chemistry paper 2 popular.doc
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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
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(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
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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]
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(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]
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(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
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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
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(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]
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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.
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(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]
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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
Agar-agar solution with potassium
hexacyanoferrate(III) and
phenolphthalein solution.
Larutan agar-agar dengan larutankalium heksianoferat( III ) dan
fenolftalein
Iron nail
Paku besi
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 Q
Paku besi dililit dengan logam Q
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…………………………………………………………………………...
[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
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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]
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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
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(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.
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......................…………………………………………………………………..
[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]
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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
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(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
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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
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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
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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
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(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]
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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
−
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(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
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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
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(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
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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
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(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
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• 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
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SECTION C
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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.
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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