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A1 © Penerbitan Pelangi Sdn. Bhd. 0 60 10 20 30 40 Total volume of gas collected (cm 3 ) Jumlah isi padu gas yang terkumpul (cm 3 ) 120 180 240 300 360 420 480 Time (s) Masa (s) 1.3 GUIDED Experiment Results Experiment I: Hydrochloric acid, HCI with large pieces of marble chips Eksperimen I: Asid hidroklorik, HCl dengan serpihan marmar yang besar Time (s) Masa (s) Burette reading (cm 3 ) Bacaan buret (cm 3 ) Total volume of gas collected (cm 3 ) Jumlah isi padu gas yang terkumpul (cm 3 ) 0 50.00 0.00 30 46.00 4.00 60 41.00 9.00 90 38.00 12.00 120 34.00 16.00 150 31.00 19.00 180 28.00 22.00 210 25.00 25.00 240 22.00 28.00 270 20.00 30.00 300 18.00 32.00 330 16.00 34.00 360 14.00 36.00 390 12.00 38.00 420 11.00 39.00 450 11.00 39.00 480 11.00 39.00 1 Chapter Rate of Reaction Kadar Tindak Balas 1.1 INQUIRY Experiment Observation Test tube Tabung uji Observation Pemerhatian I Effervescence occurred immediately. Effervescence stopped after a few seconds. Pembuakan berlaku dengan serta-merta. Pembuakan berhenti selepas beberapa saat. II A yellow precipitate was formed only after five seconds. Mendakan kuning terbentuk hanya selepas lima saat. III A white precipitate was formed immediately. Mendakan putih terbentuk dengan serta-merta. 1.2 INQUIRY Experiment Results Time (s) Masa (s) Burette reading (cm 3 ) Bacaan buret (cm 3 ) Total volume of gas collected (cm 3 ) Jumlah isi padu gas yang terkumpul (cm 3 ) 0 50.00 0.00 30 41.50 8.50 60 35.00 15.00 90 31.00 19.00 120 28.00 22.00 150 25.00 25.00 180 22.50 27.50 210 21.00 29.00 240 19.50 30.50 270 18.00 32.00 300 17.00 33.00 330 16.50 33.50 360 16.00 34.00 390 15.50 34.50 420 15.00 35.00 450 15.00 35.00 480 15.00 35.00 Answers

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A1 © Penerbitan Pelangi Sdn. Bhd.

060

10

20

30

40

Total volume of gas collected (cm3)Jumlah isi padu gas yang terkumpul (cm3)

120 180 240 300 360 420 480Time (s)Masa (s)

1.3 GUIDED Experiment

Results

Experiment I: Hydrochloric acid, HCI with large pieces of marble chipsEksperimen I: Asid hidroklorik, HCl dengan serpihan marmar yang besar

Time (s)Masa (s)

Burette reading (cm3)Bacaan buret

(cm3)

Total volume of gas collected (cm3)

Jumlah isi padu gas yang terkumpul (cm3)

0 50.00 0.00

30 46.00 4.00

60 41.00 9.00

90 38.00 12.00

120 34.00 16.00

150 31.00 19.00

180 28.00 22.00

210 25.00 25.00

240 22.00 28.00

270 20.00 30.00

300 18.00 32.00

330 16.00 34.00

360 14.00 36.00

390 12.00 38.00

420 11.00 39.00

450 11.00 39.00

480 11.00 39.00

1Chapter Rate of Reaction

Kadar Tindak Balas

1.1 INQUIRY Experiment

Observation

Test tubeTabung

uji

ObservationPemerhatian

I

Effervescence occurred immediately. Effervescence stopped after a few seconds.Pembuakan berlaku dengan serta-merta. Pembuakan berhenti selepas beberapa saat.

IIA yellow precipitate was formed only after five seconds.Mendakan kuning terbentuk hanya selepas lima saat.

III A white precipitate was formed immediately.Mendakan putih terbentuk dengan serta-merta.

1.2 INQUIRY Experiment

Results

Time (s)Masa (s)

Burette reading (cm3)

Bacaan buret (cm3)

Total volume of gas collected (cm3) Jumlah isi padu gas yang terkumpul (cm3)

0 50.00 0.0030 41.50 8.5060 35.00 15.0090 31.00 19.00120 28.00 22.00150 25.00 25.00180 22.50 27.50210 21.00 29.00240 19.50 30.50270 18.00 32.00300 17.00 33.00330 16.50 33.50360 16.00 34.00390 15.50 34.50420 15.00 35.00450 15.00 35.00480 15.00 35.00

Answers

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A2© Penerbitan Pelangi Sdn. Bhd.

Experiment II: Hydrochloric acid, HCI with crushed marble chipsEksperimen II: Asid hidroklorik, HCl dengan serpihan marmar yang kecil

Time (s)Masa (s)

Burette reading (cm3)

Bacaan buret (cm3)

Total volume of gas collected (cm3)

Jumlah isi padu gas yang terkumpul (cm3)

0 50.00 0.00

30 42.00 8.00

60 35.00 15.00

90 30.00 20.00

120 25.00 25.00

150 20.00 30.00

180 17.00 33.00

210 14.00 36.00

240 12.00 38.00

270 11.00 39.00

300 11.00 39.00

330 11.00 39.00

360 11.00 39.00

390 11.00 39.00

420 11.00 39.00

450 11.00 39.00

480 11.00 39.00

060

10

20

30

40

120 180 240 300 360 420 480

Total volume of gascollected (cm3)Jumlah isi padu gasyang terkumpul (cm3)

Time (s)Masa (s)

Experiment II : Crushed marble chipsEksperimen II : Serpihan marmar yang kecil

Experiment I : Large pieces of marble chipsEksperimen I : Serpihan marmar yang besar

1.4 GUIDED Experiment

Results

Experiment / Eksperimen 1 2 3 4 5

Volume of 0.2 mol dm–3 thiosulphate, Na2S2O3 solution,

V1 (cm3) Isi padu larutan natrium tiosulfat,

Na2S2O3 0.2 mol dm–3, V1 (cm3)

45 40 35 30 25

Volume of distilled water (cm3) Isi padu air suling (cm3) 0 5 10 15 20

Volume of 1.0 mol dm–3 sulphuric acid, H2SO4 (cm3)

Isi padu asid sulfurik, H2SO4 1.0 mol dm–3 (cm3)

5 5 5 5 5

Total volume of reactants, V2 (cm3)

Jumlah isi padu bahan tindakan, V2 (cm3)

50 50 50 50 50

Concentration of sodium thiosulphate, Na2S2O3 solution,

MV1——–V2

(mol dm–3)

Kepekatan larutan natrium tiosulfat, Na2S2O3 ,

MV1——–V2

(mol dm–3)

0.18 0.16 0.14 0.12 0.10

Time taken for the ‘X’ mark to disappear from view, t (s)

Masa yang diambil bagi tanda‘X’ tidak kelihatan, t (s)

16 20 27 41 83

1——–Time , 1––t (s–1) / 1——–Masa

, 1––t (s–1) 0.063 0.050 0.037 0.024 0.012

A Graph of concentration of sodium thiosulphate, Na2S2O3 solution (mol dm–3) against time (s)

Graf kepekatan larutan natrium tiosulfat, Na2S2O3 (mol dm–3) melawan masa (s)

100 20 30 40 50 60 70 80 90

0.020.040.060.080.100.120.140.160.180.20

Time (s)Masa (s)

Concentration of sodium thiosulphate, Na2S2O3 solution (mol dm–3)Kepekatan natrium tiosulfat, Na2S2O3 (mol dm–3)

Chemistry Form 5 Answers

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A3 © Penerbitan Pelangi Sdn. Bhd.

B Graph of concentration of sodium thiosulphate, Na2S2O3 solution (mol dm–3) against 1—–—–Time (s–1)

Graf kepekatan larutan natrium tiosulfat, Na2S2O3 (mol dm–3)

melawan 1——–Masa (s–1)

00.01 0.02 0.03 0.04 0.05 0.06 0.07

Concentration of sodium thiosulphate, Na2S2O3 solution (mol dm–3)Kepekatan natrium tiosulfat, Na2S2O3 (mol dm–3)

0.020.040.060.080.100.120.140.160.180.20

1Time

(s–1)––––

1Masa

(s–1)––––

1.5 UNGUIDED Experiment

Results

ExperimentEksperimen

Temperature (°C)

Suhu (°C)

Time taken for the ‘X’ mark to disappear from

view, t (s)Masa yang

diambil bagi tanda ‘X’ tidak kelihatan, t (s)

1———Time, 1—t

(s–1)

1———Masa

, 1—t

(s–1)

1 28 55 0.0182 40 36 0.0283 50 23 0.0434 60 17 0.0595 70 13 0.077

Graph of temperature of sodium thiosulphate, Na2S2O3 solution (°C) against 1———time (s–1)

Graf suhu larutan natrium tiosulfat, Na2S2O3 (°C) melawan 1———

masa (s–1)

00.02

20

40

60

0.04 0.06 0.08 0.10

Temperature (°C)Suhu (°C)

1Time––––(s–1)

1Masa–––– (s–1)

1.6 INQUIRY Experiment

Results

Test tubeTabung uji

ObservationPemerhatian

A

No effervescence. The glowing wooden splinter did not relight.Tiada pembuakan. Kayu uji berbara tidak menyala semula.

B

Effervescence occurred. The glowing wooden splinter relighted and burned brightly.Pembuakan berlaku. Kayu uji berbara menyala semula dan terbakar dengan terang.

1.7 GUIDED Experiment

Results

Experiment I: Decomposition of hydrogen peroxide, H2O2 with the presence of 0.2 g of manganese(IV) oxide, MnO2 powderEksperimen I: Penguraian hidrogen peroksida, H2O2 dengan kehadiran 0.2 g serbuk mangan(IV) oksida, MnO2

Time (s)Masa (s) 0 30 60 90 120 150 180 210

Burette reading (cm3)Bacaan buret (cm3)

50.00 36.00 25.00 18.00 13.00 10.00 8.00 7.00

Total volume of gas collected (cm3)Jumlah isi padu gas yang terkumpul (cm3)

0.00 14.00 25.00 32.00 37.00 40.00 42.00 43.00

Chemistry Form 5 Answers

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A4© Penerbitan Pelangi Sdn. Bhd.

Time (s)Masa (s) 240 270 300 330 360 390 420

Burette reading (cm3)Bacaan buret (cm3)

5.00 3.00 1.00 0.00 0.00 0.00 0.00

Total volume of gas collected (cm3)Jumlah isi padu gas yang terkumpul (cm3)

45.00 47.00 49.00 50.00 50.00 50.00 50.00

Experiment II: Decomposition of hydrogen peroxide, H2O2 with the presence of 0.8 g of manganese(IV) oxide, MnO2 powderEksperimen II: Penguraian hidrogen peroksida, H2O2 dengan kehadiran 0.8 g serbuk mangan(IV) oksida, MnO2

Time (s)Masa (s) 0 30 60 90 120 150 180 210

Burette reading (cm3)Bacaan buret (cm3)

50.00 33.00 19.00 11.00 6.00 3.00 0.00 0.00

Total volume of gas collected (cm3)Jumlah isi padu gas yang terkumpul (cm3)

0.00 17.00 31.00 39.00 44.00 47.00 50.00 50.00

Time (s)Masa (s) 240 270 300 330 360 390 420

Burette reading (cm3)Bacaan buret (cm3)

0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total volume of gas collected (cm3)Jumlah isi padu gas yang terkumpul (cm3)

50.00 50.00 50.00 50.00 50.00 50.00 50.00

0 60

10

20

30

40

Experiment IIEksperimen II

Experiment IEksperimen I

50

120 180 240 300 360 420 480

Total volume of gas collected (cm3)Jumlah isi padu gas yangterkumpul (cm3)

Time (s)Masa (s)

SPM ReviewSPM Review 11Objective Questions

1. C 2. D 3. C 4. C 5. D 6. A 7. B 8. A 9. B 10. B 11. C 12. A 13. C 14. A 15. C 16. D 17. D 18. C 19. B

Subjective Questions

Section A / Bahagian A

1. (a) GasGas

BasinBesen

BuretteBuret Water

AirHydrochloric acid, HClAsid hidroklorik, HCl

Marble chipsSerpihan marmar

Delivery tubeSalur penghantar

Chemistry Form 5 Answers

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A5 © Penerbitan Pelangi Sdn. Bhd.

(b) CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l) CaCO3(p) + 2HCl(ak) → CaCl2(ak) + CO2(g) + H2O(ce)

(c) Average rate of reaction in Experiment I Kadar tindak balas purata bagi Eksperimen I

= 20—–60 = 0.33 cm3 s–1

(d) (i) Experiment II Eksperimen II

(ii) This is because the concentration of hydrochloric acid in Experiment II is higher than that in Experiment I.

Ini kerana kepekatan asid hidroklorik bagi Eksperimen II adalah lebih tinggi daripada Eksperimen I.

(iii) • The number of H+ ions per unit volume in Experiment II is higher than that in Experiment I.

Bilangan ion-ion H+ per unit isi padu dalam Eksperimen II adalah lebih tinggi daripada Eksperimen I.

• The frequency of collision between H+ ions and marble chips in Experiment II is higher than that in Experiment I.

Frekuensi perlanggaran antara ion-ion H+ dan serpihan marmar dalam Eksperimen II adalah lebih tinggi daripada Eksperimen I.

• Hence, the frequency of effective collision in Experiment II is higher than that in Experiment I.

Maka, frekuensi perlanggaran berkesan dalam Eksperimen II adalah lebih tinggi daripada Eksperimen I.

(e) Volume of gas collected (cm3)Isi padu gas yang terkumpul (cm3)

Time (s)Masa (s)

Experiment IIEksperimen II

Experiment IEksperimen I

40

20

60

2. (a) K2S2O3 + 2HCl ➔ 2KCl + SO2 + S + H2O

(b) (i) 5.01000

× 0.1 = 0.005 mol

(ii) 5.01000

× 1.0 = 0.005 mol

(c) Hydrochloric acid Asid hidroklorik

(d) (i) Concentration / temperature of potassium thiosulphate solution / hydrochloric acid

Kepekatan / suhu larutan kalium tiosulfat / asid hidroklorik

(ii) Higher concentration / temperature of potassium thiosulphate solution / hydrochloric acid increases the frequency of effective collision between tiosulphate ions and hydrogen ions.

Kepekatan / suhu larutan kalium tiosulfat / asid hidroklorik yang lebih tinggi meningkatkan frekuensi perlanggaran berkesan antara ion-ion tiosulfat dan ion-ion hidrogen

Section B / Bahagian B 3. (a) • The pressure in a pressure cooker is higher than

the atmospheric pressure. [1] Tekanan di dalam periuk tekanan adalah lebih tinggi

daripada tekanan atmofera.• A pressure cooker enables water to boil at a

temperature higher than 100°C. [1] Periuk tekanan membolehkan air mendidih pada suhu

lebih tinggi daripada 100°C.• Thus, the rate of cooking of food increases. [1] Dengan demikian, kadar makanan menjadi masak

bertambah.

(b) (i) Experiment I: Average rate of reaction in the first two minutes

Eksperimen I: Kadar tindak balas purata dalam dua minit yang pertama

20.0 = —–— = 0.167 cm3 s–1 [1] 120 Experiment II: Average rate of reaction in the

first two minutes Eksperimen II: Kadar tindak balas purata dalam dua

minit yang pertama 16.0 = —–— = 0.133 cm3 s–1 [1] 120 Experiment III: Average rate of reaction in the

first two minutes Eksperimen III: Kadar tindak balas purata dalam dua

minit yang pertama 32.0 = —–— = 0.267 cm3 s–1 [1] 120

(ii) Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g) [1] Zn(p) + H2SO4(ak) → ZnSO4(ak) + H2(g)

0.2 × 20 Number of moles of H2SO4 = ——–—–– Bilangan mol H2SO4

1000 = 0.004 mol [1] Number of moles of hydrogen gas Bilangan mol gas hidrogen = 0.004 mol [1] Maximum volume of hydrogen gas Isi padu maksimum gas hidrogen = 0.004 × 24 000 = 96 cm3 [1](iii) 96 cm3 [1]

Chemistry Form 5 Answers

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A6© Penerbitan Pelangi Sdn. Bhd.

(iv)

Time (minute)Masa (minit)

Experiment IEksperimen I

Experiment IIEksperimen II

Experiment IIIEksperimen III

Volume of gas collected (cm3)Isi padu gas yang terkumpul (cm3)

96

2

32

20

16

[3](v) (i) Experiment I and experiment II: Eksperimen I dan eksperimen II:

• The rate of reaction in experiment I is higher than that of experiment II. [1]

Kadar tindak balas bagi ekperimen I adalah lebih tinggi daripada eksperimen II.

• This is because zinc powder has a bigger total surface area than zinc chips. [1]

Ini adalah kerana serbuk zink mempunyai jumlah luas permukaan yang lebih besar daripada ketulan zink.

• Hence, the frequency of collision of hydrogen ions at the surface of zinc increases and the frequency of effective collision increases. [1]

Maka, frekuensi perlanggaran ion-ion hidrogen pada permukaan zink meningkat dan frekuensi perlanggaran berkesan meningkat.

(ii) Experiment I and experiment III: Eksperimen I dan eksperimen III:

• The rate of reaction in experiment III is higher than that of experiment I. [1]

Kadar tindak balas eksperimen III adalah lebih tinggi daripada eksperimen I.

• This is because copper(II) sulphate solution lowers the activation energy. [1]

Ini adalah kerana larutan kuprum(II) sulfat merendahkan tenaga pengakitfan.

• More particles that collide against each other are able to overcome the lower activation energy. Thus, the frequency of effective collision increases. [1]

Lebih banyak zarah-zarah yang berlanggaran dapat mengatasi tenaga pengaktifan yang lebih rendah itu. Maka, frekuensi perlanggaran berkesan meningkat.

Section C / Bahagian C

4. (a) (i) A chemical substance which alters the rate of a chemical reaction but remains chemically unchanged at the end of reaction. [2]

Satu bahan kimia yang mengubah kadar suatu tindak balas kimia tetapi tidak berubah secara kimia pada akhir tindak balas.

(ii) Reactant: Hydrogen peroxide solution [1] Bahan tindak balas: Larutan hidrogen peroksida

Products: Oxygen gas and water [1] Hasil tindak balas: Gas oksigen dan air Catalyst: Manganese(IV) oxide powder [1] Mangkin: Serbuk mangan(IV) oksida

(b) (i) Carbon dioxide gas, CO2

Gas karbon dioksida, CO2

Delivery tubeSalur penghantar

Nitric acid, HNO3

Asid nitrik, HNO3

BasinBesen

BuretteBuret Water

Air

Marble chipsSerpihan marmar [2]

(ii) Procedure: Prosedur:

1. A burette is filled with water until it is full and it is inverted in a basin of water. The burette is clamped onto a retort stand. [1]

Sebuah buret diisi dengan air sehingga penuh dan ditelangkupkan ke dalam sebuah besen berisi air. Buret itu diapitkan pada sebuah kaki retort.

2. The meniscus of the water in the burette is adjusted to a reading of 50 cm3. It is recorded as the initial burette reading. [1]

Meniskus air di dalam buret diselaraskan kepada bacaan 50 cm3. Bacaan itu direkodkan sebagai bacaan awal buret.

3. 20 cm3 of 0.2 mol dm–3 nitric acid is measured into a conical flask. [1]

20 cm3 asid nitrik 0.2 mol dm–3 disukat ke dalam sebuah kelalang kon.

4. 2 g of marble chips (in excess) is weighed using an electronic balance. [1]

2 g serpihan marmar (berlebihan) ditimbang dengan menggunakan sebuah penimbang elektronik.

5. The marble chips are added into the conical flask. [1]

Serpihan marmar itu ditambahkan ke dalam kelalang kon itu.

6. The conical flask is immediately stoppered as shown in the diagram and the stopwatch is started. [1]

Kelalang kon itu ditutup dengan penyumbat dengan serta-merta seperti yang ditunjukkan dalam rajah dan jam randik dimulakan.

7. The conical flask is shaken throughout the experiment. [1]

Kelalang kon itu digoncang sepanjang eksperimen.

8. The volume of gas collected in the burette is recorded at intervals of 30 seconds for a period of 8 minutes. [1]

Isi padu gas yang terkumpul di dalam buret direkodkan pada setiap sela masa 30 saat selama 8 minit.

Chemistry Form 5 Answers

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A7 © Penerbitan Pelangi Sdn. Bhd.

Graph: Graf: A graph of the volume of gas collected against

time is plotted. [1] Graf isi padu gas yang terkumpul melawan masa

diplotkan.

Volume of gas collected (cm3)Isi padu gas yang terkumpul (cm3)

Time (minute)Masa (minit)

[2] The gradient of the graph decreases with time.

Therefore, the rate of reaction decreases as the reaction proceeds. [1]

Kecerunan graf berkurangan dengan masa. Maka kadar tindak balas berkurangan apabila tindak balas dibiarkan berterusan.

(iii) Chemical equation: Persamaan kimia: CaCO3(s) + 2HNO3(aq) → Ca(NO3)2(aq) + CO2(g) + H2O(l) CaCO3(p) + 2HNO3(ak) → Ca(NO3)2(ak) + CO2(g) + H2O(ce) [1] Note / Nota: The rate of reaction can also be studied by

measuring the change in mass of the conical flask and its contents against time.

Kadar tindak balas juga boleh dikaji dengan mengukur perubahan jisim kelalang kon dan kandungannya melawan masa.

2Chapter Carbon Compounds

Sebatian Karbon

2.1 INQUIRY Experiment

Observation

ActivityAktiviti

ObservationPemerhatian

Hexane, C6H14Heksana, C6H14

Hex-1-ene, C6H12Heks-1-ena, C6H12

I

It burned with a sooty yellow flame.Ia terbakar dengan nyala kuning berjelaga.

It burned with a very sooty yellow flame.Ia terbakar dengan nyala kuning yang sangat berjelaga.

II

The brown colour of bromine solution remained unchanged.Warna perang larutan bromin tidak berubah.

The brown bromine solution was decolourised immediately.Warna perang larutan bromin dinyahwarnakan dengan serta-merta

III

The purple colour of acidified potassium manganate(VII), KMnO4 solution remained unchanged.Warna ungu larutan kalium manganat(VII), KMnO4 berasid tidak berubah.

The purple acidified potassium manganate(VII), KMnO4 solution was decolourised immediately.Warna ungu larutan kalium manganat(VII), KMnO4 berasid dinyahwarnakan dengan serta-merta.

2.2 INQUIRY Experiment

Observation

Carbohydrate used

Karbohidrat yang digunakan

ObservationPemerhatian

Glucose, C6H12O6

Glukosa, C6H12O6

Foams were formed in the fermented mixture. A colourless gas that turned lime water milky was liberated. The distillate was a colourless liquid with a sharp smell.Banyak buih terbentuk dalam ampaian penapaian. Gas tidak berwarna yang mengeruhkan air kapur terbebas. Hasil sulingan merupakan cecair tidak berwarna yang berbau tajam.

Mashed pineapple and its juiceNanas terhancur dengan jusnya

Foams were formed in the fermented mixture. A colourless gas that turned lime water milky was liberated. The distillate was a colourless liquid with a sharp smell.Banyak buih terbentuk dalam ampaian penapaian. Gas tidak berwarna yang mengeruhkan air kapur terbebas. Hasil sulingan merupakan cecair tidak berwarna yang berbau tajam.

2.3 INQUIRY Experiment

Observation

Activity I: Combustion of ethanol, C2H5OHAktiviti I: Pembakaran etanol, C2H5OH

Aspect testedAspek yang

diujikan

ObservationPemerhatian

CombustibilityKebolehbakaran

The colourless liquid was easily ignited by the lighted wooden splinter.Cecair tidak berwarna senang dinyalakan oleh kayu uji menyala.

Colour and sootiness of the flameWarna dan kejelagaan nyala

The colourless liquid burned with a non-luminous and non-sooty blue flame.Cecair tidak berwarna terbakar dengan nyala biru yang tidak berkilau dan tidak berjelaga.

Chemistry Form 5 Answers

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Activity II: Oxidation of ethanol, C2H5OHAktiviti II: Pengoksidaan etanol, C2H5OH

Aspect testedAspek yang diujikan

ObservationPemerhatian

Reaction mixtureCampuran bahan tindak balas

The colour of the reaction mixture changed from an orange solution to a green solution.Warna campuran bahan tindak balas berubah daripada larutan jingga kepada larutan hijau.

DistillateHasil sulingan

The distillate was a colourless liquid with a vinegar smell. It turned moist blue litmus paper to red.Hasil sulingan adalah suatu cecair tidak berwarna yang berbau cuka. Ia menukarkan kertas litmus biru lembap kepada merah.

Activity III: Dehydration of ethanol, C2H5OHAktiviti III: Pendehidratan etanol, C2H5OH

Aspect testedAspek yang diujikan

ObservationPemerhatian

Colour and physical state of the productWarna dan keadaan fizik bagi hasil

A colourless gas was collected.Gas tidak berwarna dikumpulkan.

Test with bromine waterDiuji dengan air bromin

The gas decolourised the reddish-brown bromine water.Gas yang terkumpul menyahwarnakan warna perang-kemerahan air bromin.

Test with acidified potassium manganate(VII), KMnO4 solutionDiuji dengan larutan kalium manganat(VII), KMnO4 berasid

The gas decolourised the purple potassium manganate(VII), KMnO4 solution.Gas yang terkumpul menyahwarnakan warna ungu larutan kalium manganat(VII), KMnO4 berasid.

2.4 INQUIRY Experiment

Observation

Reaction withTindak balas

dengan

ObservationPemerhatian

MagnesiumMagnesium

Effervescence occurred. A colourless gas that exploded with a ‘pop’ sound was liberated when tested with a lighted wooden splinter.Pembuakan berlaku. Gas tidak berwarna yang meletup dengan bunyi ‘pop’ terbebas apabila ia diujikan dengan kayu uji menyala.

Calcium carbonate, CaCO3 (marble)Kalsium karbonat, CaCO3 (marmar)

Effervescence occurred. A colourless gas that turned lime water milky was liberated.Pembuakan berlaku. Gas tidak berwarna yang mengeruhkan air kapur terbebas.

Copper(II) oxide, CuOKuprum(II) oksida, CuO

The black powder dissolved in aqueous ethanoic acid, CH3COOH and a blue solution was formed.Serbuk hitam terlarut dalam asid etanoik, CH3COOH akueus dan larutan biru terbentuk.

Butan-1-ol, C4H9OHButan-1-ol, C4H9OH

A colourless oily layer floats on the water. The product floating on the surface of the water had a nice fragrant smell.Lapisan berminyak yang tidak berwarna terapung di permukaan air. Hasil yang terapung di permukaan air mempunyai bau manis dan wangi.

2.5 INQUIRY Experiment

Observation

Aspect / Aspek Observation / PemerhatianColour, physical state, and smell of distillate collectedWarna, keadaan fizik, dan bau hasil sulingan yang dikutipkan

The distillate collected was a colourless liquid with a nice fragrant smell.Hasil sulingan yang dikutipkan ialah cecair tidak berwarna yang berbau manis dan wangi.

2.6 INQUIRY Experiment

Observation

Physical propertySifat fizik

ObservationPemerhatian

Colour, physical state, and smellWarna, keadaan fizik, dan bau

A colourless liquid with a nice fragrant smell.Cecair tidak berwarna yang berbau manis dan wangi.

Solubility in waterKeterlarutan dalam air

Two layers of colourless liquid were formed. Ethyl ethanoate, CH3COOC2H5 floated on the surface of the water.Dua lapisan cecair tidak berwarna terbentuk. Etil etanoat, CH3COOC2H5 terapung di permukaan air.

Solubility in propanone, CH3COCH3Keterlarutan dalam propanon, CH3COCH3

Ethyl ethanoate dissolved in propanone, CH3COCH3 to form a colourless solution.Etil etanoat terlarut dalam propanon, CH3COCH3 untuk membentuk larutan tidak berwarna.

Solubility in methylated spiritKeterlarutan dalam spirit bermetil

Ethyl ethanoate, CH3COOC2H5 dissolved in methylated spirit to form a colourless solution.Etil etanoat terlarut dalam spirit bermetil untuk membentuk larutan tidak berwarna.

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2.7 INQUIRY Experiment

Observation

Beaker / Bikar Observation / Pemerhatian

R

The latex coagulated rapidly within a few minutes to form a white solid.Lateks tergumpal menjadi pepejal putih dalam masa beberapa minit.

S

No coagulation occurred. The latex still existed as a white liquid.Tiada penggumpalan berlaku. Lateks masih kekal sebagai cecair putih.

T

The latex coagulated slowly after a few hours to form a white solid.Lateks tergumpal dengan perlahan-lahan menjadi pepejal putih selepas beberapa jam.

2.8 INQUIRY Experiment

Observation

Type of rubberJenis getah

ObservationPemerhatian

Strip of natural rubberJalur getah asli

The strip of rubber was soft.Jalur getah adalah lembut.

Strip of rubber dipped into disulphur dichloride solution in methylbenzeneJalur getah direndam dalam larutan disulfur diklorida dalam metilbenzena

The strip of rubber was hard.Jalur getah adalah keras.

2.9 GUIDED Experiment

Results

Weight (g)

Pemberat (g)

Unvulcanised rubberGetah tak tervulkan

Initial length (cm)

Panjang awal (cm)

Length after the removal of weight (cm)

Panjang selepas pemberat ditanggalkan (cm)

10 8.0 8.020 8.0 8.030 8.0 8.040 8.0 9.050 9.0 10.0

Weight (g)

Pemberat (g)

Vulcanised rubberGetah tervulkan

Initial length (cm)

Panjang awal (cm)

Length after the removal of weight (cm)Panjang selepas pemberat

ditanggalkan (cm)10 8.0 8.020 8.0 8.030 8.0 8.040 8.0 8.050 8.0 8.0

SPM ReviewSPM Review 22Objective Questions

1. C 2. D 3. B 4. C 5. A 6. B 7. B 8. A 9. A 10. B 11. A 12. A 13. C 14. D 15. A 16. C 17. B 18. C 19. B 20. D 21. B 22. B 23. C 24. B

Subjective Questions

Section A / Bahagian A

1. (a) Isomers are compounds with the same molecular formula but different structural formulae.

Isomer-isomer ialah sebatian-sebatian yang mempunyai formula molekul yang sama tetapi formula struktur yang berbeza.

(b) Compound R : Pent-2-ene Sebatian R: Pent-2-ena

Compound T: 2-methylbut-2-ene Sebatian T: 2-metilbut-2-ena

(c)

H C C C H

H

H

H

H

H

HH C H

H C H

(d) Hidrogenation Penghidrogenan

(e) (i) A mixture of compound R and steam is passed over phosphoric acid as a catalyst at a temperature of 300°C and a pressure of 60 atmospheres.

Satu campuran sebatian R dan stim dialirkan melalui asid fosforik sebagai mangkin pada suhu 300°C dan tekanan 60 atmosfera.

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(ii)

H C C C C C H

H

H

H

H

H

H

H

H

oratau

OH

H

H C C C C C H

OH

H

H

H

H

H

H

H

H

H

(f) Number of moles of compound P burnt Bilangan mol sebatian P yang dibakarkan

= 30024 000

mol

= 0.0125 mol

C5H12 + 8O2 → 5CO2 + 6H2O (P) 1 mol 5 mol

1 mol of P (C5H12) burnt produces 5 mol of carbon dioxide.

1 mol P (C5H12) terbakar untuk menghasilkan 5 mol karbon dioksida.

∴ 0.0125 mol of P (C5H12) burnt produces (0.01251

× 5) = 0.0625 mol of carbon dioxide.

0.0125 mol P (C5H12) terbakar untuk menghasilkan

(0.0125

1 × 5)

= 0.0625 mol karbon dioksida.

∴ Mass of carbon dioxide (CO2) formed Jisim karbon dioksida (CO2) yang terbentuk

= 0.0625 mol × [12 + 16(2)] g mol–1

= 2.75 g

2. (a) CnH2n + 2

(b)

H C C H

HEthaneEtana

H

H

H

(c) Number of moles of the compound C2H6 burnt Bilangan mol sebatian C2H6 terbakar

= 0.3 g

—–———–30 g mol–1 = 0.01 mol

C2H6 + 7—2 O2 → 2CO2 + 3H2O

1 mol 2 mol

1 mol of C2H6 produces 2 mol of CO2 1 mol C2H6 menghasilkan 2 mol CO2

∴ Number of moles of CO2 produced Bilangan mol CO2 yang terhasil

= 2 × Number of moles of C2H6 burnt 2 × Bilangan mol C2H6 yang terbakar

= 2 × 0.01 mol = 0.02 mol

∴ Volume of carbon dioxide (gas Y) produced Isi padu CO2 (gas Y) yang terhasil

= 0.02 mol × 24 dm3 mol–1

= 0.48 dm3 at room temperature and pressure 0.48 dm3 pada suhu dan tekanan bilik

(d) (i) Substitution reaction Tindak balas penukargantian

(ii) • The reddish-brown bromine vapour is decolourised.

Wap perang-kemerahan bromin dinyahwarnakan. • White fumes / steamy fumes are produced Wasap putih / wasap stim terbebas

(e) (i) Ethene / Etena

(ii) A mixture of ethene, C2H4 gas and hydrogen, H2 gas is passed over nickel at a temperature of 180°C to 200°C.

Satu campuran gas etena, C2H4 dan hidrogen, H2 dialirkan melalui nikel pada suhu 180°C hingga 200°C.

3. (a)

HeatPanaskan

Unglazed porcelain chipsSerpihan porselin yang tidak licau

Glass woolsoaked inalcohol RWul kacaterendamdalamalkohol R

Boiling tubeTabung didih

Propene gasGas propena

Test tubeTabung uji

BeakerBikar

WaterAir

(b)

H C C C H

H

H

OH

H

H

H

H C C C OH

H

H

H

H

H

H

(c) The purple solution turns colourless. Larutan ungu bertukar menjadi larutan tidak berwarna.

(d) A mixture of propene gas and steam is passed over phosphoric acid as a catalyst at a temperature of 300°C and a pressure of 60 atmospheres.

Satu campuran gas propena dan stim dialirkan melalui mangkin asid fosforik pada suhu 300°C dan tekanan 60 atmosfera.

(e) C3H7OH + 2[O] → C2H5COOH + H2O(f) (i) Concentrated sulphuric acid Asid sulfurik pekat

(ii) • Propyl propanoate has a nice fragrant smell whereas alcohol R (propan-1-ol) has a sharp non-fragrant smell.

Propil propanoat mempunyai bau wangi manakala alkohol R (propan-1-ol) mempunyai bau sengit yang tidak wangi.

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• Propyl propanoate is insoluble in water whereas alcohol R (propan-1-ol) is soluble in water.

Propil propanoat tidak larut dalam air manakala alkohol R (propan-1-ol) larut dalam air.

(g) Sodium hydroxide solution Larutan natrium hidroksida

Section B / Bahagian B

4. (a) (i) Compound Y is an alcohol with the general formula CnH2n + 1OH. [1]

Sebatian Y ialah suatu alkohol yang mempunyai formula am CnH2n + 1OH.

Relative molecular mass of CnH2n + 1OH = 46 Jisim molekul relatif bagi CnH2n + 1OH = 46 ∴ 12n + (2n + 1)(1) + 16 + 1 = 46 [1] 14n + 18 = 46 n = 2 ∴ Molecular formula of compound Y Formula molekul bagi sebatian Y = C2H5OH [1](ii) Homologous series of compound Y is alcohol. Siri homolog bagi sebatian Y ialah alkohol. [1] Its structural formula is Fomula strukturnya ialah

H C C O H

H

H

H

H

[1](iii) C2H5OH → C2H4 + H2O [2]

(b) Similarities Persamaan

• Both the compounds P and Q have the same molecular formula of C2H4O2. [1]

Kedua-dua sebatian P dan Q mempunyai formula molekul C2H4O2 yang sama.

• Both the compounds P and Q are isomers. [1] Kedua-dua sebatian P dan Q adalah isomer.

• Both the compounds P and Q are made up of carbon, hydrogen and oxygen. [1]

Kedua-dua sebatian P dan Q terdiri daripada karbon, hidrogen dan oksigen.

Differences Perbezaan

• Functional group of compound P is carboxyl group, – C – O – H

O

Kumpulan berfungsi sebatian P ialah kumpulan karboksil, – C – O – H

O

whereas functional group of compound Q is carboxylate group, – C – O –

O

. [1]

manakala kumpulan berfungsi sebatian Q ialah kumpulan karboksilat, – C – O –

O

.

• Compound P is a carboxylic acid whereas compound Q is an ester. [1]

Sebatian P ialah suatu asid karboksilik manakala sebatian Q ialah suatu ester.

(c) (i) • About 2 cm3 of each liquid to be differentiated is poured separately into two different test tubes. [1]

Kira-kira 2 cm3 setiap cecair yang hendak dibezakan dituang secara berasingan ke dalam dua tabung uji yang berlainan.

• A few drops of acidified potassium dichromate(VI) solution are added into each test tube. Each test tube is then heated gently. [1]

Beberapa titik larutan kalium dikromat(VI) berasid dituang ke dalam setiap tabung uji itu. Setiap tabung uji itu dipanaskan dengan perlahan-lahan.

• If the colour of the acidified potassium dichromate(VI) solution changes from orange to green, then the liquid tested is methanol.

Jika warna larutan kalium dikromat(VI) berasid berubah daripada jingga kepada hijau, maka cecair yang diujikan itu ialah metanol. [1]

• If no change occurs, then the liquid tested is hexane. [1]

Jika tiada perubahan berlaku, maka cecair yang diujikan itu ialah heksana.

(ii) • About 2 cm3 of each liquid to be differentiated is poured separately into two different test tubes. [1]

Kira-kira 2 cm3 setiap cecair yang hendak dibezakan dituang secara berasingan ke dalam dua tabung uji yang berlainan.

• About 2 cm3 of bromine water is added into each test tube and shaken well. [1]

Kira-kira 2 cm3 air bromin dituang ke dalam setiap tabung uji itu dan digoncang dengan baik.

• If the brown bromine water is decolourised, then the liquid tested is pent-1-ene. [1]

Jika warna perang air bromin dinyahwarnakan, maka cecair yang diujikan itu ialah pent-1-ena.

• If no change occurs, then the liquid tested is methyl methanoate. [1]

Jika tiada perubahan berlaku, maka cecair yang diujikan itu ialah metil metanoat.

Section C / Bahagian C

5. (a) (i) A and D are isomers [1] A dan D ialah isomer

A is butan-2-ol [1] A ialah butan-2-ol

D is butan-l-ol [1] D ialah butan-l-ol

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(ii) 1 cm3 of acidified potassium dichromate(VI) solution is poured into 2 cm3 of compound B and compound D respectively and the mixtures are heated. [1]

1 cm3 larutan kalium dikromat(VI) berasid ditambah ke dalam 2 cm3 sebatian B dan sebatian D masing-masing dan campuran dipanaskan.

Compound B does not change the orange colour of the acidified potassium dichromate(VI) solution. [1]

Sebatian B tidak mengubah warna jingga larutan kalium dikromat(VI) berasid.

Compound D changes the orange colour of the acidified pottasium dichromate(VI) solution to green. [1]

Sebatian D menukarkan warna jingga larutan kalium dikromat(VI) berasid kepada hijau.

(b) (i) Structural formula of propanoic acid is Formula struktur bagi asid propanoik ialah

H C C C O H

H

H

H

H

O

H C C C O C C C H

H

H

H

H

H

H

H

H

HO

H Structural formula of propyl propanoate is Formula struktur bagi propil propanoat ialah

H C C C O H

H

H

H

H

O

H C C C O C C C H

H

H

H

H

H

H

H

H

HO

H

(ii) • A mixture of 3 cm3 of propan-1-ol and 10 cm3 of acidified potassium dichromate(VI) solution is heated slowly in a boiling tube using the set-up of apparatus as shown [1]

Satu campuran mengandungi 3 cm3 propan-1-ol dan 10 cm3 larutan kalium dikromat(VI) berasid dipanaskan dengan perlahan-lahan dalam sebuah tabung didih dengan menggunakan susunan radas seperti yang ditunjukkan.

HeatPanaskan

Propan-1-olPropan-1-ol

+Acidified

potassiumdichromate(VI)

solutionLarutan kalium

dikromat(VI)berasid

Boiling tubeTabung didih

Ice waterAir aisDistillateHasil sulingan

BeakerBikar

Test tubeTabung uji

[1]• A colourless liquid of propanoic acid is

collected as a distillate in a test tube immersed in ice water. [1]

Satu cecair tidak berwarna bagi asid propanoik dikumpulkan sebagai hasil sulingan dalam sebuah tabung uji yang terendam dalam air ais.

• Chemical equation for this reaction is [1] Persamaan kimia bagi tindak balas ini ialah C3H7OH + 2[O] → C2H5COOH + H2O

• The propanoic acid is then mixed with twice its own volume of propan-1-ol and a little concentrated sulphuric acid in a small distillation flask. [1]

Kemudian, asid propanoik dicampurkan dengan dua kali ganda isi padu propan-1-ol dan sedikit asid sulfurik pekat dalam sebuah kelalang penyulingan yang kecil.

• The mixture is heated gently using the apparatus set-up as below. Propyl propanoate is collected as distillate.

Campuran ini dipanaskan dengan perlahan-lahan dengan menggunakan susunan radas seperti yang ditunjukkan di bawah. Propil propanoat dikumpulkan sebagai hasil sulingan.

Water inAir masuk

BeakerBikar

Mixture ofpropan-1-ol,

propanoic acidand concentrated

sulphuric acidCampuran propan-1-ol,

asid propanoikdan asid sulfurik pekat

Wooden blockBongkah kayu

DistillateHasil sulingan

Conical flaskKelalang kon

AdaptorPenyesuai

Liebig condenserKondenser Liebig

HeatPanaskan

Oil bathKukus minyak

Water outAir keluar

Distillation flaskKelalang penyulingan

[1]• Chemical equation for this reaction is [1] Persamaan kimia bagi tindak balas ini ialah C2H5COOH + C3H7OH C2H5COOC3H7 + H2O

(c) L : Alcohol / Alkohol [1] M : Ester / Ester [1] Q : Alkene / Alkena [1]

3Chapter Oxidation and Reaction

Pengoksidaan dan Penurunan

3.1 INQUIRY Experiment

Observation

The magnesium ribbon burnt with a bright flame producing a white solid.Pita magnesium terbakar dengan nyalaan yang terang dan menghasilkan pepejal putih.

3.2 INQUIRY Experiment

Observation

The mixture burnt rapidly with a bright flame. A brown solid was formed.Campuran itu terbakar dengan cepat dan dengan nyalaan yang terang. Pepejal perang terbentuk.

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3.5 INQUIRY Experiment

Observation

Activity I: Halogens in aqueous solution and 1,1,1-trichloroethane, CH3CCI3Aktiviti I: Halogen dalam larutan akueus dan 1,1,1-trikloroetana, CH3CCI3

HalogenHalogen

Colour in aqueous solution

Warna dalam larutan akueus

Colour in 1,1,1-trichloroethane,

CH3CCI3Warna dalam

1,1,1-trikloroetana, CH3CCI3

ChlorineKlorin

Pale yellowKuning pucat

ColourlessTidak berwarna

BromineBromin

BrownPerang

BrownPerang

IodineIodin

BrownPerang

PurpleUngu

Activity II: Displacement of halogensAktiviti II: Tindak balas penyesaran halogen

Halogen used

Halogen yang

digunakan

Halide solutionLarutan halida

Colour ofWarna bagi

aqueous layer

lapisan akueus

1,1,1-trichloroethane, CH3CCI3 layer

lapisan 1,1,1-trikloroetana,

CH3CCI3

Chlorine water

Air klorin

Potassium bromide,

KBr solution Larutan kalium

bromida, KBr

BrownPerang

BrownPerang

Chlorine water

Air klorin

Potassium iodide, KI solution Larutan kalium

iodida, KI

BrownPerang

PurpleUngu

Bromine water

Air bromin

Potassium chloride,

KCl solutionLarutan kalium

klorida, KCl

BrownPerang

BrownPerang

Bromine water

Air bromin

Potassium iodide, KI solution Larutan kalium

iodida, KI

BrownPerang

PurpleUngu

3.3 INQUIRY Experiment

Observation

Solution usedLarutan yang

digunakan

ObservationPemerhatian

Iron(II) sulphate, FeSO4 solution + bromine waterLarutan ferum(II) sulfat, FeSO4 + air bromin

The reddish-brown bromine water was decolourised. The green iron(II) sulphate, FeSO4 solution turned brown. When sodium hydroxide, NaOH solution was added, a brown precipitate was formed. The precipitate was insoluble in excess sodium hydroxide, NaOH solution.Warna perang-kemerahan air bromin dinyahwarnakan. Larutan hijau ferum(II) sulfat, FeSO4 bertukar menjadi perang. Apabila larutan natrium hidroksida, NaOH ditambahkan, mendakan perang terbentuk. Mendakan itu tidak larut dalam larutan natrium hidroksida, NaOH berlebihan.

Iron(III) sulphate, Fe2(SO4)3 solution + zinc powderLarutan ferum(III) sulfat, Fe2(SO4)3 + serbuk zink

Part of the zinc powder dissolved in iron(III) sulphate, Fe2(SO4)3 solution. The brown solution turned green. When sodium hydroxide, NaOH solution was added into the filtrate, a green precipitate was formed. The precipitate was insoluble in excess sodium hydroxide, NaOH solution.Sebahagian serbuk zink terlarut dalam larutan ferum(III) sulfat, Fe2(SO4)3. Larutan perang itu bertukar menjadi hijau. Apabila larutan natrium hidroksida, NaOH ditambahkan kepada dalam hasil turasan, mendakan hijau terbentuk. Mendakan itu tidak larut dalam larutan natrium hidroksida, NaOH berlebihan.

3.4 INQUIRY Experiment

Observation

ReactantBahan tindak

balas

ObservationPemerhatian

Copper(II) sulphate, CuSO4 solution + zinc stripLarutan kuprum(II) sulfat, CuSO4 + kepingan zink

The blue solution turned colourless. Part of the zinc strip dissolved. A brown solid was deposited on the zinc strip.Larutan biru bertukar menjadi tidak berwarna. Sebahagian daripada kepingan zink melarut. Pepejal perang terenap pada kepingan zink.

Silver nitrate, AgNO3 solution + copper stripLarutan argentum nitrat, AgNO3 + kepingan kuprum

The colourless solution turned blue. Part of the copper strip dissolved. A shiny grey solid was deposited.Larutan tidak berwarna bertukar menjadi biru. Sebahagian daripada kepingan kuprum melarut. Pepejal kelabu berkilat terenap.

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Halogen used

Halogen yang

digunakan

Halide solutionLarutan halida

Colour ofWarna bagi

aqueous layer

lapisan akueus

1,1,1-trichloroethane, CH3CCI3 layer

lapisan 1,1,1-trikloroetana,

CH3CCI3

Iodine solutionLarutan

iodin

Potassium chloride,

KCl solution Larutan kalium

klorida, KCl

BrownPerang

PurpleUngu

Iodine solutionLarutan

iodin

Potassium bromide,

KBr solution Larutan kalium

bromida, KBr

BrownPerang

PurpleUngu

3.6 INQUIRY Experiment

Observation

ReactantBahan tindak

balas

ObservationPemerhatian

Iron(II) sulphate, FeSO4 solution + acidified potassium manganate(VII) KMnO4 solutionLarutan ferum(II) sulfat, FeSO4 + larutan kalium manganat(VII), KMnO4 berasid

The deflection of the galvanometer pointer showed that the electrode placed in iron(II) sulphate, FeSO4 solution acted as the negative terminal while the electrode placed in acidified potassium manganate(VII), KMnO4 solution acted as the positive terminal. The purple acidified potassium manganate(VII), KMnO4 solution was decolourised. The green iron(II) sulphate, FeSO4 turned yellow. When a few drops of potassium thiocyanate, KSCN solution were added, a blood-red solution was formed.Pesongan jarum galvanometer menunjukkan elektrod yang tercelup dalam larutan ferum(II) sulfat, FeSO4 bertindak sebagai terminal negatif manakala elektrod yang tercelup dalam larutan kalium manganat(VII), KMnO4 berasid bertindak sebagai terminal positif. Larutan ungu kalium manganat(VII), KMnO4 berasid dinyahwarnakan. Larutan hijau ferum(II) sulfat, FeSO4 bertukar menjadi kuning. Apabila beberapa titis larutan kalium tiosianat, KSCN ditambahkan, larutan berwarna merah darah terbentuk.

ReactantBahan tindak

balas

ObservationPemerhatian

Potassium iodide, KI solution + acidified potassium dichromate(VI), K2Cr2O7 solutionLarutan kalium iodida, KI + larutan kalium dikromat(VI), K2Cr2O7 berasid

The deflection of the galvanometer pointer showed that the electrode placed in potassium iodide, KI solution acted as the negative terminal while the electrode placed in acidified potassium dichromate(VI), K2Cr2O7 solution acted as the positive terminal. The orange acidified potassium dichromate(VI), K2Cr2O7 solution turned green. The colourless potassium iodide, KI solution turned brown. When a few drops of starch solution were added, a dark blue solution was formed.Pesongan jarum galvanometer menunjukkan elektrod yang tercelup dalam larutan kalium iodida, KI bertindak sebagai terminal negatif manakala elektrod yang tercelup dalam larutan kalium dikromat(VI), K2Cr2O7 berasid bertindak sebagai terminal positif. Larutan jingga kalium dikromat(VI), K2Cr2O7 berasid bertukar menjadi hijau. Larutan kalium iodida, KI yang tidak berwarna bertukar menjadi perang. Apabila beberapa titis larutan kanji ditambahkan, larutan berwarna biru tua terbentuk.

3.7 GUIDED Experiment

Observation

Test tubeTabung uji

ObservationPemerhatian

Intensity of dark blue colourationKeamatan warna

biru tua

Intensity of pink colouration

Keamatan warna merah jambu

A LowRendah –

B – HighTinggi

C – HighTinggi

D ModerateSederhana

LowRendah

E HighTinggi

LowRendah

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3.8 INQUIRY Experiment

Observation

MetalLogam

Colour of metal oxide formedWarna oksida logam yang terbentuk

Vigour of reactionKecergasan tindak balas

HotPanas

ColdSejuk

MagnesiumMagnesium

WhitePutih

WhitePutih

Burnt very rapidly with a bright flameTerbakar dengan cepat dengan nyalaan yang terang

CopperKuprum

BlackHitam

BlackHitam

Burnt slowly with a faint glowTerbakar secara perlahan-lahan dengan baraan yang malap

IronFerum

BrownPerang

BrownPerang

Burnt slowly with a bright glowTerbakar secara perlahan-lahan dengan baraan yang terang

LeadPlumbum

BrownPerang

YellowKuning

Burnt slowly with a moderately bright glowTerbakar secara perlahan-lahan dengan nyalaan yang sederhana terang

ZincZink

YellowKuning

WhitePutih

Burnt rapidly with a moderately bright flameTerbakar dengan cepat dengan nyalaan yang sederhana terang

3.9 INQUIRY Experiment

Observation

Activity IAktiviti I

MixtureCampuran

ObservationPemerhatian

Carbon + copper(II) oxide, CuOKarbon + kuprum(II) oksida, CuO

The mixture burnt with a bright flame. A brown solid was formed.Campuran itu terbakar dengan nyalaan yang terang. Pepejal perang terbentuk.

Carbon + magnesium oxide, MgOKarbon + magnesium oksida, MgO

No visible change.Tiada perubahan.

MixtureCampuran

ObservationPemerhatian

Carbon + aluminium oxide, Al2O3Karbon + aluminium oksida, Al2O3

No visible change.Tiada perubahan.

Carbon + zinc oxide, ZnOKarbon + zink oksida, ZnO

The mixture glowed brightly. A shiny grey solid was formed.Campuran itu membara dengan nyalaan terang. Pepejal kelabu berkilat terbentuk.

Activity IIAktiviti II

MixtureCampuran

ObservationPemerhatian

Magnesium ribbon + carbon dioxide, CO2Pita magnesium + karbon dioksida, CO2

The magnesium ribbon burnt rapidly with a bright flame. A white solid and black powder were formed.Pita magnesium terbakar dengan cepat dengan nyalaan yang terang. Pepejal putih dan serbuk hitam terbentuk.

3.10 INQUIRY Experiment

Observation

MixtureCampuran

ObservationPemerhatian

Hydrogen + copper(II) oxide, CuOHidrogen + kuprum(II) oksida, CuO

Copper(II) oxide burnt brightly. The black powder turned brown.Kuprum(II) oksida terbakar dengan terang. Serbuk hitam bertukar menjadi perang.

Hydrogen + zinc oxide, ZnOHidrogen + zink oksida, ZnO

No visible change.Tiada perubahan.

Hydrogen + lead(II) oxide, PbOHidrogen + plumbum(II) oksida, PbO

Lead(II) oxide burnt brightly. The yellow powder became shiny grey globules.Plumbum(II) oksida terbakar dengan terang. Serbuk kuning bertukar menjadi butiran kelabu berkilat.

Hydrogen + iron(III) oxide, Fe2O3Hidrogen + ferum(III) oksida, Fe2O3

Iron(III) oxide burnt brightly. The brown powder became shiny grey globules.Ferum(III) oksida terbakar dengan terang. Serbuk perang bertukar menjadi butiran kelabu berkilat.

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3.11 INQUIRY Experiment

Observation

ElectrolyteElektrolit

Observation / Pemerhatian

Anode / Anod Cathode / Katod

Molten lead(II) bromide, PbBr2Plumbum(II) bromida, PbBr2 lebur

A brown gas with a pungent smell was released.Gas perang berbau sengit dibebaskan.

A shiny grey globule was found at the bottom of the crucible.Butiran kelabu berkilat didapati di dasar mangkuk pijar.

Potassium iodide, KI solutionLarutan kalium iodida, KI

The colourless solution around the anode turned brown. The brown solution turned dark blue when tested with starch solution.Larutan tidak berwarna di sekitar anod bertukar menjadi perang. Larutan perang itu bertukar menjadi biru tua apabila diuji dengan larutan kanji.

Gas bubbles were released. A colourless gas which burnt with a ‘pop’ sound was produced.Gelembung-gelembung gas terbebas. Gas tidak berwarna yang terbakar dengan bunyi ‘pop’ terhasil.

3.12 INQUIRY Experiment

Observation

Chemical Cell

Sel kimia

Observation / Pemerhatian

VoltmeterVoltmeter

Negative terminalTerminal negatif

Positive terminal

Terminal positif

Zinc /copperZink /kuprum

The voltmeter pointer deflected. The deflection of the voltmeter pointer showed that the zinc plate acted as the negative terminal while the copper plate acted as the positive terminal.Penunjuk voltmeter terpesong. Pesongan voltmeter menunjukkan kepingan zink bertindak sebagai terminal negatif manakala kepingan kuprum sebagai terminal positif.

The zinc plate dissolved and became thinner.Kepingan zink melarut dan menjadi nipis.

The copper plate became thicker. A brown solid was deposited on the copper plate. The intensity of the blue colour of the copper(II) sulphate, CuSO4 solution decreased.Kepingan kuprum menjadi tebal. Pepejal perang terenap pada kepingan kuprum. Keamatan warna biru larutan kuprum(II) sulfat, CuSO4 berkurangan.

Chemical Cell

Sel kimia

Observation / Pemerhatian

VoltmeterVoltmeter

Negative terminalTerminal negatif

Positive terminal

Terminal positif

Iron / leadFerum /plumbum

The voltmeter pointer deflected. The deflection of the voltmeter pointer showed that the iron nail acted as the negative terminal and the lead plate acted as the positive terminal.Penunjuk voltmeter terpesong. Pesongan voltmeter menunjukkan paku besi bertindak sebagai terminal negatif manakala kepingan plumbum sebagai terminal positif.

The iron nail dissolved and became thinner. The intensity of the green colour of the iron(II) sulphate, FeSO4 solution increased.Paku besi melarut dan menjadi nipis. Keamatan warna hijau larutan ferum(II) sulfat, FeSO4 bertambah.

The lead plate became thicker. A grey solid was deposited on the lead plate.Kepingan plumbum menjadi tebal. Pepejal kelabu terenap pada kepingan plumbum.

SPM ReviewSPM Review 33Objective Questions

1. B 2. C 3. D 4. A 5. C 6. C 7. B 8. C 9. C 10. A 11. C 12. A 13. C 14. D 15. B 16. A 17. D 18. B 19. D 20. B 21. C 22. C 23. B

Subjective Questions

Section A / Bahagian A

1. (a) To allow the flow of the ions so that a complete circuit is formed as well as to separate the two aqueous solutions.

Untuk membenarkan ion-ion mengalir supaya litar yang lengkap terbentuk dan juga untuk memisahkan kedua-dua larutan akueus.

(b) (i) The oxidation number decreases from 0 to –1. Nombor pengoksidaan berkurang daripada 0

kepada –1.

(ii) Br2(aq) + 2e– → 2Br–(aq) Br2(ak) + 2e– → 2Br–(ak)

(iii) Reduction Penurunan

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(c) (i) • Iron(II) sulphate solution Larutan ferum(II) sulfat

• Potassium iodide solution Larutan kalium iodida

(ii) It acts as a reducing agent. Bromine water is reduced to bromide ions with the presence of solution X.

Ia bertindak sebagai agen penurunan. Air bromin diturunkan kepada ion bromida dengan kehadiran larutan X.

(d) (i) From 0 to +2 Daripada 0 kepada +2

(ii) Ni(s) + Cu2+(aq) → Ni2+(aq) + Cu(s) Ni(p) + Cu2+(ak) → Ni2+(ak) + Cu(p)

(iii) Copper rod. This is because copper metal is less electropositive than nickel metal. Hence, copper metal releases its electrons less readily than nickel metal.

Rod kuprum. Ini kerana logam kuprum kurang elektropositif daripada logam nikel.

Maka, logam kuprum tidak mudah membebaskan elektron berbanding dengan logam nikel.

Section B / Bahagian B

2. (a) (i) Oxidation number of copper in Cu2O Nombor pengoksidaan kuprum dalam Cu2O = +1 [1]

Oxidation number of copper in CuCl2 Nombor pengoksidaan kuprum dalam CuCl2

= +2 [1] Oxidation number of aluminium in AlCl3 Nombor pengoksidaan aluminium dalam AlCl3

= +3 [1](ii) Cu2O: Copper(I) oxide [1] Kuprum(I) oksida

CuCl2: Copper(II) chloride [1] Kuprum(II) klorida

AlCl3: Aluminium chloride [1] Aluminium klorida

(b) (i) • Metal X is less electropositive than iron. [1] Logam X kurang elektropositif daripada ferum.

• Iron is oxidised to Fe2+ ions. [1] Ferum dioksidakan kepada ion Fe2+.

• Metal Y is more electropositive than iron. [1] Logam Y lebih elektropositif daripada ferum.

• Metal Y is oxidised to ion Y. [1] Logam Y dioksidakan kepada ion Y.

(ii) In Experiment I, iron is oxidised. [1] Dalam Eksperimen I, ferum dioksidakan. Half-equation: Fe → Fe2+ + 2e– [1] Setengah persamaan: Fe → Fe2+ + 2e–

(iii)

Less electropositiveKurang elektropositif

Metal Y, iron, metal XLogam Y, ferum, logam X

[2]

(c) • Air and water are needed for rusting. [1] Udara dan air diperlukan untuk pengaratan.

• When the surface of iron is in contact with water, the middle region of the water droplet (where the concentration of dissolved oxygen is low) acts as the anode. [1]

Apabila permukaan besi terdedah kepada air, pusat titisan air (di mana kepekatan oksigen yang terlarut adalah rendah) bertindak sebagai anod.

• At the anode, iron is oxidised to Fe2+ ion. Di anod, ferum dioksidakan kepada ion Fe2+. Fe(s) → Fe2+(aq) + 2e– [1] Fe(p) → Fe2+(ak) + 2e–

• The region closer to the outside of the water droplet (where the concentration of dissolved oxygen is higher) acts as the cathode. [1]

Pinggir titisan air (di mana kepekatan oksigen yang terlarut adalah tinggi) bertindak sebagai katod.

• The electrons released flow through the metal to the cathode where dissolved oxygen is reduced.

Elektron yang terbebas mengalir melalui logam ke katod di mana oksigen yang terlarut diturunkan.

O2(g) + 2H2O(l) + 4e– → 4OH–(aq) [1] O2(g) + 2H2O(ce) + 4e– → 4OH–(ak)

• The Fe2+ ions formed combined with the OH– ions to form iron(II) hydroxide which is then oxidised by air and become the brown hydrated iron(III) oxide. This hydrated oxide is called rust. [1]

Ion Fe2+ yang terbentuk berpadu dengan ion OH– untuk membentuk ferum(II) hidroksida yang kemudiannya dioksidakan oleh udara untuk membentuk ferum(III) oksida terhidrat yang berwarna perang. Oksida terhidrat ini disebut karat.

Section C / Bahagian C 3. (a) Mg(s) → Mg2+(aq) Mg(p) → Mg2+(ak)

• 1 spatula of magnesium powder is added into a test tube containing 2 cm3 of dilute sulphuric acid. [1]

Satu spatula serbuk magnesium ditambahkan ke dalam sebuah tabung uji yang mengandungi 2 cm3 asid sulfurik cair.

• Mg(s) + 2H+(aq) → Mg2+(aq) + H2(g) [1] Mg(p) + 2H+(ak) → Mg2+(ak) + H2(g)

• In the reaction, magnesium undergoes oxidation while H+ ions undergo reduction. [1]

Dalam tindak balas itu, magnesium mengalami pengoksidaan manakala ion H+ mengalami penurunan.

• Sodium hydroxide solution is added to the product formed. [1]

Larutan natrium hidroksida ditambahkan kepada hasil tindak balas yang terbentuk.

• A white precipitate which is insoluble in excess sodium hydroxide solution is formed. [1]

Mendakan putih yang tidak larut dalam larutan natrium hidroksida berlebihan terbentuk.

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2Cl–(aq) → Cl2(g)2Cl–(ak) → Cl2(g)

• 3 mol dm–3 hydrochloric acid is electrolysed using graphite electrodes. [1]

Asid hidroklorik 3 mol dm–3 dielektrolisiskan dengan menggunakan elektrod grafit.

• 2H+(aq) + 2Cl–(aq) → H2(g) + Cl2(g) [1] 2H+(ak) + 2Cl–(ak) → H2(g) + Cl2(g)

• In the reaction, Cl– ions undergo oxidation while H+ ions undergo reduction. [1]

Dalam tindak balas ini, ion Cl– mengalami pengoksidaan manakala ion H+ mengalami penurunan.

• A piece of moist blue litmus paper is held at the mouth of the test tube containing the gas collected at the anode. [1]

Satu keping kertas litmus biru lembap dipegang dekat mulut tabung uji yang mengandungi gas yang terkumpul di anod.

• The moist blue litmus paper turns red and then white. [1]

Kertas litmus biru lembap bertukar menjadi merah dan kemudian dilunturkan.

(b) V

– +

Zinc plateKepinganzink

Copper plateKepingan kuprum

Copper(II) sulphate solutionLarutan kuprum(II) sulfat [2]

• Zinc is more electropositive than copper and releases electrons easily. [1]

Zink lebih elektropositif daripada kuprum dan membebaskan elektron dengan mudah.

• Zn(s) → Zn2+(aq) + 2e– [1] Zn(p) → Zn2+(ak) + 2e–

• Oxidation occurs. [1] Pengoksidaan berlaku.

• Cu2+ ions accept electrons to form copper metal. [1]

Ion Cu2+ menerima elektron untuk membentuk logam kuprum.

• Cu2+(aq) + 2e– → Cu(s) [1] Cu2+(ak) + 2e– → Cu(p)

• Reduction occurs. [1] Penurunan berlaku.

• The flow of electrons from the zinc plate to the copper plate results in the production of electricity. [1]

Pengaliran elektron dari kepingan zink ke kepingan kuprum menyebabkan penghasilan elektrik.

• The zinc plate is corroded. Zn2+ ions are formed. [1]

Kepingan zink terkakis. Ion Zn2+ terbentuk.

4Chapter Thermochemistry

Termokimia

4.1 INQUIRY Experiment

Observation

ReactantBahan tindak balas

Temperature change

(increased/decreased)

Perubahan suhu (bertambah/berkurang)

Heat (given out/ absorbed)

Haba (dibebaskan/

diserap)

Solid sodium hydrogen carbonate, NaHCO3 + hydrochloric acid, HCI Pepejal natrium hidrogen karbonat, NaHCO3 + asid hidroklorik, HCl

Temperature decreased.Suhu menurun.

Heat was absorbed.Haba diserap.

Solid sodium hydroxide, NaOH + hydrochloric acid, HCl Pepejal natrium hidroksida, NaOH + asid hidroklorik, HCl

Temperature increased.Suhu meningkat.

Heat was given out.Haba dibebaskan.

Solid sodium hydroxide, NaOH + distilled waterPepejal natrium hidroksida, NaOH + air suling

Temperature increased.Suhu meningkat.

Heat was given out.Haba dibebaskan.

Solid ammonium chloride, NH4Cl + distilled waterPepejal ammonium klorida, NH4Cl + air suling

Temperature decreased.Suhu menurun.

Heat was absorbed.Haba diserap.

Solid ammonium nitrate, NH4NO3 + distilled waterPepejal ammonium nitrat, NH4NO3 + air suling

Temperature decreased.Suhu menurun.

Heat was absorbed.Haba diserap.

4.2 INQUIRY Experiment

Results

Initial temperature of silver nitrate, AgNO3 solution (°C)Suhu awal larutan argentum nitrat, AgNO3 (°C)

27.0

Initial temperature of sodium chloride, NaCI solution (°C)Suhu awal larutan natrium klorida, NaCl (°C)

27.0

Highest temperature of the reaction mixture (°C)Suhu tertinggi campuran hasil tindak balas (°C) 30.5

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4.3 UNGUIDED Experiment

Results

ReactantBahan tindak

balas

Initial temperature of copper(II)

sulphate, CuSO4 solution (°C)

Suhu awal larutan kuprum(II) sulfat,

CuSO4 (°C)

Highest temperature

of the reaction mixture (°C)Suhu tertinggi

campuran hasil tindak balas (°C)

Zinc powder + copper(II) sulphate, CuSO4 solutionSerbuk zink + larutan kuprum(II) sulfat, CuSO4

27.0 37.0

Magnesium powder + copper(II) sulphate, CuSO4 solutionSerbuk magnesium + larutan kuprum(II) sulfat, CuSO4

27.5 43.5

4.4 GUIDED Experiment

Results

Reaction mixtureCampuran bahan tindak balas

Strong alkaliAlkali kuat

Sodium hydroxide, NaOHNatrium hidroksida, NaOH

Potassium hydroxide, KOHKalium hidroksida, KOH

Strong acidAsid kuat

Hydrochloric acid, HClAsid hidroklorik, HCl

Nitric acid, HNO3Asid nitrik, HNO3

Initial temperature of strong alkali (°C)Suhu awal alkali kuat (°C)

27.0 27.2

Initial temperature of strong acid (°C)Suhu awal asid kuat (°C)

27.0 27.2

Highest temperature of the reaction mixture (°C)Suhu tertinggi campuran hasil tindak balas (°C)

33.8 34.0

4.5 GUIDED Experiment

Results

ReactantBahan tindak balas

AlkaliAlkali

Sodium hydroxide, NaOHNatrium hidroksida, NaOH

Ammonia, NH3Ammonia, NH3

Ammonia, NH3Ammonia, NH3

AcidAsid

Ethanoic acid, CH3COOHAsid etanoik, CH3COOH

Hydrochloric acid, HClAsid hidroklorik, HCl

Ethanoic acid, CH3COOHAsid etanoik, CH3COOH

Initial temperature of alkali (°C)Suhu awal alkali (°C)

26.8 27.0 27.0

Initial temperature of acid (°C)Suhu awal asid (°C)

26.8 27.0 27.0

Highest temperature of reaction mixture (°C)Suhu tertinggi campuran hasil tindak balas (°C)

40.0 39.4 39.0

4.6 GUIDED Experiment

Results

AlcoholAlkohol

Methanol, CH3OHMetanol, CH3OH

Ethanol, C2H5OHEtanol, C2H5OH

Propan-1-ol, C3H7OH

Propan-1-ol, C3H7OH

Butan-1-ol, C4H9OH

Butan-1-ol, C4H9OH

Mass of lamp and alcohol before combustion (g)Jisim pelita dan alkohol sebelum pembakaran (g)

139.36 142.78 141.03 147.35

Mass of lamp and alcohol after combustion (g)Jisim pelita dan alkohol selepas pembakaran (g)

138.23 141.93 140.28 146.65

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Mass of alcohol burnt (g)Jisim alkohol terbakar (g)

1.13 0.85 0.75 0.70

Initial temperature of water (°C)Suhu awal air (°C)

27.0 27.0 27.5 27.5

Highest temperature of water (°C)Suhu tertinggi air (°C)

57.0 57.0 57.5 57.5

Increase in temperature (°C)Kenaikan suhu (°C)

30.0 30.0 30.0 30.0

SPM ReviewSPM Review 44Objective Questions

1. C 2. C 3. B 4. A 5. D 6. C 7. C 8. C 9. D 10. C 11. D 12. A 13. A 14. C 15. D 16. C

Subjective Questions

Section A / Bahagian A

1. (a) Formation of one mol of water in the neutralisation reaction liberates 57.3 kJ of heat energy.

Pembentukan 1 mol air dalam tindak balas peneutralan membebaskan 57.3 kJ tenaga haba.

(b) The plastic cup becomes warm. / The temperature of the mixture increases.

Cawan plastik menjadi panas. / Suhu campuran menaik. Explanation: Penerangan: The energy content of the reactants is higher than

that of the products. The decrease in the chemical energy content when the reactants change to the products is converted to heat energy and given out to the surroundings.

Kandungan tenaga bahan tindak balas adalah lebih tinggi daripada hasil tindak balas. Pengurangan dalam kandungan tenaga kimia semasa bahan tindak balas berubah kepada hasil tindak balas telah ditukarkan kepada tenaga haba untuk dibebaskan ke sekeliling.

(c) (i) Number of moles of sodium hydroxide = MV Bilangan mol natrium hidroksida

= 1.0 mol dm–3 × 50——–1000

dm3

= 0.05 mol Number of moles of sulphuric acid Bilangan mol asid sulfurik = MV

= 0.5 mol dm–3 × 50—–—1000 dm3

= 0.025 mol From the equation, 1 mol of NaOH reacts with

0.5 mol of H2SO4 gives out 57.3 kJ of heat. Daripada persamaan, 1 mol NaOH bertindak balas

dengan 0.5 mol H2SO4 membebaskan 57.3 kJ haba.

∴ Heat released when 0.05 mol of NaOH reacts with 0.025 mol of H2SO4

∴ Haba yang dibebaskan apabila 0.05 mol NaOH bertindak balas dengan 0.025 mol asid sulfurik

= 0.05—–—1

× 57.3

= 2.865 kJ(ii) Heat released = mc q Haba yang dibebaskan = mc q

2.865 × 1000 J = (50 + 50) × 4.2 q ∴ Temperature change, Perubahan suhu,

q = 2865—–———100 × 4.2

= 6.8°C

(d) (i) Number of moles of potassium hydroxide Bilangan mol kalium hidroksida

= MV = 0.50 mol dm–3 × 50—–—

1000 dm3

= 0.025 mol Number of moles of ethanoic acid Bilangan mol asid etanoik = MV = 0.50 mol dm–3 × 50—–—

1000 dm3

= 0.025 mol KOH(aq) + CH3COOH(aq) → 1 mol 1 mol CH3COOK(aq) + H2O(l) 1 mol

KOH(ak) + CH3COOH(ak) → CH3COOK(ak) + H2O(ce) 1 mol 1 mol 1 mol

From the equation, 1 mol of KOH reacts with 1 mol of CH3COOH produces 1 mol of water.

Daripada persamaan, 1 mol KOH bertindak balas dengan 1 mol CH3COOH menghasilkan 1 mol air.

∴ Number of moles of water produced = Bilangan mol air yang dihasilkan

Number of moles of KOH or CH3COOH reacted bilangan mol KOH atau CH3COOH yang bertindak

balas = 0.025 mol

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(ii) Heat released = mcq Haba yang dibebaskan = mc q = (50 + 50) × 4.2 × 3.25 = 1365 J = 1.365 kJ ∴ Heat of neutralisation for this reaction, ∆H Haba peneutralan bagi tindak balas ini, ∆H

1.365 kJ = – ————— 0.025 mol = –54.6 kJ mol–1

(iii) EnergyTenaga

KOH(aq) + CH3COOH(aq)KOH(ak) + CH3COOH(ak)

∆H = –54.6 kJ mol–1

CH3COOK(aq) + H2O(l)CH3COOK(ak) + H2O(ce)

(e) The value of heat of neutralisation in Experiment I is higher than that in Experiment II.

Nilai haba peneutralan dalam Eksperimen I lebih tinggi daripada nilainya dalam Eksperimen II.

Explanation: Sodium hydroxide, sulphuric acid, and potassium hydroxide dissociate completely in water. Ethanoic acid dissociates partially in water. Some of the heat released in neutralisation is used to dissociate the unionised ethanoic acid molecules.

Penerangan: Natrium hidroksida, asid sulfurik, dan kalium hidroksida bercerai dengan lengkap dalam air. Asid etanoik bercerai separa dalam air. Sebahagian tenaga haba yang terbebas dalam peneutralan telah digunakan untuk menceraikan molekul-molekul asid etanoik tak terion.

2. (a) (i) • A white precipitate is formed. Mendakan putih terbentuk.

• The temperature of the mixture drops. Suhu campuran berkurang.

(ii) Ca2+(aq) + CO32–(aq) → CaCO3(s)

Ca2+(ak) + CO32–(ak) → CaCO3(p)

(b) Polystyrene cups are poor conductors of heat, thus reducing heat loss to the surroundings during the experiment.

Cawan polistirena adalah konduktor haba yang lemah, jadi ia dapat mengurangkan kehilangan haba ke persekitaran semasa eksperimen itu.

(c) The total energy content of the product is higher than that of the reactants.

Jumlah kandungan tenaga hasilnya lebih tinggi daripada jumlah kandungan tenaga bahan tindak balas.

(d) To ensure that the temperature of the mixture is uniform.

Untuk memastikan suhu campuran adalah sekata.

(e) From the graph, the drop in temperature Daripada graf, penurunan suhu = (26.6 – 25.2)°C = 1.4°C

∴ The total heat energy absorbed in the reaction Jumlah tenaga haba yang diserap dalam tindak balas

itu = mcq = (80 + 80) g × 4.2 J g–1 °C–1 × 1.4°C = 940.8 J(f) Number of moles of Ca2+ ions Bilangan mol ion Ca2+

80 = MV = 1 × ——– = 0.08 mol 1000 Number of moles of CO3

2– ions Bilangan mol ion CO3

2–

80 = MV = 1 × ——– = 0.08 mol 1000

Ca2+(aq) + CO32–(aq) → CaCO3(s)

1 mole 1 mole 1 mole

Ca2+(ak) + CO32–(ak) → CaCO3(p)

1 mol 1 mol 1 mol

1 mole of Ca2+ ions reacts with 1 mole of CO32– ions

to form 1 mole of CaCO3. 1 mol ion Ca2+bertindak balas dengan 1 mol ion CO3

2–

untuk membentuk 1 mol CaCO3.

∴ Number of moles of CaCO3 precipitated Bilangan mol CaCO3 termendak

= 0.08 mol Precipitation of 0.08 mol of CaCO3 absorbed 940.8 J of heat energy. Pemendakan 0.08 mol CaCO3 menyerap 940.8 J tenaga

haba.

∴ The total heat energy absorbed during the precipitation of one mole of CaCO3

Jumlah tenaga haba yang diserap semasa pemendakan satu mol CaCO3

1 = —––– × 940.8 J = 11 760 J = 11.76 kJ 0.08

∴ Heat of precipitation of CaCO3 Haba pemendakan CaCO3

= +11.76 kJ mol–1

(g) The temperature of the mixture will drop by Suhu campuran menurun sebanyak

1.4°C —–—– = 0.7°C 2

Section B / Bahagian B

3. (a) • 250 cm3 of distilled water is measured and poured into a copper can. [1]

250 cm3 air suling disukat dan dituang ke dalam sebuah tin kuprum.

• The copper can is placed on a tripod stand without a wire gauze. [1]

Tin kuprum diletakkan di atas tungku kaki tiga tanpa kasa dawai.

• The initial temperature of the water is measured after 5 minutes. [1]

Suhu awal air disukat selepas 5 minit.

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• 50 cm3 of butan-1-ol is poured into a spirit lamp. The spirit lamp containing butan-1-ol is weighed. [1]

50 cm3 butan-1-ol dituangkan ke dalam sebuah pelita spirit. Pelita spirit yang mengandungi butan-1-ol ditimbangkan.

• The lamp is placed on a wooden block under the copper can as shown in the diagram. [1]

Pelita ini diletakkan di atas satu bongkah kayu di bawah tin kuprum seperti yang ditunjukkan dalam rajah.

Spirit lampPelita spirit

WindshieldPengadang angin

Wooden blockBongkah kayu

Butan-1-olButan-1-ol

WaterAir

ThermometerTermometer

Copper canTin kuprum

Tripod standTungku kaki tiga

[1]• The apparatus is shielded using a windshield to

avoid wind disturbances. [1] Radas itu dikelilingi oleh pengadang angin untuk

mencegah gangguan angin.• The wick of the lamp is lighted immediately. [1] Sumbu pelita dinyalakan dengan serta-merta.• The water is stirred continuously using the

thermometer. [1] Air dikacau berterusan dengan menggunakan

termometer.• Once the temperature of the water increases by

63.5 °C, the flame is put out. [1] Sebaik sahaja suhu air menaik sebanyak 63.5°C,

nyalaan itu dipadamkan.• The spirit lamp containing butan-1-ol is weighed

again immediately. [1] Pelita spirit yang mengandungi butan-1-ol ditimbang

semula dengan serta-merta.• Results: Keputusan: Mass of spirit lamp + butan-1-ol before combustion Jisim pelita spirit + butan-1-ol sebelum pembakaran = M1 g Mass of spirit lamp + butan-1-ol after combustion Jisim pelita spirit + butan-1-ol selepas pembakaran = M2 g Initial temperature = t1 °C Suhu awal Highest temperature = t2 °C Suhu tertinggi Volume of water = 250 cm3 [1] Isi padu air Mass of butan-1-ol burnt = (M1 – M2) g Jisim butan-1-ol yang dibakarkan = 1.85 g The rise in temperature = (t2 – t1) °C Kenaikan suhu = 63.5 °C [1]

Hence, complete combustion of 1.85 g of butan-1-ol in excess air raises the temperature of 250 cm3 of water by 63.5 °C.

Maka, pembakaran 1.85 g butan-1-ol yang lengkap dalam udara berlebihan menaikkan suhu 250 cm3 air sebanyak 63.5 °C.

Maximum: [11](b) Molar mass of butan-1-ol, C4H9OH Jisim molar butan-1-ol, C4H9OH

= (12 × 4) + (1 × 9) + (16 × 1) + (1 × 1) = 74 g mol–1

∴ Number of moles of butan-1-ol burnt Bilangan mol butan-1-ol terbakar

1.85 g = ———–—– = 0.025 mol [1] 74 g mol–1

Heat given out by the combustion of 0.025 mole of butan-1-ol

Haba dibebaskan oleh pembakaran 0.025 mol butan-1-ol

= mcq = 250 g × 4.2 J g–1 °C–1 × 63.5°C = 66 675 J [1]

∴ Heat given out by the combustion of 1 mole of butan-1-ol

Haba dibebaskan oleh pembakaran 1 mol butan-1-ol 1 = ——– × 66 675 J = 2 667 000 J = 2 667 kJ 0.025

[1] ∴ Heat of combustion of butan-1-ol

Haba pembakaran butan-1-ol

= –2667 kJ mol–1 [1](c) • The value of heat of combustion of ethanol is less

than the value of heat of combustion of butan-1-ol. [1]

Nilai haba pembakaran etanol kurang daripada nilai haba pembakaran butan-1-ol.

• This is because the number of carbon and hydrogen atoms per molecule of ethanol is less than that of butan-1-ol. [1]

Ini disebabkan oleh bilangan atom karbon dan atom hidrogen per molekul etanol kurang daripada yang terdapat dalam butan-1-ol.

(d) CH3CH2CH2CH2OH(l) + 6O2(g) → 4CO2(g) + 5H2O(l) CH3CH2CH2CH2OH(ce) + 6O2(g) → 4CO2(g) + 5H2O(ce)

• The total heat energy given out in the bond formations of the products (i.e. 4 moles of O=C=O and 5 moles of H–O–H) is higher than the total heat energy absorbed in the bond breakings of the reactants

(i.e. 1 mole of CH3CH2CH2CH2OH and 6 moles of O=O). [2]

Jumlah tenaga haba yang dibebaskan dalam pembentukan ikatan bagi hasilnya (iaitu 4 mol O=C=O dan 5 mol H–O–H) adalah lebih tinggi daripada jumlah tenaga haba yang diserap dalam pemecahan ikatan bagi bahan tindak balasnya (iaitu 1 mol CH3CH2CH2CH2OH dan 6 mol O=O)

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• Hence, excess energy is given out to the surroundings as heat. [1]

Maka, tenaga yang berlebihan dibebaskan ke persekitaran sebagai haba.

Section C / Bahagian C

4. (a) (i) • 1 mol of zinc reacts with 1 mol of copper(II) sulphate to liberate 210 kJ of heat energy.

1 mol zink bertindak balas dengan 1 mol kuprum(II) sulfat membebaskan 210 kJ tenaga haba.

• The energy content of the reactants [zinc and copper(II) sulphate] is higher than the energy content of the products [zinc sulphate and copper].

Kandungan tenaga bahan tindak balas [zink dan kuprum(II) sulfat] lebih tinggi daripada kandungan tenaga hasil tindak balas [zink sulfat dan kuprum].

(ii) This is because sulphate ions and nitrate ions are not taking part in the displacement reaction.

Hal ini kerana ion sulfat dan ion nitrat tidak mengambil bahagian dalam tindak balas penyesaran itu.

(iii) Number of moles of copper(II) sulphate reacted Bilangan mol kuprum(II) sulfat yang bertindak balas

= 1 × 501000

= 0.05 mol From the energy level diagram, 1 mol of

copper(II) sulphate reacted will liberate 210 kJ of heat.

Daripada gambar rajah aras tenaga, 1 mol kuprum(II) sulfat yang bertindak balas akan membebaskan 210 kJ haba.

∴ 0.05 mol of copper(II) sulphate reacted will

liberate 0.051 × 210 = 10.5 kJ of heat.

0.05 mol kuprum(II) sulfat yang bertindak balas

akan membebaskan 0.05

1 × 210 = 10.5 kJ haba

Heat released = mcθ Haba yang dibebaskan

∴ 10.5 × 1000 J = 50 × 4.2 θ

θ = 10.5 × 100020 × 4.2

= 50°C ∴ Maximum rise in temperature = 50°C

Kenaikan suhu yang maksimum

(b) • Variables: Pemboleh ubah:

(i) Manipulated: Types of copper(II) salt solution Dimanipulasikan: Jenis larutan garam kuprum(II)

(ii) Responding: Value of heat of displacement Bergerak balas: Nilai haba penyesaran

(iii) Fixed: Volume and concentration of copper(II) salt solution, mass of zinc powder, polystyrene cup [1]

Dimalarkan: Isi padu dan kepekatan larutan garam kuprum(II), jisim serbuk zink, cawan polistirena

• Procedure: Prosedur:

1. 50 cm3 of 0.2 mol dm–3 copper(II) sulphate solution is measured and poured into a polystyrene cup. [1]

50 cm3 larutan kuprum(II) sulfat 0.2 mol dm–3 disukatkan dan dituangkan ke dalam sebuah cawan polistirena.

2. The initial temperature of the solution is measured after 5 minutes. [1]

Suhu awal larutan ini disukatkan selepas 5 minit. 3. 1 g of excess zinc powder is poured quickly

and carefully into the copper(II) sulphate solution. [1]

1 g serbuk zink berlebihan dituangkan dengan cepat dan cermat ke dalam larutan kuprum(II) sulfat.

4. The mixture is stirred immediately with the thermometer. [1]

Campuran ini dikacau dengan serta-merta dengan menggunakan termometer.

5. The highest temperature of the reaction mixture is recorded. [1]

Suhu tertinggi bagi campuran hasil tindak balas direkodkan.

6. The experiment is repeated using 50 cm3 of 0.2 mol dm–3 copper(II) nitrate solution to replace 50 cm3 of 0.2 mol dm–3 copper(II) sulphate solution. [1]

Eksperimen ini diulang dengan menggunakan 50 cm3 larutan kuprum(II) nitrat 0.2 mol dm–3 untuk menggantikan 50 cm3 larutan kuprum(II) sulfat 0.2 mol dm–3.

• Results: Keputusan:

ReactantBahan

tindak balas

Initial temperature of copper(II) salt solution

(°C)Suhu awal

larutan garam kuprum(II) (°C)

Highest temperature

of the reaction mixture (°C)Suhu tertinggi

campuran hasil tindak balas

Zinc + copper(II) sulphateZink + kuprum(II) sulfat

t1 t2

Zinc + copper(II) nitrateZink + kuprum(II) nitrat

t3 t4

[1]

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• Calculations: Penghitungan: For zinc + copper(II) sulphate solution: Bagi zink + larutan kuprum(II) sulfat:

Zinc is in excess. Zink adalah berlebihan.

Number of moles of copper(II) sulphate Bilangan mol kuprum(II) sulfat 50 = MV = 0.2 × —–— = 0.01 mol 1000 Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s) 1 mole 1 mole

Zn(p) + CuSO4(ak) → ZnSO4(ak) + Cu(p) 1 mol 1 mol ∴ Number of moles of copper displaced by zinc Bilangan mol kuprum yang disesarkan oleh zink = 0.01 mol [1] Total heat energy given out Jumlah tenaga haba yang dibebaskan = mcq = 50 g × 4.2 J g–1 °C–1 × (t2 – t1)°C = y J

∴ Total heat energy given out when one mole of copper is displaced from CuSO4 solution by zinc

Jumlah tenaga haba yang dibebaskan apabila satu mol kuprum disesarkan daripada larutan CuSO4 oleh zink

1 = —— × y J = 100y J 0.01∴ Heat of displacement of copper from CuSO4

solution by zinc

∴ Haba penyesaran kuprum daripada larutan CuSO4 oleh zink

= –100y J mol–1 [1] For zinc + copper(II) nitrate solution: Bagi zink + larutan kuprum(II) nitrat: Zn(s) + Cu(NO3)2(aq) → Zn(NO3)2(aq) + Cu(s) Zn(p) + Cu(NO3)2(ak) → Zn(NO3)2(ak) + Cu(p)

Using the similar method of calculation as before, it can be shown that the heat of displacement of copper from copper(II) nitrate solution by zinc

Dengan menggunakan kaedah penghitungan yang sama seperti dahulu, dapat ditunjukkan bahawa haba penyesaran kuprum daripada larutan kuprum(II) nitrat oleh zink

1 = – —— × [50 × 4.2 × (t4 – t3)] 0.01 1 = – —— × w = –100w J mol–1

0.01 [1]• When comparing the values of heat of

displacement obtained, it can be observed that –100y = –100w. [1]

Apabila membandingkan nilai-nilai haba penyesaran yang diperoleh, dapat diperhatikan bahawa –100 y = –100 w.

• Hence, we can conclude that the values of heat of displacement of copper from different copper(II) salt solutions by zinc are the same. Thus, hypothesis is accepted. [1]

Jadi, dapat disimpulkan bahawa nilai-nilai haba penyesaran kuprum daripada larutan garam kuprum(II) yang berlainan oleh zink adalah sama. Maka, hipotesis dapat diterima.

5Chapter Chemicals for Consumers

Bahan Kimia untuk Pengguna

5.1 INQUIRY Experiment

Observation

TestUjian

ObservationPemerhatian

Examine on the solid productPeriksa hasil pepejal

A white solid was obtained.Pepejal putih diperoleh.

Rub the solid product between fingersGosokkan hasil pepejal antara jari

It had a slippery feeling.Ia berasa licin.

Shake the solid product with waterGoncangkan hasil pepejal dengan air

A lot of lather was formed (very foamy).Banyak buih terbentuk.

5.2 GUIDED Experiment

Observation

BeakerBikar T U V W

ObservationPemerhatian

A lot of lather was formed. The oily stain was removed. The cloth was cleaned.Banyak buih terbentuk.Tompok kotoran berminyak disingkirkan.Kain menjadi bersih.

No lather but a white precipitate was formed. The oily stain remained on the cloth.Tiada buih tetapi mendakan putih terbentuk.Tompok kotoran berminyak kekal tinggal pada kain.

A lot of lather was formed. The oily stain was removed. The cloth was cleaned.Banyak buih terbentuk.Tompok kotoran berminyak disingkirkan.Kain menjadi bersih.

A lot of lather was formed. The oily stain was removed. The cloth was cleaned.Banyak buih terbentuk.Tompok kotoran berminyak disingkirkan.Kain menjadi bersih.

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SPM ReviewSPM Review 55Objective Questions

1. A 2. C 3. C 4. B 5. A 6. B 7. A 8. A 9. C 10. D 11. A 12. A 13. A 14. C 15. A 16. A 17. C 18. C 19. A 20. C

Subjective Questions

Section A / Bahagian A

1. (a) Soap / sodium salt of fatty acid Sabun / garam natrium bagi asid lemak

(b) To allow the soap to precipitate out from the solution as sodium chloride will reduce the solubility of soap in water.

Untuk membolehkan sabun termendak keluar daripada larutan kerana natrium klorida merendahkan keterlarutan sabun dalam air.

(c)

Water inAir masuk

Water outAir keluar

Liebig condenserKondenser Liebig

HeatPanaskan

Round-bottomed flaskKelalang berdasar bulat

RetortstandKakiretort

Mixture of corn oiland concentrated sodiumhydroxide solutionCampuran minyak jagung danlarutan natrium hidroksidapekat

(d) (i) Q : Detergent / Detergen

R : Soap / Sabun

J : Hard water / Air liat

M : Soft water / Air lembut

(ii) The calcium ions and magnesium ions in hard water (J) reacts with soap (R) to form insoluble calcium salt and magnesium salt of soap called scum.

Ion-ion kalsium dan ion-ion magnesium dalam air liat (J) bertindak balas dengan sabun (R) untuk membentuk garam kalsium dan garam magnesium bagi sabun yang tidak larut dalam air yang disebut kekat.

(iii) • Able to lower the surface tension of water and hence increases the wetting ability of water.

Dapat merendahkan tegangan permukaan air, jadi kebolehan air membasahi permukaan kain bertambah.

• Able to emulsify oil or grease so as to suspend them in water.

Dapat mengemulsikan minyak atau gris supaya mengapungkannya dengan sekata dalam air.

2. (a) (i) T – Sodium nitrite T – Natrium nitrit

W – Sodium citrate W – Natrium sitrat

X – Tartrazine X – Tartrazina

(ii) Sodium nitrite is carcinogenic that can cause stomach cancer.

Natrium nitrit ialah karsinogen yang boleh menyebabkan kanser perut.

Tartrazine can cause hyperactivity in children. Tartrazina boleh menyebabkan kanak-kanak menjadi

hiperaktif.

(iii) Y – Antioxidant Pengantioksida

Z – Food dyes Pewarna makanan

(b) • Keep the food in frozen state in a rerigerator. Simpan makanan dalam keadaan beku di dalam peti

sejuk.• Dry the food under the sun to keep it in the dry

state. keringan makanan di bawah matahari untuk

mengekalkannya dalam keadaan kering.• Boil the food and then keep it in a sealed can. Didihkan makanan dan kemudian simpankannya di

dalam tin tertutup. (Any two/Mana-mana dua)

(c) Aspartame – To sweeten food Aspartame – Untuk memaniskan makanan

Monosodium glutamate – To bring out the flavour in many types of food

Mononatrium glutamat – Untuk memberikan rasa sedap dalam banyak jenis makanan

3. (a) Stabilisers and thickeners Penstabil dan pemekat

(b) (i) • Keep the food in frozen state in a refrigerator. Simpan makanan dalam keadaan beku di dalam

peti sejuk.• Dry the food under the sun to keep it in the

dry state. Keringkan makanan di bawah matahari untuk

mengekalkannya dalam keadaan kering.• Boil the food and then keep it in a sealed can. Didihkan makanan dan kemudian simpankannya

di dalam tin tertutup.

(ii) Sulphur dioxide Sulfur dioksida

(c) (i) Tartrazine / Tartrazina

(ii) Turmeric / Kunyit(d) (i) • Aspartame Aspartame

• Monosodium glutamate (MSG) Mononatrium glutamat (MSG)

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(ii) • Aspartame is a non-sugar sweetener that adds a sweet taste to food.

Aspartame ialah suatu pemanis bukan gula yang memberikan rasa manis kepada makanan.

• Monosodium glutamate (MSG) is used to improve the flavour of food so that it tastes better.

Mononatrium glutamat (MSG) digunakan untuk meningkatkan rasa makanan supaya lebih sedap.

(e) (i) To prevent the fats and oils in food from being oxidised on exposure to the air which will turn them into acids with an unpleasant smell (i.e. turn rancid).

Untuk mencegah lemak dan minyak dalam makanan daripada teroksida apabila terdedah kepada udara yang akan menukarkannya menjadi asid dengan satu bau yang tidak menyenangkan (iaitu menjadi tengik).

(ii) Ascorbic acid in fruit juice / sodium citrate in cooked cured meat / butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) in margarine

Asid askorbik dalam jus buah-buahan / natrium sitrat dalam daging masak terawet / butil hidrosianisol (BHA) dan butil hidroksitoluena (BHT) dalam marjerin.

4. (a) (i) To treat depression and for longevity Untuk merawat depresen (kemurungan) dan juga

untuk panjang umur (ii) To treat gout, diabetes, and rheumatism Untuk merawat gout, diabetes, dan reumatisme (iii) To increase male libido Untuk meningkatkan libido lelaki(b) • Not all traditional medicines are safe. Bukan semua ubat tradisional adalah selamat.

• For example, garlic capsules combined with diabetes medication can cause a sudden decrease in the glucose level in blood.

Sebagai contohnya, kapsul bawang putih bercampur dengan ubat diabetes boleh menyebabkan kandungan glukosa dalam darah berkurang secara mendadak.

(c) (i) Ensure that the full course of medicine is taken based on the dosage and instructions by the doctor.

Pastikan semua ubat habis dimakan mengikut dos dan arahan yang ditetapkan oleh doktor.

(ii) To make sure that all bacteria are killed. Otherwise, the patient may become ill again as the bacteria may become more resistant to the medicine.

Untuk memastikan semua bakteria telah dibunuh dengan sepenuhnya. Jika tidak, pesakit itu mungkin jatuh sakit semula kerana bakteria akan menjadi lebih imun terhadap ubat itu.

(iii) Penicillin and streptomycin Penisilin dan streptomisin (iv) • Penicillin is used to treat tuberculosis and

pneumonia. Penisilin digunakan untuk merawat tibi dan

pneumonia.

• Streptomycin is used to treat tuberculosis, whooping cough, and pneumonia.

Streptomisin digunakan untuk merawat tibi, batuk ayam, dan pneumonia.

(d) (i) • Aspirin is an acid that can cause internal bleeding and ulceration in the stomach.

Aspirin adalah sejenis asid yang boleh menyebabkan pendarahan dalam dan pertumbuhan ulser di dalam perut.

• Paracetamol can be used to replace aspirin. Parasetamol boleh digunakan untuk

menggantikan aspirin. (ii) It is used as a medicine to sedate, calm or relax

emotions of individuals at low doses. At higher doses, it can induce sleep.

Ia digunakan sebagai ubat untuk menenangkan emosi individu pada dos rendah. Pada dos tinggi, ia boleh menyebabkan seseorang itu tidur.

Section B / Bahagian B

5. (a) • The type of medicine prescribed to Mohamad is antibiotic. [1]

Jenis ubat yang dipreskripsikan kepada Mohamad ialah antibiotik.

• An example of this medicine is penicillin /streptomycin. [1]

Satu contoh ubat ini ialah penisilin / streptomisin.• Correct usage: Cara penggunaan ubat yang betul: Mohamad must finish taking the whole course of

antibiotics prescribed to him even though he feels better. [1]

Mohamad mesti habiskan semua antibiotik yang dipreskripsikan kepadanya walaupun dia sudah berasa lebih baik.

This is to make sure that all the bacteria are killed. Otherwise, the undestroyed bacteria may multiply again and become more resistant to the antibiotic. [1]

Tindakan ini adalah untuk memastikan semua bakteria sudah dibunuh dengan sepenuhnya. Jika tidak, bakteria yang masih belum dimusnahkan akan membiak semula dan menjadi lebih imun terhadap antibiotik itu.

• The type of medicine prescribed to Chee Kiong is an analgesic. [1]

Jenis ubat yang dipreskripsikan kepada Chee Kiong ialah analgesik.

• An example of this medicine is aspirin /paracetamol / codeine. [1]

Satu contoh ubat ini ialah aspirin / parasetamol / kodeina.• This medicine is used to relieve pain. [1] Ubat ini digunakan untuk melegakan kesakitan.• Correct usage: Cara penggunaan ubat yang betul: Chee Kiong must take the medicine at the

recommended dose as prescribed by the doctor. [1]

Chee Kiong harus makan ubat ini mengikut dos yang disyorkan seperti yang dipreskripsikan oleh doktor.

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(b) (i) • Common salt (sodium chloride) absorbs water by drawing water out of the cells of microorganisms. [2]

Garam biasa (natrium klorida) menyerap air dengan menarik air keluar daripada sel-sel mikroorganisma.

• This retards the growth of microorganisms. [1] Ini menghalang pertumbuhan mikroorganisma.

(ii) • Sodium nitrite is added to meat to preserve the meat and also to stabilise the red colour of meat so as to make it look fresh. [1]

Natrium nitrit ditambahkan kepada daging untuk mengawet daging ini dan juga menstabilkan warna merah daging ini supaya ia kelihatan segar.

• When meat is cooked, the nitrite ions in sodium nitrite will change to nitrosamines which are carcinogenic. This is the side effect. [1]

Apabila daging dipanaskan, ion-ion nitrit dalam natrium nitrit berubah kepada nitrosamina yang bersifat karsinogenik. Ini adalah kesan sampingannya.

(iii) • When exposed to air, fats, and oils in oily food are oxidised to acid with an unpleasant smell. Hence, the food turns rancid. [1]

Apabila terdedah kepada udara, lemak dan minyak dalam makanan berminyak akan dioksidakan kepada asid dengan bau yang tidak sedap. Maka, makanan menjadi tengik.

• This problem can be overcome by adding antioxidants to the oily food to prevent oxidation of fats and oils. [1]

Masalah ini dapat diatasi dengan menambahkan antipengoksida kepada makanan berminyak untuk mencegah pengoksidaan lemak dan minyak.

• For example, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are used as antioxidant in margarine whereas sodium citrate is used as antioxidant in cooked cured meat. [1]

Sebagai contohnya, butil hidroksianisol (BHA) dan butil hidroksitoluena (BHT) digunakan sebagai antipengoksida dalam marjerin manakala natrium sitrat digunakan sebagai antipengoksida dalam daging masak terawet.

(iv) • Pectin is used as a thickener in jams and jellies. [1]

Pektin digunakan sebagai pemekat dalam jam dan agar-agar.

• Acacia gum is also used as a thickener in chewing gum, jelly, and wine. [1]

Gam acacia digunakan sebagai pemekat dalam gula-gula getah, agar-agar, dan wain.

• The function of thickeners is used to thicken food. [1]

Fungsi pemekat adalah digunakan untuk memekatkan makanan.

• Apart from that, acacia gum is also used as a stabiliser in food which helps to prevent an emulsion of oil droplets suspended in water from separating out. [1]

Selain daripada itu, gam acacia juga digunakan sebagai penstabil dalam makanan yang dapat mencegah suatu emulsi bagi titisan-titisan minyak terapung dengan sekata dalam air daripada terpisah keluar.

Section C / Bahagian C

6. (a) (i) Ascorbic acid is used as antioxidant. Its function is to prevent oxidation of oil in the food so that it does not turn rancid. [1]

Asid askorbik digunakan sebagai pengantioksida. Fungsinya untuk menghalang pengoksidaan minyak dalam makanan supaya tidak menjadi tengik.

Monosodium glutamate (MSG) is used as flavouring. Its function is to bring out / enhance the flavour of food so that it becomes tastier.

Mononatrium glutamat (MSG) digunakan sebagai perisa. Fungsinya untuk meningkatkan rasa makanan supaya ia menjadi lebih sedap.

Tartrazine is used as food dye. Its function is to add or restore the yellow colour in food.

Tartrazina digunakan sebagai pewarna. Fungsinya untuk memberi warna kuning kepada makanan atau memulihkan warna kuning dalam makanan.

(Any one) (Mana-mana satu)

(ii) Potassium chloride [1] Kalium klorida

(b) (i) Substance E is sulfuric acid. [1] Bahan E ialah asid sulfurik.

Gas Y is sulphur dioxide. [1] Gas Y ialah sulfur dioksida.(ii) • Sulphur dioxide is an acidic and poisonous

gas. The gas can cause air pollution, water pollution, and soil pollution by making the air, water, and soil acidic. [1]

Sulfur dioksida ialah gas berasid dan beracun. Gas ini boleh menyebabkan pencemaran udara, pencemaran air dan pencemaran tanah akibat udara, air, dan tanah menjadi berasid.

• Acid rain caused by sulphur dioxide can corrode buildings, monuments, and statues made from metals and marbles. [1]

Hujan asid yang disebabkan oleh sulfur dioksida boleh menghakiskan bangunan, monumen, dan patung yang diperbuat daripada logam dan marmar.

• Acidic water caused by sulphur dioxide can kill aquatic organisms like planktons, fish, and plants. [1]

Air berasid yang disebabkan oleh sulfur dioksida boleh membunuh organisma akuatik seperti plankton, ikan, dan tumbuhan.

(iii) Sodium alkylbenzene sulphonate [1] Natrium alkilbenzena sulfonat

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(c) Method I: Kaedah I: Freezing food in a refrigerator. [1] Membekukan makanan dalam peti sejuk. Explanation: Penerangan: All the water in the food is frozen to become ice.

The absence of water in the form of liquid retards or prevents the growth of microorganisms. [1]

Semua air dalam makanan itu dibekukan untuk menjadi ais. Ketidakhadiran air dalam bentuk cecair menghalang atau mencegah pertumbuhan mikroorganisma.

Method 2: Kaedah II: Drying food under the hot sun. [1] Mengeringkan makanan di bawah matahari yang panas. Explanation: Penerangan: Under the hot sun, all the water in the food is

vapourised, leaving the food completely dried. The absence of water prevents microorganisms from growing. [1]

Di bawah matahari panas, semua air dalam makanan itu akan tersejat, meninggalkan makanan yang kering sepenuhnya. Ketidakhadiran air dalam keadaan cecair mencegah pertumbuhan mikroorganisma.

(Any of the two methods) (Salah satu kaedah)

(d) • A soap particle consists of two parts: Satu zarah sabun mengandungi dua bahagian:

– A long chain hydrocarbon part which is hydrophobic (i.e. soluble in fat / grease but insoluble in water).

Bahagian hidrokarbon berantai panjang yang bersifat hidrofobik (iaitu larut dalam lemak/gris tetapi tidak larut dalam air).

– Ionic part –COO– which is hydrophilic (i.e. soluble in water but insoluble in fat / grease).

Bahagian ion –COO– yang bersifat hidrofilik (iaitu larut dalam air tetapi tidak larut dalam lemak / gris). [1]

• An example of a soap particle is shown below: Satu contoh zarah sabun ditunjukkan di bawah: [1]

CH3

Hydrophobic part Hydrophilic partBahagian hidrofobik Bahagian hidrofilik

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

CH2

C

O

O–

• Oily stains stuck onto the surface of the piece of cloth. Soap ions move randomly in the water. [1]

Tompok kotoran berminyak terlekat pada permukaan sehelai kain. Ion-ion sabun bergerak secara rawak di dalam air.

• The long-chain hydrocarbon part of the soap ions (i.e.hydrophobic part) dissolve in oil while the ionic part, –COO– of soap ions (i.e. hydrophilic part) dissolve in water. Soap ions bind the water and oil together. [1]

Bahagian hidrokarbon berantai panjang bagi ion sabun (iaitu bahagian hidrofobik) larut dalam minyak manakala bahagian ion, –COO– bagi ion sabun (iaitu bahagian hidrofilik) larut dalam air. Ion-ion sabun memegangkan air dan minyak bersama.

• Soap ions reduce the surface tension of water. This allows water to wet the surface of the cloth and causes the oil to detach from the surface of the cloth. The oil moves away from the surface as tiny droplets. [2]

Ion-ion sabun merendahkan tegangan permukaan air. Ini membolehkan air membasahi permukaan kain dan menyebabkan minyak tertanggal daripada permukaan kain. Minyak bergerak menjauhi permukaan kain sebagai titisan-titisan kecil.

• The tiny droplets of oil with negative charges on their surfaces repel each other. This prevents them from redepositing onto the surface of the cloth. [1]

Titisan-titisan minyak kecil yang mempunyai cas-cas negatif di permukaannya menolak satu sama lain. Ini mencegahnya daripada terenap semula pada permukaan kain.

• The oil droplets disperse in the water forming an emulsion. Disposal of emulsified water and lather followed by rinsing, leave the surface clean. [1]

Titisan-titisan minyak ini bersebar dalam air untuk membentuk emulsi. Pembuangan air beremulsi dan buih-buihnya diikuti dengan pembilasan akan menjadikan permukaannya bersih.

Chemistry Form 5 Answers