Transition metals Flashcards
Define term ligand and explain what is meant by the term coordinate bond
Ligand - Atom which can donate a pair of electrons to a metal ion
Coordinate bond - Covalent bond in which both electrons are donated by one atom
What is deltaE
Energy absorbed by electron ground to excited state
What is h
Planck constant
Give three factors which result in a change in frequency of light absorbed as a result of reaction of a complex ion
Oxidation state
Ligand
Coordination number
State origin of colour of transition metal complexes
D electrons moving energy levels in a visible range
Outline a plan for experiments using this solution and this apparatus which would enable you to determine the concentration of ion (III) ions in a solution of unknown concentration
Add appropriate ligand to intensify colour
Make up solutions of known conc
Measure absorption
Plot graph of results or calibration curve
Measure absorbance of unknown and compare
Suggest why the coloured filter is used
To select colour that is absorbed
Why chloride ions not considered to by ligands
No coordinate bonds
Cl- not donating lone pair to Cu2+
Why colorimetry cannot be used to determine conc of solutions containing [CuCl2]-
3d10
Colourless
Describe briefly how colorimetry can be used to determine the conc of this solution
Make known conc
Plot graph of absorbance vc conc
Compare unknown conc from calibration curve
Explain why carbon particulates are formed
Incomplete combustion
Other than having variable oxidation states, explain why Fe2+ ions are good catalysts for this reaction
Pos ions attract neg ions in a catalysed process
Pt acts as a heterogenous catalyst, describe the stages of this alternative route
Reactants adsorbed onto the Pt active sites
Reaction occurs on the surface
Desorption of product
Explain why Fe3+ ions are as effective as Fe2+ in catalysing this reaction
Equation 1 and 2 can occur in any order
Explain why the reaction is initally slow
Two negative ions repel
Little catalyst at the start
The activation energy for reaction is high
