6A.21

[Marjan MJ Stuckart 3A]

Can somebody please advise me on how to begin solving problem 6A.21 in the textbook? The question asks for the molar concentration of H3O+ ions at 37 degrees celsius and for the molar concentration of OH- in neutral water at 37 degrees celsius given that the Kw for water at body temperature (37 degrees celsius) is 2.1 * 10^-14. Any help is appreciated. Thank you!

[705903057]

H3O+ is nothing but H+ + H2O or we can say it is just H+ as water (a pure liquid) will not be counted.

You'll want to set up your ICE table first, reflecting the equation: H2O <--> H^+ + OH^-

Set up the equation: K=[H+][OH-]/[H2O]
and solve from there!

[SophieCacdac_3H]

When looking at the ice table H3O and OH are going to have the same concentrations.
I used kw=[H+][OH-] (H2O is not written in the equation because it is constant)
Plug in the values --> 2.1*10^-14 = x^2 and solve for x