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Chemistry question
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  1. The table below shows some of the ores of iron.oreformulahaematitemagnetitesideriteFe 2 O 3 Fe 3 O 4 FeCO 3 (a) Which ore in the table contains the greatest percentage by mass of iron? !plain your answer. 2# ..........................................................................................................................................................................................................................................................................................(b) $i%e the e&uations for the redox reactions ta'ing place in the e!traction of iron from haematite.(n each case state which substance is o!idised and which is reduced. 4# .................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(c) (ron is malleable. )escribe how this property can be e!plained in terms of its structure. 2# .......................................................................................................................................................................................................................................................................................... (d) *tate and e!plain how the properties of iron can be changed by the addition of carbon. 2# .......................................................................................................................................................................................................................................................................................................................................................................................................................................2. (ron is one of the most important metals. (t is a transition element.+ost iron is used in the alloy steel. (a) !plain, in terms of metallic bonding, why iron is a good electrical conductor........................................................................................................................................................................................................................................................................................................................................................................................................................... 2# (b) )escribe how different proportions of carbon can modify the physical properties of steel........................................................................................................................................................................................................................................................................................................................................................................................................................... 2# (c) When underwater, iron pipes will rust relati%ely rapidly.  (i) *tate the essential conditions needed for the rusting of iron. ................................................................................................................................... (ii) -ieces of magnesium are often attached to underwater iron pipes. !plain how the magnesium protectsthe iron pipes against rusting. ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... 3# (d) Write two typical properties that are generally common only to transition elements.. ......................................................................................................................................2. .................................................................................................................................. 2# 3. This diagram shows an electrolysis tan' used industrially to produce aluminium from aluminium o!ide.$raphite anode *teel tan'  molten aluminum o!ide and cryolite at /01 o C  $raphite anode molten aluminium outOne reason that this process is e!pensi%e is that the graphite anodes need replacing regularly. (a) !plain, with the help of an e&uation, why the graphite anodes need replacing regularly. 2#.............................................................................................................................................................................................................................................................................................................................................................................................................................................  (b) dding molten cryolite reduces the cost of the process by lowering energy demand.!plain how adding molten cryolite reduces the energy demand of the process. 2#   ............................................................................................................................................... ............................................................................................................................................... (c) *tate two uses of aluminium. *tate the property of aluminium which ma'es it suitable for eachuse. 2# ............................................................................................................................................... ............................................................................................................................................... 4. (ron is e!tracted by reducing iron ore in a blast furnace. The raw materials used are iron ore, co'e, air and limestone. (a)  ame an ore of iron....................................................................................................................................... # (b) !plain, by reference to the chemical reactions in%ol%ed, why limestone is used in the blast furnace................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 3# (c) Co'e burns in o!ygen to form carbon dio!ide.!plain, in terms of bond brea'ing and bond ma'ing, why this reaction is e!othermic................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... 3# (d) (n the centre of the blast furnace iron ((( 5 o!ide, Fe 2 O 3 , is reduced by carbon mono!ide to form iron and  carbon dio!ide. ear the bottom of the blast furnace the remaining iron ((( 5 o!ide is reduced by carbon toform iron and carbon mono!ide.Write e&uations for both of these reactions................................................................................................................................................................................................................................................................................. 2#
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