Question

(a) Arrange the following types of spectroscopic transition in order of increasing energy: vibrational, electronic, rotational. (b) In which regions of the electromagnetic spectrum do each of the transitions in part occur? (c) The red colour of tomatoes is due to the presence of lycopene, a carotenoid pigment, which absorbs strongly at 22,222 cm-1. (d) What wavelength of light does lycopene absorb? Give your answer in nm. (e) What colour is this light? (f) What type of spectroscopic transition gives rise to this absorption? (g) When light of a certain wavelength passes through a 1 cm cell containing a solution of lycopene of concentration 1×10-6mol dm-3, the absorbance is 0.22. Another solution of lycopene in a cell of the same path length has an absorbance of 0.30 at this wavelength. Determine the concentration of this solution.

Answer 1