Changes with temp?

Acidity
Basicity
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MKearney_4G
Posts: 50
Joined: Fri Aug 30, 2019 12:18 am

Changes with temp?

Postby MKearney_4G » Sun Dec 01, 2019 11:42 pm

I heard from a friend that Kw changes with temperature, could somebody explain why? What is the trend? (higher temp higher KA? or the other way around)

Angus Wu_4G
Posts: 102
Joined: Fri Aug 02, 2019 12:15 am

Re: Changes with temp?

Postby Angus Wu_4G » Mon Dec 02, 2019 2:18 am

"The dissociation of water molecules into ions is bond breaking and is therefore an endothermic process (energy must be absorbed to break the bonds). Endothermic processes are favored by an increase in temperature and so as the temperature rises the equilibrium moves further to the right hand side and Kw gets larger." -Google search

Basically, because the splitting of H20 into H+ and OH- involves the breaking of bonds, it requires energy and is an endothermic process. When temperature increases, there is more heat energy readily available, therefore water splits into its ions more often, hence why the Kw increases when the temperature increases, and decreases when the temperature decreases.

Jessica Li 4F
Posts: 115
Joined: Fri Aug 09, 2019 12:16 am

Re: Changes with temp?

Postby Jessica Li 4F » Mon Dec 02, 2019 11:53 am

It is easier for molecules to dissociate as you increase the temperature, as this increases energy. So you can think of it with any molecule - if you increase energy, it is easier to break bonds.


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