1. What is Beer's Law?

Beer's Law (Beer-Lambert Law) relates the absorption of light to the properties of the material through which the light is traveling. It states that the concentration of a solution is directly proportional to its absorbance.

2. How Does the Calculator Work?

The calculator uses Beer's Law equation:

Where:

• \( c \) — Concentration (mol/L)
• \( A \) — Absorbance (dimensionless)
• \( \epsilon \) — Molar absorptivity (L/mol)

Explanation: The equation shows that concentration can be determined by dividing the measured absorbance by the molar absorptivity coefficient.

3. Importance of Concentration Calculation

Details: Accurate concentration determination is crucial in analytical chemistry, biochemistry, and environmental science for quantifying substances in solution.

4. Using the Calculator

Tips: Enter absorbance (typically between 0.1-1.0 for best accuracy) and molar absorptivity (specific to the substance and wavelength). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are typical molar absorptivity values?
A: ε values range widely from 10 to 100,000 L/mol·cm depending on the substance. Strong absorbers have higher ε values.

Q2: What are the limitations of Beer's Law?
A: Beer's Law assumes monochromatic light, dilute solutions, and no scattering or fluorescence. Deviations occur at high concentrations.

Q3: What path length is assumed in this calculation?
A: The standard equation assumes 1 cm path length. For other path lengths, divide by the actual path length in cm.

Q4: Can this be used for mixtures?
A: For mixtures, you need to account for absorbance contributions from all components at the measured wavelength.

Q5: How accurate is this calculation?
A: Accuracy depends on the quality of your absorbance measurement and the accuracy of the ε value used.