POK OI HOSPITAL TANG PUI KING MEMORIAL COLLEGE

 FIRST TERM EXAMINATION ( 1997-1998 )

S5  CHEMISTRY I

 

Class                :           ________________                Date     :           __________________

Name               :           ________________                Time allowed: 90 minutes

Class Number  :           ________________                ( P.1 - P.5 /38 )

 

Instructions to students:

 1. Answer ALL questions.

2. Write your answers on the answer book provided.

3. The total score is 90 marks.

 

 

Section A ( 36 marks )

 

1. (a) Give IUPAC names of the following compounds:

      

 

    (b) Draw structural formulae for the following compounds:

         (i)    2,2,3-trimethylbutan-1-ol

         (ii)   3-methylpentanoic acid                                        ( 4 marks )

 

2. (a) Write the structural formula for

         (i)    BCF ( bromochlorodifluoromethane )

         (ii)   BTM ( bromotrifluoromethane )

     (b) State three reasons why BCF can be used for extinguishing fires caused by

         electrical faults.

     (c) Explain why BTM should be used in open spaces.

( 6 marks )

 

3. Three colourless gases, A, B and C are present in town gas. The following table shows

    the products of combustion of the three gases:

 

Gas

Product of combustion

A

Gas X and Liquid Y

B

Gas X only

C

Liquid Y only

 

    Gas X can turn lime water milky.

     (a) Name gas X and liquid Y.

     (b) Name gas C and write a balanced equation for its complete combustion in air.

     (c) Name gas B and write a balanced equation for its complete combustion in air.

     (d) Suggest two elements which are present in gas A. Explain your answer.  

                                                                                                ( 6 marks )

 

 4. Petrol, the fuel used in car engines, is a mixture of hydrocarbons. One of the

  hydrocarbons present in petrol is octane ( C8H18 ) which can burn completely in

  oxygen.

     (a) Write an equation for the combustion of octane.

     (b) The process is exothermic. What does it mean?

     (c) Give reasons why

          (i)    a black solid is collected in the exhaust pipes,

         (ii)   it is dangerous to run a car engine in a closed garage.

                                                                                        ( 6 marks )

 

5. Consider the following figure for cracking of paraffin oil.

 

 

    (a) What is the meaning of the term ¡¥cracking¡¦?

     (b) Explain why heating is applied on the porous pot instead of the paraffin.

     (c) At the end of the experiment, should the heating be removed first or the delivery

         tube removed from the beaker first? Why?

     (d) What would be observed if several drops of bromine water are added to the test

         tube of gas? What would you conclude about the nature of the gas?

                                                                                            (6 marks )

 

6. People are worried about the ¡¥global greenhouse effect¡¦. What is meant by

  ¡¥greenhouse effect¡¦ and how it affects the environment?

 

( 3 of the 9 marks for this question will be awarded for the effective communication of knowledge in Chemistry. )                                           ( 8 marks )

 

  

Section B ( 54 marks )

 

7. (a) (i)    State three advantages and disadvantages of using plastic things.

        (ii)   Nowadays, most modern cars use plastic bumpers instead of steel ones. Give

                 the advantages of such use to

                 (1)    the manufacturer

                 (2)    the car owner

                 (3)    a pedestrian struck by the bumper in an accident.

                                                                                                ( 9 marks )

 

    (b) Refer to the following compounds.

 

 

    (i)    (1)    Which one of the above compounds can be used to make an addition

                polymer?

          (2)    What special feature does this compound possess enabling it to form

                 addition polymer?

          (3)    Write the repeating unit of this polymer.

     (ii)   (1)    Which two of the above compounds can react to form a condensation

                polymer?

         (2)    What special feature do these compounds possess enabling them to form condensation polymer?

         (3)    Write the repeating unit of this polymer.

    (iii)  (1)    Which one of the above compounds can form condensation polymer by

               itself?

        (2)    Write the repeating unit of this polymer.

        (3)    What small molecule is eliminated during the polymerization?

                                                                                                    ( 9 marks )

 

 8. (a) One source of ethanol is from the crushed sugar cane and the juices collected are

     mixed with yeast. The mixture is allowed to stand for 2 or 3 days at around 30 ¢XC.

     The liquid product is then fractionally distilled, and ethanol is obtained as one of

      the fractions.

 

   (i)    Write an equation for the conversion of sugar to ethanol.

   (ii)   State the purpose of the yeast in the reaction.

   (iii)  Explain why this reaction is not speeded up even if the mixture is boiled.

   (iv)  Give the name of the process that converts glucose into ethanol in this way.

   (v)   In some countries, ethanol is used as a fuel. What advantage of using ethanol

         as a fuel for running car engine over petrol?

   (vi)  Methylated spirits is a mixture of ethanol ( about 90 % ) and methanol ( about 

        10 % ) together with a small quantity of purple dye. Explain why the ethanol-

        methanol mixture is treated in this way before being sold.

                                                                                            ( 7 marks )

 

   (b) The following drinks contain approximate equal amounts of pure ethanol.

 

 

          (I)    Which drink has the greatest concentration of ethanol?

           (ii)   The beer and wine are prepared by fermentation.

                (1)    What raw material is used to make beer?

                 (2)    What raw material is used to make wine?

          (iii) (1)    The ethanol in beer and wine does not exceed about 18 %. Why not?

                (2)    Draw a labelled diagram of suitable laboratory apparatus that can increase the ethanol content to

                        over 60 %.

               (3)    Name the method which can increase the concentration of ethanol.

            (iv) State one effect of heavy drinking on

                (1)    the body

                 (2)    society

                                                                                                                ( 11 marks )

   

9. (a) An effect method of dealing with crude oil on sea water is to spray the oil with

     liquid detergent.

          (i)    A detergent particle is represented as   ¾¾O  . Explain how these particles help to disperse the oil.

         (ii)   Sea water is hard water.

                 (1)    What makes the water hard?

                 (2)    To disperse oil on sea water, would a soapy or soapless detergent be used? Give a reason.

          (iii) The detergents used on oil spills are biodegradable.

                  (1)    What is meant by ¡¥biodegradable¡¦?

                 (2)    What would happen if non-biodegradable detergents were used?

                 (3)    State two problems with the use of biodegradable detergents.

                                                                                                        ( 11 marks )

 

    (b) The structural formulae of three detergents are shown below, the zig-zag line

         represents a hydrocarbon chain.

 

 

         (i)    How will the cleaning property of detergent A be affected if the hydrocarbon part is reduced from 17

                carbon atoms to 5 carbon atoms? Explain briefly.

          (ii)   Name two starting materials for the preparation of detergent C in the

              laboratory.

          (iii)  Explain why detergent C has poor cleaning action in acidic solution.

              Give appropriate equation(s) if necessary.

          (iv)  Detergent B causes the greatest pollution problem when discharged into river or sea, Explain this in

                terms of its structure.

                                                                                                                    ( 7 marks )

 

  

END OF PAPER

 

 

  

POK OI HOSPITAL TANG PUI KING MEMORIAL COLLEGE

 FIRST TERM EXAMINATION ( 1997-1998 )

S5  CHEMISTRY II

 

Class                :           ________________                Date     :           __________________

Name               :           ________________                Time allowed: 60 minutes

Class Number  :           ________________                ( P.1 - P.11 /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 of the following diagrams shows an INCORRECT procedure or set-up?

 

 

2. A worker in a factory accidentally poured a large amount of concentrated sulphuric

    acid on the floor. What should be done immediately?

 

    A.    Use tissue paper to soak the acid, and then remove it.

    B.    Add water to the floor, and then remove the mixture.

    C.    Add sodium hydroxide solid to the acid, and then remove the mixture.

    D.    Pour sand on the acid, and then remove it.

 

 

3. Which method of reading the volume marking on a burette is correct?

 

 

4. Which procedure should NOT be done in the laboratory?

 

    A.    Add concentrated sulphuric acid to a large amount of water while stirring.

    B.    Add a piece of potassium to kerosene.

    C.    Heat a beaker of ethanol using a Bunsen burner.

    D.    Add concentrated sulphuric acid to a plastic cup.

 

 

5. All the substances in the Periodic Table are

 

    A.    solids.

    B.    elements.

    C.    compounds.

    D.    metals.

 

 

6. One substance is classified as a non-metal even though it conducts electricity. This

    substance is

 

    A.    iodine.

    B.    iron.

    C.    oxygen.

    D.    graphite.

 

 

7. The table below gives the melting points and boiling points of four elements. Which

    element is a liquid at room temperature?

 

Element

Melting point (¢XC)

Boiling point (¢XC)

A

660

2470

B

-7

59

C

-101

-35

D

1540

2750

 

 

8. Which properties are common to all metals?

 

    (1)    high electrical conductivity

    (2)    high thermal conductivity

    (3)    denser than water

 

    A.    (1) and (2) only

    B.    (1) and (3) only

    C.    (2) and (3) only

    D.    (1), (2) and (3)

 

 

9. Which statement concerning elements at room conditions is correct?

 

    A.    Non-metals are either gases or liquids.

    B.    All metals are solids.

    C.    All non-metals are non-conductors.

    D.    All metals are conductors.

 

10. Which statement(s) concerning atoms is/are correct?

 

      (1)    Compared to a proton or neutron, the mass of an electron is negligible.

      (2)    Electrons move around the nucleus in shells.

      (3)    The number of neutrons is equal to the number of protons.

 

      A.    (1) only

      B.    (1) and (2) only

      C.    (2) and (3) only

      D.    (1), (2) and (3)

 

 

11.

Element

Melting point (¢XC)

Boiling point (¢XC)

Electrical conductivity

X

-39

357

high

Y

>3500

medium

Z

113

447

low

 

      Which statement is INCORRECT?

 

      A.    X must be a metal.

      B.    Y must be a metal.

      C.    Z must be a non-metal.

      D.    Z is a solid at room temperature.

 

 

12. Particles X and Y have the following numbers of subatomic particles:

 

Particle

Protons

Electrons

Neutrons

X

12

10

12

Y

12

12

12

 

      Which statement(s) about X and Y is / are correct?

 

      (1)    X and Y are isotopes of the same element.

      (2)    X is an ion and Y is an atom.

      (3)    Y can change to X by losing 2 electrons.

 

      A.    (1) only

      B.    (1) and (2) only

      C.    (2) and (3) only

      D.    (1), (2) and (3)

 

 

13. The cation of element X, the atom of element Y and the anion of element Z all have

      the same electronic arrangement. The atomic numbers are in the order of

 

      A.    X > Y > Z

      B.    Y > X > Z

      C.    Y > Z > X

      D.    Z > Y > X

 

 

Directions: Questions 14 to 16 refer to the following Periodic Table. Choose the best one from ¡¥elements¡¦ A, B, C and D to answer the questions.

 

 14. Which element is most likely a liquid at room temperature?

 15. Which element is an electrical conductor at room temperature?

 16. Which element is most likely to have the highest melting point?

 17. The atom of element X has 17 protons, and the atom of element Y has 13 protons.

      The compound formed is

 

      A.    XY

      B.    X2Y

      C.    YX2

      D.    YX3

  

18. If a compound formed between element X and chlorine is XCl3, then X and calcium

      form compound

 

      A.    CaX.

      B.    CaX2.

      C.    Ca2X3.

      D.    Ca3X2.

 

 

Directions: Questions 19 to 21 refer to the following structures.

 

  

19. Which of the structures best represents quartz?

 

      A.    (1)

      B.    (2)

      C.    (3)

      D.    (5)

  

20. Which of the structures best represents lithium fluoride?

 

      A.    (1)

      B.    (2)

      C.    (3)

      D.    (4)

 

 21. Which of the structures best represents silicon?

 

      A.    (1)

      B.    (2)

      C.    (3)

      D.    (5)

  

22. Which of the following pairs of substances react when heated?

 

      A.    Zinc and aluminium oxide

      B.    Zinc and magnesium oxide

      C.    Iron and copper(II) oxide

      D.    Iron and zinc oxide

 

 23. Which of the following does NOT occur when sodium metal is added to a beaker of

      water?

 

      A.    It sinks to the bottom.

      B.    Large amount of heat is evolved.

      C.    Hydrogen gas is given out.

      D.    It melts to a silvery ball.

  

24. A metal X displaces lead from aqueous lead(II) nitrate solution but does not displace

      magnesium from aqueous magnesium sulphate solution. Which of the following

      represents an increasing order for the reducing power of the metals?

 

      A.    Pb < X < Mg

      B.    X < Pb < Mg

      C.    Mg < X < Pb

      D.    Mg < Pb < X

  

25. Which of the following will occur when zinc metal rod is put into an aqueous

      copper(II) sulphate solution?

 

          Colour change of solution                    Other observation

       A.    no change                                     zinc metal dissolves

      B.    blue to colourless                      the solution becomes cool

      C.    blue to pale blue                       reddish-brown solid formed        

      D.    pale blue to blue                           grey solid formed

 

 

26. Tin plating can used to prevent rusting of iron because

 

      A.    tin is at a lower position than iron in the metal reactivity series.

      B.    tin metal acts as a sacrifice.

      C.    tin prevents iron from contact with oxygen and water.

      D.    tin and iron form an alloy which does not rust.

 

 

27. In which of the following cases would the rusting of iron nail be the fastest?

 

28. Which of the following gases would reduce hot copper(II) oxide to copper?

 

      (1)    Nitrogen dioxide

      (2)    Hydrogen chloride

      (3)    Town gas

 

      A.    (3) only

      B.    (1) and (2) only

      C.    (2) and (3) only

      D.    (1), (2) and (3)

  

29. Which metals are suitable to be coinage metals?

 

      A.    Gold and copper

      B.    Gold and silver

      C.    Copper and aluminium

      D.    Nickel and copper

  

30. Which of the following methods is the most suitable one to prevent a bicycle chain

      from rusting?

 

      A.    Painting

      B.    Oiling

      C.    Galvanizing

      D.    Connecting to magnesium metal

  

31. Which of the following pairs of metals gives the largest voltage when used as

   electrodes in a simple chemical cell?

 

      A.    zinc and copper

      B.    copper and silver

      C.    magnesium and silver

      D.    magnesium and zinc

  

32. Metals zinc and silver are arranged as in the diagram.

 

      Which statements are correct?

 

      (1)    Electrons flow from silver to zinc.

      (2)    Chemical energy is changed into electrical energy.

      (3)    Zinc is the negative electrode.

 

      A.    (1) only

      B.    (3) only

      C.    (1) and (2) only

      D.    (2) and (3) only

 

 33. Which liquids are NOT suitable as electrolytes in a chemical cell?

 

      (1)    dilute sulphuric acid

      (2)    copper(II) sulphate solution

      (3)    distilled water

      (4)    sugar solution

 

      A.    (1) and (2) only

      B.    (2) and (4) only

      C.    (1) and (3) only

      D.    (3) and (4) only

  

34. What is the oxidizing agent in the following cell reaction?

 

2Br- (aq) + 2Fe3+ (aq) ® Br2 (aq) + 2Fe2+ (aq)

 

      A.    Br- (aq)

      B.    Fe3+ (aq)

      C.    Br2 (aq)

      D.    Fe2+ (aq)

  

35. The diagram shows a simple cell of iron and copper in dilute hydrochloric acid.    

   What substance is reduced in this cell?

 

      A.    iron

      B.    copper

      C.    hydrogen ions

      D.    hydrogen

  

36. In which pair of substances are the oxidation numbers of the sulphur and the

      manganese the same?

 

      A.    H2SO4, KMnO4

      B.    SO2, MnO2

      C.    FeS, MnCl2

      D.    SO3, Mn2O3

  

37. Which of the following equations is NOT a redox reaction?

 

      A.    2Na (s) + Cl2 (g) ® 2NaCl (s)

      B.    AgNO3 (aq) + HCl (aq) ® AgCl (s) + HNO3 (aq)

      C.    Mg (s) + 2HCl (aq) ® MgCl2 (aq) + H2 (g)

      D.    S (s) + 2H2SO4 (l) ® 3SO2 (g) + 2 H2O (l)

 

38. Which one of the following shows the results for the electrolysis of potassium

      chloride solution?

 

 

At the anode (+)

At the cathode (-)

A.

hydrogen

chlorine

B.

potassium

chlorine

C.

chlorine

hydrogen

D.

oxygen

potassium

  

39. In the refining of copper by electrolysis, the cathode is

 

      A.    carbon

      B.    pure copper

      C.    impure copper

      D.    platinum

  

40. A student tries to plate an iron ring with copper using the apparatus below.

 

      Which of the following combinations is correct?

 

 

Anode

Cathode

Electrolyte

A.

iron ring

copper strip

Cu2+ (aq)

B.

copper strip

iron ring

Cu2+ (aq)

C.

iron ring

copper strip

Fe2+ (aq)

D.

copper strip

iron ring

Fe2+ (aq)

  

Directions: Questions 41 and 42 refer to the following longitudinal section of a dry cell.

 

41. Which combination is correct?

 

              X                     Y                        Z

      A.    C               C + MnO2                NH4Cl

      B.    C                 NH4Cl                 C + MnO2

      C.    MnO2             NH4Cl                    C

      D.    MnO2              C                       NH4Cl

  

42. Which reaction is NOT found in the cell?

 

      A.    Zn (s) ® Zn2+ (aq) + 2e-

      B.    C (s) + MnO2 (s) ® Mn (s) + CO2 (g)

      C.    2NH4+ (aq) + 2e- ® 2NH3 (aq) + H2 (g)

      D.    2MnO2 (s) + H2 (g) ® Mn2O3 (s) + H2O (l)

  

43. The price of zinc-carbon (1), alkaline manganese (2), and nickel-cadmium (3) cells of identical size is in the order of

 

      A.    (1) < (2) < (3)

      B.    (1) < (3) < (2)

      C.    (2) < (3) < (1)

      D.    (2) < (1) < (3)

  

44. The diagrams below show particle models for two solutions. The ¡¥¡P¡¦ represent

   particles of solute. If solution X has a concentration of 1M, then the concentration of

   solution Y is:

 

 

      A.    0.5M

      B.    1M

      C.    2M

      D.    3M

 

 45. What volume of 5M sulphuric acid must be diluted with water to make 250 cm3 of

      0.1M sulphuric acid.

 

      A.    5 cm3

      B.    10 cm3

      C.    20 cm3

      D.    100 cm3

  

Directions:  Each question below (Questions Nos. 46 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:

 

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.  Only one statement is true while the other is false.

D.  Both statements are false.

 

 

1 st statement

 

2 nd statement

46.

Calcium reacts less violently with dilute sulphuric acid than magnesium.

Magnesium is at a higher position than calcium in the reactivity series.

 

 

47.

 

 

The concentration of the electrolyte does not change during the discharge of a chemical cell.

 

 

Is a chemical cell, only the anode and the cathode undergo chemical change.

 

 

 

48.

 

 

Concentrated nitric acid must be stored in brown bottles.

 

 

Concentrated nitric acid is a strong oxidizing agent.

 

 

49.

 

 

Sulphuric acid does not react with copper.

 

 

Copper cannot be oxidized by sulphuric acid.

 

 

50.

 

 

10 cm3 of 0.1M hydrochloric acid contains the same number of hydrogen ions as 10 cm3 of 0.1M sulphuric acid.

 

 

Both hydrochloric acid and sulphuric acid completely ionize in water.

 

  

END OF PAPER