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

To find the energy generated by uv radiation with a wavelength of 280 nm, we can use the following equation:

E = hc / λ

E = energy = ?

h = Plancks constant = 6.626x10-³⁴ Jsec

c = speed of light = 3x10⁸ m/sec

λ = wavelength in meters = 280x10^-9 m

Solving for E, we have...

E =(6.626x10^-23 Jsec)(3x10⁸ m/sec) / 280x10^-9 m)

E = 7.10x10^-8 J

This should be the energy needed to INITIATE the decomposition. Of course, it will take significantly more energy to decompose the entire 3x10⁸ tons of ozone,