SKOR A KIMIA 2014TAJUK: REDOKSSET 1A pupil carried out an experiment to investigate a redox reaction. Diagram 6 shows the set-up of apparatus used in the experiment. Seorang pelajar menjalankan satu eksperimen untuk mengkaji tindakbalasredoks.Rajah 6 menunjukkan susunan radas yang digunakan didalam eksperimen ini.

(a) Name one substance that can replace bromine water in this experiment.Namakan satu bahan yang boleh menggantikan air bromin dalam eksperimen ini.

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

(b) The half equation of the reaction at electrode Y is as below.Persamaansetengahbagitindakbalaspadaelektrod Y adalahseperti di bawah.

Fe2+ Fe3+ + e

(i) State the colour change of iron (II) sulphate solution in this reaction.Nyatakan perubahan warna larutanferum (II) sulfat di dalam tindakbalas ini.

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

(ii) This reaction is an oxidation reaction. What is meant by oxidation reaction in terms of electron transfer? Tindakbalas ini adalah tindakbalas pengoksidaan.Apakah yang dimaksudkan dengan tindakbalas pengoksidaan dari segi pemindahanelektron?

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

(iii) Name a reagent to identify Fe3+ ion produced at electrode Y.Namakan satu reagen untuk mengenalpasti ion Fe3+ yang terhasil pada elektrod Y.

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

(c) (i) Iron undergoes oxidation reaction during rusting .Write half equation for the oxidation of iron. Besi mengalami pengoksidaan semasa berkarat. Tuliskan setengah persamaan untuk pengoksidaan besi.

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

(ii) Draw a labeled diagram for rusting of iron to show how the condition of rusting of iron involves the flow of electron, negative pole and positive pole. Lukiskan gambarajah berlabel bagi proses pengaratan besi yang menunjukkan bagaimana syara tuntuk pengaratan besi melibatkan pengaliran elektron, kutub negative dan kutub positif.

[3 marks]

(iii) Describe the transfer of electron and the reaction that take place at the positive pole after iron is oxidized.Huraikan pemindahan electron dan tindakbalas yang berlaku pada kutub positif selepas besi dioksidakan.

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[3 mark]

SKOR A KIMIA 2014TAJUK: REDOKSSET 2Diagram 5 shows an experiment of displacement of halogen from its halide solution.Rajah 5 menunjukkan suatu eksperimen penyesaran halogen daripada larutan halidanya.

(a) (i) State an observation for the reaction in the test tube before 1,1,1 - trichloroethane is added

Nyatakan satu pemerhatian bagi tindak balas di dalam tabung uji sebelum1,1,1- trikloroetana ditambahkan.

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

(ii) State the name of the substance that is oxidizedNyatakan nama bahan yang dioksidakan.

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

(iii) Write the oxidation reaction equation for this reaction.

Tuliskan persamaan tindak balas pengoksidaan bagi tindak balas ini.

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

(b) After 1,1,1- trichloroethane is added into the test tube, state the colour of X layer

Selepas 1,1,1- trikloroetana ditambahkan ke dalam tabung uji, nyatakan warna lapisan X.

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

(c) Name the oxidising agent for this reaction and give reason in terms of electron transfer.

Namakan agen pengoksidaan dalam tindak balas ini dan berikan sebab daripada segi pemindahan elektron.

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

(d) State the change of oxidation number for chlorine water.

Nyatakan perubahan nombor pengoksidaan air klorin

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

(e) State another reagent that can replace chlorine water.

Nyatakan satu bahan reagen lain yang boleh menggantikan air klorin.

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

(f) By using suitable chemical substance and apparatus, draw a a labelled diagram to show the transfer of electron at a distance.

Dengan menggunakan bahan kima dan alat radas yang sesuai, lukiskan gambar rajah berlabel untuk menunjukkan pemindahan elektron pada suatu jarak.

[2 markah]

SKOR A KIMIA 2014TAJUK: REDOKSSET 3(a) The following are the equations of two reactions:

Berikut adalah persamaan bagi dua tindak balas:

Reaction I : NaOH + HCl NaCl + H2OTindak balas I

Reaction II : Mg + Zn(NO2)3 Mg(NO2)3 + ZnTindak balas I I

Determine which reaction is a redox reaction. Explain your answer in term of oxidation number.Tentukan tindak balas manakah tindak balas redoks. Terangkan jawapan anda dari segi nombor pengoksidaan.

[4 marks]……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

(j) Diagram 8 shows two redox reactions that take place in test tubes P and Q.Rajah 8, menunjukkan dua tindak balas redoks yang berlaku dalan tabung uji P dan Q.

ChlorineKlorin

Iron (II) sulphateFerum (II) sulfat

Potassium iodideKalium iodida

Test tube PTabung uji P

Test tube QTabung uji Q

Diagram 8Rajah 8

Write the ionic equation for the redox reaction in test tubes P and Q.Tuliskan persamaan ion untuk tindak balas redoks dalam tabung uji P dan Q

[6 marks]………………………………………………………………………………………………….………………………………………………………………………………………………….………………………………………………………………………………………………….………………………………………………………………………………………………….

(c) Table 8 shows the observations of two experiments to determine the position of carbon the reactivity series of metal.Jadual 8 menununjukkan pemerhatian bagi dua eksperimen untuk menentukan kedudukan karbon dalam siri kereaktifan logam.

Experiment Reactants Observation

I Carbon + oxide of metal PKarbon + oksida logam P

A flame spreads to the whole mixture. A brown residue is formed.

Nyalaan merebak ke ke seluruhan campuran. Baki berwarna perang terbentuk.

IICarbon + oxide of metal QKarbon + oksida logam Q

No changeTiada perubahan

III Carbon + oxide of metal RKarbon + oksida logam R

A glow spreads to the whole mixture. Agrey residue is formed.

Baraan merebak ke keseluruhan campuran. Baki berwarna kelabu terbentuk.

Table 8Jadual 8

Based on observations in Table 8, arrange the reactivity of metals P, Q, and R in descending order. Explain your answer.Suggest one metal for Q.Berdasarkan pemerhatian dalam Jadual 8, susun kereaktifan logam-logam P, Q dan R dalam turutan menurun. Terangkan jawapan anda.Cadangkan satu logam bagi Q.

[10 marks]

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SKOR A KIMIA 2014TAJUK: REDOKSSET 4(a) Diagram 6.1 shows the apparatus set-up of an experiment to investigate the transfer of

electrons at a distance.Rajah 6.1 menunjukkan susunan radas eksperimen untuk mengkaji pemindahan elektron pada suatu jarak.

(i) State the name of the oxidizing agent in this reaction.Nyatakan nama agen pengoksidaan dalam tindak balas ini.

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

(ii) Referring to the reaction that takes place at carbon X :Merujuk pada tindak balas yang berlaku di karbon X :

Write the half equation for the reaction.Tuliskan persamaan setengah untuk tindak balas itu.

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

State one observation that occurred.Nyatakan satu pemerhatian yang berlaku.

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

(iii) Show the direction of the electron flow in Diagram 6.1Tunjukkan arah pengaliran elektron dalam Rajah 6.1 [ 1 mark]

(iv) Referring to the reaction that takes place at carbon Y, calculate the oxidation number of manganese in MnO -

Merujuk pada tindak balas yang berlaku pada karbon Y, hitungkan no pengoksidaan bagi mangan dalam MnO4

-

[ 2 marks]

(b) Diagram 6.2 shows the apparatus set-up to investigate the displacement of halogen from its halide solution. Chlorine water was added to a test tube containing a potassium iodide solution and organic solvent, 1,1,1-trichloroethane.Rajah 6.2 menunjukkan susunan radas untuk mengkaji penyesaran halogen daripada larutan halidanya. Air klorin ditambah ke dalam tabung uji yang mengandungi larutan kalium iodida dan pelarut organik 1,1,1-trikloroetana.

(i) Write the ionic equation for the reaction.Tuliskan persamaan ion bagi tindak balas itu.

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

(ii) What is the function of chlorine water?Apakah fungsi air klorin?

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

(iii) State the change of oxidation number for iodine.Nyatakan perubahan nombor pengoksidaan bagi iodin.

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

(iv) State the name of another reagent that can replace chlorine water.Nyatakan nama satu bahan uji lain yang boleh menggantikan air klorin.

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

SKOR A KIMIA 2014TAJUK: REDOKSSET 5(a) Define redox reaction in terms of transfer of electrons and give and example of the reaction.

Takrifkan tindak balas redoks dari segi pemindahan electron dan berikan satu contoh tindakbalas redoks.………………………………………………………………………………………………………………………………………………………………………………………………………………………………

[2 markah](b) Describe the electrolysis of concentrated copper(II) chloride solution using carbon

electrodes in terms of redox reaction. In your description , include all the half equations. Huraikan elektrolisis bagi larutan kuprum(II) sulfat pekat menggunakan elektrod karbon merujuk kepada tindak balas redoks. Dalam huraian anda, sertakan semua persamaan ion.

[8 marks / 8 markah]………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

(c) Transfer of electrons in a distance will happen when an oxidizing agent is connected to a reducing agent with the presence of electrolyte.

Pemindahan elektron dalam satu jarak yang jauh boleh berlakuapabila satu agen pengoksidaan disambung kepada satu agen penurunan dengan kehadiran suatu elektrolit.

Using appropriate chemical substances and apparatus, describe an experiment to support the statement above.Dengan menggunakan bahan kimia dan alat radas yang sesuai, huraikan satu eksperimen untuk menyokong kenyataan di atas.

[10 marks / 10 markah]

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SKOR A KIMIA 2014TAJUK: REDOKSSET 6a) Diagram 5.1 shows a reaction between lithium and chlorine gas.

Rajah 5.1 menunjukkan satu tindak balas antara litium dan gas klorin

(i) Write a chemical equation for the reaction. Tulis persamaan kimia bagi tindak balas ini.

………………………………………………………………………………………………………………………………[1 mark] (ii) State the changes in oxidation number for chlorine. Nyatakan perubahan nombor pengoksidaan bagi klorin.

……………………………………………………………..…………………………………………………………………[1 mark](iii) Explain why lithium acts as the reducing agent in terms of electron transfer.

Terangkan mengapa litium bertindak sebagai agen penurunan dari segi pemindahan elektron. …………………………………………………………………………………………………………………………………

…………………………………………………………………………………………………………………………………[1 mark]b) Diagram 5.2 shows the addition of bromine water into a test tube containing potassium

iodide solution until in excess.Rajah 5.2 menunjukkan penambahan air bromin ke dalam tabung uji mengandungi larutan kalium iodida sehingga berlebihan.

Bromine waterAir bromin

Potassium iodide solutionLarutan kalium iodida

(i) A small amount of 1,1,1-trichloroethane liquid is added to the product in the test tube and the mixture is shaken.What is the colour of 1,1,1-trichloroethane layer?Sedikit cecair 1,1,1-trikloroetana ditambah kepada hasil di dalam tabung uji dan campuran digoncang. Apakah warna lapisan 1,1,1-trikloroetana?

………………………………………………………………………………………………………………………… [1 mark](ii) Write the ionic equation for the reaction between bromine and potassium iodide solution.

Tulis persamaan ion bagi tindak balas antara bromin dengan larutan kalium iodida.

…………………………………………………………………………………………………………………… [1 markah](iii) What is the role of bromine water in this reaction?

Apakah peranan air bromin dalam tindak balas ini?

……………………………………………..……………………………………………………………………[1 markah]

(c) Diagram 5.3 shows the set-up of apparatus for an experiment to compare the reactivity of reactions between metal oxides and hydrogen gas.Rajah 5.3 menunjukkan susunan radas bagi satu eksperimen untuk membandingkan kereaktifan tindak balas antara oksida logam dan gas hidrogen.

Table 5 shows the result of the experiment:Jadual 5 menunjukkan keputusan eksperimen:

Experiment/Eksperimen Result/Keputusan

Hydrogen + oxide of metal JHidrogen + oksida logam J

Metal oxide powder glows brightly.Black powder turned brown.Serbuk oksida logam berbara dengan terang.Serbuk hitam menjadi perang.

Hydrogen + oxide of metal THidrogen + oksida logam T

No reaction.Powder turns yellow when hot and white when cold.

Tiada tindak balas. Serbuk bertukar kuning apabila panas dan putih apabila sejuk.

Hydrogen + magnesium oxide Hidrogen + magnesium oksida

No reaction.White powder remained.Tiada tindak balas. Serbuk putih kekal.

Jadual 5

(i) Suggest a name for metal T.Cadangkan nama bagi logam T.

……………………………………………………………………………….……………………………………………………………………… [1 markah]

(ii) Arrange the reactivity of J, T, Magnesium and Hydrogen in ascending order.Susun kereaktifan J, T, Magnesium dan Hidrogen dalam susunan menaik.

……………………………………………………………………………………………….…………………………………………………………………… [1 markah]

(iii) Based on the observations, explain how you obtain the arrangement in (c)(ii).Berdasarkan pemerhatian, terangkan bagaimana susunan dalam (c) (ii) diperolehi.

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[3 markah]

SKOR A KIMIA 2014TAJUK: REDOKSSET 6Diagram 6 shows the set- up of apparatus to investigate the reaction between potassium iodide solution and chlorine water through the transfer of electrons at a distance..Rajah 6 menunjukkan susunan radas untuk menyiasat tindak balas di antara larutan kalium iodide dan air klorin melalui pemindahan elektron pada satu jarak.

(a) What is the function of dilute sulphuric acid?Apakah fungsi asid sulfurik cair?

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

(b) On the diagram 6, draw the direction of the flow of electrons.Pada rajah 6, lukiskan arah pengaliran elektron – elektron.

1 markah(c) (i) What is the colour change in the solution around electrode P?

Apakah perubahan warna dalam larutan di sekitar elektrod?

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

(ii) Describe a chemical test to determine the product formed in the solution at electrode P.Huraikan satu ujian kimia untuk menentukan hasil yang terbentuk dalam larutan di elektrod P.

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

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

(d) What is the substance that is being oxidised in the experiment? Explain why.Apakah bahan yang dioksidakan dalam eksperimen?Terangkan mengapa.

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

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

(e) Write a half equation for the reaction that occurs at electrode Q.Tuliskan satu persamaan setengah bagi tindak balas yang berlaku di elektrod Q.

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

(f) Suggest another reagent that can replace chlorine water.Cadangkan reagen lain yang boleh menggantikan air klorin.

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

(g) What is the change in oxidation number of chlorine in the reaction?Apakah perubahan nombor pengoksidaan bagi klorin dalam tindak balas?

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