Decrease in pKw with increase in temperature...why?

[HotHamH2O]

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The dissociation of water into H⁺ and OH^- is an endothermic reaction. So adding heat to the reaction would cause a shift towards more dissociation. Why then does added heat cause a decrease in pK_w which would indicate a shift towards the association of H⁺ and OH^- into H₂O?

It makes more sense that pK_wwould increase because heat would drive the reaction to the right increasing both the concentration of H⁺and OH^-.

 

[QrtrLifeCrisis]

The dissociation of water into H⁺ and OH^- is an endothermic reaction. So adding heat to the reaction would cause a shift towards more dissociation. Why then does added heat cause a decrease in pK_w which would indicate a shift towards the association of H⁺ and OH^- into H₂O?

It makes more sense that pK_wwould increase because heat would drive the reaction to the right increasing both the concentration of H⁺and OH^-.

As temperature increases, Kw increases. pKw decreases because pKw = -log (Kw).

Increase in temperature would shift towards disassociation of H2O into H+ and OH-.

 

[HotHamH2O]

As temperature increases, Kw increases. pKw decreases because pKw = -log (Kw).

Increase in temperature would shift towards disassociation of H2O into H+ and OH-.

ohhh...duh. Right! an increase in H+ and OH- increases Kw not pKw. Thanks for setting me straight.