Question

O₂ undergoes photochemical dissociation into one normal oxygen and one excited oxygen atom, 1.967 eV more energetic than normal. The dissociation of O₂ into two normal atoms of oxygen atoms requires 498kJ mole^–1. What is the maximum wavelength effective for photochemical dissociation of O₂?  #(For competitive exam)

Answer 1

= 498 x 10³ / 6.023 x 10²³J per molecule = 8.268 x 10^–19 J

Total energy required for photochemical dissociation of O₂

= 8.268 x 10^–19 + 3.146 x 10^–19 = 11.414 x 10^–19 J hc/λ = 11.414 x 10^–19J

λ = 6.626 x 10^-34x 3 x 10⁸ / 11.414 x 10^-19= 1.7415 x 10^–7 m = 1741.5 Å