Calculator Inputs
Enter conductance, concentration, and cell constant values. The calculator returns specific conductivity, molar conductivity, a comparison index, and a dilution trend graph.
Plotly Graph
Example Data Table
| Electrolyte | Concentration (mol/L) | Conductance (mS) | Cell Constant (cm⁻¹) | Specific Conductivity (S/cm) | Molar Conductivity (S·cm²/mol) |
|---|---|---|---|---|---|
| KCl | 0.0100 | 1.25 | 1.00 | 0.00125 | 125.00 |
| NaCl | 0.0200 | 1.90 | 1.00 | 0.00190 | 95.00 |
| CH₃COOH | 0.0050 | 0.28 | 1.10 | 0.000308 | 61.60 |
| NH₄Cl | 0.0150 | 1.55 | 0.98 | 0.001519 | 101.27 |
Formula Used
1) Specific conductivity: κ = G × K
2) Molar conductivity: Λm = (κ × 1000) / c
Where:
- κ = specific conductivity in S/cm
- G = measured conductance in S
- K = cell constant in cm⁻¹
- c = concentration in mol/L
- Λm = molar conductivity in S·cm²/mol
The factor 1000 converts liters to cubic centimeters so the molar conductivity remains consistent with common laboratory conductivity units.
How to Use This Calculator
- Enter the electrolyte name for easier recordkeeping.
- Provide the solution concentration in mol/L.
- Enter measured conductance from your conductivity setup in mS.
- Type the calibrated cell constant in cm⁻¹.
- Optionally enter the measurement temperature for comparison.
- Press the calculation button to display the result section above the form.
- Review the graph to see how molar conductivity changes with dilution.
- Use CSV or PDF export to save your results.
Frequently Asked Questions
1. What does molar conductivity measure?
Molar conductivity measures how effectively one mole of electrolyte carries electric current through a solution at a stated concentration and temperature.
2. Why does molar conductivity often rise on dilution?
Dilution reduces interionic interactions and can improve ion mobility. Weak electrolytes also ionize more as dilution increases, which further raises molar conductivity.
3. What is the difference between conductance and conductivity?
Conductance is the measured ease of current flow in a specific cell. Conductivity adjusts that reading using the cell constant, giving a geometry-independent material property.
4. Why is the cell constant important?
The cell constant corrects for electrode spacing and area. Without it, conductance values from different cells cannot be compared accurately.
5. Which units are used here?
This calculator uses mol/L for concentration, mS for measured conductance, cm⁻¹ for cell constant, S/cm for conductivity, and S·cm²/mol for molar conductivity.
6. Does temperature affect the result?
Yes. Higher temperature usually increases ion mobility and conductivity. The adjusted value shown here is a simple comparison aid, not a full thermodynamic correction.
7. Can this be used for weak electrolytes?
Yes. It works for weak electrolytes, but interpretation needs care because ionization changes strongly with concentration and may require limiting conductivity analysis.
8. What makes a result look unreasonable?
Common causes include wrong unit conversions, an incorrect cell constant, temperature drift, contaminated samples, or concentration values entered in the wrong scale.