AQA Jun 2011 Paper 5 Q7

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section b answer all questions in the spaces provided do not write outside the box this question is about copper chemistry a aqueous copper ii ions cu h o aq are blue a i with reference to electrons explain why aqueous copper ii ions are blue marks extra space a ii by reference to aqueous copper ii ions state the meaning of each of the three terms in the equation e hv marks extra space wmp jun chem do not write outside the box a iii write an equation for the reaction in aqueous solution between cu h o and an excess of chloride ions state the shape of the complex produced and explain why the shape differs from that of the cu h o ion marks extra space b draw the structure of the ethanedioate ion c o explain how this ion is able to act as a ligand marks question continues on the next page turn over wmp jun chem do not write outside the box c when a dilute aqueous solution containing ethanedioate ions is added to a solution containing aqueous copper ii ions a substitution reaction occurs in this reaction four water molecules are replaced and a new complex is formed c i write an ionic equation for the reaction give the co ordination number of the complex formed and name its shape marks c ii in the complex formed the two water molecules are opposite each other draw a diagram to show how the ethanedioate ions are bonded to a copper ion and give a value for one of the o cu o bond angles you are not required to show the water molecules marks wmp jun chem

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