Paper 1 Section B Question-Answer Book B

8/13/2019 Paper 1 Section B Question-Answer Book B

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2 1 2 D S

HONG KONG EXAMINATIONS AND ASSESSMENT H O R I T YHONG KONG DIPLOMA OF SECONDARY EDUCATION EXAMINATION 2012

C s C ? Q u e s A n s w e r

This paper must be answered in English

I N S R U C T I O N S OR SECTION B(1) After the announcement of the start of theexamination , you should first write your CandidateNumber in the space provided on Page and stickbarcode labels in the spaces provided on Pages ,3, 5, 7 and 9.

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Please stick the barcode label here.

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2/20

PARTI

Answer ALL questions. Write your answers in the provided.Neon occurs naturally in three isotopes with the abundance of each isotope shown in the table below :

Isotope Abundance ( )20Ne 90 4821Ne 0.2722Ne 9.25

is meant by the term 'isotope' ?a)

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Calculate the relative atomic mass of neon.oA


3/20


Poly ethenyl ethanoate) is a polymer. 1ts monomer is ethenyl ethanoate with the structure shown below :

\ C G 0\ 1/ CH3

2.

Ethene s the raw material used n making ethenyl ethanoate. Ethene can be produced fromhydrocarbons ofhigher molecular mass by an important industrial process.

a)

Name this ndustrial process.1

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Explain why this process is important.1i

2 marks)Draw the structure of poly ethenyl ethanoate).b)


4/20

Consider the information conceming the lemon cells shown in the diagrams below :.

metal Y strip

multimeter

lemon

copper stnpe t a l s t r i p

multimeter

copper stnp

Cellelll

EUS

What is the function ofthe lemons in these cells ?a)

1 mark)By completing the table below arrange metal metal Y and copper in increasing order ofreducing power.

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5/20

Please stick the barcode label here .

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h

With the aid o a diagram explain the formation ofhydrogen bonding in hydrogen uoride..


6/20

In order to prepare 50 dm3 of 0.1 M CuS04(aq) an inexperienced electroplating worker added the requiredexact amount of CUS04 5H20 s) to water in a plastic container. He then stined the mixture with an ironrod until the CUS04 5H20 s) dissolved completely. Finally he sent a sample ofthe solution to the Qualityo n t r a b o r a t o r y for analysis but found that the concentration of CuS04(aq) was lower than 0.1 M.

5.

the aid of a chemical equation explain why the concentration of the CuS04(aq) preparedwas lower than 0.1 M.(a)

(2 marks)The worker used the prepared CuS04(aq) to coat a layer of copper on a metallic object byelectrolysis. He used an unreasonably high voltage and found that some bubbles were formed onthe object and the copper layer easily aked off

Explain why copper can be coated on the metallic object by electrolysis.

Suggest what the bubbles were and explain why the copper layer easily aked off.

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7/20


Outline the steps in preparing solid lead II) sulphate from solid lead II) nitrate. You have to state theadditional chemical reagents that are required but need NOT mention the apparatus involved.*6. 4 marks)

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8/20

A fertilser only contains ammonium nitrate ~ N 0 3 ) and potassium chloride (KCl). An experiment wasp e r f o to determine the percentage by mass of NH4N03 in this fertiliser. The set-up used is shownbelow:

7.

oS

water

50.0 cm3of 8M KOH(aq)

3.150 g offertiliser

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9/20


25.00 cm3 of S was transferred to a conical ask, and then titrated with 0.100M NaOH aq)using methyl orange as an indicator. 4 o cm3 of the NaOH aq) was required to reach the endpoint.d).

Name the apparatus that should be used to transfer 25.00 cm3 of S .I

State the colour change at the end point ofthe titration.11,

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Calculate the percentage by mass ofNH4N0 3 in this fertiliser.Molar mass o f N N g).11I.

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10/20

Upon heating, KHC03 decomposesotassium hydrogencarbonate KHC03) can be used to bake bread.into K2C03, H20 and CO2.8.Explain the purpose ofusing KHC03 in bread baking.a)

1 mark)Write the chemical equation for the decomposition ofKHC03 upon heating.LU

(l mark)The enthalpy change of d e c o m p o s of KHC03s) can be determined indirectly from theenthalpy changes ofthe following two reactions :c)

S

R e a c t i o n 1)HC0 3s) + HC1 aq) KC1 aq) + CO2g)--- Reaction 2)

In an experiment to determine the enthalpy change of Reaction 1), 3.39 g of KHC03 s) wasadded to excess H C 1 in an expanded polystyrene cup. The experimental data obtained areshown below :

lnitial t e m p e r a r e ofthe reacting solution: 25.8 0C

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K2C03 S) + 2HC1 aq) 2KCl aq) + 1 ) + CO2g)


11/20

In another experiment performed under the same conditions, the enthalpy change ofReaction 2) was found to be -49.1 kJ mor1 Calculate the enthalpy change ofdecomposition ofKHC03s) under the experimental conditions.

11c).

4 marks)According to the t e r a t u standard enthalpy changes offormation ofK2C03 S), KHC03s),CO2g) and H as fo lIows :

d)

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Compound A 298/ kJ mor1K2C03 S)KHC03s) -959COigH20 1) -286

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12/20

The diagram below shows an experimental set-up for investigating the factors affecting rusting..

iron nail B wrapped with magnesium ribbon

gel containing NaCl aq)K3Fe CN)6 aq) andphenolphthalein

iron nail A

iron nail C sealed with greaseWh at would be observed i an iron nail in the above rusts ?a)

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1 mark)Suggest which o the iron nails in the above set-up would NOT rust during the experiment.Explain your answer.

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13/20

PARTII

Answer ALL questions. Write your answers in the spaces provided.In an experiment 50 cm3 of2 0 M HCl(aq) was added to a conical f ask containing 2.0 g ofzinc powder.The curve in the graph below shows the volume measured at room temperature and pressure of thehydrogen gas liberated in the first few minutes of the experiment. The dotted line in the graph is thetangent to the curve at the start ofthe reaction.

11.

on

60

40u

4

The initial rate of a reaction is defined as the instantaneous o f t h reaction. Withreference to the graph above calculate the initial rate of the reaction with respect to the volumeof hydrogen gas liberated.

(a)


14/20

The s t r u c oinnamon which can be used as a flavouring contains cinnamaldehyde cinnamaldehyde is shown below :12.

Draw the n s i s o m e r for the above u c t u r e .a)

1 mark)

Explain why ethyl ethanoate is a better solvent than water for dissolving cinnamaldehyde. U

1 mark)

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15/20

Outline a synthetic route with no more th n three s t e p s o m p l i s h the following conversion.For each step give the reagent s) reaction conditions as appropriate) and structure ofthe organicproduct

d)2.

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16/20

Consider the reaction represented by q u a t i o n below :3.

Fe3+ aq) + N F e S C N i + a q

In an experiment, 25.0 cm3 ofO.Ol0 M Fe2 S04)3 aq) and 25.0 cm3 ofO.Ol0 M KSCN aq) were mixed in aconical flask at room temperature, and equilibrium was attained.

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The concentration of F S C N in the mixture was 0.0043 M when equilibrium was attained.Calculate the equilibrium constant for the above reaction at room temperature.a)

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17/20

The diagram below shows the conversion of an oil molecule X to a fat molecule Y

H c

HH H

14.

YGiven that all alkyl groups in both X and Y are straight chains label the chiral carbon s)y s i n g : : f in the above diagram.

X1a)

With reference to i) explain whether a change in optical activity is involved in theabove conversion.

11

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18/20

SUH

Use electron diagrams to illustrate step by step how CH4 reacts with Br2 under sunlight to form CH3Br.Show electI ons in the out rmost sh lls only.)15 .

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19/20

Consider the following oxides :6.C120

Which ofthe oxides listed above can conduct electricity in molten s t tS 240 1i 2lz 3gOa2

a)

1 mark)Explain why Si 2has the highest melting point among the covalent oxides listed above.hU

2 marks)Write a chemical equation for the reaction between Alz 3 s) and NaOH aq).c)

I mark)

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20/20

ERIODIC

lK 2H He1 II 1.0.. IV V VI VII 4.03 4 5 6 7 g 9 10Li Be B C N F Ne6.9 9.0 10.8 12.0 14.0 16.0 19.0 20.2

11 12 relative atomic m a s s 13 14 15 16 17 18Na Al Si P S l r23.0 24.3 27.0 28.1 31.0 32 .1 35.5 40.0

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36K Ca Sc Ti V Cr Fe Co Ni Cu Zn Ga Ge As Se Br Kr39.1 40.1 45.0 47.9 50.9 52.0 54.9 55.8 58.9 58.7 63.5 65 .4 69.7 72.6 74.9 79.0 79.9 83.837 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

Rb Sr Y Zr Nb Tc Rh Pd Ag Cd In Sn Sb Te E Xe85.5 87.6 88.9 91.2 92.9 95.9 10 1.1 102.9 106.4 107.9 112.4 114.8 118.7 12 1.8 127.6 126.9 13 1.355 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86Cs Ba La Hf Ta W Re Os Ir P Au Hg TI Pb Bi PO t Rn132.9 137.3 138.9 178.5 180.9 183.9 186.2 190 .2 192.2 195.1 197.0 200.6 204.4 207 .2 209.0 209) 210) 222)87 88 104 105

Fr Ra Ac Rf Db223) 226) 227) 262)

atomic n u m b e r

No

58 59 60 61 62 63 64 65 66 67 68 69 70 71Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu140.1 140.9 144.2 145) 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0

90 91 92 93 94 95 96 97 98 99 100 101 102 103Th Pa U Np PU Am Cm Bk Cf Es Fm No Lr232.0 23 1) 238.0 237) 244) 243) 247) 247) 251) 252) 257) 258) 259) 260)

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Paper 1 Section B Question-Answer Book B

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