2019-DSE
CHEM
PAPER 1A
Candidate Number :
HONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION 2019
MOCK EXAM
CHEMISTRY
PAPER 1
13 February 2019
8.25 am – 10.55 am (2 hours and 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 page 20 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 and insert the information required in the spaces
provided (including shading the boxes for Class and Class No).
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
answer 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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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 page 20 of Question-Answer Book B.
PART I
1.
Which of the following has a sharp boiling point ?
A.
B.
C.
D.
2.
kerosene
vinegar
acetone
lubricating oil
Limewater can be prepared from limestone through the processes as shown below :
Limestone
Process 1
Substance A
Process 2
Limewater
Which of the following combinations is correct ?
A.
B.
C.
D.
3.
Substance A
quicklime
slaked lime
calcium chloride
calcium chloride
Process 2
add water
add water
add dilute sodium hydroxide solution
add water
Which substance has the following properties ?
•
•
•
low melting point
very soluble in water
does not conduct electricity when molten
A.
B.
C.
D.
4.
Process 1
strong heating
strong heating
add dilute hydrochloric acid
add dilute hydrochloric acid
silicon carbide, SiC
glucose, C6H12O6
sodium chloride, NaCl
tetrachloromethane, CCl4
Which of the following compounds is arranged in order of increasing boiling point ?
A.
B.
C.
D.
H2S < CH4 < H2O
CH4 < H2S < H2O
CH4 < H2O < H2S
H2S < H2O < CH4
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5.
Which combination best describes the type of bonding present and the melting point of silicon and silicon
dioxide ?
A.
B.
C.
D.
6.
silicon
ionic bonding
high melting point
metallic bonding
high melting point
covalent bonding
high melting point
covalent bonding
low melting point
Aluminium can be obtained from the electrolysis of a molten mixture of alumina (Al2O3) and cryolite (Na3AlF6).
Which of the following correctly describes the oxidation number of Al in Al2O3 and in Na3AlF6 and the electrode
at which aluminium is produced during the electrolysis ?
O.N. of Al in Al2O3
+2
+2
+3
+3
A.
B.
C.
D.
7.
silicon dioxide
ionic bonding
low melting point
covalent bonding
low melting point
covalent bonding
high melting point
ionic bonding
high melting point
O.N. of Al in Na3AlF6
+2
+3
+2
+3
Electrode at which Al is produced
anode
cathode
anode
cathode
Two experiments are performed on three different metals, X, Y and Z, and their oxides.
X
Action of metal on
zinc sulphate solution
Action of heat on
metal oxide
Y
Z
No observable change
A gas is given off
No observable change
A solid with metallic
lustre is formed
No observable change
No observable change
Which of the following arrangements represents the order of increasing reactivity of the three metals ?
A.
B.
C.
D.
8.
X<Z<Y
Y<X<Z
Y<Z<X
Z<X<Y
When pyrite, FeS2, is roasted in air, the following reaction takes place.
4FeS2(s) + 11O2(g) → 2Fe2O3(s) + 8SO2(g)
Roasting 60.0 g of the ore produces 36.7 g of iron(III) oxide. What is the percentage by mass of FeS2 in the
pyrite ? (Relative atomic masses: O = 16.0, S = 32.1, Fe = 55.8)
A.
B.
C.
D.
27.6 %
46.0 %
55.2 %
92.0 %
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9.
Which of the following methods can be used to distinguish between 0.1 mol dm-3 HCl(aq) and 0.1 mol dm-3
CH3COOH(aq) ?
(1)
(2)
(3)
Use each solution as electrolyte in the set-up shown below and compare the brightness of the bulb.
Adding magnesium ribbons of the same length to each solution and compare the volume of gas evolved.
Add 10 cm3 of 0.1 mol dm-3 NaOH(aq) to 10 cm3 of each acid solution and compare the temperature
change.
graphite electrode
graphite electrode
electrolyte solution
A.
B.
C.
D.
10.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
When an alkaline manganese cell discharges, the following reactions occur at its electrodes :
Reaction 1:
Reaction 2:
Zn(s) + 2OH(aq)  ZnO(s) + H2O(l) + 2e
2MnO2(s) + H2O(l) + 2e  Mn2O3(s) + 2OH(aq)
Which of the following statements are correct ?
(1)
(2)
(3)
Zinc is the reducing agent.
Reaction 2 occurs at the cathode.
The amount of hydroxide ions in the cell decreases when the cell discharges.
A.
B.
C.
D.
11.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
Which of the following is endothermic ?
A.
B.
C.
D.
N2(g) → N2(l)
ZnCO3(s) + 2H+(aq) → Zn2+(aq) + H2O(l) + CO2(g)
C10H22(l) → C2H6(g) + C6H12(l) + C2H4(g)
2C4H10(g) + 13O2(g) → 8CO2(g) + 10H2O(l)
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12.
The following set-up shows two electrolytic cells, X and Y, connected in series.
of graphite while electrodes R and S are made of copper.
Electrodes P and Q are made
cell Y
cell X
R
S
Q
P
Which of the following statements concerning the set-up is INCORRECT ?
A.
B.
C.
D.
13.
The solution around electrode P turns blue.
The theoretical volume ratio of the two gases collected in cell X is 1 : 1.
Colourless gas bubbles evolve at electrode S.
The pH value of the solution in cell Y remains unchanged during electrolysis.
Consider the solutions W, X, Y and Z below :
W
100 cm3 of 0.20 M HCl(aq)
X
50 cm3 of 0.20 M HNO3(aq)
Y
100 cm3 of 0.20 M H2SO4(aq)
Z
50 cm3 of 0.20 M KOH(aq)
Which of the following statements is correct ?
A.
B.
C.
D.
14.
The pH of Y equals 2 × (–log 0.2).
Mixing W and Z gives a neutral solution.
The pH of the mixture of W and Y is the same as that of W.
The pH of the mixture of W and X is the same as that of W.
In the reaction between ethane with chlorine, which of the following is NOT involved in the propagation step ?
A.
B.
C.
D.
CH3CH3 + Cl  CH3CH2 + HCl
CH3CHCl + Cl2  CH3CHCl2 + Cl
CH3CH2 + Cl2  CH3CH2Cl + Cl
CH3CHCl + Cl  CH3CHCl2
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15.
Different volumes of aqueous sodium phosphate was added to 12.0 cm3 of an aqueous solution of the nitrate of
metal T. The concentration of both solutions was 1.00 mol dm-3. When the precipitate had settled, its height
was measured. What is the formula of the phosphate of metal T ?
Volume of sodium phosphate solution / cm3
A.
B.
C.
D.
16.
Which of the following can distinguish a sample of AgNO3(aq) from a sample of NaNO3(aq) ?
(1)
(2)
(3)
adding MgCl2(aq) to the samples
adding zinc granules to the samples
adding KOH(aq) to the samples
A.
B.
C.
D.
17.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
Which of the following equations do the enthalpy change of neutralization apply to ?
(1)
(2)
(3)
NH3(aq) + HCl(aq) → NH4Cl(aq)
HI(aq) + NaOH(aq) → NaI(aq) + H2O(l)
Ca(OH)2(aq) + H2SO4(aq) → CaSO4(s) + 2H2O(l)
A.
B.
C.
D.
18.
TPO4
T3(PO4)2
T3PO4
T2(PO4)3
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
Consider the following reaction :
5CO(g) + I2O5(s)
I2(g) + 5CO2(g)
What is the unit of the equilibrium constant for the equilibrium system ?
A.
B.
C.
D.
no unit
mol dm3
mol1 dm3
mol2 dm6
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19.
The standard enthalpy changes of neutralization between different strong acids and different alkalis are given
below :
Acid A + Alkali X
–56.3
Acid A + Alkali Y
–50.4
Acid B + Alkali Y
–52.6
Acid B + Alkali Z
–54.5
Which of the following statements is true concerning the strength of alkalis X, Y and Z ?
A.
B.
C.
D.
20.
Z>X>Y
Y>Z>X
X>Z>Y
X>Y>Z
Graphene is an individual single layer of graphite. Its structure is shown below :
Which of the following statements concerning graphene is / are correct ?
(1)
(2)
(3)
It is a strong material.
It cannot conduct electricity.
It has a low melting point.
A.
B.
C.
D.
21.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
A mixture of 40 cm3 of methane and 100 cm3 of oxygen at room temperature and pressure is ignited. After
complete combustion, the resulting mixture is cooled to room temperature and pressure. What is the final
volume of the mixture ?
A.
B.
C.
D.
40 cm3
60 cm3
120 cm3
140 cm3
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22.
One of the allotropes of phosphorus is white phosphorus (P4).
white phosphorus molecule.
The following diagram shows the structure of a
Which of the following statements about white phosphorus is INCORRECT ?
(Relative atomic mass: P = 31.0)
A.
B.
C.
D.
23.
The oxidation number of phosphorus in P4 is 0.
Each phosphorus atom in P4 is joined to three other phosphorus atoms by single covalent bond.
Covalent bonds are present between the white phosphorus molecules.
The mass of one mole of P4 is 124.0 g.
The x-axis of the graph below represents the atomic number of the elements in Period 3.
Which variable could represent the y-axis ?
A.
B.
C.
D.
24.
melting point
electronegativity
electrical conductivity
density
Consider the following statements and choose the best answer :
1st statement
2nd statement
Sulphur trioxide is a non-polar molecule.
Sulphur trioxide does not obey the octet rule.
A.
B.
C.
D.
Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
Both statements are true but the 2nd statement is NOT a correct explanation of the 1st
statement.
The 1st statement is false but the 2nd statement is true.
Both statements are false.
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PART II
25.
In which of the following experiments can the progress of the reaction be best followed by using an electronic
balance ?
A.
B.
C.
D.
26.
Adding a piece of zinc to copper(II) sulphate solution
Adding a piece of magnsium to dilute hydrochloric acid.
Mixing silver nitrate solution with sodium chloride solution
Decomposing hydrogen peroxide solution in the presence of manganese(IV) oxide
In the following graph, curve X was obtained by following the progress of reaction between excess calcium
carbonate powder and 100 cm3 of 0.80 M hydrochloric acid at 25C.
Volume of CO2
Y
X
Time
Which of the following changes of the experimental conditions would give curve Y ?
(1)
(2)
(3)
Using excess calcium carbonate granules
Using 200 cm3 of 0.50 M hydrochloric acid
Lowering the temperature to 15C
A.
B.
C.
D.
27.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
50 cm3 of sodium thiosulphate solution is allowed to react with 50 cm3 of dilute hydrochloric acid according to
the following equation.
S2O32-(aq) + 2H+(aq)  SO2(g) + H2O(l) + S(s)
If the average rate of formation of sulphur is 0.05 mol min-1, what is the average rate of consumption of dilute
hydrochloric acid in mol dm-3 min-1 ?
A.
B.
C.
D.
0.05 mol dm-3 min-1
0.1 mol dm-3 min-1
0.5 mol dm-3 min-1
1 mol dm-3 min-1
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28.
The structure of a carbon compound is shown below :
Which of the following statements concerning the compound is correct ?
A.
B.
C.
D.
29.
It exhibits cis-trans isomerism.
It can separately turn Br2(aq) and acidified KMnO4(aq) colourless.
It gives a single product when heated with concentrated sulphuric acid.
It can be oxidized to form a carboxylic acid.
Consider the following two compounds :
X
Y
Which of the following statements is INCORRECT ?
A.
B.
C.
D.
30.
The solubility of X in water is lower than that of Y.
Hydrogen bonds exist between the molecules in X and in Y.
X and Y are functional group isomers.
Both X and Y do not react with acidified potassium dichromate solution.
Consider the structure of phenolphthalein shown below :
Which of the following statements about phenolphthalein is INCORRECT ?
A.
B.
C.
D.
It is an achiral molecule.
It contains 20 carbon atoms.
It undergoes alkaline hydrolysis when heating with sodium hydroxide solution.
It undergoes addition reaction when mixed with bromine (in CH3CCl3).
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31.
The structure of lactic acid is shown below :
Which of the following types of reactions can lactic acid undergo ?
(1)
(2)
(3)
Oxidation when reacting with acidified potassium permanganate solution
Esterification when heating with an alcohol or a carboxylic acid in the presence of concentrated
sulphuric acid
Condensation polymerization when heated under suitable conditions
A.
B.
C.
D.
32.
Which of the following statements about aspirin is / are correct ?
(1)
(2)
(3)
It is used to relieve toothache and reduce fever.
It should be taken regularly at high doses as it can prevent heart attack.
The ester group in aspirin can undergo acid hydrolysis in stomach.
A.
B.
C.
D.
33.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1) only
(2) only
(1) and (3) only
(2) and (3) only
Consider the following equilibrium :
Ag+(aq) + Br(aq)
AgBr(s)
Kc = 1.30 × 1012 mol2 dm6
If the equilibrium concentration of silver ion is 4.13 × 108 mol dm3, what is the equilibrium concentration of
bromide ion ?
A.
B.
C.
D.
1.86 × 10-5 mol dm3
4.13 × 10-8 mol dm3
8.26 × 10-8 mol dm3
1.30 × 10-12 mol dm3
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34.
Consider the following chemical equilibrium :
I2(g) + H2(g)
2HI(g)
H = 9.6 kJ mol1
Which of the following combinations describes the changes when the volume of the system decreases ?
A.
B.
C.
D.
35.
Colour intensity of the mixture
decreases
decreases
increases
increases
Value of Kc
decreases
no change
no change
decreases
Consider the following equilibrium system in a closed reaction vessel :
CH3CHO(g)
CH4(g) + CO(g)
H > 0
What would happen if some CH4(g) is added to the system ?
A.
B.
C.
D.
36.
The amount of all substances increases, relative to their previous equilibrium amount.
The value of Kc increases.
Only the amount of CH3CHO(g) and CO(g) increases, relative to their previous equilibrium
amount.
Only the amount of CH3CHO(g) and CH4(g) increases, relative to their previous equilibrium
amount.
Consider the following statements and choose the best answer :
2nd statement
The oxidations of secondary alcohols using
acidified potassium dichromate solution give
ketones as the final products.
1st statement
Ketones do not undergo oxidation reactions with
acidified potassium dichromate solution.
A.
B.
C.
D.
Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
Both statements are true but the 2nd statement is NOT a correct explanation of the 1st
statement.
The 1st statement is false but the 2nd statement is true.
Both statements are false.
END OF SECTION A
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