Formula Used:
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Definition: The mean activity coefficient measures ion-ion interactions in solutions containing both cations and anions, specifically for uni-trivalent electrolytes.
Purpose: It helps chemists understand the non-ideal behavior of electrolyte solutions and predict solution properties accurately.
The calculator uses the formula:
Where:
Explanation: The mean ionic activity is divided by the product of the molality and the 4th root of 27 (which accounts for the specific properties of uni-trivalent electrolytes).
Details: Accurate calculation of activity coefficients is essential for understanding solution behavior, predicting reaction equilibria, and designing chemical processes.
Tips: Enter the mean ionic activity in mol/kg and the molality in mol/kg. Both values must be > 0.
Q1: What is a uni-trivalent electrolyte?
A: A uni-trivalent electrolyte consists of one monovalent ion (charge ±1) and one trivalent ion (charge ±3), like LaCl₃ or Na₃PO₄.
Q2: Why is 271/4 used in the formula?
A: This factor accounts for the specific stoichiometry and charge effects in uni-trivalent electrolytes (ν₊|z₊z₋| = 1×3 = 3, ν₋|z₊z₋| = 3×1 = 3, product is 3×3×3=27).
Q3: What's a typical range for γ±?
A: For dilute solutions, γ± is typically between 0.1 and 1.0, approaching 1 as concentration decreases.
Q4: How do I find mean ionic activity?
A: Mean ionic activity can be determined experimentally from electrochemical measurements or calculated from theoretical models.
Q5: Does this work for other electrolyte types?
A: No, this specific formula is only for uni-trivalent electrolytes. Different formulas exist for 1:1, 2:2, etc. electrolytes.