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Hydrogen Ion Concentration Equation:
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The hydrogen ion concentration ([H+]) is a measure of the acidity of a solution. It is inversely related to pH, which is defined as the negative logarithm of the hydrogen ion concentration. The relationship between pH and [H+] is fundamental in chemistry, biology, and environmental science.
The calculator uses the following equation:
Where:
Explanation: The pH scale is logarithmic, meaning each whole pH value below 7 is ten times more acidic than the next higher value. For example, pH 3 is ten times more acidic than pH 4.
Details: Knowing the hydrogen ion concentration is crucial for understanding chemical reactions, biological processes, and environmental conditions. It affects enzyme activity, chemical equilibrium, and many other fundamental processes.
Tips: Enter a pH value between 0 and 14. The calculator will display the hydrogen ion concentration in both scientific notation (e.g., 1.00e-7 M) and decimal notation (e.g., 0.0000001000 M).
Q1: What is the [H+] of pure water at 25°C?
A: Pure water has a pH of 7.0 at 25°C, so [H+] = 10⁻⁷ = 0.0000001 M (or 1.0 × 10⁻⁷ M).
Q2: How does temperature affect pH and [H+]?
A: The pH of pure water changes with temperature due to changes in water's self-ionization. However, the relationship [H+] = 10⁻ᵖᴴ always holds.
Q3: What is the [H+] range for typical solutions?
A: For pH 0-14, [H+] ranges from 1 M (very acidic) to 10⁻¹⁴ M (very basic).
Q4: Why use scientific notation for [H+]?
A: Scientific notation is more convenient for very small numbers like typical [H+] values in neutral and basic solutions.
Q5: How is [H+] related to pOH?
A: In aqueous solutions at 25°C, pH + pOH = 14, where pOH = -log[OH⁻]. [H+] and [OH⁻] are related by the water ionization constant Kw = [H+][OH⁻] = 10⁻¹⁴.