TRIAL TERENGGANU 2012

(a) State the name of cell X and cell Y. Namakan sel X dan sel Y

Cell X/ sel X : ………………………………………………………………………………………………………………………………………………..

Cell Y/ sel Y : ……………………………………………………………………………………………………………………………………………….[1 mark]

(b) Write the formulae of all anions present in copper(II) chloride solution. Tuliskan formula bagi semua anion yang hadir dalam larutan kuprum (II) klorida

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

(c) Based on the cell X Berdasarkan sel X

(i) State the observation at electrode carbon Q Nyatakan pemerhatian pada elektrod karbon Q

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

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

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

(iii) If copper (II) chloride solution 2 mol dm-3 is replaced by copper (II) chloride solution 0.001 mol dm-3. State the product formed at electrode carbon P. Jika larutan kuprum (II) klorida 2 mol dm-3 diganti dengan larutan kuprum (II) klorida 0.001 mol dm-3. Nyatakan bahan yang terhasil di elektrod karbon P

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

(d) Based on the cell P: Berdasarkan sel Y

(i) Draw arrow ( ) to show the direction of the electron flow Lukiskan anak panah ( ) untuk menunjukkan arah pengaliran electron

[1 mark]

(ii) Which electrode act as negative terminal? Elektrod yang manakah bertindak sebagai terminal negative?

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

(iii) Compare the intensity of blue colour of copper (II) chloride solution after a few minutes in both cells. Explain your answer Bandingkan keamatan warna biru larutan kuprum (II) klorida selepas beberapa minit dalam kedua-dua sel. Terangkan jawapan anda.

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

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

TRIAL TERENGGANU 2007

2. Diagram 2 shows the set-up of apparatus of a voltaic cell. Rajah 2 menunjukkan susunan radas satu sel kimia.

Based on Diagram 2 , answer the following questions. Berdasarkan Rajah 2, jawab soalan- soalan berikut:

(a) What is the energy change that occurs in the voltaic cell?Apakah perubahan tenaga yang berlaku dalam sel kimia?

.....................................................................................................................[1 mark](b) Write the formula of all ions in copper (II) sulphate solution.

Tuliskan formula semua ion dalam larutan kuprum (II) sulfat.

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

(c) (i) Name the negative terminal of the voltaic cell.Namakan terminal negatif bagi sel kimia.

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

Copper (II) nitrate solution /

Larutan kuprum (II) nitrat

Copper plate / Kepingan kuprum

Zinc

Plate / Kepingan zink

V

(ii) Explain your answer in (b)(i).Terangkan jawapan anda dalam (b)(i).

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

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

(d) (i) State one observation at copper plate.Nyatakan satu pemerhatian pada kepingan kuprum.

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

(ii) Write the half equation for the reaction occur at the copper plate. Tuliskan persamaan setengah bagi tindak balas yang berlaku pada kepingan kuprum.

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

(e) What is the colour change of the copper(II) sulphate solution? Explain your answer.Apakah perubahan warna larutan kuprum (II) sulfat ? Jelaskan jawapan anda.

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

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

(f) Another experiment is carried out by replacing the zinc plate with P, Q and R metals. Table 3.2 shows the results.

Eksperimen lain dijalankan bagi menggantikan kepingan zink dengan logam P, Q dan R. Jadual 3.2 menunjukkan keputusannya.

Pair of metal/Pasangan logam

Voltage/Voltan (V)

Negative terminal/ Terminal negative

P/Cu 2.7 P

Q/Cu 2.0 Q

R/Cu 0.5 R

(i) Arrange P, Q, R and Cu metal in ascending order of electropositivity.Susunkan logam P, Q, R dan Cu mengikut tertib menaik keelektropositifan.

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

(ii) Predict the voltage for pair of Q/R.Ramalkan nilai voltan bagi pasangan Q/R

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

3 Diagram 3 shows the set up of the apparatus with the combination of electrolytic cell and chemical cell.Rajah 3 menunjukkan susunan radas gabungan sel elektrolisis dan sel kimia..

(a) Which cell will produce electrical energy?Sel yang manakah akan menghasilkan tenaga elektrik?

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

(b) Write the formulae of all ions that are present in copper(II) sulphate solution.Tuliskan formula semua ion yang hadir di dalam larutan kuprum(II) sulfat

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

(c) Based on the chemical cellBerdasarkan kepada sel kimia

(i) Label the negatif terminal of the cell.Labelkan terminal negatif sel itu.

[1 mark](ii) State the flow of electron.

Nyatakan arah pengaliran elektron.

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

(iii) State the observation at copper electrode.Nyatakan pemerhatian pada elektrod kuprum.

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

(iv) Write half equation for the reaction at cooper.Tuliskan persamaan setengah bagi tindak balas di kuprum.

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

(d) Based on the reaction in electrolytic cellBerdasarkan tindakbalas pada sel elektrolisis

(i) What is the observation at anodeApakah pemerhatian di anod

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

Larutan kuprum(II) sulfatSel Elektrolisis Sel Kimia

V

Zinc electrodeElektrod zinkCopper electrode

Elektrod kuprum

Copper electrodeElektrodkuprum

(ii) Explain the observation in (d)(i)Terangkan pemerhatian di (d)(i)

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

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

(iii) Name the product formed at cathode.Namakan hasil yang terbentuk pada katod.

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

4. Diagram 1 and diagram 2 below show two types of cell.Rajah 1 dan rajah 2 di bawah menunjukkan dua jenis sel.

Cell PSel P

Rajah 1

Salt bridgeJambatangaram

Cell QSel Q

Rajah 2(a) What is the energy change that happens in cell P?

Apakah perubahan tenaga yang berlaku di dalam sel P?

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

Copper plate

Kepingan kuprum

Copper plate

Kepingan kuprum

Copper (II)sulphate solution

Larutan kuprum(II)sulfat

Copper plate

Kepingan kuprum

Copper(II) nitrate

Solution

Larutan kuprum(II)

Magnesium plate

Kepingan magnesium

Magnesium

Nitrate solution

Larutan magnesium

(b) (i) State all the ions present in the copper(II) sulphate solution.Nyatakan semua ion yang hadir dalam larutan kuprum(II) sulfat.

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

(ii) Write a half equation for the reaction that occurs at the cathode of cell P.Tuliskan persamaan setengah bagi tindakbalas yang berlaku di katod sel P.

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

(c ) (i) State the direction of the flow of electrons in cell Q.Nyatakan arah pengaliran electron di dalam sel Q.

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

(ii) Write half equation that occurs at the magnesium plate in cell Q.Tuliskan persamaan setengah yang berlaku pada kepingan magnesium sel Q.

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

(iii) What will happen to the cell voltage if the copper plate is replaced with a silver plate.Apakah yang akan berlaku pada voltan sel jika kepingan kuprum digantikan dengan kepingan argentum.

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

(d) A student planned to electroplate an iron spoon with silver metal.Seorang pelajar merancang untuk menyadu rsudu besi dengan logam argentum.(i) Draw a labelled diagram to show the set up of apparatus to electroplate an iron spoon with silver

metal.Lukiskan gambar rajah berlabel untuk menunjukkan susunan radas untuk menyadur sudu besi dengan logam argentum.

(ii) Give one condition that must be taken to get a better electroplated spoon.Berikan satu keadaan yang perlu diambil untuk mendapatkan saduran yang baik pada sudu tersebut.

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

SOALAN ESEI BAB ELEKTROKIMIA

TRIAL JOHOR 2008

Diagram 10.2 shows two types of cells.Rajah 10.2 menunjukkan dua jenis sel.

Diagram 10.2Rajah 10.2

Construct a table to show the differences between Cell I and Cell II in terms of energy change, half-equations at the anode and the direction of electrons flow.Bina satu jadual untuk membezakan antara Sel I dan Sel II dari segi perubahan tenaga, setengah persamaan pada anod dan arah pengaliran elektron.

[6 marks]

Copper plate Plat kuprum Copper(II)

sulphate solutionLarutan kuprum(II) sulfat

Copper plate

Plat kuprum

BatteryBateri

Zinc platePlat zink

A B

V

C DCopper plate Plat kuprum

Voltmeter

Cell ISel I

Cell II

Sel II

7. (a) Dilute ethanoic acid (vinegar) is electrolysed using carbon electrodes. What is produced at the cathode? Write a half-equation for the reaction.Elektrolisis asid etanoik cair telah dijalankan menggunakan elektrod –elektrod karbon. Apakah yang terhasil di katod. Tuliskan setengah persamaan bagi tindak balas tersebut.

[2 marks]

(b) Diagram 7 shows two types of cells.Rajah 7 menunjukkan dua jenis sel.

Cell A Cell B DIAGRAM 7

Compare and contrast cell A and cell B. Include in your answer the observations and half equations for the reactions at the electrodes in both cells.Banding dan bezakan sel A dan sel B. Sertakan dalam jawapan anda pemerhatian dan setengah persamaan bagi tindakbalas di elektrod-elektrod kedua-dua sel.

[8 marks]

(c) A student intends to electroplate an iron ring with silver.Seorang pelajar ingin menyadur cincin besi dengan argentum.

(i) State two purposes of electroplating the iron ring.Nyatakan dua tujuan menyadur cincin besi tersebut.

[2 marks

(ii) Design a laboratory experiment to electroplate the iron ring.Rancangkan satu eksperimen makmal untuk menyadur cincin besi tersebut.

Your answer should consist of the following Procedures of the experiment. A labelled diagram showing the set up of apparatus. Half equations for the reactions at both electrodes. Observations at both electrodes.

Jawapan anda hendaklah termasuk perkara-perkara berikut: Langkah-langkah eksperimen. Gambar rajah susunan radas berlabel. Setengah persamaan bagi tindak balas di kedua-dua elektrod. Pemerhatian di kedua-dua elektrod.

[8 marks]

Copper

Copper(II) nitrate

solution

Magnesium

Magnesium

chloride

Copper

Copper(II) nitrate solution

7 (a) An electrolytic cell is prepared using copper(II) sulphate solution as an electrolyte. The apparatus set up are shown in Diagram 7.Sel elektrolisis disediakan menggunakan larutan kuprum(II) sulfat sebagai elektrolit. Susunan radas bagi eksperimen tersebut ditunjukkan pada Rajah 7.

(i) What is meant by electrolyte? [2 marks]Apakah yang dimaksudkan dengan elektrolit.?

(iI) State the ions present in the copper(II) sulphate solution.Nyatakan ion-ion yang hadir dalam larutan kuprum(II) sulfat.

[2 marks]

(iiI) Write a half equation and state the observations that will occur at the anode and cathode. Explain your answers.Tuliskan persamaan setengah dan nyatakan pemerhatian yang akan berlaku pada anod dan katod. Jelaskan jawapan anda.

[6 marks]

(b ) A student intends to electroplate an iron key with a suitable metal to beautify it.Design a laboratoty experiment to electroplate the iron key.Your answer should consist of the following :

Chemical required Diagram showing the set up apparatus Procedures of the experiment Chemical equation involved in the reaction Observation

Seorang pelajar ingin menyadur elektrik kunci besi dengan satu logam yang sesuai supaya kelihatan cantik.Reka bentuk satu eksperimen di makmal untuk menyadur elektrik kunci besi.Jawapan anda hendaklah mengandungi yang berikut:

Bahan kimia yang diperlukan Gambar rajah susunan radas yang digunakan Prosedur menjalankan eksperimen Persamaan kimia yang terlibat dalam tindak balas Pemerhatian

[ 10 markah ]