Question

Rose bengal is a chromophore used in biological staining that has an absorption maximum at 559.1 nm and several other shorter wavelength absorption bands in the ultraviolet and visible regions of the spectrum when dissolved in ethanol. What is the energy difference (in kJ/mol) between the absorption maximum at 559.1 nm and a band at 321.7 nm?

Answer 1

E₁= hc/λ

= (6.626 x 10¯³⁴ J s) x3.00 x 10⁸ m/s/ 5.591 x 10¯⁷ m

= 213.9600 kJ/mole

E₂= hc/λ

= (6.626 x 10¯³⁴ J s) x3.00 x 10⁸ m/s/ 3.217 x 10¯⁷ m

=371.8600 kJ/mole

The energy difference = E₂-E₁

                                                   ₌371.8600 kJ/mole- 213.9600 kJ/mole

                                       = 157.9 kJ/mole