Photolysis of Water (Vacuum UV)

H2O → H· + OH·

Aperçu

Vacuum UV radiation (< 185 nm) directly dissociates water molecules into hydrogen and hydroxyl radicals. This reaction is significant in atmospheric chemistry on Mars and early Earth, where the photolysis of water vapor contributed to the loss of hydrogen to space and the oxidation of surface minerals.

Participants

Rôle Substance Coefficient État
Réactif Water H₂O 1 (g)

Exemple du quotidien

Mars lost most of its water over billions of years partly because UV photolysis split water vapor in the upper atmosphere.

Importance industrielle

Vacuum UV water photolysis is used in ultrapure water treatment for semiconductor manufacturing and in space environment simulation.

Propriétés

Type
Photochemical
Réversible
Non
Énergie
Endothermique
ΔH
498,0 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 Photolysis of Water (Vacuum UV)?
The balanced equation is: H₂O → H· + OH·.
What type of reaction is Photolysis of Water (Vacuum UV)?
Photolysis of Water (Vacuum UV) is a photochemical reaction.
Is Photolysis of Water (Vacuum UV) exothermic or endothermic?
Photolysis of Water (Vacuum UV) is endothermic (absorbs energy). The enthalpy change (ΔH) is 498.0 kJ/mol.