pH calculation

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MichelleRamirez_2F
Posts: 63
Joined: Fri Sep 28, 2018 12:28 am

pH calculation

Postby MichelleRamirez_2F » Thu Dec 06, 2018 8:20 pm

When we are loking for pH why is pH= log10[H30]? How do we know what the value of [H3O] is?

Tiffany_Cacy_3D
Posts: 70
Joined: Fri Sep 28, 2018 12:24 am

Re: pH calculation

Postby Tiffany_Cacy_3D » Thu Dec 06, 2018 8:25 pm

Usually this value is given to you as the molarity of the solution or you are given moles and volume of a certain solution and you have to find the molarity by dividing moles of solute by liters of solution to find the molarity to in turn plug into the pH equation.

Tony Chung 2I
Posts: 60
Joined: Fri Sep 28, 2018 12:19 am

Re: pH calculation

Postby Tony Chung 2I » Thu Dec 06, 2018 9:59 pm

This is normally given to you in the problem as a molarity

Lydia Luong 4L
Posts: 59
Joined: Fri Sep 28, 2018 12:24 am

Re: pH calculation

Postby Lydia Luong 4L » Thu Dec 06, 2018 10:04 pm

The molarity is usually given to you!

Michael_Navarro_1H
Posts: 29
Joined: Fri Sep 28, 2018 12:17 am

Re: pH calculation

Postby Michael_Navarro_1H » Thu Dec 06, 2018 11:07 pm

To clarify, if you are dealing with a strong acid, the molarity of the acid will equal the molarity of the H3O+ in solution. So for example, if you were given a solution of HCl with molarity 0.20 M and were asked to calculate the pH of the solution, the molarity of the H3O+ ions in solution would also be 0.20 M and the pH would be determined using -log[0.20].


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