pH Calculation Calculator
Calculates the acidity or alkalinity of a solution based on the logarithmic concentration of hydrogen ions ([H⁺]).
Formula first
Overview
The pH scale provides a convenient way to express the concentration of hydrogen ions in a solution, as these values are often extremely small. Because the scale is logarithmic, a change of one pH unit represents a tenfold change in [H⁺] concentration. This relationship is critical in biological systems where even minor deviations in hydrogen ion concentration can have drastic effects on enzyme activity and cellular function.
Symbols
Variables
[H^+] = Hydrogen Ion Concentration (mol/L), pH = Potential of Hydrogen
Apply it well
When To Use
When to use: Apply this when the concentration of hydrogen ions ([H⁺]) in mol/L is provided and you need to determine the acidity or alkalinity of a physiological fluid or chemical solution.
Why it matters: Maintaining precise pH levels is vital for human homeostasis; for example, blood pH must be kept within a very narrow range (7.35–7.45) to prevent acidosis or alkalosis.
Avoid these traps
Common Mistakes
- Forgetting the negative sign in the calculation.
- Confusing the base 10 log with the natural log (ln).
One free problem
Practice Problem
Calculate the pH of a solution where the hydrogen ion concentration [H⁺] is 1.0 x 10⁻⁷ mol/L.
Solve for:
Hint: The negative log of 10^-x is simply x.
The full worked solution stays in the interactive walkthrough.
References
Sources
- Sørensen, S. P. L. (1909). Enzyme Studies: II. On the measurement and the importance of the hydrogen ion concentration in enzymatic processes.
- Atkins, P., & de Paula, J. (2014). Physical Chemistry for the Life Sciences.
- AQA A-Level Chemistry Specification / Pearson Edexcel International A-Level Chemistry