Acids and Bases

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Lindsey Chheng 1E
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Joined: Fri Aug 30, 2019 12:16 am

Acids and Bases

Postby Lindsey Chheng 1E » Tue Jan 14, 2020 9:16 pm

During lecture, Lavelle said that K does not change when an acid or base is added and that even though [H3O+] > [OH-] or vice versa, the product of them would still be equal to 1.0 x 10^-14. Why is this? I understand that Kw = 1.0 x 10^-14, but if an acid or base is added to water, wouldn't it not be considered water anymore? Or is he only talking about weak acids and bases?

haileyramsey-1c
Posts: 105
Joined: Thu Jul 25, 2019 12:18 am

Re: Acids and Bases

Postby haileyramsey-1c » Tue Jan 14, 2020 10:27 pm

Adding acids and bases do not affect the K value because the concentration must still multiply to 1.0x10^-14. Kw represents the equilibrium constant of water and although concentration of the acid and base in solution may change water is in large excess that it remains unchanged and unaffected by a shift. I am a bit confused by this as well but that's how I understand it.

Hui Qiao Wu 1I
Posts: 56
Joined: Fri Aug 30, 2019 12:16 am

Re: Acids and Bases

Postby Hui Qiao Wu 1I » Tue Jan 14, 2020 11:13 pm

I remember Lavelle saying that when one concentration increases, the other concentration decreases (but didn't catch why). So when you multiply the two, they still give you 1.0 x 10^-14. In addition, the concentration affects the intensity of the reaction happening, not the ratio of products over reactants. So when there is a higher concentration of reactants, the reaction will happen more intensely.

Caitlyn Tran 2E
Posts: 100
Joined: Fri Aug 09, 2019 12:15 am

Re: Acids and Bases

Postby Caitlyn Tran 2E » Tue Jan 14, 2020 11:23 pm

The way I understood this was that when an acid is added to water, it just introduces more hydrogen ions that will bond with water to create hydronium ions and bond with hydroxide ions to produce water. This is why the hydronium ion concentration will increase while the hydroxide ion concentration will decrease, thereby maintaining the equilibrium constant of water at the same value. Hope this helps!


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