AQA Jun 2010 Paper 2 Q9

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do not write outside the box the method of extraction of zinc has changed as different ores containing the element have been discovered and as technology has improved extraction process in the earliest process calamine impure zinc carbonate was heated with charcoal in earthenware pots this two stage process gave a low yield of zinc znco s zno s c s zno s co g zn s co g extraction process deposits of calamine were being used up and a new two stage process was developed using zinc sulfide ores all of the waste gases from this process were released into the atmosphere zns s o g zno s c s zno s so g zn s co g extraction process the modern process uses the electrolysis of aqueous solutions of very pure zinc sulfate the first step in this process is the same as the first step in extraction process the second step uses sulfuric acid made from the so collected in the first step the third step involves the electrolysis of zinc sulfate solution to form pure zinc zns s o g zno s h so aq zno s so g znso aq h o i znso aq electrolysis zn s a in the first stage of extraction process the following equilibrium is established when zinc carbonate is heated in a closed container znco s zno s co g use le chatelier s principle to suggest and explain the effect on the yield of zinc oxide of allowing the carbon dioxide to escape from the container marks extra space wmp jun chem do not write outside the box b state and explain one environmental reason why extraction process is an improvement over extraction process marks extra space c give one reason why extraction process is an expensive method of making zinc but one which is justified in terms of the product formed marks extra space question continues on the next page turn over wmp jun chem do not write outside the box d deduce the half equation for the formation of zinc from zinc ions during the electrolysis of zinc sulfate solution and identify the electrode at which this reaction occurs marks extra space e identify one reaction from the three extraction processes that is not a redox reaction and state the type of reaction that it is in terms of redox state what happens to the carbon in extraction process marks extra space wmp jun chem do not write outside the box f zinc and magnesium both react with steam in a similar way write an equation for the reaction of zinc with steam and name the products of this reaction marks extra space end of questions wmp jun chem

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