transition metals

What is meant by a bidentate ligand (1 mark)
Write an equation for a reaction in which the co-ordination number of the metal in a complex ion changes and state the colour change (4 marks)
Sketch a graph to show how the concentration of MnO4- ions varies with time as potassium manganate (VII) and sodium ethanedioate react and explain the graph shape (4 marks)
the complex ion [Cu(NH3)4(H2O)2]2+ reacts with 1,2-diaminoethane and only the ammonia molecules are replaced. Suggest why the enthalpy change is approximately zero (2 marks)
Explain why an aqueous solution containing [Fe(H2O)6]3+ ions has a lower pH than an aqueous solution containing [Fe(H2O)6]2+ ions (3 marks)
[Al(H2O)6]3+(aq) and NaOH(aq) equation and condition (2 marks)
Suggest a reagent for the reation of Fe3+ to Fe2+ (1 mark)
Calcium fluoride crystals absorb ultra-violet light. Some of the energy gained is given out as visible light. The name of this process, fluorescence, comes from the name of the mineral, fluorite. Use your knowledge of the equation ΔE = hν to suggest what happens to the electrons in fluorite when ultra-violet light is absorbed and when visible light is given out. (2 marks)
With reference to haemoglobin, explain why CO is toxic (2 marks)
Name a substance that poisons the heterogeneous catalyst used in the Contact process (1 mark)