pH definition trouble

[lsutiger]

I was designing an experiment to do in my intro bio lab on the effects of acid rain on crop yields and realized that I had no idea how to create aqueous solutions of various pH. I can't seem to find out whether pH is the measure of [H+]/[H3O+] (whichever you prefer) ions per mole, milliliter, or other measurement. When I came upon this I felt slightly embarassed that I did not know it, but upon consultation of my textbook and the internet, I found I could not find an answer. Any help would be greatly appreciated.

[ydoaPs]

I was designing an experiment to do in my intro bio lab on the effects of acid rain on crop yields and realized that I had no idea how to create aqueous solutions of various pH. I can't seem to find out whether pH is the measure of [H+]/[H3O+] (whichever you prefer) ions per mole, milliliter, or other measurement. When I came upon this I felt slightly embarassed that I did not know it, but upon consultation of my textbook and the internet, I found I could not find an answer. Any help would be greatly appreciated.

IIRC, your concentration of hydronium should be in moles/liter.

[lsutiger]

thank you so much.

[Mr Skeptic]

Uh, pH is logarithmic. You would want to convert it to a linear scale like moles per liter, then you can treat it like any other concentration.

[John Cuthber]

Please don't fall into the trap of trying to make (for example) a pH8 solution by dissolving 10^-8 moles of HCl in a liter of water.

I think you will need to learn a bit about buffers.