Chemistry

Beer-Lambert Law Calculator

Find concentration from absorbance.

Absorbance (A)

Molar absorptivity (ε) (L/mol·cm)

Path length

Calculated Output

Concentration (mol/L) 0.0001

Formula: A = ε·l·c → c = A ÷ (ε·l)

Step-by-Step Breakdown

1. Values used:

2. Absorbance (A) = 0.45

3. Molar absorptivity (ε) = 9,000 L/mol·cm

4. Path length = 1

6. Concentration = Absorbance (A) / Molar absorptivity (ε) = 0.45 / 9,000 = 0.0001mol/L

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The math behind it

A = ε × path length × concentration, so concentration = A ÷ (ε × l).

A 0.45, ε 9000, 1 cm → 5 × 10⁻⁵ M.

Use?

Spectrophotometry — measuring concentration from light absorption.