1. What is Molar Absorptivity?

Molar absorptivity (ε), also known as molar extinction coefficient, is a measure of how strongly a chemical species absorbs light at a particular wavelength. It is a fundamental property in spectroscopy and quantitative analysis.

2. How Does the Calculator Work?

The calculator uses the Beer-Lambert law:

Where:

• \( ε \) — Molar absorptivity (L/mol·cm)
• \( A \) — Absorbance (unitless)
• \( c \) — Concentration (mol/L)
• \( l \) — Path length (cm)

Explanation: The Beer-Lambert law describes the linear relationship between absorbance and concentration of an absorbing species.

3. Importance of Molar Absorptivity

Details: Molar absorptivity is crucial for quantitative analysis in spectroscopy, determining unknown concentrations, characterizing compounds, and validating analytical methods.

4. Using the Calculator

Tips: Enter absorbance (typically between 0.1-1.0 for accurate measurements), concentration in mol/L, and path length in cm. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical range for molar absorptivity?
A: Values range from near 0 for non-absorbing species to over 100,000 L/mol·cm for strongly absorbing compounds.

Q2: Does molar absorptivity depend on wavelength?
A: Yes, molar absorptivity is wavelength-specific and varies with the absorption spectrum of the compound.

Q3: What are the limitations of Beer-Lambert law?
A: The law assumes monochromatic light, dilute solutions, and no chemical interactions that might affect absorption.

Q4: How is molar absorptivity used in practice?
A: It's used to create calibration curves, determine unknown concentrations, and characterize molecular properties.

Q5: What factors affect molar absorptivity measurements?
A: Temperature, solvent, pH, and instrumental factors can all influence measured values.