers.
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Mock Exam Paper 1
1
CHEMISTRY
Mock Exam Paper
This section consists of two parts. There are 24 questions in PART I and 12 questions in PART
II.
Choose the best answer for each question.
Candidates may refer to the Periodic Table printed on the back of Question-Answer Book B.
Part I
1.
2.
Element E forms an ionic compound with calcium and the formula of the compound is CaE2.
The ion of E has the same electronic arrangement as a magnesium ion. E could be
A.
fluorine.
B.
chlorine.
C.
carbon.
D.
sodium.
The following hazard warning label can be found on a reagent bottle containing an element.
The element could probably be
3.
A.
iodine.
B.
sulphur.
C.
mercury.
D.
bromine.
A fertilizer contains 52% by mass of sulphate ions. 2.0 g of this fertilizer is completely
dissolved in water and excess calcium nitrate solution is added to the resultant solution. What
is the mass of precipitate obtained?
(Relative atomic masses: O = 16.0, S = 32.1, Ca = 40.1)
A.
0.52 g
B.
1.04 g
C.
1.47 g
D.
2.83 g
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4.
X, Y and Z are three different metals. Some reactions of these metals and their oxides are
summarized below.
Metal
Adding the metal to HCl(aq)
Heating the metal oxide with H2(g)
X
No observable change
A silvery solid forms
Y
Colourless gas bubbles evolve
No observable change
Z
Colourless gas bubbles evolve
A silvery solid forms
Which of the following correctly shows the three metals in order of decreasing reactivity?
5.
6.
7.
8.
A.
Y, Z, X
B.
Z, Y, X
C.
Y, X, Z
D.
X, Z, Y
What is the systematic name of CH3CBr2CH=CHCH=CHCH3?
A.
2,2-dibromohepta-3,5-diene
B.
6,6-dibromohepta-3,5-diene
C.
2,2-dibromohepta-2,4-diene
D.
6,6-dibromohepta-2,4-diene
Which of the following preparations of salts usually involves the use of a burette and a pipette?
A.
Magnesium sulphate from magnesium carbonate and dilute sulphuric acid
B.
Sodium nitrate from sodium hydroxide solution and dilute nitric acid
C.
Lead(II) sulphate from lead(II) nitrate solution and sodium sulphate solution
D.
Iron(II) chloride from iron powder and dilute hydrochloric acid
Which of the following neutralization reactions would produce the largest temperature rise?
A.
50.0 cm3 of 2.0 M HNO3(aq) + 50.0 cm3 of 2.0 M NaOH(aq)
B.
100.0 cm3 of 2.0 M HNO3(aq) + 50.0 cm3 of 2.0 M NaOH(aq)
C.
50.0 cm3 of 1.0 M HNO3(aq) + 50.0 cm3 of 1.0 M NaOH(aq)
D.
50.0 cm3 of 2.0 M HNO3(aq) + 100.0 cm3 of 2.0 M NaOH(aq)
Which of the following statements concerning a hydrogen-oxygen fuel cell is correct?
A.
An external power supply is used to recharge the cell.
B.
Water forms at the anode.
C.
The cell uses oxygen as the fuel.
D.
Gaseous products are recycled into the cell.
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9.
25.0 cm3 of 0.55 M iron(III) sulphate solution is diluted to 500.0 cm3. What is the
concentration of iron(III) ions in the diluted solution?
A.
0.011 M
B.
0.028 M
C.
0.055 M
D.
0.083 M
10. 20.0 cm3 of a 0.20 M acid solution requires 24.0 cm3 of 0.50 M potassium hydroxide solution
for complete neutralization. What is the basicity of the acid?
A.
1
B.
2
C.
3
D.
4
11. Which of the following molecules have the same shape as a water molecule?
A.
NCl3
B.
CS2
C.
BF3
D.
SCl2
12. Consider the following set-up:
dry gas
moist gas
drying agent
Which of the following combinations about the gas to be dried and the drying agent used is
correct?
Gas
Drying agent
A.
Chlorine
Concentrated hydrochloric acid
B.
Hydrogen
Concentrated hydrochloric acid
C.
Ammonia
Concentrated sulphuric acid
D.
Sulphur dioxide
Concentrated sulphuric acid
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13. Astatine is a Group VII element in the Periodic Table. Which of the following combinations
about astatine is correct?
Physical state under room conditions
Reaction with NaI(aq)
A.
solid
the solution turns brown
B.
solid
no observable change
C.
liquid
no observable change
D.
liquid
the solution turns brown
14. What is the stoichiometric coefficient of Zn(s) when the following equation is balanced?
__Zn(s) + __VO2+(aq) + 8H+(aq)  __Zn2+(aq) + __V2+(aq) + __H2O(l)
A.
1
B.
2
C.
3
D.
4
15. Consider the following set-up.
limewater
gas G
ice-water bath
tube A
tube B
When G is burnt, a colourless liquid is collected in tube A but there is no observable change in
tube B. G could be
A.
hydrogen.
B.
methane.
C.
town gas.
D.
liquefied petroleum gas.
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16. Solution S gives a dark brown precipitate when mixed with aqueous ammonia. The precipitate
dissolves in excess aqueous ammonia to give a colourless solution. Which of the following
cations may solution S contain?
A.
Aluminium ion
B.
Iron(II) ion
C.
Iron(III) ion
D.
Silver ion
17. Which of the following compounds contain both ionic bonds and covalent bonds?
(1) Calcium carbonate
(2) Potassium nitrate
(3) Ammonium bromide
A.
(1) and (2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
18. Which of the following equations represent the propagation steps of the substitution reaction of
methane with bromine?
(1) CH3• + HBr  CH3Br + H•
(2) CH3• + Br2  CH3Br + Br•
(3) CH3Br + Br•  CH2Br• + HBr
A.
(1) and (2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
19. Sodium hydroxide pellets are NOT used as primary standards because
(1) they are corrosive.
(2) they absorb water vapour from air.
(3) sodium hydroxide has a low formula mass.
A.
(1) only
B.
(2) only
C.
(1) and (3) only
D.
(2) and (3) only
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20. Consider the following set-up.
iron wool
air
water
After a few days, the water level in the test tube rose. Which of the following statements
concerning the experiment is/are correct?
(1) The iron wool turned black.
(2) A redox reaction occurred inside the test tube.
(3) The pressure inside the test tube increased.
A.
(1) only
B.
(2) only
C.
(1) and (3) only
D.
(2) and (3) only
21. A clear colourless solution contains Ba2+(aq), Ag+(aq) and one anion X. Anion X would be
(1) NO3(aq).
(2) SO42(aq).
(3) Cl(aq).
A.
(1) only
B.
(2) only
C.
(1) and (3) only
D.
(2) and (3) only
22. Aluminium is commonly used in making soft drink cans because
(1) it has a low density.
(2) it is a good conductor of electricity.
(3) it is corrosion resistant.
A.
(1) and (2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
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23. The following diagram shows a set-up for the electrolysis of 1.0 M A(aq) and 1.0 M B(aq). All
the electrodes (W, X, Y and Z) are made of platinum.
W
X
Y
Z
B(aq)
A(aq)
cell I
cell II
During electrolysis, the mass of X and that of Z increase. The increase in mass of X and that of
Z are different. Which of the following statements must be correct?
(1) X and Z are the cathodes.
(2) The number of electrons flowing in cell I is greater than that in cell II.
(3) The cation in A(aq) is lower than the cation in B(aq) in the Electrochemical Series.
A.
(1) only
B.
(2) only
C.
(1) and (3) only
D.
(2) and (3) only
24. Consider the following statements and choose the best answer:
1st statement
2nd statement
Sulphur dioxide is an oxidizing agent
when it reacts with acidified potassium
permanganate solution.
Sulphur dioxide is soluble in water.
A.
Both statements are true and the 2nd statement is a correct explanation of the 1st
statement.
B.
Both statements are true but the 2nd statement is NOT a correct explanation of the
1st statement.
C.
The 1st statement is false but the 2nd statement is true.
D.
Both statements are false.
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Part II
Concentration / mol dm3
25. The concentration-time graph for a reaction in a sealed flask is shown below.
C(g)
B(g)
A(g)
Time / s
Which of the following chemical equations correctly represents the reaction?
A.
A(g) + B(g)
3C(g)
B.
A(g) + 3B(g)
C.
2A(g) + 2B(g)
3C(g)
D.
7A(g) + 5B(g)
6C(g)
6C(g)
26. What is the purpose of adding saturated sodium chloride solution in the preparation of soap?
A.
To speed up the saponification
B.
To reduce the solubility of soap in water
C.
To make the soap harder
D.
To form a stable emulsion with water
27. Beaker A contains 100 cm3 of 1.0 M HCl(aq) while beaker B contains 50 cm3 of 1.0 M
H2SO4(aq). Equal masses of iron powder are added to the two beakers respectively. Some iron
powder is left in the two beakers after the reaction. Which of the following statements
concerning the experiment is correct?
A.
The acids in the two beakers have the same basicity.
B.
The reactions occurred in the two beakers have the same initial rate.
C.
The final concentrations of iron(II) ions in the two beakers are the same.
D.
The same volume of hydrogen, measured at the same temperature and pressure, is
released in the two beakers.
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28. At 25C, the equilibrium constant, Kc, for the following reaction is 41.
X2(g) + Y2(g)
2XY(g)
The initial concentrations of X2(g), Y2(g) and XY(g) are 0.04 mol dm3, 0.02 mol dm3 and 0.06
mol dm3 respectively. What is the concentration of XY(g) when the system attains equilibrium
at 25C?
A.
0.013 M
B.
0.053 M
C.
0.073 M
D.
0.087 M
29. Cinnamic acid is a carbon compound that can be found in some plants. The structure of
cinnamic acid is shown below.
Which of the following reagents would react with cinnamic acid under the conditions given?
H2, Pt
NaBH4(aq)
Heat with CH3CH2OH (in the
presence of conc. H2SO4)
A.
no
yes
no
B.
yes
no
no
C.
yes
no
yes
D.
no
yes
yes
30. Consider the following three reactions at equilibrium.
Reaction
NH3(aq) + H+(aq)
+
NH4 (aq)
NH3(aq) + H2O(l)

H2O(l)
Equilibrium constant
K
NH4+(aq) + OH(aq)
+
K1
K2
OH (aq) + H (aq)
Which of the following expressions is correct?
A.
K=
B.
K=
K2
K1
K1
C.
K2
K = K1K2
D.
K=
1
K1K2
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31. Which of the following statements concerning aluminium oxide is/are correct?
(1) Aluminium atoms and oxygen atoms are held together by covalent bonds.
(2) It is soluble in sodium hydroxide solution.
(3) When aluminium oxide is added to water, the pH of the resultant mixture is greater than
7.
A.
(1) only
B.
(2) only
C.
(1) and (3) only
D.
(2) and (3) only
32. Which of the following compounds can be produced from propene as the major product?
(1) 1,2-dichloropropane
(2) propane-1,2-diol
(3) 1-chloropropane
A.
(1) and (2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
33. Oxandrolone is a synthetic hormone. The structure of oxandrolone is shown below.
Which of the following statements concerning oxandrolone are correct?
(1) It has seven chiral carbon atoms.
(2) It turns acidified potassium dichromate solution from orange to green.
(3) It can be hydrolysed by dilute sulphuric acid on heating.
A.
(1) and (2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
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34. Molecule A, H2NCH2CH2CH2CH2COOH, forms a polymer in which the polymer chains
contain 1000 repeating units on average. Which of the following statements about the polymer
formed is/are correct?
(Relative atomic masses: H = 1.0, C = 12.0, N = 14.0, O = 16.0)
(1) Molecule A undergoes addition polymerization to form the polymer.
(2) The polymer chains contain amide linkages.
(3) The approximate relative molecular mass of a polymer chain is 99000.
A.
(1) only
B.
(2) only
C.
(1) and (3) only
D.
(2) and (3) only
35. Consider the reaction between sodium thiosulphate solution and dilute hydrochloric acid.
Na2S2O3(aq) + 2HCl(aq)  2NaCl(aq) + SO2(g) + S(s) + H2O(l)
Which of the following properties can be measured in order to follow the progress of the
reaction?
(1) Electrical conductivity of the reaction mixture
(2) Pressure of the reaction system
(3) Volume of the gaseous product
A.
(1) only
B.
(2) only
C.
(1) and (3) only
D.
(2) and (3) only
36. Consider the following statements and choose the best answer:
1st statement
2nd statement
Under room conditions, carbon has the
highest electrical conductivity among
the Period 2 elements.
Graphite can conduct electricity under
room conditions.
A.
Both statements are true and the 2nd statement is a correct explanation of the 1st
statement.
B.
Both statements are true but the 2nd statement is NOT a correct explanation of the
1st statement.
C.
The 1st statement is false but the 2nd statement is true.
D.
Both statements are false.
END OF SECTION A
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CHEMISTRY
Mock Exam Paper
B
Name
HONG KONG DIPLOMA OF SECONDARY EDUCATION
EXAMINATION
CHEMISTRY
Class
Class no.
(MOCK EXAMINATION)
SECTION B : Question-Answer Book B
This paper must be answered in English.
INSTRUCTIONS FOR SECTION B
(1) Write your name, class and class number in the space
provided on this page.
Question
No.
Marks
1
2
(2) Refer to the general instructions on the cover of the
Question Paper for Section A.
3
4
(3) This section consists of TWO parts, Part I and
Part II.
(4) Answer ALL questions in both Parts I and II. Write your
answers
in the spaces provided in this
Question-Answer Book. Do not write in the margins.
Answers written in the margins will not be marked.
5
6
7
8
9
(5) An asterisk (*) has been put next to the questions
where one mark will be awarded for effective
communication.
10
11
12
(6) Supplementary answer sheets will be provided on
request. Write your name, class, class number and
question number on the answer sheets and fasten
them with a string INSIDE this Question-Answer Book.
13
Total
(7) No extra time will be given to you for filling in your
name, class and class number in the Question-Answer
Book after the ‘Time is up’ announcement.
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Mock Exam Paper
PART I
Answer ALL questions. Write your answers in the spaces provided.
1.
Magnesium sulphide forms by the reaction between magnesium and sulphur.
Mg + S  MgS
(a) State the appearance of magnesium sulphide under room conditions.
(1 mark)
(1 mark)
(c) By using the oxidation number concept, identify the oxidizing agent in the reaction
between magnesium and sulphur.
(1 mark)
(d) When magnesium sulphide is added to water, hydrogen sulphide and magnesium
hydroxide form.
(i)
Write a chemical equation for the reaction between magnesium sulphide and water.
(ii) In terms of bonding and structure, explain why hydrogen sulphide exists as a gas
while magnesium hydroxide exists as a solid under room conditions.
(3 marks)
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Answers written in the margins will not be marked.
(b) Draw the electron diagram for magnesium sulphide, showing ELECTRONS IN THE
OUTERMOST SHELLS only.
CHEMISTRY
Mock Exam Paper
2.
Limestone is a common rock that contains calcium carbonate.
(a) Besides limestone, name another rock that contains calcium carbonate.
(1 mark)
Step 1:
Dissolve 0.750 g of finely ground limestone sample in 25.0 cm3 of 1.00 M
hydrochloric acid in a conical flask.
Step 2:
Heat and stir the reaction mixture until all the limestone has been dissolved.
Step 3:
Titrate the reaction mixture with 0.50 M sodium hydroxide solution.
Phenolphthalein is used as an indicator. 27.05 cm3 of sodium hydroxide solution
is required for complete reaction.
(i)
Name the apparatus used to grind the limestone sample.
(ii) How do you know that all calcium carbonate in the limestone has been reacted
completely?
(iii) State the colour change at the end point of the titration.
(iv) Calculate the percentage by mass of calcium carbonate in the limestone sample.
(Relative atomic masses: C = 12.0, O = 16.0, Ca = 40.1)
(6 marks)
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Answers written in the margins will not be marked.
(b) Standard hydrochloric acid is used to determine the percentage by mass of calcium
carbonate in a limestone sample. The procedure is outlined below.
CHEMISTRY
Mock Exam Paper
3.
The diagram below shows how a steel pipeline is protected from rusting.
power
ground
steel pipeline
graphite blocks
(1 mark)
(b) Explain how this method can protect the steel pipeline from rusting.
(2 marks)
(c) The steel pipeline can also be protected from rusting by connecting it to another metal.
Suggest what the metal can be and explain how the metal can protect the steel pipeline
from rusting with the aid of a half equation.
(3 marks)
(d) The following reduction half equations are extracted from the Electrochemical Series:
O2(g) + 2H2O(l) + 4e
4OH(aq)
(higher in the Electrochemical Series)
O2(g) + 4H+(aq) + 4e
2H2O(l)
(lower in the Electrochemical Series)
Explain why iron will rust faster in acidic medium than in neutral medium.
(1 mark)
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Answers written in the margins will not be marked.
(a) Name the above method of rust prevention.
CHEMISTRY
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4.
A simple chemical cell is connected to a voltmeter as shown in the diagram below.
salt bridge
silver electrode
zinc electrode
100.0 cm3 of 1.0 M
AgNO3(aq)
100.0 cm3 of 1.0 M
Zn(NO3)2(aq)
(a) State the function of the salt bridge in the set-up.
(b) Identify the anode of this chemical cell.
(1 mark)
(c) Write the ionic equation for the overall cell reaction.
(1 mark)
(d) The initial mass of the zinc electrode is 8.0 g and that of the silver electrode is 10.0 g.
After a period of time, the zinc electrode is removed from the electrolyte solution, washed
with distilled water and dried. The mass of the zinc electrode has changed by 2.00 g.
(i)
Calculate the final mass of the silver electrode.
(Relative atomic masses: Zn = 65.4, Ag = 107.9)
(ii) Calculate the final concentration of silver ions in the right half cell.
(4 marks)
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Answers written in the margins will not be marked.
(1 mark)
CHEMISTRY
Mock Exam Paper
5.
Petrol is commonly used as the fuel for motor cars. Cracking is an important process in industry
because it can produce extra petrol. The following diagram shows the set-up used to
demonstrate cracking in the laboratory.
broken pieces of porous pot
glass wool soaked
with liquid
paraffin
gaseous
product
heat
water
(1 mark)
(b) Besides cracking, suggest a method that can be used to obtain petrol in industry.
(1 mark)
(c) Explain why the gaseous products can be collected by the method as shown in the
diagram.
(1 mark)
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Answers written in the margins will not be marked.
(a) What is meant by the term ‘cracking’?
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5.
(d) The following equation represents a reaction occurred during cracking.
C18H38(l)  C11H22(l) + Y(l) + Z(g)
It is known that Y is a liquid saturated hydrocarbon. Deduce what Z is.
(2 marks)
Answers written in the margins will not be marked.
(i)
Write the half equation for the reaction that takes place at each of the following
terminal when a hydrogen-oxygen fuel cell is operating.
(1) Positive terminal
(2) Negative terminal
(ii) Apart from the risk of an explosion, state one disadvantage of using hydrogen over
using petrol as a fuel for a car.
(3 marks)
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(e) Besides petrol, cars can be powered by hydrogen-oxygen fuel cells.
CHEMISTRY
Mock Exam Paper
A student performs an experiment to determine the enthalpy change of combustion of
propanone. A metal can is used as a calorimeter. The diagram below shows an incomplete
set-up for the experiment.
Answers written in the margins will not be marked.
water
metal can
The experimental results are listed in the table below.
Mass of propanone burnt
1.16 g
Volume of water in the metal can
200 cm3
Initial temperature of water
23.0C
Maximum temperature of water
66.5C
(a) Add suitable drawing and labels to the above diagram to show how the experiment can be
carried out.
(2 marks)
(b) Calculate the energy (in kJ) produced by the combustion of propanone.
(Density of water = 1.0 g cm3; specific heat capacity of water = 4.2 J g1 K1)
(1 mark)
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6.
CHEMISTRY
Mock Exam Paper
6.
(c) Calculate the enthalpy change of combustion of propanone.
(Relative atomic masses: H = 1.0, C = 12.0, O = 16.0)
(1 mark)
(d) The standard enthalpy changes of formation of CO2(g) and H2O(l) are as follows:
Answers written in the margins will not be marked.
Construct an enthalpy change cycle to calculate the standard enthalpy change of formation
of propanone.
(3 marks)
(e) Calculate the energy generated when 1 kg of carbon dioxide is released from the
combustion of propanone.
(Relative atomic masses: C = 12.0, O = 16.0)
(2 marks)
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ΔHfꝋ / kJ mol1
393.5
285.8
Compound
CO2(g)
H2O(l)
CHEMISTRY
Mock Exam Paper
7.
A student proposed using the method shown in the diagram below to dilute concentrated
sulphuric acid.
distilled
water
concentrated sulphuric acid
(1 mark)
(b) The following shows the simplified electron diagram for a sulphuric acid molecule (only
the outermost shell electrons are shown).
Explain whether a sulphuric acid molecule obey the octet rule.
(1 mark)
(c) (i)
Explain why it is dangerous to dilute concentrated sulphuric acid using the method
proposed by the student.
(ii) Describe how the student should dilute concentrated sulphuric acid properly.
(2 marks)
(d) After dilution, the student forgot to label the diluted sulphuric acid. Suggest how you could
distinguish a beaker of concentrated sulphuric acid and a beaker of dilute sulphuric acid.
State the expected observation.
(2 marks)
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(a) Circle TWO hazard warning labels that should be shown on a reagent bottle containing
concentrated sulphuric acid.
CHEMISTRY
Mock Exam Paper
*8. Three unlabelled reagent bottles each contains one of the following colourless solutions:
•
potassium carbonate solution
•
calcium nitrate solution
•
lead(II) nitrate solution
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Answers written in the margins will not be marked.
You are allowed to use one additional reagent only. Suggest how you would carry out a
chemical test to distinguish the three solutions. Write the ionic equations for the reactions
involved.
(6 marks)
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CHEMISTRY
Mock Exam Paper
PART II
Answer ALL questions. Write your answers in the spaces provided.
9.
The oxidation of oxalate ions gives carbon dioxide only. To study the reaction between acidified
potassium dichromate solution and oxalate ions, a student added an excess of acidified
potassium dichromate solution to 120 cm3 of 0.1 M oxalic acid (H2C2O4).
(a) State an expected observation in the reaction.
(1 mark)
(1 mark)
(c) Hence, illustrate one characteristic of transition metals exhibited by chromium.
(1 mark)
(d) The progress of the reaction can be followed by measuring the mass of the reaction
mixture.
(i)
Calculate the theoretical volume of carbon dioxide released (measured at room
temperature and pressure) in the reaction.
(Molar volume of gas at room temperature and pressure = 24 dm3 mol1)
(ii) The actual volume of carbon dioxide released is lower than the theoretical value.
Suggest why.
(3 marks)
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Answers written in the margins will not be marked.
(b) Write a chemical equation for the redox reaction between acidified potassium dichromate
solution and oxalate ions.
CHEMISTRY
Mock Exam Paper
10. A mixture of carbon monoxide (CO), chlorine (Cl2) and phosgene (COCl2) was placed in a
closed container. The concentration-time graph for the reaction system is shown below.
Cl2(g) + CO(g)
CO(g)
Cl2(g)
COCl2(g)
Time / min
(a) Determine the equilibrium constant Kc for the reaction at the 3rd min.
(1 mark)
st
(b) At the 1 min, the temperature of the container was increased. With reference to the graph,
explain whether the decomposition of phosgene is exothermic or endothermic.
(2 marks)
(c) Deduce what has been done to the system at the following instant:
(i)
At the 4th min
(ii) At the 6th min
(3 marks)
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Concentration / mol dm3
COCl2(g)
CHEMISTRY
Mock Exam Paper
11. Butan-2-ol can be prepared by mixing butanone and reagent X in water. The structure of
butan-2-ol is shown below.
(1 mark)
(b) Name the type of reaction between butanone and reagent X.
(1 mark)
(c) Butan-2-ol is optically active.
(i)
In the above diagram, label the chiral carbon(s) of the molecule by using a ‘*’.
(ii) Name the instrument that can be used to measure the optical activity of a compound.
(2 marks)
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Answers written in the margins will not be marked.
(a) Suggest what reagent X is.
CHEMISTRY
Mock Exam Paper
11. (d) When passing butan-2-ol vapour over hot aluminium oxide, a mixture (consisting of two
compounds) forms. The mixture is collected by displacement of water.
Draw a labelled diagram for the set-up used in the experiment.
(ii) What is the isomeric relationship between the two compounds in the mixture?
(3 marks)
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(i)
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Melting point
12. The following diagram shows the variation in melting points of elements across Period 3 of the
Periodic Table.
Si
P
S
Cl
Ar
(a) Explain why the melting point of magnesium is higher than that of sodium.
(2 marks)
(b) Do you expect that the electrical conductivity of the elements in Period 3 shows a similar
pattern of variation as the melting point? Explain briefly.
(2 marks)
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Na Mg Al
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*13. The diagram below shows the structure of sodium stearate.
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Answers written in the margins will not be marked.
Explain the emulsifying property of sodium stearate in terms of its structure.
(5 marks)
END OF SECTION B
END OF PAPER
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Mock Exam Paper
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