OCR A Jun 2016 Paper 5 Q1

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Answer all the questions. This question is about the chemistry of copper compounds and complex ions. (a) The flowchart shows two reactions of aqueous copper(II) sulfate. In the boxes, write the formulae and colours of the complex ions formed. CuSO4(aq) NH3(aq) HCl(aq) complex ion:complex ion:colour:colour:(b) Cu2+ ions form a complex ion A with two ethanedioate ions and two water molecules. The ethanedioate ion is a bidentate ligand. The skeletal formula of the ethanedioate ion is shown in Fig. 1.1 below. [3] O O Fig. 1.1 (i) What is meant by the term bidentate ligand ?[1]OCR 2016<br />
 (ii) The complex ion A exists as three stereoisomers. The shape of one of the stereoisomers is shown below. The charge has been omitted. H2O Cu H2O Complex A Complete the 3D diagrams of the other two stereoisomers of A. You do not need to include any charges. Indicate with ticks whether the stereoisomers are cis, trans, optical or a combination of these types. Stereoisomer Cu Cu Type cis trans optical cis trans optical (iii) What is the empirical formula, including the charge, of the complex ion A?[2] [3]OCR 2016 [Total: 9] Turn over<br />

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