Question

1) In molecular spectroscopy, the energy of a transition is usually expressed in terms of wavenumbers(cm-1) instead of Hertz.(a)Show that 83.6 cm-1 is equivalent to 1 kJ/mol.(b)Calculate the energy (in kJ/mol) of a transition that occurs at 2100 cm-1.

2) Beside using mass spectrometry, suggestone spectroscopic methodfor differentiatingCH3(C=O)CH3(acetone) from CH3CH(OH)CH3 (isopropanol).

3) Octahedral geometry is a common molecular structure in transition metal chemistry. Draw all isomeric forms of six-coordinated (a) MA2B4, and (b) MA3B3 complexes.

4) (i)The [Fe(H2O)6]3+cationic complexis paramagnetic. Using the valence bond theory, write down the valence electronic configuration of the [Fe(H2O)6]3+ion. Write down the hybridization of the Fe(III) center in [Fe(H2O)6]3+.(ii)An aqueous solution containing the [Fe(H2O)6]3+ionisyellowish brown, while the Fe(II) counterpart [Fe(H2O)6]2+is light green. Why do these two iron ionshavedifferent colours?

Answer 1