1. What is pH Calculation from CO₂ Concentration?

This calculator estimates pH from CO₂ concentration using the approximation for CO₂ in water forming carbonic acid. The calculation is based on the equilibrium constant K₁ for the dissociation of carbonic acid.

2. How Does the Calculator Work?

The calculator uses the following equations:

Where:

• \( [H⁺] \) — Hydrogen ion concentration (mol/L)
• \( [CO₂] \) — Carbon dioxide concentration (mol/L)
• \( K_1 \) — Equilibrium constant for carbonic acid dissociation (mol/L)
• \( pH \) — pH value (dimensionless)

Explanation: This approximation assumes that CO₂ dissolves in water to form carbonic acid, which then partially dissociates to produce hydrogen ions.

3. Importance of pH Calculation

Details: Accurate pH calculation is crucial for understanding acid-base balance in various systems, including biological fluids, environmental waters, and industrial processes.

4. Using the Calculator

Tips: Enter CO₂ concentration in mol/L and the K₁ constant value. The default K₁ value is set to 4.3×10⁻⁷ mol/L (typical value for carbonic acid dissociation at 25°C).

5. Frequently Asked Questions (FAQ)

Q1: What is the typical value of K₁?
A: The typical value for carbonic acid dissociation constant K₁ is approximately 4.3×10⁻⁷ mol/L at 25°C.

Q2: Why is this an approximation?
A: This is an approximation because it simplifies the complex equilibrium system of CO₂ dissolution and carbonic acid dissociation.

Q3: What factors affect the accuracy of this calculation?
A: Temperature, ionic strength, and the presence of other ions can affect the accuracy of pH calculations.

Q4: Can this be used for seawater calculations?
A: For seawater, additional factors such as salinity and borate concentration need to be considered for accurate pH calculations.

Q5: How does temperature affect the calculation?
A: The K₁ value is temperature-dependent. For precise calculations, the K₁ value should be adjusted for the specific temperature.