Beer-Lambert LawChemistry

Beer-Lambert Law Spectrophotometry & Absorbance Calculator

Calculate optical absorbance (A), percent transmittance (%T), molar extinction coefficient (ε), and unknown analyte concentration using UV-Vis spectrophotometry.

Calculated Result

Optical Absorbance (A)

0.5A

Calculator Inputs

L/(mol*cm)
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mol/L
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Optical Absorbance (A)

0.5A

Percent Transmittance (%T)

0 %

Optimal Linear Dynamic Range (0.2 - 0.8): Measured absorbance falls directly in the lowest photometric noise error window.

Spectrophotometric Absorbance vs Transmittance

Absorbance A
0.5 -(100%)

Standard analytical chemistry and molecular spectroscopy tool for concentration determination.

Calculation Methodology

Beer-Lambert Law: A = ε * c * l. Where A is absorbance, ε is molar absorptivity (L/(mol cm)), c is concentration (mol/L), and l is cuvette path length (cm). Transmittance Relation: A = -log10(%T / 100) = 2 - log10(%T). Unknown concentration: c = A / (ε * l).

Frequently Asked Questions

At high concentrations (> 0.01 M), electrostatic solute-solute interactions alter the charge distribution and extinction coefficient, while refractive index shifts and stray light induce negative deviation.

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