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DSE Chemistry – Paper 1aQuestion & Answersby Alan Cheng

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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.

Part I

1. Element Z occurs in nature in two isotopes, 35Z and 37Z. The relative atomic mass of Z is 35.5.

What is the relative abundance of the isotope 37Z?

A. 25% B. 45%

C. 55% D. 75%

2. Which of the following molecules is non-polar?

A. NH3 B. OF2

C. SiH4 D. SO2

3. Consider the following chemical equation:

xMn2+

(aq) + O2(g) + yOH-

(aq) + zH2O(l) xMn(OH)3(s)

Which of the following combination is correct?

x y z

A. 2 4 2

B. 2 8 2

C. 4 8 2

D. 4 5 3

4. Which of the following compounds has the highest melting point?

A. HBr B. SO2

C. PCl3 D. KI

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5. Which of the following statement(s) about ionic bond is / are correct?

(1) It is a strong and non-directional electrostatic force between oppositively charged ions.

(2) It exists between the compound formed by metal and non-metal only.

(3) It can be found between atoms in a molecule.

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

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

6. Which of the following compound can change acidified potassium dichromate solution from

orange to green?

A. Propene B. Sodium sulphiteC. Potassium iodide D. Ethyl ethanoate

7. Consider the set-up shown below:


X Y Z

A. Platinum sodium sulphate solution Platinum

B. Carbon Copper(II) nitrate solution Silver

C. Carbon sodium sulphate solution Carbon

D. Magnesium Copper(II) nitrate solution Carbon

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COOH PCl5

COCl+

8. 25 cm3 of 0.25 M hydrochloric acid mixed with solution Y, the pH value of the resulting

solution remain unchanged. What is solution Y?

A. 25 cm3 of 0.25 M ethanoic acid B. 25 cm3 of 0.25 M nitric acid

C. 25 cm3 of 0.25 M sulphuric acid D. 25 cm3 of 0.25 M ethanedioic acid

9. Which of the following metal oxides can be reduced to the metal when heated with local town

gas?

(1) magnesium oxide

(2) iron (III) oxide

(3) copper (II) oxide

A. (1) and (2) only B. (1) and (3) only

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

10. Which of the following reaction is / are neutralization?

(1) CH3COOH + CH3CH2OH CH3COOCH2CH3 + H2O

(2) CuO + 2HCl CuCl2 + H2O

(3)



11. Which of the following measures can be used to reduce the effect of acid rain?

(1) Installing catalytic converter in motor vehicles.

(2) Installing electrostatic precipirator in factories.

(3) Using fuel of lower sulphur contents


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

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12. Which of the following processes is exothermic?

A. PbCl2(l) Pb(l) + Cl2(g)

B. C14H30(l) C6H14(l) + C8H16(l)

C. H2O(g) H2O(l)

D. CO2(s) CO2(g)

13. Which of the following experiments would give a colour change?

(1) Sulphur dioxide is passed into a beaker containing limewater.

(2) Sulphur dioxide is passed into a gas jar containg moist purple flower petals.

(3) Sulphure dioxide is passed into a beaker containing dilute hydrochloric acid.


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

14. When substance Y is treated with an aqueous solution of iron(III) nitrate, the iron(III) ions

act as oxidizing agent. Y may be

A. Sodium hydroxide solutionB. Potassium iodide solution

C. Acidified potassium permanganate solution

D. Magnesium ribbon

15. Which of the following statement about Group I metal is INCORRECT?

A. They are soft metal.

B. Their melting point decrease down the group.

C. Their reducing power decrease down the group.

D. Their atomic radius increase down the group.

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16. Which of the following substance has a sharp melting point?

A. Concentrated hydrochloric acid B. Diesel oil

C. Molten wax D. Graphite

17. Which of the following statement(s) concerning carbon dioxide gas is / are correct?

(1) It can decolorize acidified potassium permanganate solution.

(2) It can be collected by downward delivery.

(3) It can effectively be prepared by the reaction between limestone and dilute sulphuric

acid.

A. (1) only B. (2) onlyC. (1) and (3) only D. (2) and (3) only

18. Which of the following statements concerning C 126

and C 146

are correct?

(1) They have different physical properties.

(2) They have the same chemical properties.

(3) They have different number of neutron.


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

19. Which of the following chemicals must be stored in brown bottle?

(1) Acidified potassium permanganate solution.

(2) Acidified iron(II) sulphate solution.

(3) Concentrated nitric acid.


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

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20. Which of the following compound can undergo disproportionation?

A. HClO3 B. HClO4

C. HMnO4 D. H2Cr2O4

21. One mole of potassium dichromate contains

A. 2 moles of cations. B. 2 moles of anions.

C. 1 mole of molecules. D. 3 moles of atoms.

22. Which of the following species will NOT react with hot HNO3(aq) or hot KOH(aq)?

A. CuSO4(aq) B. Na2SO3(aq)

C. K 2SO4(aq) D. NH4Cl(aq)

23. A mixture consists of three solids, potassium chloride, calcium nitrate and zinc oxide. Which

of the following methods can be used to separate zince oxide from the mixture?

(1) Add dilute hydrochloric acid to the mixture and then filter.(2) Add water to the mixture and then filter.

(3) Add ethoxyethane to the mixture and then filter.



24. Which of the following substance can be used to distinguish between dilute hydrochloric acid

and dilute sulphuric acid?

A. Magnesium ribbon B. Sodium hydrocarbonate solid

C. Copper(II) oxide D. Silver nitrate solution

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Part II

25. Which of the following statements concerning one mole of bromine is/are correct?

(1) It contains 6.02 × 1023 of molecules.

(2) It contains 2 moles of ions.

(3) It occupies the same volume as 1 mole ethanol at room temperature and pressure.

(Avogadro constant = 6.02 × 10²³ mol-1)

A. (1) only

B. (2) only

C. (1) and (3) only

D. (2) and (3) only

26. 15.0 cm3 of a 2.0 M acid solution requires 15.0 cm3 of 2.0 M sodium carbonate solution for

complete neutralization. What is the basicity of the acid?

A. 1

B. 2

C. 3D. 4

27. During the electrolysis of concentrated copper(II) nitrate solution by using copper electrodes.


Anode Cathode

A. oxygen liberated copper deposited

B. copper dissolved copper deposited

C. chlorine liberated hydrogen liberated

D. copper deposited hydrogen liberated

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28. Which of the following statements concerning soapy detergent are correct?

(1) It is an ester.

(2) Its solution is alkaline.

(3) It can be used in hard water with water softener.


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

29. Consider the following equilibrium system:

CO(g) + 2H2(g) ⇋ CH3OH(g) H < 0

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

(1) When the temperature is increased, the product yield increased.

(2) When the temperature is decreased, the product yield increased and the rate of the

forward reaction decreased.

(3) When helium gas is injected to the system, the product yield remains unchanged.


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

30. The structure of Paracetamol is shown below:

Which of the following statements about Paracetamol is INCORRECT?

A. It can undergo degradation in alkaline medium.

B. It possesses a hydroxy group.

C. It acts as analgesic drug.

D. It has a giant covalent network structure.

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Br

Br

Br

Br

X Y

CCH3CH

2

O

CH2-N

H

H

Z

31. Consider the structures of compound X and Y as follows:

Which of the following statement about compound X and Y is correct?

A. They have different optical activity.

B. They have the same chemical properties.

C. They have different physical properties.

D. They belong to different homologous series.

32. Consider the following reaction:

A(g) + 3B(g) AB3(g)

25 cm3 of A(g) and 60 cm3 of B(g) are mixed in a closed vessel. What is the volume of the

resultant gaseous mixture?

A. 25 cm3 B. 30 cm3

C. 35 cm3 D. 40 cm3

33. Consider the following structure of compound Z:

Which of the following statement about compound Z is correct?

A. It gives colourless gas bubbles with sodium hydrocarbonate solution.

B. It can undergo addition reaction with hydrogen bromine in the absence of light.

C. When it mixed with dilute hydrochloric acid solution, one layer is formed.

D. It undergoes hydrolysis in acidic medium.

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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.

34. Which of the following steps should be involved in an experiment to prepare solid zinc

sulphate?

A. Adding excess dilute sulphuric acid to zinc oxide.

B. Adding excess zinc oxide to dilute sulphuric acid.

C. Adding excess zinc nitrate solution to dilute sulphuric acid.

D. Adding excess dilute sulphuric acid to zinc nitrate solution.

Direction: Each question below (Question Nos. 35 to 36) consists of two separate statements.

Decide whether each of the two statements is true or false; if both are true, then

decide whether or not the second statement is a correct explanation of the first

statement. Then select one option from A to D according to the following table:

1

st

statement 2

nd

statement

35. The anode electrode in electrolytic cell

undergoes oxidation while in chemical

cell it undergoes reduction.

The polarity of anode is positive in

electrolytic cell while it is negative in

chemical cell.

36. Polystyrene is a thermoplastic. Polystyrene is an addition polymer.

END OF SECTION A

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1. A 10. B 19. D 28. C

2. C 11. B 20. A 29. C

3. C 12. C 21. A 30. D

4. D 13. A 22. C 31. C

5. A 14. D 23. B 32. A

6. B 15. C 24. D 33. C

7. D 16. D 25. A 34. B

8. B 17. B 26. B 35. C

9. C 18. D 27. B 36. B

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