A molecular species in solution exhibits a strong absorption band at λ=520nm that corresponds to an electronic transition from its ground state to an excited state.
(a) Calculate the energy, in kJ mol−1, associated with photons of wavelength 520 nm. Use h=6.626×10−34J s, c=3.00×108m s−1, and NA=6.022×1023mol−1.
(b) Determine the frequency, in THz, of the absorbed radiation.
(c) The visible spectrum can be approximated by the following dominant colour regions: violet (400 nm), blue (450 nm), green (500 nm), yellow (570 nm), orange (590 nm), red (650 nm). Based on this scale, predict the perceived colour of the solution that contains the species. Explain your reasoning in terms of complementary colours.