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### 6A.21

Posted: Tue Jan 21, 2020 11:30 am
The value of Kw for water at body temperature (37 C) is 2.1 x 10^14. (a) What is the molar concentration of H3O+ ions at 37 C? (b) What is the molar concentration of OH- in neutral water at 37 C?

In this problem, how would you find the molar concentration of H3O+ ions? Would the concentrations of H3O+ and OH- still be equal to each other in this case?

### Re: 6A.21

Posted: Tue Jan 21, 2020 11:36 am
Since temperature is not changing, neither would the Kw. Therefore to find the concentrations of both ions, simply take the square root of the Kw to find the answer.

### Re: 6A.21

Posted: Tue Jan 21, 2020 11:41 am
Kw is equal to the concentration of OH- ions multiplied by the concentration of H3O+ ions. While Kw varies with temperature, the concentrations of the two ions will still be equal to each other for water. Therefore, you would simply take the square root of Kw to find the concentrations of the two ions since they are equal in pure water.