Understanding the Relationship
* pH: A measure of the acidity or alkalinity of a solution. It's defined as the negative logarithm (base 10) of the hydronium ion concentration.
* Hydronium Ion (H₃O⁺): A positively charged ion formed when a water molecule (H₂O) gains a proton (H⁺). It's a measure of the acidity of a solution.
The Formula
The relationship between pH and hydronium ion concentration is:
pH = -log[H₃O⁺]
Solving for [H₃O⁺]
1. Rearrange the formula:
[H₃O⁺] = 10⁻pH
2. Plug in the pH value:
[H₃O⁺] = 10⁻⁸.²
3. Calculate:
[H₃O⁺] ≈ 6.31 × 10⁻⁹ M (moles per liter)
Therefore, the hydronium ion concentration when the pH is 8.2 is approximately 6.31 × 10⁻⁹ M.
