Mock Examination for S6 CHEMISTRY PAPER 1

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Mock Examination for S6 CHEMISTRY PAPER 1

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 Page 24 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. After the announcement of the start of the examination, you should first stick a barcode label and insert the information required in the spaces provided. No extra time will be given for sticking on the barcode label after the ‘Time is up’

announcement.

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.

L.H.M. CHUNG

Not to be taken away before the end of the examination session

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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 27 of Question-Answer Book B.

PART I

1. Rhenium (Re) has two naturally occurring isotopes, ¹⁸⁵Re and ¹⁸⁷Re. The relative atomic mass of rhenium is 186.2. What are the abundance of these isotopes?

A. 20% of ¹⁸⁵Re and 80% of ¹⁸⁷Re B. 40% of ¹⁸⁵Re and 60% of ¹⁸⁷Re C. 60% of ¹⁸⁵Re and 40% of ¹⁸⁷Re D. 80% of ¹⁸⁵Re and 20% of ¹⁸⁷Re

2. ₂₁⁴⁵Sc forms a cation carrying a charge of +3. How many electrons and neutrons are there in the cation?

Number of electrons Number of neutrons

A. 18 21

B. 18 24

C. 21 24

D. 21 21

3. Consider the following information of four metals W, X, Y and Z:

(1) W can only be extracted by electrolysis of its molten salt.

(2) Putting X in FeSO4(aq) gives a grey deposit on the metal.

(3) Putting Y in dilute HCl(aq) gives a colourless gas.

(4) Heating the oxide of Z gives metal Z.

Which of the metals is the LEAST reactive?

A. W B. X C. Y.

D. Z

4. An impure sample of tin(IV) oxide of mass 24.0 g is reduced to tin by heating with carbon. 16.4 g of tin are obtained.

What is the percentage by mass of tin(IV) oxide in the sample?

(Relative atomic masses: O = 16.0, Sn = 118.7) A. 39.4%

B. 68.3%

C. 77.5%

D. 86.7%

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HKDSE-S6-CHEM 1A-3 3 5. Which of the following combinations is INCORRECT?

Iron article Method to prevent iron from rusting

A. food can galvanisation

B. bath tap chromium-plating

C. fence painting

D. ship’s hull sacrifical protection

6. Which of the following pairs of aqueous solutions, when mixed, would give a precipitate?

A. Calcium nitrate and sodium chloride B. Copper(II) sulphate and sodium nitrate C. Lead(II) nitrate and potassium iodide

D. Iron(II) sulphate and acidified potassium dichromate

7. Dilute aqueous ammonia is added to a 0.1 mol dm^–3 solution until in excess. Which of the following combinations is correct?

Solution Observation

A. copper(II) sulphate green precipitate formed B. lead(II) nitrate colourless solution formed C. magnesium nitrate white precipitate formed D. zinc sulphate white precipitate formed

8. Which of the following is NOT a redox reaction?

A. 2Mg + SO2 2MgO + S

B. Cu2O + H2SO4 CuSO4 + Cu + H2O C. 2KClO3 2KCl + 3O2

D. 2KHCO3 K2CO3 + H2O + CO2

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9. Consider the fuel cell shown below.

Which of the following statements about the fuel cell is correct?

A. Electrode X is the anode.

B. OH^–(aq) ions move towards electrode X.

C. Electrons flow from electrode Y to electrode X in the external circuit.

D. Both H2(g) and O2(g) function as fuels in the cell.

10. Which of the following statements is correct for the electrolysis of 1 mol dm copper(II) chloride solution using carbon electrodes?

A. Chlorine is produced at the anode.

B. Copper(II) ions are oxidised at the cathode.

C. The anode gains in mass due to deposition of copper.

D. The blue colour of the copper(II) chloride solution remains the same.

11. Which of the following statements concerning petroleum is INCORRECT?

A. It is a source of aliphatic hydrocarbons.

B. It is a fossil fuel derived from ancient marine plants and animals.

C. It is a non-renewable energy source.

D. It can be separated into liquids of different densities by using a separating funnel.

12. What is the systematic name of the compound below?

A. 2-ethyl-3-methylpropan-2-ol B. 2-ethylbutan-2-ol

C. 3-ethylbutan-3-ol D. 3-methylpentan-3-ol

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HKDSE-S6-CHEM 1A-5 5

13. Which of the following compounds has the LOWEST boiling point?

14. When 10 cm³ of 2 mol dm^–3 HCl(aq) react with 10 cm³ of 2 mol dm^–3 NaOH(aq), the temperature change is ΔT.

HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)

The reaction is repeated using 20 cm³ of 1 mol dm^–3 HCl(aq) and 20 cm³ of 1 mol dm^–3 NaOH(aq). What is the temperature change?

A. ΔT B. 2ΔT C. ^Δ𝑇𝑇₂

D. 2 x 10 x ΔT

15. Consider the elements in the second period of the Periodic Table, from lithium to fluorine. Which of the following statements is correct?

A. They show a gradual decrease in melting point.

B. They show a gradual decrease in reactivity.

C. They show a gradual increase in electronegativity.

D. They show a gradual increase in the number of occupied electron shells in their atoms.

16. Which of the following statements about an ammonia molecule is / are correct?

(1) The number of bonding electrons contributed by each hydrogen atom in the molecule is 1.

(2) The number of bonding electrons contributed by the nitrogen atom in the molecule is 5.

(3) The total number of electrons in the molecule is 8.

A. (1) only B. (2) only

C. (1) and (3) only D. (2) and (3) only

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17. The set-up of an experiment for studying the movement of ions is shown below.

Which of the following statements is / are correct?

(1) FeSO4(aq) is yellow-brown in colour.

(2) The filter paper is soaked with K2SO4(aq) instead of water to increase the electrical conductivity of the filter paper.

(3) A blue colour appears around the middle of the filter paper.

18. The structure of graphite is shown below.

Which of the following statements concerning graphite are correct?

(1) It is soft because of the weak forces between the layers of carbon atoms.

(2) It conducts electricity due to the presence of delocalised electrons along the layers of carbon atoms.

(3) It has a low melting point because of the weak forces between the layers of carbon atoms.

A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)

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19. Which of the following statements concerning aluminium and its compounds is / are correct?

(1) During the electrolytic extraction of aluminium, purified bauxite is added to molten cryolite.

(2) The strength of aluminium can be increased by anodisation.

(3) Al(OH)3 can react with dilute hydrochloric acid but not with dilute sodium hydroxide solution.

20. A gas with a pungent smell is formed when Ba(OH)2(s) is heated with NH4Cl(s). Which of the following set-ups can be used to collect the gas?

21. The diagram below shows a set-up for the electrolysis of a colourless solution of 1 mol dm^–3K2SO4(aq) containing phenolphthalein indicator.

Which of the following statements concerning the electrolysis are correct?

(1) Gas bubbles are produced at both electrodes.

(2) The solution near electrode B turns pink.

(3) The concentration of K2SO4(aq) increases at the end of the electrolysis.

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22. Consider the following reaction of a hydrocarbon:

Which of the following statements about the reaction is / are correct?

(1) Excess Br2(l) should be used.

(2) Light is needed.

(3) The reaction gives a single product.

23. Which of the following processes are exothermic?

(1) Adding solid sodium hydrogencarbonate to dilute ethanoic acid (2) Placing magnesium powder into silver nitrate solution

(3) Adding concentrated sulphuric acid to water 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:

1^st statement 2^nd statement

A sulphide ion contains one more occupied electron shell than a sulphur atom.

A sulphur atom gains electrons to form a sulphide ion.

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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HKDSE-S6-CHEM 1A-9 9 PART II

25. The set-up shown below is used to study the rate of the reaction between calcium carbonate and different acids.

The conical flask is shaken to overturn the vial in order to start the reaction. The initial rate of the reaction with respect to the gas liberated is determined.

Which of the following pairs of chemicals, upon mixing at the same temperature, has the HIGHEST initial rate of the reaction?

A. 1 g of CaCO3 lumps and 10 cm³ of 1 mol dm^–3 CH3COOH(aq) B. 1 g of CaCO3 powder and 10 cm³ of 1 mol dm^–3 CH3COOH(aq) C. 1 g of CaCO3 lumps and 10 cm³ of 1 mol dm^–3 HCl(aq)

D. 1 g of CaCO3 powder and 10 cm³ of 1 mol dm^–3 HCl(aq)

26. Ammonium chlorate can decompose violently under room conditions.

2NH4ClO3(s) N2(g) + Cl2(g) + O2(g) + 4H2O(l)

What is the volume gas formed, at room temperature and pressure, from 0.550 g of ammonium chlorate?

(Relative atomic masses: H = 1.0, N = 14.0, O = 16.0, Cl = 35.5; molar volume of gas at room temperature and pressure = 24.0 dm³ mol^–1)

A. 130 cm³ B. 195 cm³ C. 228 cm³ D. 455 cm³

27. The following substances have attained equilibrium in a fixed volume container:

2NO(g) N2(g) + O2(g) ΔH < 0

Which of the following is correct if the temperature of the system is increased?

A. The position of equilibrium shifts to the right.

B. The equilibrium constant of the reaction increases.

C. Both the rates of forward and backward reactions increase.

D. The respective yields of N2(g) and O2(g) increase to the same extent.

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28. Which of the following graphs (not drawn to scale) shows the variation in melting points of the elements in the third period of the Periodic Table?

29. Which of the following compounds is achiral?

30. Which of the following alcohols can be dehydrated to give three different isomeric alkenes?

A. CH3CH2CH(OH)CH3

B. CH3CH2CH(OH)CH2CH3

C. CH3CH2CH2CH2OH D. CH3C(CH3)2CH2OH

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31. Ibuprofen is a drug used for the relief of pain. Its structure is shown below.

Which of the following statements about Ibuprofen are correct?

(1) Its molecular formula is C12H18O2.

(2) It has enantiomers.

(3) It liberates carbon dioxide with sodium carbonate solution.

32. The diagram below shows an experimental set-up.

Which of the following processes can be demonstrated by the experimental set-up shown?

(1) Dehydration of ethanol (liquid X) (2) Cracking of octane (liquid X) (3) Oxidation of ethanol (liquid X)

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33. Consider the organic conversion shown below.

Which of the following statements about the conversion is / are correct?

(1) A condensation reaction occurs.

(2) Acidified K2Cr2O7(aq) is used as a reactant.

(3) The conversion is catalysed by concentrated sulphuric acid.

34. Silicon is an element in Group IV of the Periodic Table. The oxide of silicon has the chemical formula SiO2.

Which of the following statements about silicon and its oxide is / are correct?

(1) Silicon is a good conductor of electricity.

(2) SiO2 is a hard material at room conditions.

(3) SiO2 is an amphoteric oxide.

35. The structure of a soap is shown below:

Which of the following statements concerning this soap is / are correct?

(1) It can decrease the surface tension of water.

(2) It is manufactured from chemicals derived from petroleum.

(3) The hydrophilic part responsible for its cleansing action is Na+.

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36. Consider the following statements and choose the best answer:

1^st statement 2^nd statement

The electrical conductivity of magnesium is greater than that of sodium.

The atomic number of magnesium is greater than that of sodium.

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