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Understanding the Concepts of pH and pOH, and the Relationships Surrounding Concentration, Moles, Molarity, and Number of Molecules

An aqueous solution of an unknown substance has a pH of 3.0. If you have 0.25 L of the substance, how many (a) H+ ions, and (b) OH-ions, are present?

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Please refer to the attached file for the complete solution. Equation formatting, etc., will likely be incorrect in the text listed below.

At first, this problem may be confusing. How can you figure out the number of ions, when you don't know what the solution is made of, or what the concentration of the "mystery substance" in the solution is? The answer is that if you know the pH of a solution, you can do some quick calculations to determine the [H+] and [OH-] in a solution, regardless of what "else" is in that solution.

To solve this problem, you will need three equations. The first is the equation that defines "pH". The second is the equation that defines "pOH". The third ...