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If water decomposes at 1,000C, then how does it boil at 100C? (self.askchemistry)

submitted 1 year ago by TheSmartDude to c/askchemistry

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[–] slazer2au 1 points 1 year ago (1 children)

Does water decompose?

[–] TheSmartDude 3 points 1 year ago

Yes, at 1,000C.

[–] pianoplant 1 points 1 year ago* (last edited 1 year ago)

Decompose is different than boil/evaporate:

boil/evaporate: phase change into a gas. Water in gas form is still water (H2O)

decompose: breaks down into constituent smaller part. 2* H2O is broken down into 2* H2 and an O2 molecule.

Basically they're two very different things and it makes sense they happen at different energy levels.

Also: significant water decomposition happens at much higher temperatures. At 2200c only around 3% of water in a given volume will decompose. At 3000c around half will decompose.