Chemistry Formula
pH Formula
Calculates acidity from the hydrogen ion concentration.
Formula Summary
pH
Calculates acidity from the hydrogen ion concentration.
- Category
- Chemistry
- Equation
- pH = −log₁₀[H⁺]
- Calculator
- Use pH Calculator →
Equation
pH = −log₁₀[H⁺]
Variables
- pH = acidity scale value
- [H⁺] = hydrogen ion concentration
How to Use This Formula
- Identify the known values from the problem statement.
- Convert all values into compatible units.
- Substitute the values into the equation and calculate the result.
- Check that the final answer has the correct unit and meaning.
Explanation
The pH formula measures how acidic or basic a solution is by relating pH to the concentration of hydrogen ions. Lower pH values indicate higher acidity, while higher values indicate greater alkalinity.
Worked Example
If the hydrogen ion concentration is 1 × 10⁻³ M, the pH is −log₁₀(10⁻³) = 3.
Common Mistakes
- Using the wrong hydrogen ion concentration value.
- Confusing pH with concentration directly.
- Forgetting that the pH scale is logarithmic.
Applications
- Acid-base chemistry experiments.
- Water quality testing.
- Laboratory solution preparation.
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