Beer’s Law Molar Absorptivity Calculator
Understanding Beer’s Law and Molar Absorptivity
What is Beer’s Law?
Beer-Lambert Law relates the absorption of light to material properties: A = εlc, where:
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| A | Absorbance | Unitless | 0.1-2.0 |
| ε | Molar Absorptivity | L·mol⁻¹·cm⁻¹ | 0-10⁵ |
| l | Path Length | cm | 0.1-10 |
| c | Concentration | mol/L | 0.001-1 |
Practical Examples
Example 1: For A=0.4, l=1cm, c=0.02M:
ε = 0.4/(1×0.02) = 20 L·mol⁻¹·cm⁻¹
Using the Calculator
- Measure sample absorbance using spectrophotometer
- Enter exact path length of cuvette
- Input known solution concentration
Key Factors Affecting ε
- Wavelength of incident light
- Solvent composition
- Temperature effects
- Chemical equilibrium states
FAQ
Q: Can ε values exceed 100,000?
A: Yes, some transition metal complexes have extremely high ε values.