autoprotolysis

[Karina Kong 2H]

Could someone explain how autoprotolysis of water leads to Kw?

[John Liang 2I]

The autoprotolysis of water gives rise to Kw because of its equilibrium expression. K=products/reactants, so Kw=[H30+][OH-] while the H2O(l) is left out of the equation since it's a liquid. Hope this helps!

[dtolentino1E]

Kw basically means the ratio of products/reactants in the breakdown of water (2H2O <--> H3O+ + OH-)

[Jasmine 2C]

Could someone explain how autoprotolysis of water leads to Kw?

need help on this too; also, does anyone know how much we need to know about the topic of autoprotolysis for the test?

[Gabriella Bates 2L]

The autoprotolysis of water occurs when water molecules react with each other to form OH- and H3O+. The equation is 2H2O(l) <--> OH- + H3O+. Since water is a pure liquid, the equilibrium expression for this reaction is Kw = [OH-] [H3O+]. In order to calculate the value of Kw, we must remember that water is neutral, meaning that the pH and pOH are equal to 7. Therefore, [OH-] = [H3O+] = 1.0 x 10^-7, and Kw = (1.0 x 10^-7)(1.0 x 10^-7) = 1.0 x 10^-14.

[Rory Simpson 2F]

Could someone explain how autoprotolysis of water leads to Kw?

need help on this too; also, does anyone know how much we need to know about the topic of autoprotolysis for the test?

In the autoprotolysis reaction 2H2O(l) H3O+(aq) + OH-(aq), we get an equilibrium constant Kw = [H3O+][OH-] (water doesn't appear because it is a pure liquid). In pure water at 25 degrees C, the concentrations of H3O+ and OH- are around 10^-7 mol/L, so multiplying those gets us a Kw = 10^-14 mol/L. We can use Kw to find out concentrations of H3O+ and OH- in any aqueous solution because it is an equilibrium constant. For example, if you add more acid to a solution, Kw will still equal 10^-14 because the amount of OH- will decrease as H3O+ increases.