Beer-Lambert Law Calculator
This calculator is designed for advanced chemistry students and professionals to compute absorbance or concentration using the Beer-Lambert Law. It helps in understanding how light absorption by a solution is related to its concentration and path length.
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Data Source and Methodology
All calculations are based on the Beer-Lambert Law as detailed in 'Principles of Instrumental Analysis' by Skoog et al. (ISBN: 978-1-305-57721-3).
All calculations are rigorously based on the formulas and data provided by this source.
The Formula Explained
\( A = \epsilon \cdot c \cdot l \)
Where:
- \( A \) is the absorbance
- \( \epsilon \) is the molar absorptivity in L/mol·cm
- \( c \) is the concentration in mol/L
- \( l \) is the path length in cm
Glossary of Variables
- Concentration: The amount of solute per unit volume of solution, expressed in mol/L.
- Path Length: The distance light travels through the solution, usually in cm.
- Molar Absorptivity: A measure of how strongly a chemical species absorbs light at a given wavelength, expressed in L/mol·cm.
How It Works: A Step-by-Step Example
Consider a solution with a concentration of 0.5 mol/L, a path length of 1 cm, and a molar absorptivity of 200 L/mol·cm. The absorbance is calculated as follows:
\( A = 200 \times 0.5 \times 1 = 100 \)
The solution has an absorbance of 100 under these conditions.
Frequently Asked Questions (FAQ)
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.
Why is molar absorptivity important?
Molar absorptivity is a constant that indicates how well a substance absorbs light at a particular wavelength, crucial for calculating absorbance.
How do I measure path length?
Path length is typically the width of the cuvette used in a spectrophotometer, usually 1 cm.
Can the Beer-Lambert Law be applied to all solutions?
It is generally applicable to dilute solutions where the solute does not cause scattering of light.
What units should I use for concentration?
Concentration should be expressed in mol/L for consistency with the formula and standard practice.