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(i) Which method will be used to convert each of them to their respective metal oxides ?
(a) Carbonate ore (b) Sulphide ore
(ii) Write a chemical reaction to illustrate the use of aluminium for joining cracked railway tracks.
(iii) During extraction of metals, electrolytic refining is used to obtain pure metals. Which material will be used as anode and cathode for the refining of copper metal by this process ?
(a) Carbonate ore (b) Sulphide ore
(ii) Write a chemical reaction to illustrate the use of aluminium for joining cracked railway tracks.
(iii) During extraction of metals, electrolytic refining is used to obtain pure metals. Which material will be used as anode and cathode for the refining of copper metal by this process ?
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(i) (a) Carbonate ore: Calcination
$\ce{ZnCO3(s) ->[Heat] ZnO(s) + CO2(g)}$ (½ Mark)
(b) Sulphide ore : Roasting
$\ce{2ZnS(s) + 3O2(g) ->[Heat] 2ZnO(s) + 2SO2(g)}$ (½ Mark)
(ii) $\ce{Fe2O3(s) + 2Al(s) -> 2Fe(l) + Al2O3(s) + Heat}$ (1 Mark)
(iii) • Anode: Impure copper rod. (½ Mark)
• Cathode: Pure copper strip. (½ Mark)
$\ce{ZnCO3(s) ->[Heat] ZnO(s) + CO2(g)}$ (½ Mark)
(b) Sulphide ore : Roasting
$\ce{2ZnS(s) + 3O2(g) ->[Heat] 2ZnO(s) + 2SO2(g)}$ (½ Mark)
(ii) $\ce{Fe2O3(s) + 2Al(s) -> 2Fe(l) + Al2O3(s) + Heat}$ (1 Mark)
(iii) • Anode: Impure copper rod. (½ Mark)
• Cathode: Pure copper strip. (½ Mark)