Equations for Kw and pKw

Acidity
Basicity
The Conjugate Seesaw

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Ellie_Keenan_2A
Posts: 87
Joined: Fri Sep 29, 2023 10:36 am

Equations for Kw and pKw

Postby Ellie_Keenan_2A » Wed Jan 24, 2024 8:56 pm

Why does the equation Kb x Ka = Kw use multiplication but the equation pKa + pKb = pKw uses addition?
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Isaac Wong 3F
Posts: 82
Joined: Fri Sep 29, 2023 11:57 am

Re: Equations for Kw and pKw

Postby Isaac Wong 3F » Wed Jan 24, 2024 8:56 pm

It's because pKw is -log (Ka*Kb) which is equivalent to (-log Ka) + (-log Kb)
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Anh Nguyen 3E
Posts: 40
Joined: Wed Nov 15, 2023 9:22 am

Re: Equations for Kw and pKw

Postby Anh Nguyen 3E » Sat Feb 03, 2024 3:58 pm

(Kb)(Ka)= Kw but when turned to Pka and Pkb they use addition because they were both placed into -log. And since that was applied to both values you can add them. As stated below -log(a*b) is equal to -loga+-logb.
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