## molarity question

Science questions not covered in Chem 14A and 14B. Try to limit questions to chemistry (inorganic chemistry, physical chemistry, organic chemistry, biophysical chemistry, biochemistry, materials science, environmental chemistry).

905084274
Posts: 42
Joined: Fri Sep 28, 2018 12:22 am

### molarity question

For the 6th edition textbook homework 12.23 part (a), how do you know that since the Kw provided is 2.1x10^-14 that that is equivalent to x^2. So the problem can be set up as (H3O+)(OH-)=x^2. Is this because if you take the square root of 2.1x10^-14 is 1.4x10^-7 mol/L? I wouldn't have thought of this as a way to solve this problem, so some clarification would be nice :)

Elisa Bass 4L
Posts: 61
Joined: Fri Sep 28, 2018 12:23 am

### Re: molarity question

In pure water, the H3O+ and OH- concentrations are equal. Therefore, because they gave you Kw, you can find each of the concentrations by square rooting the given value.

Jennifer Su 2L
Posts: 47
Joined: Wed Nov 21, 2018 12:20 am

### Re: molarity question

Just remember that pure water has the neutral pH of 7, so as the comment above states, [H3O+] and [OH-] should always be equal. If they are not equal, the solution will either be more acidic (higher concentration of H3O+) or more basic (higher concentration of OH-).