JK-TK/Newdata huggingface dataset:
(iv) Pb2+ ions form a white precipitate when any soluble SO42-, SO32-, CO32-, Cl-, is added while Al3+ ions do not form a white precipitate
30 (v) Pb2+ ions form a yellow precipitate when any soluble I-(e.g. Potassium/sodium Iodide) is added while Al3+ ions do not form a yellow precipitate. (vi) Pb2+ ions form a black precipitate when any soluble S-(e.g. Potassium/sodium sulphide) is added while Al3+ ions do not form a black precipitate.i.e; Observation Inference White precipitate in excess 2M NaOH (aq) Zn2+, Pb2+, Al3+ ions White precipitate that dissolves to form a colourless solution in excess 2M NH3(aq) Zn2+ ions White precipitate in excess 2M NH3(aq) Pb2+, Al3+ ions White precipitate on adding about 4 drops of either Na2CO3(aq), Na2SO3(aq), Na2SO4(aq), H2SO4(aq), HCl(aq), NaCl(aq) Pb2+ions Yellow precipitate on adding about 4 drops of of KI(aq).NaI (aq) Pb2+ ions Black precipitate on adding aout 4 drops of Na2S(aq)/K2S(aq) Pb2+ ions
31 6.GENERAL SUMMARY OF METALS a) Summary methods of extracting metal from their ore The main criteria used in extraction of metals is based on its position in the electrochemical/reactivity series and its occurrence on the earth’s crust. Position on the earth’s crust If near the surface use open cast mining / quarrying If deep on the earth’s crust use deep mining Add oil, water, and blow air to form froth to concentrate the ore if it is a low grade Roast the ore first if it is a carbonate / sulphide of Zinc, Iron, Tin, Lead, and copper to form the oxide Electrolyse the ore if it is made of reactive metals; Potassium, Sodium, Magnesium, Calcium, Aluminium Reduce the oxide using carbon in a furnace if it is made of Zinc ,Tin, Lead ,Copper and Iron
32 b) Summary of extraction of common metal.
(vi) Pb2+ ions form a black precipitate when any soluble S-(e.g. Potassium/sodium sulphide) is added while Al3+ ions do not form a black precipitate.i.e; Observation Inference White precipitate in excess 2M NaOH (aq) Zn2+, Pb2+, Al3+ ions White precipitate that dissolves to form a colourless solution in excess 2M NH3(aq) Zn2+ ions White precipitate in excess 2M NH3(aq) Pb2+, Al3+ ions White precipitate on adding about 4 drops of either Na2CO3(aq), Na2SO3(aq), Na2SO4(aq), H2SO4(aq), HCl(aq), NaCl(aq) Pb2+ions Yellow precipitate on adding about 4 drops of of KI(aq).NaI (aq) Pb2+ ions Black precipitate on adding aout 4 drops of Na2S(aq)/K2S(aq) Pb2+ ions
31 6.GENERAL SUMMARY OF METALS a) Summary methods of extracting metal from their ore The main criteria used in extraction of metals is based on its position in the electrochemical/reactivity series and its occurrence on the earth’s crust. Position on the earth’s crust If near the surface use open cast mining / quarrying If deep on the earth’s crust use deep mining Add oil, water, and blow air to form froth to concentrate the ore if it is a low grade Roast the ore first if it is a carbonate / sulphide of Zinc, Iron, Tin, Lead, and copper to form the oxide Electrolyse the ore if it is made of reactive metals; Potassium, Sodium, Magnesium, Calcium, Aluminium Reduce the oxide using carbon in a furnace if it is made of Zinc ,Tin, Lead ,Copper and Iron
32 b) Summary of extraction of common metal. Metal Chief ore/s Chemical formula of ore Method of extraction Main equation during extraction Sodium Rock salt NaCl(s) Downs process Through electrolysis of molten NaCl (CaCl2 lower m.pt from 800oC-> 600oC) Cathode: 2Na+(l) + 2e -> 2Na(l) Anode: 2Cl-(l) -> Cl2(g) + 2e Sodium/ sodium hydroxide Brine NaCl(aq) Flowing mercury cathode cell Through electrolysis of concentrated NaCl(aq) Cathode: 2Na+(aq)+2e ->2Na(aq) Anode: 2Cl-(aq) -> Cl2(g) + 2e Aluminium Bauxite Al2O3.2H2O Halls process Through electrolysis of molten Al2O3.
Potassium/sodium sulphide) is added while Al3+ ions do not form a black precipitate.i.e; Observation Inference White precipitate in excess 2M NaOH (aq) Zn2+, Pb2+, Al3+ ions White precipitate that dissolves to form a colourless solution in excess 2M NH3(aq) Zn2+ ions White precipitate in excess 2M NH3(aq) Pb2+, Al3+ ions White precipitate on adding about 4 drops of either Na2CO3(aq), Na2SO3(aq), Na2SO4(aq), H2SO4(aq), HCl(aq), NaCl(aq) Pb2+ions Yellow precipitate on adding about 4 drops of of KI(aq).NaI (aq) Pb2+ ions Black precipitate on adding aout 4 drops of Na2S(aq)/K2S(aq) Pb2+ ions
31 6.GENERAL SUMMARY OF METALS a) Summary methods of extracting metal from their ore The main criteria used in extraction of metals is based on its position in the electrochemical/reactivity series and its occurrence on the earth’s crust. Position on the earth’s crust If near the surface use open cast mining / quarrying If deep on the earth’s crust use deep mining Add oil, water, and blow air to form froth to concentrate the ore if it is a low grade Roast the ore first if it is a carbonate / sulphide of Zinc, Iron, Tin, Lead, and copper to form the oxide Electrolyse the ore if it is made of reactive metals; Potassium, Sodium, Magnesium, Calcium, Aluminium Reduce the oxide using carbon in a furnace if it is made of Zinc ,Tin, Lead ,Copper and Iron
32 b) Summary of extraction of common metal. Metal Chief ore/s Chemical formula of ore Method of extraction Main equation during extraction Sodium Rock salt NaCl(s) Downs process Through electrolysis of molten NaCl (CaCl2 lower m.pt from 800oC-> 600oC) Cathode: 2Na+(l) + 2e -> 2Na(l) Anode: 2Cl-(l) -> Cl2(g) + 2e Sodium/ sodium hydroxide Brine NaCl(aq) Flowing mercury cathode cell Through electrolysis of concentrated NaCl(aq) Cathode: 2Na+(aq)+2e ->2Na(aq) Anode: 2Cl-(aq) -> Cl2(g) + 2e Aluminium Bauxite Al2O3.2H2O Halls process Through electrolysis of molten Al2O3. (Cryolite lower m.pt from 2015oC -> 800oC) Cathode: 4Al3+(l) + 12e -> 4Al(l) Anode: 6O2-(l) -> 3O2(g) + 12e Iron Haematite Magnetite Fe2O3 Fe3O4 Blast furnace Reduction of the ore by carbon(II)oxide Fe2O3(s)+ 3CO(g) 2Fe(l) +3CO2(g) Fe3O4(s)+ 4CO(g) 3Fe(l) +4CO2(g) Copper Copper pyrites CuFeS2 Roasting the ore in air to get Cu2S.
Position on the earth’s crust If near the surface use open cast mining / quarrying If deep on the earth’s crust use deep mining Add oil, water, and blow air to form froth to concentrate the ore if it is a low grade Roast the ore first if it is a carbonate / sulphide of Zinc, Iron, Tin, Lead, and copper to form the oxide Electrolyse the ore if it is made of reactive metals; Potassium, Sodium, Magnesium, Calcium, Aluminium Reduce the oxide using carbon in a furnace if it is made of Zinc ,Tin, Lead ,Copper and Iron
32 b) Summary of extraction of common metal. Metal Chief ore/s Chemical formula of ore Method of extraction Main equation during extraction Sodium Rock salt NaCl(s) Downs process Through electrolysis of molten NaCl (CaCl2 lower m.pt from 800oC-> 600oC) Cathode: 2Na+(l) + 2e -> 2Na(l) Anode: 2Cl-(l) -> Cl2(g) + 2e Sodium/ sodium hydroxide Brine NaCl(aq) Flowing mercury cathode cell Through electrolysis of concentrated NaCl(aq) Cathode: 2Na+(aq)+2e ->2Na(aq) Anode: 2Cl-(aq) -> Cl2(g) + 2e Aluminium Bauxite Al2O3.2H2O Halls process Through electrolysis of molten Al2O3. (Cryolite lower m.pt from 2015oC -> 800oC) Cathode: 4Al3+(l) + 12e -> 4Al(l) Anode: 6O2-(l) -> 3O2(g) + 12e Iron Haematite Magnetite Fe2O3 Fe3O4 Blast furnace Reduction of the ore by carbon(II)oxide Fe2O3(s)+ 3CO(g) 2Fe(l) +3CO2(g) Fe3O4(s)+ 4CO(g) 3Fe(l) +4CO2(g) Copper Copper pyrites CuFeS2 Roasting the ore in air to get Cu2S. Heating Cu2S ore in regulated supply of air.
Metal Chief ore/s Chemical formula of ore Method of extraction Main equation during extraction Sodium Rock salt NaCl(s) Downs process Through electrolysis of molten NaCl (CaCl2 lower m.pt from 800oC-> 600oC) Cathode: 2Na+(l) + 2e -> 2Na(l) Anode: 2Cl-(l) -> Cl2(g) + 2e Sodium/ sodium hydroxide Brine NaCl(aq) Flowing mercury cathode cell Through electrolysis of concentrated NaCl(aq) Cathode: 2Na+(aq)+2e ->2Na(aq) Anode: 2Cl-(aq) -> Cl2(g) + 2e Aluminium Bauxite Al2O3.2H2O Halls process Through electrolysis of molten Al2O3. (Cryolite lower m.pt from 2015oC -> 800oC) Cathode: 4Al3+(l) + 12e -> 4Al(l) Anode: 6O2-(l) -> 3O2(g) + 12e Iron Haematite Magnetite Fe2O3 Fe3O4 Blast furnace Reduction of the ore by carbon(II)oxide Fe2O3(s)+ 3CO(g) 2Fe(l) +3CO2(g) Fe3O4(s)+ 4CO(g) 3Fe(l) +4CO2(g) Copper Copper pyrites CuFeS2 Roasting the ore in air to get Cu2S. Heating Cu2S ore in regulated supply of air. Reduction of Cu2O by Cu2S 2CuFeS2 (s)+ 4O2(g) -> Cu2S(s)+3SO2(g) +2FeO(s) 2Cu2S (s)+ 3O2(g) -> 2Cu2O(s)+2SO2(g) Cu2S (s)+ 2Cu2O(s) -> 6Cu(s)+ SO2(g) Zinc Calamine ZnCO3 Roasting the ore in air to get ZnO ZnCO3(s)-> ZnO(s) + CO2(g)
33 Blast furnace /reduction of the oxide by Carbon(II)Oxide/Carbon 2ZnS(s) +3O2(g) -> 2ZnO(s) + 2SO2(g) ZnO(s) + CO(g)-> Zn(s) + CO2(g) Lead Galena PbS Blast furnaceReduction of the oxide by carbon(II)oxide /Carbon PbO(s) + CO(g)-> Pb(s) + CO2(g) c) Common alloys of metal.
(Cryolite lower m.pt from 2015oC -> 800oC) Cathode: 4Al3+(l) + 12e -> 4Al(l) Anode: 6O2-(l) -> 3O2(g) + 12e Iron Haematite Magnetite Fe2O3 Fe3O4 Blast furnace Reduction of the ore by carbon(II)oxide Fe2O3(s)+ 3CO(g) 2Fe(l) +3CO2(g) Fe3O4(s)+ 4CO(g) 3Fe(l) +4CO2(g) Copper Copper pyrites CuFeS2 Roasting the ore in air to get Cu2S. Heating Cu2S ore in regulated supply of air. Reduction of Cu2O by Cu2S 2CuFeS2 (s)+ 4O2(g) -> Cu2S(s)+3SO2(g) +2FeO(s) 2Cu2S (s)+ 3O2(g) -> 2Cu2O(s)+2SO2(g) Cu2S (s)+ 2Cu2O(s) -> 6Cu(s)+ SO2(g) Zinc Calamine ZnCO3 Roasting the ore in air to get ZnO ZnCO3(s)-> ZnO(s) + CO2(g)
33 Blast furnace /reduction of the oxide by Carbon(II)Oxide/Carbon 2ZnS(s) +3O2(g) -> 2ZnO(s) + 2SO2(g) ZnO(s) + CO(g)-> Zn(s) + CO2(g) Lead Galena PbS Blast furnaceReduction of the oxide by carbon(II)oxide /Carbon PbO(s) + CO(g)-> Pb(s) + CO2(g) c) Common alloys of metal. Alloy name Constituents of the alloy Uses of the alloy Brass Copper and Zinc Making scews and bulb caps Bronze Copper and Tin Making clock springs,electrical contacts and copper coins Soldier Lead and Tin Soldering, joining electrical contacts because of its low melting points and high thermal conductivity Duralumin Aluminium, Copper and Magnesium Making aircraft , utensils ,windows frames because of its light weight and corrosion resistant. Steel Iron, Carbon ,Manganese and other metals Railway lines , car bodies girders and utensils.
Reduction of Cu2O by Cu2S 2CuFeS2 (s)+ 4O2(g) -> Cu2S(s)+3SO2(g) +2FeO(s) 2Cu2S (s)+ 3O2(g) -> 2Cu2O(s)+2SO2(g) Cu2S (s)+ 2Cu2O(s) -> 6Cu(s)+ SO2(g) Zinc Calamine ZnCO3 Roasting the ore in air to get ZnO ZnCO3(s)-> ZnO(s) + CO2(g)
33 Blast furnace /reduction of the oxide by Carbon(II)Oxide/Carbon 2ZnS(s) +3O2(g) -> 2ZnO(s) + 2SO2(g) ZnO(s) + CO(g)-> Zn(s) + CO2(g) Lead Galena PbS Blast furnaceReduction of the oxide by carbon(II)oxide /Carbon PbO(s) + CO(g)-> Pb(s) + CO2(g) c) Common alloys of metal. Alloy name Constituents of the alloy Uses of the alloy Brass Copper and Zinc Making scews and bulb caps Bronze Copper and Tin Making clock springs,electrical contacts and copper coins Soldier Lead and Tin Soldering, joining electrical contacts because of its low melting points and high thermal conductivity Duralumin Aluminium, Copper and Magnesium Making aircraft , utensils ,windows frames because of its light weight and corrosion resistant. Steel Iron, Carbon ,Manganese and other metals Railway lines , car bodies girders and utensils. Nichrome Nichrome and Chromium Provide resistance in electric heaters and ovens German silver Copper,Zinc and Nickel Making coins d) Physical properties of metal. Metals form giant metallic structure joined by metallic bond from electrostatic attraction between the metallic cation and free delocalized electrons. This makes metals to have the following physical properties: (i)High melting and boiling points The giant metallic structure has a very close packed metallic lattice joined by strong electrostatic attraction between the metallic cation and free delocalized electrons.The more delocalized electrons the higher the melting/boiling points e.g. Aluminium has a melting point of about 2015oC while that of sodium is about 98oC.This is mainly because aluminium has more/three delocalized electrons than sodium/has one.
Metals form giant metallic structure joined by metallic bond from electrostatic attraction between the metallic cation and free delocalized electrons. This makes metals to have the following physical properties: (i)High melting and boiling points The giant metallic structure has a very close packed metallic lattice joined by strong electrostatic attraction between the metallic cation and free delocalized electrons.The more delocalized electrons the higher the melting/boiling points e.g. Aluminium has a melting point of about 2015oC while that of sodium is about 98oC.This is mainly because aluminium has more/three delocalized electrons than sodium/has one. Aluminium has a boiling point of about 2470oC while that of sodium is about 890oC.This is mainly because aluminium has more/three delocalized electrons than sodium/has one. 34 (ii)High thermal and electrical conductivity All metals are good thermal and electrical conductors as liquid or solids. The more delocalized electrons the higher the thermal and electrical conductivity. e.g. Aluminium has an electrical conductivity of about 3.82 x 19-9 ohms per metre. Sodium has an electrical conductivity of about 2.18 x 19-9 ohms per metre. (iii)Shiny/Lustrous The free delocalized electrons on the surface of the metal absorb, vibrate and then scatter/re-emit/lose light energy. All metals are therefore usually shades of grey in colour except copper which is shiny brown.e.g. Zinc is bluish grey while iron is silvery grey. (iv)High tensile strength The free delocalized electrons on the surface of the metal atoms binds the surface immediately when the metal is coiled/folded preventing it from breaking /being brittle. (v)Malleable. Metals can be made into thin sheet. The metallic crystal lattice on being beaten/pressed/hammered on two sides extend its length and width/bredth and is then immediately bound by the delocalized electrons preventing it from breaking/being brittle. (vi)Ductile. Metals can be made into thin wires. The metallic crystal lattice on being beaten/pressed/hammered on all sides extend its length is then immediately bound by the delocalized electrons preventing it from breaking/being brittle.
(vi)Ductile. Metals can be made into thin wires. The metallic crystal lattice on being beaten/pressed/hammered on all sides extend its length is then immediately bound by the delocalized electrons preventing it from breaking/being brittle. Revision questions 1.Given some soil , dilute sulphuric(VI)acid,mortar,pestle,filter paper,filter funnel and 2M aqueous ammonia,describe with explanation,how you would show that the soil contain Zinc. Place the soil sample in the pestle. Crush using the mortar to reduce the particle size/increase its surface area. Add dilute sulphuric(VI)acid to free the ions in soil sample. Filter to separate insoluble residue from soluble filtrate To filtrate,add three drops of aqueous ammonia as precipitating reagent. A white precipitate of Zn(OH)2, Pb(OH)2 or Al(OH)3 is formed Add excess aqueous ammonia to the white precipitate. If it dissolves the Zn2+ ions are present. Zn(OH)2 react with excess ammonia to form soluble [Zn(OH)4]2+ complex. 2.In the extraction of aluminium,the oxide is dissolved in cryolite. (i)What is the chemical name of cryolite? Sodium hexafloroaluminate/Na3AlF6
35 (ii)What is the purpose of cryolite? To lower the melting point of the electrolyte/Aluminium oxide from about 2015oC to 900oC (iii)Name the substance used for similar purpose in the Down cell Calcium chloride/CaCl2 (iv)An alloy of sodium and potassium is used as coolant in nuclear reactors.Explain. Nuclear reactors generate a lot of heat energy. sodium and potassium alloy reduce/lower the high temperature in the reactors. (v)Aluminium metal is used to make cooking utensils in preference to other metals.Explain. Aluminium (i) is a very good conductor of electricity because it has three delocalized electrons in its metallic structure (ii)is cheap,malleable,ductile and has high tensile strength (iii)on exposure to fire/heat form an impervious layer that prevent it from rapid corrosion. 3.Study the scheme below and use it to answer the questions that follow.
(v)Aluminium metal is used to make cooking utensils in preference to other metals.Explain. Aluminium (i) is a very good conductor of electricity because it has three delocalized electrons in its metallic structure (ii)is cheap,malleable,ductile and has high tensile strength (iii)on exposure to fire/heat form an impervious layer that prevent it from rapid corrosion. 3.Study the scheme below and use it to answer the questions that follow. (a)Identify: (i)solid residue L Iron(III)Oxide/Fe2O3 (ii)Solid N Aluminium hydroxide /Al(OH)3
36 (iii)Filtrate M Sodium tetrahydroxoaluminate/ NaAl(OH)4 and sodium silicate/ NaSiO3 (iv)Solid P Aluminium oxide/ Al2O3 (v)Gas Q Oxygen/O2 (vi)Process K1 Filtration (vii)Process K2 Electrolysis (b)Write the equation for the reaction taking place in the formation of solid P from solid N 2Al(OH)3 -> Al2O3 (s) + 3H2O(l) (c)Name a substance added to solid N before process Process K2 take place. Cryolite/Sodium tetrahydroxoaluminate/ NaAl(OH)4 (d)State the effect of evolution of gas Q on (i)process K2 Oxygen produced at the anode reacts with the carbon anode to form carbon(IV) oxide which escape. The electrolytic process needs continuous replacement of the carbon anode. (ii)the environment Oxygen produced at the anode reacts with the carbon anode to form carbon(IV) oxide which escape to the atmosphere.CO2 is a green house gas that cause global warming. (e)An aluminium manufacturing factory runs for 24 hours. If the total mass of aluminium produced is 27000kg, (i)Calculate the current used. (Faraday constant=96500Coulombs, Al=27.0).
(e)An aluminium manufacturing factory runs for 24 hours. If the total mass of aluminium produced is 27000kg, (i)Calculate the current used. (Faraday constant=96500Coulombs, Al=27.0). (ii)assuming all the gas produced react with 200kg of anode ,calculate the loss in mass of the electrode.(Molar gas volume at room temperature = 24dm3,C=12.0) Working Equation at Cathode Al3+(l) + 3e -> Al(l) 27g Al -> 3 Faradays = 3 x 96500C (27000kg x 1000) g -> (27000kg x 1000) g x 3 x 96500C 27g =289500000000 Coulombs
37 Current = Quantity of electricity =>289500000000 Coulombs Time in seconds 24 x 60 x 60 3350690Ampheres Working Equation at Anode 2O2-(l) + 4e -> O2(g) 4 Faradays -> 4 x 96500C24dm3 O2(g) - 289500000000 Coulombs -> 289500000000 Coulombs x 24dm3 4 x 96500C 18,000,000dm3 Chemical equation at anode O2(g) + C (s) -> CO2(g) Method 1 24dm3 of O2(g) -> 12.0g Carbon 18,000,000dm3 of O2(g) -> 18,000,000dm3 x 12 = 9000000g = 9000kg 24dm3 1000g Loss in mass of the carbon graphite anode = 9000kg NB:Mass of the carbon graphite anode remaining =27000kg - 9000kg =18000kg The flow chart below shows the extraction of iron metal.Use it to answer the questions that follow.
If the total mass of aluminium produced is 27000kg, (i)Calculate the current used. (Faraday constant=96500Coulombs, Al=27.0). (ii)assuming all the gas produced react with 200kg of anode ,calculate the loss in mass of the electrode.(Molar gas volume at room temperature = 24dm3,C=12.0) Working Equation at Cathode Al3+(l) + 3e -> Al(l) 27g Al -> 3 Faradays = 3 x 96500C (27000kg x 1000) g -> (27000kg x 1000) g x 3 x 96500C 27g =289500000000 Coulombs
37 Current = Quantity of electricity =>289500000000 Coulombs Time in seconds 24 x 60 x 60 3350690Ampheres Working Equation at Anode 2O2-(l) + 4e -> O2(g) 4 Faradays -> 4 x 96500C24dm3 O2(g) - 289500000000 Coulombs -> 289500000000 Coulombs x 24dm3 4 x 96500C 18,000,000dm3 Chemical equation at anode O2(g) + C (s) -> CO2(g) Method 1 24dm3 of O2(g) -> 12.0g Carbon 18,000,000dm3 of O2(g) -> 18,000,000dm3 x 12 = 9000000g = 9000kg 24dm3 1000g Loss in mass of the carbon graphite anode = 9000kg NB:Mass of the carbon graphite anode remaining =27000kg - 9000kg =18000kg The flow chart below shows the extraction of iron metal.Use it to answer the questions that follow. (a)Identify: (i)gas P Carbon(IV)oxide/CO2 (ii)Solid Q
38 Carbon/coke/charcoal (iii)Solid R Carbon/coke/charcoal (iv)Solid V Limestone/calcium carbonate/CaCO3 (v)Solid S Iron/Fe (b)Write the chemical equation for the reaction for the formation of: (i)Solid S Fe2O3(s) + 3CO(g) -> 2Fe(s) + 3CO2(g) (ii)Carbon(II)oxide C(s) + CO2 (g) -> 2CO (g) (iii)Slag SiO2(s) + CaO(s) -> CaSiO3(s) Al2O3 (s) + CaO(s) -> Ca Al2O4(s) (iv)Gas P C(s) + O2 (g) -> CO2 (g) (c)State two uses of: (i)Solid S Iron is used in making: (i)gates ,pipes, engine blocks, rails, charcoal iron boxes, lamp posts because it is cheap.
(Faraday constant=96500Coulombs, Al=27.0). (ii)assuming all the gas produced react with 200kg of anode ,calculate the loss in mass of the electrode.(Molar gas volume at room temperature = 24dm3,C=12.0) Working Equation at Cathode Al3+(l) + 3e -> Al(l) 27g Al -> 3 Faradays = 3 x 96500C (27000kg x 1000) g -> (27000kg x 1000) g x 3 x 96500C 27g =289500000000 Coulombs
37 Current = Quantity of electricity =>289500000000 Coulombs Time in seconds 24 x 60 x 60 3350690Ampheres Working Equation at Anode 2O2-(l) + 4e -> O2(g) 4 Faradays -> 4 x 96500C24dm3 O2(g) - 289500000000 Coulombs -> 289500000000 Coulombs x 24dm3 4 x 96500C 18,000,000dm3 Chemical equation at anode O2(g) + C (s) -> CO2(g) Method 1 24dm3 of O2(g) -> 12.0g Carbon 18,000,000dm3 of O2(g) -> 18,000,000dm3 x 12 = 9000000g = 9000kg 24dm3 1000g Loss in mass of the carbon graphite anode = 9000kg NB:Mass of the carbon graphite anode remaining =27000kg - 9000kg =18000kg The flow chart below shows the extraction of iron metal.Use it to answer the questions that follow. (a)Identify: (i)gas P Carbon(IV)oxide/CO2 (ii)Solid Q
38 Carbon/coke/charcoal (iii)Solid R Carbon/coke/charcoal (iv)Solid V Limestone/calcium carbonate/CaCO3 (v)Solid S Iron/Fe (b)Write the chemical equation for the reaction for the formation of: (i)Solid S Fe2O3(s) + 3CO(g) -> 2Fe(s) + 3CO2(g) (ii)Carbon(II)oxide C(s) + CO2 (g) -> 2CO (g) (iii)Slag SiO2(s) + CaO(s) -> CaSiO3(s) Al2O3 (s) + CaO(s) -> Ca Al2O4(s) (iv)Gas P C(s) + O2 (g) -> CO2 (g) (c)State two uses of: (i)Solid S Iron is used in making: (i)gates ,pipes, engine blocks, rails, charcoal iron boxes, lamp posts because it is cheap. (ii)nails, cutlery, scissors, sinks, vats, spanners, steel rods, and railway points from steel.
(ii)assuming all the gas produced react with 200kg of anode ,calculate the loss in mass of the electrode.(Molar gas volume at room temperature = 24dm3,C=12.0) Working Equation at Cathode Al3+(l) + 3e -> Al(l) 27g Al -> 3 Faradays = 3 x 96500C (27000kg x 1000) g -> (27000kg x 1000) g x 3 x 96500C 27g =289500000000 Coulombs
37 Current = Quantity of electricity =>289500000000 Coulombs Time in seconds 24 x 60 x 60 3350690Ampheres Working Equation at Anode 2O2-(l) + 4e -> O2(g) 4 Faradays -> 4 x 96500C24dm3 O2(g) - 289500000000 Coulombs -> 289500000000 Coulombs x 24dm3 4 x 96500C 18,000,000dm3 Chemical equation at anode O2(g) + C (s) -> CO2(g) Method 1 24dm3 of O2(g) -> 12.0g Carbon 18,000,000dm3 of O2(g) -> 18,000,000dm3 x 12 = 9000000g = 9000kg 24dm3 1000g Loss in mass of the carbon graphite anode = 9000kg NB:Mass of the carbon graphite anode remaining =27000kg - 9000kg =18000kg The flow chart below shows the extraction of iron metal.Use it to answer the questions that follow. (a)Identify: (i)gas P Carbon(IV)oxide/CO2 (ii)Solid Q
38 Carbon/coke/charcoal (iii)Solid R Carbon/coke/charcoal (iv)Solid V Limestone/calcium carbonate/CaCO3 (v)Solid S Iron/Fe (b)Write the chemical equation for the reaction for the formation of: (i)Solid S Fe2O3(s) + 3CO(g) -> 2Fe(s) + 3CO2(g) (ii)Carbon(II)oxide C(s) + CO2 (g) -> 2CO (g) (iii)Slag SiO2(s) + CaO(s) -> CaSiO3(s) Al2O3 (s) + CaO(s) -> Ca Al2O4(s) (iv)Gas P C(s) + O2 (g) -> CO2 (g) (c)State two uses of: (i)Solid S Iron is used in making: (i)gates ,pipes, engine blocks, rails, charcoal iron boxes, lamp posts because it is cheap. (ii)nails, cutlery, scissors, sinks, vats, spanners, steel rods, and railway points from steel. Steel is an alloy of iron with carbon, and/or Vanadium, Manganese, Tungsten, Nickel ,Chromium.