chemistry paper 2 popular.doc

7/27/2019 chemistry paper 2 popular.doc

http://slidepdf.com/reader/full/chemistry-paper-2-populardoc 1/31

Section A

[60 marks]

Answer all questions.

1 Diagram 1 shows the apparatus set-up for preparing soap.

Rajah 1 menunjukkan susunan radas bagi penyediaan sabun.

(a) (i) State the name of the process to prepare soap.

Nyatakan nama bagi proses untuk menyediakan sabun.

………………………………………………………………………………...[1 mark]

(ii) What is the homologous series of palm oil?

Apakah siri homolog bagi minyak sawit ?

..........………………………………………………………………………….

[1 mark]

(iii) Why is sodium chloride added to the mixture?

Mengapakah natrium klorida ditambah kepada campuran itu?

………………………………………………………………………………...

[1 mark]

1

Palm oil + concentrated sodium

hydroxide solution

Minyak sawit + larutan natrium

hidroksida pekat

Diagram 1

Rajah 1

Heat Panaskan

Sodium chloride

Natrium klorida



(iv) Suggest another solution which can replace sodium hydroxide

Cadangkan satu larutan lain yang boleh menggantikan natrium hidroksida.

………………………………………………………………………………..

[1 mark]

(b) The cleansing action of a detergent is more effective than soap in hard water

Tindakan pencucian detergen adalah lebih berkesan daripada sabun dalam air liat.

(i) What is hard water?

Apakah air liat ?

…….…………………………………………………………………………..

[1 mark]

(ii) Explain why detergent is more effective than soap in hard water.Terangkan mengapa detergen adalah lebih berkesan daripada sabun dalam

air liat .…...…………………………………………………………………………...

…...…………………………………………………………………………...[2 marks]

(c) Sodium benzoate, ascorbic acid and monosodium glutamate are examples of

food additives.Natrium benzoat, asid askorbik dan mononatrium glutamat adalah contoh-

contoh bahan tambah makanan.

(i) Complete the table below:

Lengkapkan jadual di bawah:

Type of food

additive

Jenis bahan

tambah makanan

Example

Contoh

Function

Fungsi

Preservatives

Pengawet

Sodium benzoatein tomato sauce

Natrium benzoat

di dalam sostomato

……………………………………

……………………………………

…………………….

…………………….

Ascorbic acid infruit juice

Asid askorbik di

dalam jus buah

To preserve the colour of fruit juice

Mengekalkan warna jus buah

2



X37

17 Y40

19W24

12V

35

17

[2 marks]

(ii) Monosodium glutamate is a permitted flavouring. What is the effect of monosodium glutamate to a person who is sensitive to it?

Mononatrium glutamat adalah perisa makanan yang dibenarkan. Apakah

kesan mononatrium glutamat kepada orang yang sensitif dengannya?

…….…………………………………………………………………………..

[1 mark]

2 (a) Diagram 2.1 shows the symbol for elements V, W, X and Y.

Rajah 2.1 menunjukkan simbol-simbol bagi unsur-unsur V, W, X dan Y.

Diagram 2.1

Rajah 2.1

(i) State the name of the three subatomic particles in an atom.

Nyatakan nama bagi tiga zarah subatom dalam suatu atom.

…………………………………………………………………………………..

[1 mark]

(ii) Draw the electron arrangement of an ion of element X.

Lukiskan susunan elektron bagi satu ion bagi unsur X.

[1 mark]

(iii) Which of the atoms above are isotopes of an element? Explain your answer.

Yang manakah atom-atom di atas adalah isotop bagi suatu unsur?Terangkan jawapan anda.

.……………………………………………………………………………….

………………………………………………………………………………..

[2 marks]

3



(iv) State the position of element Y in the Periodic Table of Elements.

Nyatakan kedudukan unsur Y dalam Jadual Berkala Unsur.

………….……………………………………………………………………..

[1 mark]

(v) What is the number of neutrons in atom V? Berapakah bilangan neutron dalam atom V?

………..…………………………………………………………………………

[1 mark]

(b) Table 2 shows the melting point and boiling point of substances P, Q, R and S.

Jadual 2 menunjukkan takat lebur dan takat didih bagi bahan P, Q, R dan S.

Substance Melting point (oC) Boiling point (oC)

P −42 −10

Q 65 110

R −8 54

S 200 450

Table 2

Jadual 2

(i) Draw the arrangement of particles of substances Q and R at room

temperature.

Lukis susunan zarah-zarah bagi bahan Q dan R pada suhu bilik.

Substance Q Substance R

Bahan Q Bahan R[2 marks]

4



(ii) Diagram 2.2 shows the cooling graph of liquid Q.

Rajah 2.2 menunjukkan graf penyejukan bagi cecair Q.

Diagram 2.2 Rajah 2.2

State the value of K .

Give reason why the temperature remains constant at K oC from t1 to t2.

Nyatakan nilai K.

Beri sebab mengapa suhu tidak berubah pada K oC dari t 1 hingga t 2

…………………………………………………………………………………….

…………………………………………………………………………………….

[2 marks]

5

Temperature (oC)

Suhu (o

C)

Time(s)

Masa(s)

K

t1

t2



3 Diagram 3 shows the set-up of apparatus to investigate the electrolysis of sodium chloride

solution as electrolyte and carbon as electrodes. Rajah 3 menunjukkan susunan radas untuk mengkaji elektrolisis larutan natrium klorida

sebagai elektrolit dan karbon sebagai elektrod.

(a) What is the meaning of electrolyte?

Apakah yang dimaksudkan dengan elektrolit?

.............................................................................................................................................

[1 mark]

(b) Write the formulae of all ions present in sodium chloride solution.Tuliskan formula bagi semua ion yang hadir dalam larutan natrium klorida.

..................................................................

……………………………………………………[1 mark]

(c) Refer to the reaction at the carbon electrode Q

Merujuk kepada tindak balas pada elektrod karbon Q

(i) Name the gas collected.

Namakan gas yang terkumpul.

.............................................................………………….......…………..

…………..

[1 mark]

6

Diagram 3

Rajah 3

Test tube

Tabung uji

Electrode P

Elektrod P

A

Electrode Q

Elektrod Q

0.001 mol dm-3 sodium chloride solution Larutan natrium klorida 0.001 mol dm-3



(ii) Write the half equation for the reaction.

Tuliskan setengah persamaan bagi tindak balas.

…………………………………...…………………………….…………………..

[1 mark]

(iii) Give a reason for your answer in (c)(ii).

Berikan sebab bagi jawapan anda di (c)(ii).

……………………………………………..………………………………………

[1 mark]

(d) The experiment is repeated using 2.0 mol dm-3 of sodium chloride solution. Eksperimen ini diulangi dengan menggunakan larutan natrium klorida 2.0 mol dm-3.

(i) Name the product formed at electrode P.

Namakan hasil yang terbentuk di elektrod P.

.........................………………………………………………………..……………

[1 mark]

(ii) Write the half equation for the reaction at electrode P.

Tuliskan setengah persamaan bagi tindak balas pada elektrod P.

…………………………………...…………………………….…………………..

[1 mark](iii) What is the factor affected the product formed at electrode P?

Apakah faktor yang mempengaruhi hasil yang terbentuk pada elektrod P?

………………………………...…………………………….……………………[1 mark]

(e) Draw a labelled diagram to show the electroplating of an iron spoon with silver by using

silver nitrate solution as the electrolyte. Lukis gambar rajah berlabel untuk menunjukkan penyaduran sudu besi dengan

argentum menggunakan larutan argentum nitrat sebagai elektrolit.

[2 marks]

7



4 Table 4 shows concentration and pH value of three solutions.

Jadual 4 menunjukkan kepekatan dan nilai pH bagi tiga larutan.

Solution

Larutan

Sulphuric acid

Asid sulfurik

Ethanoic acid

Etanoik asid

Sodium hydroxide

Natrium hidroksida

Concentration Kepekatan

0.5 mol dm-3 0.5 mol dm-3 X mol dm-3

pH value

Nilai pH1 5 13

Table 4

Jadual 4

(a) Sodium hydroxide is a strong alkali. What is the meaning of strong alkali?

Natrium hidroksida ialah alkali kuat. Apakah yang dimaksudkan dengan alkali

kuat?

……………………………………………………………………………………

[1 mark ]

(b) (i) Which of the solution in Table 4 has the highest concentration of hydrogen

ions?Larutan manakah dalam Jadual 4 mempunyai kepekatan ion hidrogen yang

paling tinggi?

………………………………………………………………………………...

[1 mark ]

(ii) Explain your answer.Terangkan jawapan anda.

…………………………………………………………………………...[1 mark ]

(c) A student carried out an experiment to determine the value of X . In the

experiment, 20 cm3 of sulphuric acid in Table 4 is used to neutralize 25 cm3 of

sodium hydroxide solution using titration method.

Seorang pelajar telah menjalankan eksperimen untuk menentukan nilai X. Dalam eksperimen tersebut, 20 cm3 asid sulfurik dalam Jadual 4 telah

digunakan untuk meneutralkan 25 cm3 larutan natrium hidroksida

menggunakan kaedah pentitratan.

8



(i) State an indicator that can be used in the experiment.

Nyatakan satu penunjuk yang boleh digunakan dalam eksperimen itu.

…………………………………………………………………………………

[1 mark ]

(ii) State the observation in the experiment.

Nyatakan pemerhatian dalam eksperimen itu.

……………………………………………………………………………….

[1 mark ]

(iii) Write the chemical equation involved.

Tuliskan persamaan kimia yang terlibat .

………………………………………………………………………………

[2 marks]

(ii) Calculate the value of X.

Hitungkan nilai X.

[3 marks]

9



5 (a) Diagram 5.1 shows the set-up of apparatus to study the effect of metals P and Q on

the rusting of iron nail. The results are recorded after one day.Rajah 5.1 menunjukkan susunan radas untuk mengkaji kesan logam P dan Q ke

atas pengaratan paku besi. Keputusan dicatatkan selepas satu hari.

Experiment

Eksperimen

Observation after 1 day

Pemerhatian selepas 1 hari

A

Some dark blue

precipitate.Sedikit mendakan

biru.

B

Large amount of dark

blue precipitate Banyak mendakan

biru.

C

No dark blue precipitate. Solution

turns pink.

Tiada mendakan biru. Larutan bertukar

merah jambu.

Diagram 5.1

Rajah 5.1

(i) State the function of potassium hexacyanoferrate(III) solution in thisexperiment.

Nyatakan fungsi larutan kalium heksasianoferat( III ) dalam eksperimen

ini.

10

Agar-agar solution with potassium

hexacyanoferrate(III) and phenolphthalein

solution.

Larutan agar-agar dengan larutan kalium

heksianoferat( III ) dan fenolftalein

Iron nail wrapped with metal P

Paku besi dililit dengan logam P


hexacyanoferrate(III) and

phenolphthalein solution.

Larutan agar-agar dengan larutankalium heksianoferat( III ) dan

fenolftalein

Iron nail

Paku besi


hexacyanoferrate(III) and

phenolphthalein solution.

Larutan agar-agar dengan larutan

kalium heksianoferat( III ) dan

fenolftalein

Iron nail wrapped with metal Q

Paku besi dililit dengan logam Q



…………………………………………………………………………...

[1 mark ]

(ii) Write the half equation for the formation of iron(II) ion from iron.

Tuliskan setengah persamaan bagi pembentukan ion ferum( II )daripada ferum.

…………………………………………………………………………...[1 mark ]

(iii) In which test tube, iron rust the fastest? Explain your answer.

Dalam tabung uji manakah menunjukkan pengaratan besi yang paling cepat. Terangkan jawapan anda.

…………………………………………………………………………...

…………………………………………………………………………..

[2 marks]

(iv) Arrange the metal Fe, P and Q in decreasing order of electropositivity.

Susun logam Fe , P dan Q mengikut urutan menurun keelektropositifan.

…………………………………………………………………………...

[1 mark ]

(b) Diagram 5.2 shows the set-up of apparatus to investigate the reaction between

potassium manganate(VII) solution and iron(II) chloride solution through the

transfer of electrons at a distance. Rajah 5.2 menunjukkan susunan radas untuk menyiasat tindak balas di

antara larutan kalium manganat( VII ) dan larutan ferum( II ) klorida melalui

pemindahan elektron pada satu jarak ..

11

Carbon electrode

Elektrod karbon

Carbon electrode

Elektrod karbon

Iron(II) chloride solution

Larutan ferum( II ) klorida

Dilute sulphuric acid

Asid sulfurik cair

Potassium manganate (VII)

Kalium manganat( VII )

Diagram 5.2/ Rajah5.2

P Q



The incomplete ionic equation for the reaction is :

Persamaan ion yang tidak lengkap bagi tindak balas tersebut ialah :

………. Fe2+ + MnO4- + 8H+ → 5Fe3+ + Mn2+ + …………. H2O

(i) Complete the above equation.

Lengkapkan persamaan di atas.[1 mark ]

(ii) What is the change in colour at electrode P?

Apakah perubahan warna dalam larutan pada elektrod P?

…………………………………………………………………………...[1 mark ]

(iii) What is the substance that undergoes oxidation in this experiment?Explain why.

Apakah bahan yang mengalami pengoksidaan dalam eksperimen ini?

Terangkan mengapa.

…………………………………………………………………………

………………………………………………………………………….[2 marks]

(iii) Describe a chemical test to determine the product formed at electrode Q.

Huraikan satu ujian kimia untuk menentukan hasil yang terbentuk di

elektrod Q.

……………………………………………………………………………

……………………………………………………………………………[2 marks]

12



6.Diagram 6 shows a series of changes on alcohol J with a molecular formula C3H8O.

Rajah 6 menunjukkan siri penukaran alkohol J dengan formula molekul C 3 H 8O.

Diagram 6

Rajah 6

(a) Write the chemical equation for the reaction in process I.

Tuliskan persamaan kimia di dalam proses I.

..................………………………………………………………………………….

[1 mark ]

(b) Alcohol J can be converted into propanoic acid through process II. Alkohol J boleh ditukarkan kepada asid propanoik melalui proses II.

(i) Name process II.Namakaan proses II.

…………………………………………………………………………………...[1 mark ]

13

Alcohol J

Alkohol J

C3H8O

Carbon dioxide and water

Karbon dioksida dan air

Compound Y

Sebatian Y

Propanoic acid Asid propanoik

CH3CH2COOH

I

II

Concentrated sulphuric acid

Asid sulfurik pekat

Propene

Propena

Dehydration Pendehidratan

III



(ii) Describe briefly the method to prepare propanoic acid from alcohol J. Huraikan secara ringkas kaedah menyediakan asid propanoik dari alkohol J.

……………………………………………………………………………..

……………………………………………………………………………..

[2 marks]

(iii) Draw the structural formula for all the isomers of alcohol J.

Lukiskan formula struktur semua isomer bagi alkohol J .

[2 marks]

(c) Compound Y is produced from the reaction between alcohol J and propanoic acid

through process III.

Sebatian Y dihasilkan dari tindak balas antara alkohol J dan asid propanoik melalui proses III.

(i) State the name of compound Y.Nyatakan nama bagi sebatian Y.

............…………………………………………………………………………..[1 mark ]

(ii) State a special characteristic for compound Y.

Nyatakan sifat istimewa bagi sebatian Y.

14



......................…………………………………………………………………..

[1 mark ]

(d) Propene can be converted to propane by the hydrogenation process.Desribe briefly one chemical test to differentiate between propene and propane

Propena boleh ditukarkan kepada propana melalui proses penghidrogenan.

Huraikan secara ringkas satu ujian kimia untuk membezakan antara propena dan propana.

...................................................................................................................................

.

...................................................................................................................................

.

...................................................................................................................................

.[2 marks]

15



Section B[20 marks]

Answer any one question from this section.

Jawab mana-mana satu soalan daripada bahagian ini.

7 Diagram 7 shows the electron arrangement of a compound formed between element Q

and element R.

Rajah 7 menunjukkan susunan elektron bagi sebatian yang terbentuk antara unsur Qdan unsur R.

Diagram 7

Rajah 7

(a) Explain the position of R in the Periodic Table of Elements.

Terangkan kedudukan R di dalam Jadual Berkala Unsur.

[4 marks]

(b) Based on Diagram 8, explain how the compound is formed.

Berdasarkan Rajah 8, terangkan bagaimana sebatian itu terbentuk.

[7 marks]

(c) Element R can also react with carbon, C to form a compound.

Unsur R juga bertindak balas dengan karbon, C untuk membentuk suatu

sebatian.

(i) Write the formula of the compound formed.

Tuliskan formula bagi sebatian yang terbentuk.

(ii) Draw the electron arrangement of the compound formed.

Lukiskan susunan elektron bagi sebatian yang terbentuk.[3 marks]

16

− 2+ −

Q R R



(d) The compounds formed in (b) and (c) have different physical properties.Explain the differences between the two compounds based on:

• Melting point

• Electrical conductivity

Sebatian yang terbentuk dalam (b) dan (c) mempunyai sifat fizik yang

berlainan. Terangkan perbezaan di antara kedua-dua sebatian berdasarkankepada:

• Takat lebur

• Kekoduksian elektrik

[6 marks]

8. (a) The knowledge of factors affecting the rate of reaction is applied in Haber Process.

Pengetahuan tentang faktor yang mempengaruhi kadar tindak balas diaplikasikan

dalam Proses Haber.

(i) Write a chemical equation to represent the formation of ammonia gas in Haber

Process.

Tuliskan persamaan kimia bagi pembentukan gas ammonia dalam Proses Haber. [1 mark]

(ii) Describe three methods that can increase the rate of reaction to produce

ammonia gas.

Huraikan tiga kaedah untuk meningkatkan kadar tindak balas bagi penghasilan

gas ammonia.

[3 mark

(b) Graph 8 shows the results of Experiment I and Experiment II to investigate thefactor of catalyst in the reaction of zinc and hydrochloric acid.

Graf 9 menunjukkan keputusan bagi Eksperimen I dan Eksperimen II untuk mengkaji faktor mangkin dalam tindak balas antara zink dan asid hidroklorik

17

Volume of

hydrogen gas (cm3)

Time(s)

Experiment II

Experiment I



Graph 9

Graf 9

(i) Which experiment used catalyst? State the name of the catalyst used.

Eksperimen yang manakah menggunakan mangkin? Nyatakan nama bagi

mangkin yang digunakan.

[2 marks]

(ii) The reaction between zinc and hydrochloric acid releases energy.

Draw an energy profile diagram for both reactions in Experiment I andExperiment II. Label Ea for the activation energy without a catalyst and

E’a for the activation energy with a catalyst.

Tindak balas antara zink dengan asid hidroklorik membebaskan tenaga.

Lukiskan satu gambar rajah profil tenaga bagi kedua-dua tindak balas

dalam

Eksperimen I dan Eksperimen II. Labelkan E a bagi tenaga pengaktian tanpamangkin dan E ’ a bagi tenaga pengaktifan dengan mangkin.

[4 marks]

(iii) Explain the difference in the rate of reaction between Experiment I

and Experiment II based on the collision theory.Terangkan perbezaan dalam kadar tindakbalas antara Eksperimen I dan

Eksperimen II berdasarkan teori perlanggaran.

[4 marks]

(c) Table 8 shows three experiments that were carried out to investigate the effect of

concentration on the rate of reaction.

Jadual 8 menunjukkan tiga eksperimen yang telah dijalankan untuk mengkajikesan kepekatan ke atas kadar tindak balas.

Experiment

EksperimenReactants

Bahan tindak balas

I Excess of calcium carbonate powder + 40 cm3 of 0.5 mol dm-3

hydrochloric acid.

Serbuk kalsium karbonat berlebihan + 40 cm3 0.5 mol dm-3 asid

hidroklorik

18



II Excess of calcium carbonate powder + 20 cm3 of 1.0 mol dm-3

hydrochloric acid.Serbuk kalsium karbonat berlebihan + 20 cm3 1.0 mol dm-3 asid

hidroklorik

III Excess of calcium carbonate powder + 20 cm3

of 1.0 mol dm-3

sulphuric acid.Serbuk kalsium karbonat berlebihan + 20 cm3 1.0 mol dm-3 asid

sulfurik

Table 8

Jadual 8

Sketch a graph to show the volume of carbon dioxide gas released against time

taken for the three experiments on the same axis.

Lakarkan satu graf untuk menunjukkan isi padu gas karbon dioksida melawan

masa yang diambil untuk ketiga-tiga eksperimen itu pada paksi yang sama. [3 marks]

Compare the volume of gas released between Experiment I and II and between

Experiment II and III. Explain why. Bandingkan isi padu gas yang terbebas antara Eksperimen I dan II dan antara

Eksperimen II dan III . Terangkan mengapa. [3 marks]

Section C

[20 marks] Answer any one question.

9. (a) Diagram 10 show the energy level of Reaction I and Reaction II.

Rajah 10 menunjukkan aras tenaga bagi Tindak balas I dan Tindak balas II.

19

N2 (g)+ 2O2(g)

2NO2 (g)

H = +66 kJ mol-1

Energy

Solutions X and Tenaga

Reaction I

Tindak balas I

Reaction II

Tindak balas II

KCl + AgNO3

AgCl + KNO3

H = -50.4 kJ mol-1

Energy

Tenaga



Based on Diagram 10, compare the energy level diagram between Reaction I and

Reaction II.

Berdasarkan Rajah 10, bandingkan gambar rajah aras tenaga antara Tindak balas I dan Tindak balas II.

[3 marks]

(b) Table 9 shows the molecular formula and the heat of combustion for propanol

and butanol.

Jadual 9 menunjukkan formula molekul dan haba pembakaran bagi propanol dan butanol

Alcohol

Alkohol

Molecular Formula

Formula molekul

Heat of combustion/ kJ mol-1

Haba Pembakaran/ kJ mol -1

Propanol Propanol

C3H7OH -2100

Butanol

Butanol C4H9 OH -2877

Based on the information in Table 9, compare the heat of combustion between

propanol and butanol. Explain why there is a difference in the values of the heat

of combustion between propanol and butanol.

Berdasarkan maklumat dalam Jadual 9 , bandingkan haba pembakaran di antara propanol dan butanol. Terangkan mengapa mengapa terdapat perbezaan antara

nilai haba pembakaran bagi propanol dan butanol

[3 marks](c) In an experiment to determine the heat of displacement, excess zinc is added to

100 cm3 of 0.5 mol dm-3 silver nitrate solution. Calculate the temperature change

if the heat of displacement is −105 kJmol-1.

[Specific heat capacity of the solution = 4.2 J g-1 oC-1;Density of the solution = 1 g cm -3]

Dalam eksperimen untuk menentukan haba penyesaran, zink berlebihan

ditambahkan kepada 100 cm3 0.5 mol dm-3 larutan argentum nitrat. Hitungkanperubahan suhu jika haba penyesaran dalam eksperimen itu ialah -105 kJ mol -1.

[Muatan haba tentu larutan = 4.2 J g -1 OC -1 ;

Ketumpatan larutan= 1 g cm-3 ][4 marks]

20

Diagram 10 Rajah 10

Table 9 Jadual 9



(d) By using a named example of an alcohol, describe a laboratory experiment to

determine the heat of combustion.

In your description, include a labeled diagram and the calculations involved.[Relative atomic mass: C =12, O =16, H = 1]

[Specific heat capacity of solution = 4.2 J g-1 OC-1 ; Density of solution = 1 g cm-3 ]

Dengan menggunakan satu contoh alkohol yang dinamakan, huraikan satueksperimen makmal untuk menentukan haba pembakaran.

Dalam penerangan anda sertakan gambar rajah berlabel dan langkah pengiraan

yang terlibat.[Jisim atom relatif: C =12, O =16, H = 1]

[Muatan haba tentu larutan = 4.2 J g -1 OC -1 ; Ketumpatan larutan = 1 g cm-3

[10 marks]

10 (a) Diagram 10 shows types of salts.

Jadual 10 menunjukkan jenis-jenis garam.

Potassium carbonate, Zinc carbonate

Sodium sulphate, lead(II) sulphate

Diagram 10

Rajah 10Based on Diagram 10, choose two salts which are insoluble in water

Berdasarkan Rajah 10, pilih dua garam tak larut dalam air.

[2 marks]

(b) Zinc chloride salt is soluble in water.

Describe the preparation of zinc chloride in the laboratory.

In your description, include chemical equation involved. Zink klorida adaalah larut dalam air.

Huraikan penyediaan zink kjlorida dalam makmal.

Dalam huraian anda, sertakan persamaan kimia yangt terlibat .[10 marks]

(c) The labels on the reagent bottles containing zinc sulphate and zinc nitrate were

removed. Using suitable chemical substances, explain briefly how you conduct thechemical tests in the laboratory to identify both solution in the reagent bottles.

[8 marks]

21



MARKING SCHEME OF POPULAR CHEMISTRY QUESTIONS 2013

SECTION A

Question Description Mark

1 (a) (i) Saponification 1

(ii) Ester 1

(iii) To reduce the solubility of soap in water//

To precipitate the soap

1

(iv) Potassium hydroxide 1

(b) (i) Water that contains calcium / magnesium ions

(ii) Soaps form scum

Detergents do not form scum

1

1

(c) (i) Function: To slow down/ prevent the growth of bacteria and fungi/

microorganisms

Type: Antioxidants

1

1

(ii) Headache/ nausea/ thirsty/ chest pain/ difficulty breathing 1

Total 10

Question Description Mark

2 (a) (i) Proton, electron and neutron 1

(ii)

[shows 2.8.8]

1

(iii) V and X

Because both have the same proton number but different in nucleon number

1

1

(iv) Group 1, Period 4 1

(v) 18 1

22

−



(b) (i)

Q: or

-Minimum three layers.

-No overlapping

-All particles must touch each other

R:

1

1

(ii) K = 65oC

Because the heat loss to the surroundings is exactly balanced by the heat

energy liberated / released as the particles attract one another to form a solid.

Or

During freezing process, the particles of Q arrange closer to each other (to

form stronger forces of attraction). This arrangement release heat energy which

is equal to the heat loss to the surroundings.

1

1

Total 10

3 (a) Electrolyte is chemical substances that conduct electricity in molten

or aqueous and undergoes chemical reaction.

1

(b) Na+ , Cl- , H+, OH- 1

Hydrogen 1

(c) (i) 2H+ + 2e H2 1

(ii) Hydrogen ion selected to discharge//

Hydrogen ion accept electron to formed hydrogen molecules

1

(d) (i) Chlorine gas 1(ii) 2Cl- Cl2 + 2e 1

(iii) Concentration of electrolyte 1

Functional diagram

labelled

1+1

Total 10

23



4 (a) Chemical substance which ionise completely in water to form hydroxide ion

1

(b) (i) Sulphuric acid 1

(ii) Lowest pH value

(c) (i) Phenolphthalein // Methyl orange 1

(ii) Pink to colourless // Yellow to arange 1

(iii) H2SO4 + 2NaOH → Na2 SO4 + 2H2O

[Chemical formulae of reactants and products]

[ Balanced ]

1

1

(iv)

Number of mole of H2SO4 = 0.5 × 20 = 0.01 mol

mole H2SO4 : mole NaOH

0.01 : 0.02 //

1: 2

X = 0.8 mol dm-3

1

1

1

TOTAL 10

5 (a) (i) To detect the presence of iron(II) ions / Fe2+. 1

(ii) Fe → Fe2+ + 2e 1

(iii) Test tube B.

Iron/Ferum is more electropositive than P.

1

1

(iv) Q, Fe, P 1

(b) (i) …5…Fe2+ + MnO4- + 8H+ → 5Fe3+ + Mn2+ + …4... H2O 1

(ii) purple to colourless 1

(iii) Iron(II) ion // Fe2+

Oxidation number of iron increased // Fe2+ donate electron

1

1

(iv) Add sodium hydroxide/ammonia solution.

Brown precipitate formed.

1

1

Total 11

6 (a) 2C3H8O + 9O2 6CO2 + 8H2O//C3H8O + 9/2O2 3CO2 + 4H2O//

1

(b) (i) Oxidation 1

(ii) Add 2 cm3 of dilute sulphuric acid into a test tube that containing 2 cm 3

potassium manganate (VII) solution/potassium dichromate (VI) solution

Pour 2 cm3 of alcohol J into the above acidified solution

1

1

(iii

)

1 + 1

24



(c) (i) Propyl propanoate 1

(ii) Sweet / pleasant smell 1

(d) Flow / Bubble propene and propane into two different test tubes

containing bromine water / acidified potassium manganate(VII)

Propene : Brorwn / purple turns colourless

Propane : no change

1

1

Total

10

SECTION B

7 (a) Atom R has 7 valence electrons and 3 shells occupied with electrons.

Thus, R is located at Group 17 and Period 3.

1+1

1+1

(b) 1. Atom Q has electron arrangement of 2.8.2 / 2 valence electrons.

2. Atom Q losses 1 electron/the single valence electron to achieve the stable

octet electron arrangement/2.8.8

3. An positive ion, Q2+ is formed

4. Atom R has electron arrangement of 2.8.7 / 7 valence electrons.5. Two atoms R, each receives 1 electron from atom Q to achieve the stable

octet electron arrangement/2.8.8

6. Two negative ions, R − are formed.

7. An ion Q2+ and two ion R - are attracted together by strong electrostatic

forces.

1

1

1

1

1

1

1

7

(c) (i)

(ii)

CR 4 1

2

25

C

R

R

R

R



3

(d) Melting pointCompound (b) has high melting point whereas compound (c) has lowmelting point.

Compound (b) consists of negative and positive ions which are held

together by strong electrostatic forces.[A lot of energy is required to overcome the strong forces.]

Compound (c) consists of molecule which are held together by weak

intermolecular forces.[Less energy is required to overcome the weak intermolecular forces.]

Electrical conductivity

Compound (b) can conduct electricity in liquid or aqueous solution state.Compound (c) can not conduct electricity in any state.

In liquid or aqueous solution state, the ions in the compound (b) can move

freely.

Compound (c) does not consists of free moving ions.

1

1

1

1

1

1

6

Total 20

8 (a) N2 + 3H2 2NH3 1

• Use iron as catalyst

•The reaction is carried out in high temperature /450

o

C to 550o

C• The reaction is carried out in high pressure/200 atm

1

11

4

(b) (i) Experiment I

Copper(II) sulphate / copper sulphate

1

1

2

26



(ii)

• Label of energy on vertical axis

• The position of the energy level of the reactants is higher than the

energy level of the product.

• Correct position for Ea

• Correct position for E’a

1

1

1

1

4

(iii) 1. When a catalyst/copper(II) sulphate is used in Experiment I,

it provides an alternative path with a lower the activation energy / lower the

activation energy.

2. More colliding particles /zinc atoms and hydrogen ions are able to overcome

that lower activation energy.

3. This causes the frequency of effective collision increases.

4. Hence, the rate of reaction of Experiment I increases.

1

1

1

1

4

(c)

27

Energy

Reaction path

EaE’

a

Zn + 2HCl

ZnCl2

+ H2



• Correct position of the curve of Experiment I

• Correct position of the curve of Experiment II

• Correct position of the curve of Experiment III

1

1

1

3

• The volume of carbon dioxide gas in Experiment I is the same as in

Experiment II.

• The concentration of H+ ions in Experiment I and Experiment II is the

same.

• The volume of carbon dioxide gas in Experiment III is double/two times

greater than in Experiment II.

• The concentration of H+ ions in Experiment III is double then in

Experiment II //

The concentration/number of hydrogen ions in sulphuric acid is double/two

times the concentration/number of hydrogen ions in hydrochloric acid //

Suphuric acid is a diprotic acid whereas hydrochloric acid is a monoproticacid.

1

1

1

1

Max

3

Total 20

28

Volume of carbon dioxide

(cm3)

Time (s)

Experiment III

Experiment I

Experiment II



SECTION C

29



30

9 (a)

Reaction I Reaction II

Endothermic//heat absorbed from the

surrounding

Exothermic//heat released

to the surrounding

The total energy of content of calcium nitrate

and potassium carbonate/reactant is lower than

the total energy content of calcium carbonateand potassium nitrate/product

The total energy of the

content of zinc and

copper(II)sulphate/reactants is higher

than the total energy

content of zinc sulphate

and copper/productHeat absorbed during the reaction is 66 kJ mol -1 Heat released during thereaction is 50.4 kJ mol-1

(b) Heat of combustion of butanol is higher than propanolThe molecular size/number of carbon atom per molecule butanol is bigger/higher

than propanol

Butanol produce more carbon dioxide and water molecules than propanol//releasedmore heat energy

(c ) Methanol/ethanol/ propanol,

Diagram:

-labelled diagram

-arrangement of apparatus is functional

Procedure :

1. (100-250 cm3 )of water is measured and poured into a copper can and the

copper can is placed on a tripod stand

2. The initial temperature of the water is measured and recorded

3. A spirit lamp with ethanol is weighed and its mass is recorded4. The lamp is then placed under the copper can and the wick of the lamp is

lighted up immediately

5. The water in the can is stirred continuously until the temperature of the water increases by about 30oC.

6. The flame is put off and the highest temperature reached by the water isrecorded.



10 (a) Zinc carbonate

Lead(II) sulphate

(b) 1 Pour 50 cm3 of 1.0 mol dm-3 hydrochloric acid into a beake and heat it gently.2 Add zinc oxide powder bit by bit to the acid until some of it no longer

dissolves

3 Stir the mixture.

4 Filter the solution mixture to remove the excess powder 5 Pour the filtrate into an evaporating dish

6 Heat the solution gently until become saturated solution

7 Allow the solution to cool to room temperature

8 Filter out the crystals

9 Dry by pressing between a few pieces of filter papers

10 The chemical equation to represent the reaction is:-

ZnO + 2 HCl ZnCl2 + H2O

(c ) Confirmatory test for Zn2+

1 Add ammonia solution to the solution containing Zn2+

2 White precipitate formed and dissolved in excess ammonia solution.

Confirmatory test for SO42- :-

3 Add a little dilute hydrochloric acid into a test tube containing containingSO4

2-

4 Add a little barium chloride solution to the solution

5 White precipitate formed

Confirmatory test for NO3- :-

6 Add dilute alittle dilute sulphuric acid into a test tube containing NO 3-

7 Add a little iron(II) sulphate solutiuon8 Add slowly//carefully//drop by drop of concentrated sulphuric acid

9 Brown ring formed M

Total

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