Formula Used:
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Definition: The electromotive force (EMF) of a concentration cell is the potential difference developed between two half-cells with different concentrations of the same electrolyte.
Purpose: This calculator helps determine the EMF for dilute solutions where ion transference between half-cells is negligible.
The calculator uses the Nernst equation for concentration cells:
Where:
Explanation: The formula calculates the potential difference created by the concentration gradient of ions in the cell.
Details: Accurate EMF calculation is crucial for understanding electrochemical cell behavior, designing batteries, and corrosion studies.
Tips: Enter the temperature in Kelvin and both concentrations in mol/m³. All values must be positive numbers.
Q1: What is a concentration cell?
A: An electrochemical cell that generates voltage from a concentration difference of the same electrolyte solution.
Q2: Why multiply by 2 in the formula?
A: The factor of 2 accounts for the two electrons transferred in the redox reaction of a typical concentration cell.
Q3: What temperature range is valid?
A: The formula works for any temperature above absolute zero, but standard calculations typically use 298K (25°C).
Q4: What if concentrations are equal?
A: The EMF will be zero since ln(1) = 0, indicating no concentration gradient to drive the cell.
Q5: How does temperature affect EMF?
A: Higher temperatures generally increase EMF for a given concentration ratio, as seen in the direct proportionality to T.