Ozone Decomposition by UV

2O3 → 3O2

Aperçu

UV-C radiation (< 240 nm) and UV-B (240–320 nm) break ozone back into molecular oxygen and atomic oxygen. This absorption of UV is precisely what protects life on Earth. The steady-state balance between ozone formation and decomposition maintains the ozone layer thickness.

Participants

Rôle Substance Coefficient État
Réactif Ozone O₃ 2 (g)

Exemple du quotidien

Sunscreen with high SPF is needed because not all UV is filtered by ozone — the remaining UV-A and some UV-B still reach the surface.

Importance industrielle

Understanding ozone photochemistry is critical for monitoring the ozone hole and predicting UV exposure levels worldwide.

Propriétés

Type
Photochemical
Réversible
Non
Énergie
Exothermique
ΔH
-285,4 kJ/mol

Réactions associées

Photochemical Smog Formation (NO₂ Photolysis) Photochromism of Spiropyran Chlorophyll Fluorescence Photodegradation of Methylene Blue by TiO₂ Photodissociation of Chlorine Gas Silver Bromide Photodecomposition Cis-Trans Isomerization of Retinal Photosynthesis Ozone Formation by UV Light Dye-Sensitized Solar Cell (Grätzel Cell)

Frequently Asked Questions

What is the equation for Ozone Decomposition by UV?
The balanced equation is: 2O₃ → 3O₂.
What type of reaction is Ozone Decomposition by UV?
Ozone Decomposition by UV is a photochemical reaction.
Is Ozone Decomposition by UV exothermic or endothermic?
Ozone Decomposition by UV is exothermic (releases energy). The enthalpy change (ΔH) is -285.4 kJ/mol.