: ELECTROCHEMISTRY (SECTION B)
SET 2 : ELECTROCHEMISTRY (SECTION B)
5. (a) Table 5.1 show the results of series of experiments carried out to construct the Electrochemical Series.
The positive terminal and value for the potential difference for the pair of metals S and copper, Cu is not given. Q, R and S are not actual symbols of the metals. Jadual 5.1 menunjukkan keputusan satu siri eksperimen yang dijalankan untuk membina Siri Elektrokimia. Terminal positif dan nilai beza keupayaan bagi pasangan logam P dan kuprum, Cu tidak diberi, Q, R dan S bukan simbol sebenar logam-logam itu.
Pair of metals
Positive terminal
Potential difference(V)
Pasangan logam
Terminal positif
Beza keupayaan, (V)
Table 5.1/Jadual 5.1
(i) Based on the values of the potential differences, arrange the metals in descending order in the
Electrochemical Series. Berdasarkan nila beza keuayaan, susun logam-logam tersebut dalam tertib menurun dalam Siri Elektrokimia.
[1 mark]
(ii) Predict the positive terminal and potential difference for the pair of metal S and metal Cu. Explain your answer. Ramalkan nilai terminal positif dan beza keupayaan bagi pasangan logam S dan Cu.
[3 marks]
(b) Diagram 5.1 shows a voltaic cell. Metal P is situated above copper in the electrochemical series.
Rajah 5.1menunjukkan suatu sel kimia. Logam P terletak di atas kuprum dalam siri elekrokimia.
Copper
Metal P Logam P
Copper(II) sulphate
Solution Q
Kuprum(II) sulfat
Larutan Q
Diagram 5.1/Rajah 5.1
(i) State the positive terminal and the negative terminal of this cell. Nyatakan terminal positif dan terminal negatif bagi sel ini.
(ii) Suggest a metal that is suitable as metal P and a solution that is suitable as solution Q. Cadangkan logam yang sesuai sebagai logam P dan larutan yang sesuai sebagai logam P dan laturan yang sesuai sebagai larutan Q.
[4 Marks]
(c) Diagram 5.2 shows the apparatus set-up to investigate an electrolysis process of 1 mol dm -3 potassium chloride solution using carbon electrodes.
Rajah - 5.2 menunjukkan susunan radas untuk menyiasat proses elektrolisis larutan kalium klorida 1 mol dm
3 menggunakan elektrod-elektrod karbon.
Gas X
Gas Y
Carbon electrodes Potassium chloride solution Elektrod karbon
Larutan kalium klorida
Diagram 5.2/Rajah 5.2
(i) State the observation at anode and cathode Nyatakan pemerhatian di anode dan di katod. [2 marks] (ii) Name of gas X and gas Y. Namakan gas X dan gas Y [2 marks]
(iii) Explain your answer in terms of selective discharged of ion. Write the half-equations at the anode and cathode. Terangkan jawapan anda berdasarkan pemilihan discas ion. Tulis persamaan setengah di anod dan di katod.
[8 marks]
6. Diagram 6.1 shows the apparatus set-up to investigate the electrical conductivity of substances S and R. Rajah 6.1 menunjukkan susunan radas untuk mengkaji kekonduksian elektrik bahan S dan R.
Carbon
Substance S
electrode
Substance R
Bahan R Bahan S
Elektrod karbon
Bulb light up
Bulb does not light up
Mentol menyala
Mentol tidak menyala
Diagram 6.1/Rajah 6.1
(a) Based on the observations in diagram 6.1 Berdasarkan pemerhatian dalam diagram 6.1.
(i)
Give example of substance S and R. Beri contoh bagi bahan S amd R
[2 marks] (ii)
Explain the observations Terangkan pemerhatian di atas.
[3 marks]
(b) Diagram 6.2 shows the apparatus set-up for chemical cell. Rajah 6.2 menunjukkan susunan radas untuk satu sel kimia.
Zinc electrode
Copper electrode
Elektrod zink
Elektron
kuprum
Dilute sulphuric acid Asid sulfurik cair
Diagram 6.2/Rajah 6.2
Based on Diagram 6.2 Berdasarkan Rajah 6.2
(i) Identify positive and negative terminal of the chemical cell Kenal pasti terminal positif dan terminal negatif bagi sel kimia. [2 marks]
(ii) State the observation and half equation at zinc electrode. Nyatakan pemerhatian dan persamaan setengah pada elektrod zink. [2 marks]
(iii) If zinc electrode is replaced with iron electrode, what will happen to the potential difference of the cell? Explain why. Jika elektrod zink digantikan dengan elektrod ferum, apakah akan berlaku pada bacaan beza upaya sel tersebut. Terangkan mengapa.
[2 marks]
(c) Diagram 6.3 shows the arrangement of particles of a compound in two different states, A dan B.
Rajah 6.3 menunjukkan susunan zarah-zarah satu sebatian dalam dua keadaan yang berbeza,
A dan B.
State A
State B
Keadaan A
Keadaan B
Diagram 6.3/Rajah 6.3
(i) The compound can conduct electricity in state B but cannot do so in state A. Name one example of a compound with this property. Sebatian ini boleh mengalirkan arus elektrik dalam keadaan B dan tidak boleh mengalirkan arus elektrik dalam keadaan A.
[1 mark]
(ii) Explain an experiment for the electrolysis of the compound you named in (c)(i). Your explanation must include the following: Terangkan satu eksperimen bagi elektrolisis sebatian yang anda namakan di(c)(i). Penerangan anda haruslah merangkumi yang berikut :
A labeled diagram showing the apparatus set-up
Rajah berlabel yang menunjukkan susunan radas
The observation at the anode and cathode
Pemerhatian di anod dan di katod
Half equations at both electrodes
Setengah perasmaan bagi tindak balas di anod dan di katod
Products at the anode and cathade
Hasil di anod dan di katod
[8 marks]