POK OI HOSPITAL TANG PUI KING MEMORIAL COLLEGE

 MOCK EXAMINATION ( 1997-1998 )

S5  CHEMISTRY I

Class                :           ________________                Date     :           __________________

Name               :           ________________                Time allowed: 90 minutes

Class Number  :           ________________                ( P.1 - P.6 /38 )

Instructions to students:

 1. There are TWO sections in this paper, Section A and Section B.

2. Answer ALL questions in Section A and any THREE questions in Section B.

3. Write your answers on the answer book provided.

4. The total score is 90 marks.

Section A ( Answer ALL questions. )

1. Six elements lettered A, B, C, D, E and F, together with their respective atomic

    numbers, are shown in the following table.

    (a) Identify two elements which have chemical similarities. Briefly explain your

         answer.

     (b) Which of the six elements consist(s) of monoatomic molecules?

     (c) Suppose elements B and D can form compounds with element F. Write down the formulae of the      

          compounds formed and draw diagrams (show the outermost electrons only ) to show their electronic

          structures.

     (d) Which compound in (c) should have a higher melting point?                ( 8 marks )

2. Consider the set-up with AB connected, as shown in the figure below.

    (a) What will be the direction of electron flow?

     (b) After a period of time, will there be any observable change in the copper electrode and the copper nitrate

           solution?

     (c) Write down the overall ionic reaction for the cell in each of the following cases:

         (i)    AB is connected,

         (ii)   AC is connected.                                                                        ( 5 marks )

3. An organic molecule X has the following structural formula:

    (a) Give the IUPAC name of molecule X.

     (b) What happens when a bromine in tetrachloromethane solution is added to

      molecule X? Write a chemical equation for the reaction.

     (c) Molecule X can be polymerized to give a polymer Y.

         (i)    Draw the repeating unit of polymer Y.

         (ii)   Do you think polymer Y is a thermosetting plastic ? Explain briefly.    ( 7 marks )

For questions 4 and 5, candidates are required to give paragraph-length answers. 3 of the marks for each of these two questions will be awarded for the effective communication of knowledge in Chemistry.

4. You are given a solution of ethanoic acid and a solution of hydrochloric acid of the

  same concentration. Besides pH measurement, suggest another experimental method

  to distinguish between a strong acid and a weak acid.                            ( 8 marks )

5. Discuss the importance of recycling plastics and the problems involved in the process.

                                                                                                                    ( 8 marks )

END OF SECTION A

Section B ( Answer any THREE questions )

6. (a) Read the label of a bottle of fizzy orange juice and answer the questions that

     follow.

         (i)    Is the orange juice a fresh orange juice? Explain your answer.

          (ii)   E110 is an artificial colouring, what colour do you think E110 is?

          (iii)  Why is sulphur dioxide added to the orange juice? Explain the chemical principle behind.

          (iv)  What do you understand by the term ‘fizzy’? Why is the orange juice fizzy?

          (v)   Artificial flavouring has been added to the orange juice. Do you think we should use artificial

                flavouring in food? Give your opinions.                                            ( 9 marks )

     (b) The diagram below shows a simple experimental set-up by which ethyl ethanoate can be prepared in the

            laboratory.

          Ethanol and ethanoic acid are heated in the presence of concentrated

          sulphuric acid as shown above.

          (i)    How would you distinguish between ethanol and ethanoic acid, apart from smell?

          (ii)   (1) Write an equation for the formation of ethyl ethanoate.

                  (2) What is the formation of ethyl ethanoate called?

                  (3) Calculate the theoretical yield ( mass ) of ethyl ethanoate which can be obtained from 23g of

                         ethanol and an excess of ethanoic acid.

           (iii)  Give two functions of concentrated sulphuric acid in the reaction.

           (iv)  Explain why the ethyl ethanoate formed is passed into cold water.

           (v)   How does ethyl ethanoate smell like?

    ( Relative atomic masses: H = 1.0, C = 12.0, O = 16.0 )                        ( 9 marks )

7. (a) Study the map shown below:

           During the rainy season, the wind blows from the south-west.

           (i)    Give one advantage and one disadvantage of locating the oil storage tanks as shown in the map.

           (ii)   What are the effects of rain water on the farms located near to Z?

           (iii)  If you were going to build a fish farm, which location, X or Y, would you choose? Explain your

                   answer.                                                                                    ( 9 marks )

    (b) In an experiment to determine the empirical formula of copper oxide.

         The following data were obtained:

                        mass of test-tube = 11.05g

                        mass of test-tube and copper oxide before heating = 11.71g

                        mass of test-tube and its content after heating = 11.58g

        (i)    Explain why the town gas is burnt at the outlet of the tube.

         (ii)   Explain why the town gas is allowed to flow for some time before it is burned in the outlet.

         (iii)  After the experiment, what was the colour of the residue?

         (iv)  Why is it necessary to allow the town gas keep on flowing until the tube cools down?

         (v)   What is the empirical formula of the copper oxide?

    ( Relative atomic masses: Cu = 63.5, O = 16.0 )                                    ( 9 marks )

8. (a) Ammonia can be made industrially as follows:

        (i)    (1) What is the name of gas X?

              (2) How can you obtain gas X?

              (3) How can you obtain hydrogen gas?

         (ii)   Name the catalyst used.

         (iii)  Write a balanced chemical equation for the reaction occurring in the catalytic conversion chamber.

         (iv)  (1) Why are the gases recycled?

                 (2) Why is ammonia liquefied?

          (v)   Ammonia is said to be “good and evil”. Explain why with suitable examples.

                                                                                                                        ( 9 marks )

    (b) The cast of a car shown below is protected from rusting by a method called

         galvanizing.

          (i)    Rusting is a redox reaction. What are the oxidizing agent and reducing agent involved?

          (ii)   Why is a coat of paint itself not sufficient to protect the iron cast from rusting?

          (iii)  State two functions of zinc in protecting the iron cast.

          (iv)  Explain why zinc-plating is not used in food can.

          (v)   Predict which part of the car corrodes most easily. Explain your answer.

                                                                                                                                    ( 9 marks )

 9. (a) Domestic bleach is well known to be prepared by the electrolysis of brine. The set-

           up is shown in the following diagram.

        (i)    What is the chemical name for brine?

        (ii)   What is the product given out at electrode A? Give the equation for the reaction at electrode A.

        (iii) What is the product given out at electrode B? Give the equation for the reaction at electrode B.

        (iv)  Some people think that sodium is formed at the negative electrode but it is not true. Explain briefly.

        (v)   What products are formed if the gas from the positive electrode is allowed to react with sodium

                 hydroxide solution?

         (vi)  Give the equation for the reaction in (g).                                    ( 9 marks )

    (b) A student has done an experiment on the effect of light on chlorine water. He

         inverted a test tube over a beaker of chlorine water as shown in the following

         diagram. After an hour, gas X was collected in the test tube.

        (i)    How is chlorine water made in the laboratory?

         (ii)   What happens when a piece of pH paper is put into the chlorine water?

         (iii)  What is gas X? Suggest a chemical test for the gas.

         (iv)  Write chemical equations for the formation and decomposition of chlorine water.

         (v)   We usually store chlorine water in a dark-coloured reagent bottle. Explain why.

                                                                                                            ( 9 marks )

END OF PAPER

POK OI HOSPITAL TANG PUI KING MEMORIAL COLLEGE

 MOCK EXAMINATION ( 1997-1998 )

S5  CHEMISTRY II

Class                :           ________________                Date     :           __________________

Name               :           ________________                Time allowed: 60 minutes

Class Number  :           ________________                ( P.1 - P.10 /38 )

Instructions to students:

1. Answer ALL questions.

2. Write your answers on the answer sheet provided.

3. The total score is 60 marks.

1. Which chemical in cigarettes is a suspected carcinogen?

     A. Tar

    B. Nicotine

    C. Carbon monoxide

    D. Carbon dioxide

2. Which is the most abundant element in the earth’s crust?

     A. Oxygen

    B. Iron

    C. Silicon

    D. Aluminium

3. Which of the following sets of the elements is/ are in the same group in the Periodic

    Table?

    (1) Calcium, iron, magnesium

    (2) Lithium, sodium, potassium

    (3) Oxygen, nitrogen, sulphur

    (4) Fluorine, chlorine, iodine

    A. (4) only

    B. (1) and (3) only

    C. (2) and (4) only

    D. (1), (2) and (3) only

4. Nitrogen exists in two isotopic forms, N-14 and N-15, with relative abundance of

    99.64% and 0.36% respectively. The relative atomic mass of nitrogen is

     A. 14.0

    B. 14.3

    C. 14.45

     D. 14.5

5. A group in the Periodic Table contains

    (1) elements with the same atomic number.

    (2) either metals or non-metals bur not both.

    (3) elements with similar properties.

    A. (3) only

    B. (1) and (3) only

    C. (2) and (3) only

    D. (1) and (2) only

6. Refer to the following experiment which is done on lead(II) bromide.

     Which of the following observations is correct?

    A. Lead(II) bromide conducts electricity in the solid state only.

    B. Lead(II) bromide conducts electricity in the molten state only.

    C. Lead(II) bromide conducts electricity in the solid and molten states.

    D. Lead(II) bromide does not conduct electricity at all.

 7. Which of the following pairs has the same number of electrons?

   A. Na⁺ and Ca²⁺

    B. Cl^- and Na

    C. K⁺ and O^2-

    D. O^2- and F^-

8. Which of the following structural formula is wrong?

Directions: Q.9 to 11 refer to the following diagram which represents the structure of a

common metal.

9. What is the bonding in this structure?

   A. Ionic bonding

    B. Covalent bonding

    C. Metallic bonding

    D. Van der Waals’ forces

10. What is responsible for the high densities of most metals?

     A. The free-moving electrons

      B. The positive ions

      C. The close packing of atoms

      D. The giant lattices

11. What is responsible for the electrical conductivity of metals?

      A. The free-moving electrons

      B. The positive ions

      C. The close packing of atoms

      D. The giant lattices

12. Three metals, X, Y and Z, undergo the following reactions.

      Arrange X, Y and Z in decreasing order of reactivity.

      A. X, Y, Z

      B. X, Z, Y

      C. Z, X, Y

      D. Z, Y, X

13. An alloy is generally stronger and harder because

      A. the metal atoms cannot slide over each other easily.

      B. different metal atoms strongly attract each other.

      C. the elements in the alloy formed a more stable compound.

      D. a new type of bond is formed in the alloy.

14. Consider the following conversion:

Fe²⁺ (aq) ® Fe³⁺ (aq) + e^-

      A. The Fe²⁺ ions are reduced.

      B. The oxidation number of Fe is increased by 1.

      C. This is a reduction reaction.

      D. Fe²⁺ ions are electron acceptors.

15. Which of the following is not a use of ethanol?

      A. It is used as a solvent.

      B. It is used for producing vinegar.

      C. It is used as a fertilizer.

      D. It is used in alcoholic beverages.

16. Gasohol, a car fuel, is a mixture of

      A. petrol and water.

      B. petrol and ethanol.

      C. ethanol and water.

      D. ethanol and methanol.

17. Which of the following groups of organic compounds is used to produce flavouring

       in food?

      A. Alkanoic acids

      B. Alcohols

      C. Alkanes

      D. Esters

18. Which hazard warning label(s) should be on a bottle of concentrated nitric acid?

      A. (1) only

      B. (1) and (3) only

      C. (2) and (3) only

      D. (1), (2) and (3)

19. Which has the largest mass?

   [ Relative atomic masses: H = 1.0, He = 4.0, C = 12.0, O = 16.0 ]

     A. 0.1 mole of CH₄

      B. 0.2 mole of H₂O

      C. 1 mole of He

      D. 1 mole of H₂

20. When 50 cm³ of 0.01M NaOH is mixed with 10 cm³ of 0.1M NaOH, the

      concentration of NaOH becomes

      A. 0.025 M.

      B. 0.055 M.

      C. 0.075 M.

      D. 0.085 M.

21. If 1g of gas X contains the same number of atoms as 1g of carbon monoxide, which

      substances may gas X be?

      [ Relative atomic masses : H = 1.0, C = 12.0, N = 14.0, O = 16.0,

        Avogadro’s number = 6.02 x 10^-23 mol^-1]

      (1) N₂

      (2) C₂H₄

      (3) CO₂

      A. (1) only

      B. (2) only

      C. (3) only

      D. (1) and (2) only

 22. Which is the correct procedure when using pH paper to test the pH of a solution?

      A. Dip dry pH paper into the solution and observe the colour.

      B. Dip moist pH paper into the solution and observe the colour.

      C. Wet a glass rod tip with the solution, press it on dry pH paper and observe the

        colour.

      D. Dilute the solution with water, dip dry pH paper into it and observe the colour.

Directions : Q.23 to 25 refer to the following titration.

23. If phenolphthalein is the indicator, the colour changes from

      A. colourless to red

      B. red to colourless

      C. yellow to red

      D. red to yellow

24. Calculate the molarity of the diluted vinegar.

     A. 0.13 M

      B. 0.26 M

      C. 0.53 M

      D. 1.05 M

25. Calculate the mass of ethanoic acid in the original solution.

      [ Relative atomic masses : H = 1.0, C = 12.0, O = 16.0 ]

      A. 0.13 g

      B. 0.79 g

      C. 1.31 g

      D. 7.86 g

26. Which of the following set-ups is/ are dangerous?

      A. (1) only

      B. (1) and (2) only

      C. (2) and (3) only

      D. (1), (2) and (3)

27. Why is it important to conserve our reserves of fossil fuels?

      (1) They are non-renewable energy sources.

      (2) The supply is limited.

      (3) The energy of the fossil fuels comes from the sun.

      (4) They are expensive.

      A. (1) and (2) only

      B. (2) and (3) only

      C. (3) and (4) only

      D. (1), (2) and (3) only

28. Which of the following statements about alkanes is not true?

      A. Methane, ethane and propane are the first three members of this homologous

           series.

      B. They have the general formula of C_nH_2n+2.

      C. They are saturated compounds.

      D. They contain carbon, hydrogen and oxygen only.

29. In a homologous series, which of the following properties will increase as the number of carbon atoms decreases?

      A. Boiling point

      B. Solubility in water

      C. Melting point

      D. Density

Directions: Q30 to 32 refer to the following diagram.

 30.  Why is the tube heated in the middle?

      A. The paraffin may explode if heated directly.

      B. The reaction occurs at the red- hot catalyst.

      C. The paraffin should remain at a low temperature during the reaction.

      D. The middle of the tube is the most heat- resistant.

31. What catalyst can be used?

      (1) Broken porcelain

      (2) Pumice stone

      (3) Calcium chloride

     A. (1) only

      B. (2) and (3) only

      C. (1) and (3) only

      D. (1) and (2) only

32. The first tube is not collected because

      A. it is not very pure.

      B. it is toxic.

      C. it is inflammable.

      D. it contains mainly air.

33. An odourant ( tetrahydrothiophene ) is added to town gas to

      A. act as a catalyst.

      B. increase the temperature of the flame.

      C. remove the sulphur in the gas.

      D. warn consumers of gas leakage.

34. Which of the following colour codes is wrong?

      A. Water- type extinguishers are red.

      B. Foam- type extinguishers are yellow.

      C. Carbon dioxide-type extinguishers are blue.

      D. BCF-type extinguishers are green.

35. Which of the following is not a problem caused by oil spillage?

      A. Oil floats on water and blocks the oxygen supply to marine organisms.

      B. Oil dissolves in water to form a toxic solution.

      C. Oil is flammable.

      D. Birds cannot fly when their feathers are covered by a layer of oil.

36. Which of the following is not an effect of acid rain?

      A. It damages the root structure of plants.

      B. It makes the water acidic and kills the water organisms.

      C. It corrodes buildings.

      D. It uses up the oxygen in the sea, and kills the sea organisms.

37. Nylon 6,6 is produced from the following two monomers:

      The repeating unit in the nylon 6,6 polymer is

38. Which of the following are soapless detergent?

      A. (1) and (2) only

      B. (3) and (4) only

      C. (1), (2) and (3) only

      D. (2), (3) and (4) only

39. Which of the following is/ are limitation(s) of soap?

      (1) It cannot be used in hard water.

      (2) It cannot be used in acidic water.

      (3) It is biodegradable.

      A. (1) only

      B. (2) only

      C. (1) and (2) only

      D. (1), (2) and (3)

40.                 2CO (g) + O₂ (g) ® 2CO₂ (g)

       What volume of carbon dioxide will be formed when 500 cm³ of carbon monoxide reacts with 200 cm³ of

        oxygen?

      A. 200 cm³

      B. 400 cm³

      C. 500 cm³

      D. 700 cm³

Directions: Q41 to 42 refer to the Contact process for the manufacture of sulphuric

acid.

41. Which of the following stages is not involved in the process?

      A.   S (s) + O₂ (g) ® SO₂ (g)

      B.   2SO₂ (g) + O₂ (g) ® 2SO₃ (g)

      C.   SO₃ (g) + H₂O (l) ® H₂SO₄ (aq)

      D.   SO₃ (g) + H₂SO₄ (l) ® H₂S₂O₇ (l)

42. What are the conditions for the oxidation of sulphur dioxide to sulphur trioxide?

      A. 450 °C,  1 atmosphere with vanadium(V) oxide as the catalyst

      B. 450 °C, 100 atmosphere without catalyst

      C. At the room temperature and pressure with vanadium(V) oxide as the catalyst

      D. At the room temperature and pressure with platinum as the catalyst

43. When a piece of wet blue litmus paper is put into a jar of sulphur dioxide,

      A. the blue litmus paper turns red.

      B. the blue litmus paper remains unchanged.

      C. the blue litmus paper turns colourless.

      D. the blue litmus paper turns red then white.

44. Which of the following are the household uses of bleach?

      (1) As preservatives

      (2) Use in laundry

      (3) As germicides

      A. (1) and (2) only

      B. (1) and (3) only

      C. (2) and (3) only

      D. (1), (2) and (3)

Directions:  Each question below (Questions Nos. 45 to 50) 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:

END OF PAPER