1. What is the Beer-Lambert Law?

The Beer-Lambert Law relates the attenuation of light to the properties of the material through which the light is traveling. It is commonly used in chemistry to measure the concentration of chemical solutions.

2. How Does the Calculator Work?

The calculator uses the Beer-Lambert Law equation:

Where:

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

Explanation: The law states that absorbance is directly proportional to the concentration of the absorbing species and the path length of the light through the sample.

3. Importance of Beer-Lambert Law

Details: This law is fundamental in spectrophotometry for determining concentrations of substances in solution. It's widely used in analytical chemistry, biochemistry, and molecular biology.

4. Using the Calculator

Tips: Enter molar absorptivity in L/mol·cm, concentration in mol/L, and path length in cm. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are the limitations of Beer-Lambert Law?
A: The law assumes monochromatic light, dilute solutions, and no scattering or fluorescence. Deviations occur at high concentrations (>0.01M).

Q2: What is a typical molar absorptivity value?
A: Values range from 0 to about 10^5 L/mol·cm. Strong absorbers have ε > 10,000 L/mol·cm.

Q3: What is the optimal absorbance range for measurements?
A: Between 0.1 and 1.0 absorbance units for best accuracy. Values above 2 are often unreliable.

Q4: Can this law be used for mixtures?
A: Yes, for mixtures, the total absorbance is the sum of absorbances of all components at that wavelength.

Q5: What's the difference between absorbance and transmittance?
A: Absorbance (A) is -log10 of transmittance (T), where T is the fraction of light transmitted through the sample.