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Beer-Lambert Law:
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The molar absorptivity constant (ε) is a measure of how strongly a chemical species absorbs light at a particular wavelength. It is a fundamental property in spectrophotometry and is used in the Beer-Lambert law to relate absorbance to concentration.
The calculator uses the Beer-Lambert law formula:
Where:
Explanation: The Beer-Lambert law states that absorbance is directly proportional to the concentration of the absorbing species and the path length of the light through the sample.
Details: Molar absorptivity is crucial in quantitative analysis for determining unknown concentrations of substances in solution. It is widely used in chemistry, biochemistry, and environmental science for analytical measurements.
Tips: Enter absorbance (typically between 0.1 and 1.0 for accurate measurements), concentration in mol/L, and path length in cm. All values must be positive numbers.
Q1: What is the typical range for molar absorptivity values?
A: Molar absorptivity values typically range from 0 to over 100,000 L/mol·cm, with higher values indicating stronger absorption.
Q2: Why is the Beer-Lambert law important?
A: It provides the fundamental relationship for quantitative spectrophotometric analysis, allowing determination of unknown concentrations from absorbance measurements.
Q3: What are the limitations of the Beer-Lambert law?
A: The law assumes monochromatic light, dilute solutions, and no chemical interactions that might affect absorption. Deviations can occur at high concentrations.
Q4: How does path length affect absorbance?
A: Absorbance is directly proportional to path length - doubling the path length doubles the absorbance, assuming constant concentration.
Q5: Can this calculator be used for any wavelength?
A: Yes, but molar absorptivity is wavelength-dependent, so the calculated value applies only to the specific wavelength used for the absorbance measurement.