3 x 10^8 tons of ozone naturally form and decom­pose every day in the stratosphere. Ozone decomposition is naturally activated by UV radiation with wavelengths around 280 nm (UV-B radiation).

Question

Use the information provided to estimate the energy required (in kJ/mol) to initiate the decomposition of ozone molecules.

Answer 1

E = hc/λ h = 6.626 × 10^-34 m² kg / s c = 3.00 x 10⁸ m/s λ = 280 x 10^-9 m

E = 6.626 × 10^-34 x 3 x 10⁸ / (280 x 10^-9) = 7.1 x 10^-19 J = 7.10 x 10^-22 KJ for one molecule

7.10 x 10^-22 x 6.022 x 10²³ = 430 KJ/mol