Kw in Lecture

[Eileen Quach Dis 2A]

In today's lecture for the example that involved the reaction Ba(OH)2--> Ba+2OH, I was wondering why Professor Lavelle wrote Kw as equal to the hydronium concentration multiplied by the hydroxide equation. Why didn't he include Ba in the equilibrium constant when it's not a solid or liquid?

[Arezo Ahmadi 3J]

Since Ba(OH)2 is a strong base, Ba2+ is a spectator ion. Spectator ions end up being cancelled out, so that is why it is not included in the Kw equation.

[Sophia Hu 1A]

Kw is the equilibrium constant of water not for the reaction of Ba(OH)2.

What he wanted to show with that chemical reaction equation is that Ba(OH)2 is a strong base which is completely ionized that will form 2 OH- molecules. Since it is completely ionized then the 0.0030 M of Ba(OH)2 will completely dissociate into OH-, but there are 2 moles of OH- which is why it is 0.0060.

Kw is considered separately. He used Kw = [H3O+][OH-] in order to find the concentration of [H3O+] because we know Kw (always constant) and [OH-].

[Abby Lam 3F]

Kw is not the equilibrium constant of the Ba equation. Kw is separate and is equal to [H3O][OH]. He isolated [H3O] so he could solve for it.

[Alara Aygen 3K]

Kw is the equilibrium constant for: [H3O+][OH-] (the autoprotolysis of water)

[Inderpal Singh 2L]

Kw is the equilibrium constant for [H30+][OH-], not the equilibrium constant for the Ba equation.