Activity of Cathodic Electrolyte of Concentration Cell with Transference Calculator

Formula Used:

\[ a_2 = \exp\left(\frac{E_{cell} \cdot F}{t_- \cdot R \cdot T}\right) \cdot a_1 \]

EMF of Cell (E_cell):

Transport Number of Anion (t_-):

Temperature (T):

Anodic Ionic Activity (a₁):

mol/kg

Cathodic Ionic Activity (a₂): mol/kg

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Cathodic Ionic Activity?

Definition: Cathodic Ionic Activity is the measure of the effective concentration of a molecule or ionic species in a cathodic half-cell.

Purpose: This calculator determines the activity of ions in the cathodic electrolyte of a concentration cell with transference.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ a_2 = \exp\left(\frac{E_{cell} \cdot F}{t_- \cdot R \cdot T}\right) \cdot a_1 \]

Where:

\( a_2 \) — Cathodic ionic activity (mol/kg)
\( E_{cell} \) — EMF of the cell (V)
\( F \) — Faraday constant (96485.33212 C/mol)
\( t_- \) — Transport number of anion
\( R \) — Universal gas constant (8.314 J/mol·K)
\( T \) — Temperature (K)
\( a_1 \) — Anodic ionic activity (mol/kg)

Explanation: The formula relates the ionic activities in both half-cells to the cell potential and transport properties.

3. Importance of Ionic Activity Calculation

Details: Accurate calculation of ionic activities is crucial for understanding electrochemical systems, predicting cell potentials, and designing batteries.

4. Using the Calculator

Tips: Enter the EMF of the cell (in volts), transport number of anion (0-1), temperature (in Kelvin), and anodic ionic activity (in mol/kg).

5. Frequently Asked Questions (FAQ)

Q1: What is the transport number of an anion?
A: It's the fraction of the total current carried by the anion in the electrolyte (typically between 0 and 1).

Q2: Why is temperature important in this calculation?
A: Temperature affects both the Nernst equation and the transport properties of ions in solution.

Q3: What are typical values for ionic activities?
A: Ionic activities typically range from 1e-15 to 1 mol/kg, depending on the system.

Q4: How do I measure the EMF of a cell?
A: Use a high-impedance voltmeter connected between the two electrodes of the cell.

Q5: What's the difference between concentration and activity?
A: Activity accounts for non-ideal behavior in solutions and is the effective concentration that determines chemical potential.