(mock examination) time allowed: 2 hours 30 minutes this

Microsoft Word - 2CA_S6_Mock_exam_paper_1_2019_engCHEMISTRY Mock Exam Paper
HKDSE CHEMISTRY — A Modern View (Second Edition) Mock Exam Paper 1 © Aristo Educational Press Ltd 2019 1
HONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION
CHEMISTRY Paper 1
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.
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. Which of the following statements is correct?
A. All aqueous solutions contain OH(aq) ions.
B. Under room conditions, the pH of an alkaline solution may be a negative value.
C. All alkaline substances contain hydroxide ion as their constituent ions.
D. A ‘corrosive’ hazard warning label must be displayed on a bottle of alkaline solution.
2. Which of the following processes will NOT produce carbon dioxide?
A. Adding dilute ethanoic acid to marble
B. Adding water to quicklime
C. Burning butane in air
D. Heating limestone strongly in air
3. A student was asked to identify an element, which has the following properties:
(1) It is a solid stored in an air-tight reagent bottle at room temperature.
(2) It is insoluble in water but soluble in non-polar solvents.
(3) It can oxidize sulphite ions to sulphate ions.
To which group of the Periodic Table does this element belong?
A. Group I
B. Group III
C. Group V
D. Group VII
4. Which of the following hydroxides CANNOT be prepared by the given reaction?
A. Fe(OH)2 from the reaction between FeCl2(aq) and excess NH3(aq)
B. Cu(OH)2 from the reaction between CuSO4(aq) and excess NaOH(aq)
C. Fe(OH)3 from the reaction between FeCl3(aq) and excess NH3(aq)
D. Pb(OH)2 from the reaction between Pb(NO3)2(aq) and excess NaOH(aq)
5. Which of the following solutions turns blue immediately upon the addition of 1 M FeSO4(aq)?
A. KI(aq)
B. KOH(aq)
C. K3Fe(CN)6(aq)
D. KSCN(aq)
6. Which of the following statements about covalent bonds is correct?
A. All atoms in covalent compounds do not carry net charges.
B. The bonding electrons must be evenly distributed between the two atoms.
C. Atoms of non-metals can form covalent bonds only.
D. In a single covalent bond, the bonding electrons must be contributed by each bonding atom.
7. Potassium peroxodisulphate (K2S2O8) decomposes to potassium sulphate, sulphur trioxide and oxygen upon heating. What is the mole ratio of sulphur trioxide and oxygen produced?
A. 1 : 2
B. 2 : 1
C. 3 : 2
D. 2 : 3
8. The following three set-ups are used to investigate rusting. The three test tubes are allowed to stand for one week.
(1)
(2)
(3)
Which of the following combinations about the three set-ups is correct?
Rusting observed No rusting observed
A. Amount of rust: (3) > (2) (1)
B. Amount of rust: (2) > (3) (1)
C. Amount of rust: (1) > (3) (2)
D. Amount of rust: (3) > (1) (2)
cotton wool
anhydrous CaCl2
9. Which of the following reactions has a negative enthalpy change?
A. Zn(s) + H2SO4(aq) ZnSO4(aq) + H2(g)
B. 2NH3(g) N2(g) + 3H2(g)
C. CuCO3(s) CuO(s) + CO2(g)
D. 2NaCl(aq) + 2H2O(l) 2NaOH(aq) + Cl2(g) + H2(g)
10. 20.0 cm3 of 0.10 mol dm3 NaOH(aq) is required for the complete neutralization of 0.568 g of an organic acid, which has a formula of CnH2n+1COOH. What is the value of n?
(Relative atomic masses: H = 1.0, C = 12.0, O = 16.0)
A. 15
B. 16
C. 17
D. 18
11. Which of the following combinations about the uses of polymers is correct?
Polymer Use
B. Low-density polyethene Lunch box for fast food
C. Polystyrene Food wrapper
12. Consider the following conversion:
In which step the change in oxidation number of nitrogen is the greatest?
A. Step 1
B. Step 2
C. Step 3
D. Step 4
Step 2 Step 3 HNO3
Step 4
13. A solution contains Na+, Mg2+, Cl and SO4 2. It is found that the mole ratio of Na+, Mg2+ and
Cl in the solution is 4 : 5 : 12. If there is 0.100 mol of Na+, how many moles of SO4 2 are
there in the solution?
A. 0.0125 mol
B. 0.025 mol
C. 0.050 mol
D. 0.100 mol
14. Consider the following set-ups, in which metal X is connected to the positive terminal of the voltmeter.
Voltmeter reading 1.26 V 0.76 V 1.62 V
Which of the following is the correct ascending order of the reactivity of W, X, Y and Z?
A. Z < Y < X < W
B. W < X < Y < Z
C. Z < X < Y < W
D. Y < W < X < Z
15. Nitrogen forms nitrogen oxides in thunderstorms:
In which of the above nitrogen-containing species does the nitrogen atom NOT have an octet electronic arrangement?
A. N2 and NO only
B. NO and NO2 only
C. NO2 only
N2 + O2 2NO 2NO2
16. The pH of 500 cm3 of 0.10 M HCl is found to be 1. Which of the following actions will NOT change the pH of the hydrochloric acid?
A. Adding 250 cm3 of distilled water to the acid
B. Adding 5 g of calcium carbonate powder to the acid
C. Adding 5 g of copper powder to the acid
D. Adding 5 g of sodium hydroxide granules to the acid
17. Which of the following observable changes can be made when adding a very small piece of sodium to 50 cm3 of copper(II) sulphate solution?
(1) Sodium dissolves in the solution.
(2) A pale blue precipitate forms.
(3) Colourless gas bubbles evolve.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
18. The temperature change of the reaction between 2 M KOH and 2 M HCl in an insulated container is recorded as follows:
Which of the following statements about the above experiment are correct?
(1) The reaction is exothermic.
(2) ΔT will be smaller if 2 M HCl is replaced by an equal volume of 2 M CH3COOH.
(3) ΔT will be smaller if 2 M HCl is replaced by 1 M HCl.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
Volume of 2 M HCl(aq) (cm3)
Te m
pe ra
tu re
19. The following set-up is used to determine the empirical formula of hydrocarbon H:
Which of the following statements about the experiment are correct?
(1) The experiment should be carried out in the fume cupboard as there is a risk of explosion of unburnt H.
(2) The number of moles of hydrogen in H can be found from the increase of mass in tube A.
(3) The number of moles of carbon in H can be found from the increase of mass in tube B.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
20. Which of the following methods can be used to distinguish between Na2CO3(s) and NaHCO3(s)?
(1) Heating the two solids separately
(2) Adding hydrochloric acid to the two solids separately
(3) Adding saturated calcium chloride solution to the two solids separately
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
21. Aluminium is the most abundant metal in the Earth’s crust. However, it is still important to recycle aluminium. Which of the following are the reasons to recycle aluminium?
(1) The extraction of aluminium consumes much electrical energy.
(2) Aluminium ore is non-renewable.
(3) The extraction of aluminium causes serious pollution.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
gaseous hydrocarbon H
22. Consider the following polymerization:
Which of the following statements is/are correct?
(1) A mixture of products is produced.
(2) The polymerization occurs at room temperature without using catalyst.
(3) The polymer produced can dissolve in dilute sulphuric acid.
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only
23. Which of the following statements about ethanedioic acid are correct?
(1) Its empirical formula is C2H2O4.
(2) All the hydrogen atoms in an ethanedioic acid molecule are ionizable.
(3) The basicity of ethanedioic acid is 2.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
24. Consider the following statements and choose the best answer:
1st statement 2nd statement
Both (NH4)2SO4 and (NH4)2HPO4 have the same percentage by mass of nitrogen.
Both (NH4)2SO4 and (NH4)2HPO4 are effective nitrogenous fertilizers.
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.
Part II
25. Which of the following statements about transition metals is INCORRECT?
A. The melting points of all transition metals are higher than 25C.
B. Iron and its ions can act as catalysts in some reactions.
C. Most compounds of chromium and manganese are coloured.
D. Nickel and cobalt form compounds with variable oxidation states.
26. Which of the following compounds is optically active?
A.
B.
C.
D.
27. NO(g) and O2(g) are added to a 2 dm3 sealed container. The following reaction occurs:
2NO(g) + O2(g) 2NO2(g)
The change in number of moles of NO(g) is shown in the following table.
Time (s) 0 1 2 3 4 5
Number of moles of NO(g) (mol)
0.020 0.010 0.008 0.007 0.007 0.007
What is the rate of consumption of O2(g) in the first two seconds?
A. 0.0450 mol dm3 s1
B. 0.0060 mol dm3 s1
C. 0.0030 mol dm3 s1
D. 0.0015 mol dm3 s1
28. When 0.12 g of sodium is added to water, 51.9 cm3 of hydrogen is produced at room temperature and pressure.
2Na(s) + 2H2O(l) 2NaOH(aq) + H2(g)
What is the percentage yield of hydrogen?
(Relative atomic mass: Na = 23.0; molar volume of gas at room temperature and pressure = 24.0 dm3 mol1)
A. 41.4%
B. 82.9%
C. 95.6%
D. 100%
What is the major product Y?
A. CH3CH2CH2CH2Br
B. CH3CH2CHBrCH3
C. CH3CHBrCHBrCH3
D. CH2BrCH2CH2CH2Br
30. Paradol is a compound that can be found in ginger. Its structure is shown below:
Which of the following statements about paradol is correct?
A. It is insoluble in water.
B. The carbonyl group can be oxidized to a hydroxyl group.
C. It can undergo addition polymerization.
D. It exhibits enantiomerism.
31. Consider the following three equilibrium systems:
(1) PCl5(g) PCl3(g) + Cl2(g)
(2) H2(g) + I2(g) 2HI(g)
(3) 2NO(g) + O2(g) 2NO2(g)
Initially, the underlined species have the same equilibrium concentration. The volumes of the equilibrium mixtures are then reduced by half at the same temperature. What is the correct order of the concentrations of the underlined species when the reactions restore equilibrium?
A. [PCl3] > [HI] > [NO2]
B. [HI] > [NO2] > [PCl3]
C. [NO2] > [PCl3] > [HI]
D. [NO2] > [HI] > [PCl3]
32. Which of the following compounds can react with NaBH4(aq) to form an alcohol?
(1)
(2)
(3)
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
33. Gases X and Y are mixed in a closed container at 298 K. They react and finally reach an equilibrium. The following table shows the changes in concentrations of the gases:
Gas X Y Z
Initial concentration (mol dm3) 0.10 0.20 0
Final concentration (mol dm3) 0.05 0.05 0.10
Which of the following information can be obtained from the given data?
(1) The reaction involved is X(g) + Y(g) 2Z(g).
(2) The value of Kc for this reaction is 1600 mol2 dm6.
(3) The system is a homogeneous equilibrium.
A. (1) only
B. (2) only
34. Consider the following chemical equilibrium in a sealed container:
2NO(g) + 2CO(g) N2(g) + 2CO2(g)
Which of the following can indicate that an equilibrium has been established?
(1) When two moles of nitrogen monoxide is consumed, one mole of nitrogen forms.
(2) The pressure of the reaction mixture remains unchanged.
(3) The density of the reaction mixture remains unchanged.
A. (1) only
B. (2) only
35. Element P can undergo the following reactions:
Which of the following statements about element P are correct?
(1) P must be a transition metal which can form compounds of variable oxidation states.
(2) P may be iron.
(3) Q is an oxidizing agent.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
36. Consider the following statements and choose the best answer:
1st statement 2nd statement
Aspirin can be regarded as a polyester. Aspirin contains an ester group.
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
where m > n
B
CHEMISTRY Paper 1 (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.
(2) Refer to the general instructions on the cover of the Question Paper for Section A.
(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) An asterisk (*) has been put next to the questions where one mark will be awarded for effective communication.
(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.
(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.
Name
Class
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PART I Answer ALL questions. Write your answers in the spaces provided.
1. Aluminium and iron are the first two most abundant metals in the Earth’s crust. They are widely used today.
(a) The electronic arrangement of an iron atom is 2, 8, a, 2. Deduce the value of a.
(1 mark)
(b) The bonding in aluminium and iron are similar. Describe the bonding of metals in solid state.
(1 mark)
(c) Complete the following table by stating the natural source and the method of extraction from the source for each metal.
Metal Natural source Method of extraction
Aluminium
Iron
(d) The uses of metals are related to their properties.
(i) Suggest one property of iron which makes it suitable for making car bodies.
(ii) Suggest one property of aluminium which makes it suitable for making kitchen foil.
(2 marks)
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2. For each of the following experiments, state the expected observable change(s) and write the ionic equation(s) for the reaction(s) involved.
(a) Bubbling ammonia gas into copper(II) sulphate solution until in excess
(4 marks)
(2 marks)
(c) Adding chlorine water to potassium iodide solution until in excess
(2 marks)
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3. Propane can be used as fuel in fuel cells. In the following fuel cell, concentrated sulphuric acid is the electrolyte.
(a) Write the half equations for the reaction occurring at
(i) the anode, and
(2 marks)
(b) Write the overall equation for the reaction occurred in the fuel cell.
(1 mark)
(c) The membrane for proton exchange only allows protons to pass through. Label the direction of the flow of protons () in the fuel cell.
(1 mark)
(d) The electrolyte used contains 98% of sulphuric acid by mass and its density is 1.83 g cm3. Calculate the concentration, in mol dm3, of sulphuric acid in the electrolyte.
(Relative atomic masses: H = 1.0, O = 16.0, S = 32.1)
(2 marks)
C3H8
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4. Methane reacts with chlorine when exposed to sunlight. Chloroform (CHCl3) is one of the products of the reaction. It is an oily liquid that floats on sodium chloride solution.
(a) What would be observed when the reaction between methane and chlorine has started?
(1 mark)
(b) Name the type of reaction between methane and chlorine.
(1 mark)
(c) Besides chloroform and hydrogen chloride, write the chemical formula of another chlorine-containing product of this reaction.
(1 mark)
(d) Chloroform vapour undergoes oxidation on standing in air in the presence of light to form phosgene (COCl2) and hydrogen chloride.
(i) Write the chemical equation for the reaction involved.
(ii) Phosgene is a highly toxic gas. Suggest a chemical test to show whether the oxidation of chloroform has occurred.
(3 marks)
saturated NaCl(aq)
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5. An iron oxide is reduced to iron using the following set-up:
(a) What type of structure does the iron oxide have?
(1 mark)
(b) Draw the electron diagram for a carbon monoxide molecule, showing electrons in the outermost shells only.
(1 mark)
(c) With the aid of a chemical equation, state the function of limewater in the set-up.
(2 marks)
(d) Carbon monoxide is highly toxic. Suggest one safety precaution in carrying out this experiment.
(1 mark)
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5. (e) Let the chemical formula of the oxide be FexOy. Write a chemical equation for the reaction between the oxide and carbon monoxide in terms of x and y.
(1 mark)
(f) 1.60 g of the oxide is heated until red hot. Then carbon monoxide is passed over the heated oxide and 1.12 g of iron is obtained. Calculate the empirical formula of this oxide.
(Relative atomic masses: O = 16.0, Fe = 55.8)
(2 marks)
*6. With the aid of chemical equations, outline how you would carry out tests to distinguish three gases: carbon dioxide, sulphur dioxide and nitrogen monoxide.
(5 marks)
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7. A student carried out the electrolysis of acidified potassium dichromate solution.
(a) State what would be observed at the iron electrode.
(1 mark)
(b) During the electrolysis, the electrolyte turns from orange to green.
(i) Write the half equation for the reaction involved.
(ii) Is this reaction an oxidation or a reduction?
(2 marks)
(c) When the electrolysis has been run for some time, colourless gas bubbles are seen on the graphite electrode. Suggest what the gas bubbles are and explain the formation of the gas with the aid of a half equation.
(3 marks)
(d) In electroplating industry, the effluent containing dichromate ions is treated by electrolysis as shown above. The solution obtained after electrolysis contains several metallic ions. How should the solution be treated so as to minimize the impact on the environment?
(2 marks)
graphite electrode iron electrode
acidified potassium dichromate solution
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8. Ethene can be prepared from the dehydration of ethanol by concentrated sulphuric acid at high temperatures. The following equation shows the reaction involved:
CH3CH2OH(g) CH2=CH2(g) + H2O(g)
(1 mark)
(b) State one safety precaution when heating the mixture of ethanol and concentrated sulphuric acid.
(1 mark)
(c) Suggest a test to show that the product mixture contains an unsaturated compound.
(2 marks)
(d) Calculate the enthalpy change of the above reaction by using the data in the table below:
Reaction Enthalpy change
2CH3OH(g) CH2=CH2(g) + 2H2O(g) ΔH2 = 29.2 kJ mol1
CH3CH2OH(g) CH3OCH3(g) ΔH3 = +50.7 kJ mol1
(3 marks)
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PART II
9. The following equation shows the reaction between propanone and iodine in the presence of dilute sulphuric acid:
The diagram below shows an instrument used to follow the progress of the reaction.
(a) Name the above instrument.
(1 mark)
(b) What is the physical parameter of the reaction mixture measured by the instrument?
(1 mark)
(c) Sketch a graph of the physical parameter against time.
(1 mark)
colour filter
light source
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9. (d) Describe briefly how to show that dilute sulphuric acid is the catalyst for the reaction. State the expected result.
(2 marks)
(e) Suggest another reaction for which the progress of the reaction can also be followed by the above instrument.
(1 mark)
*10. Arrange magnesium, aluminium, silicon and phosphorus in increasing order of melting points. Explain your answer in terms of bonding and structure.
(5 marks)
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11. Ethanol can be prepared from the reaction between carbon dioxide and hydrogen. The equilibrium constant of the reaction at 298 K is 2.95 × 1011 mol4 dm12.
2CO2(g) + 6H2(g) CH3CH2OH(g) + 3H2O(g)
(a) A student thinks that the reaction at 298 K should be very fast as the value of Kc is very large. Do you agree? Explain briefly.
(1 mark)
(b) At different temperatures and constant pressure, the percentage of carbon dioxide reacted is shown below.
Volume ratio of
1.5 45 20
2.0 60 28
3.0 83 37
(i) Deduce whether the forward reaction is exothermic or endothermic.
(ii) What are the theoretical conditions for a high yield of ethanol? Explain briefly.
(iii) Comment on whether it is possible to employ these theoretical conditions in industry.
(5 marks)
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(2 marks)
(b) Name the type of reaction involved between wintergreen oil and sodium hydroxide solution.
(1 mark)
(c) Suggest a chemical test to distinguish between wintergreen oil and Y.
(2 marks)
NaOH(aq) X
heat Y
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13. When heating calcium ethanoate strongly, acetone is produced. Acetone is a common solvent used in the school laboratory.
(a) What is the systematic name for acetone?
(1 mark)
(b) Write a chemical equation for the thermal decomposition of calcium ethanoate.
(1 mark)
(c) Acetone can be converted to isopropyl alcohol.
(i) Draw the structural formula of isopropyl alcohol.
(ii) Suggest the reagents required for the conversion.
(iii) Which compound, acetone or isopropyl alcohol, has a higher boiling point? Explain your answer.
(4 marks)

(mock examination) time allowed: 2 hours 30 minutes this

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