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Beer's Law Equation:
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Beer's Law (Beer-Lambert Law) describes the relationship between the absorption of light and the properties of the material through which the light is traveling. It states that absorbance is directly proportional to the concentration of the absorbing species and the path length of the light through the material.
The calculator uses the Beer's Law equation:
Where:
Explanation: The equation calculates the molar absorption coefficient, which is a measure of how strongly a chemical species absorbs light at a given wavelength.
Details: The molar absorption coefficient is a fundamental property in spectroscopy that helps identify substances, determine concentrations, and study molecular properties. It is widely used in analytical chemistry, biochemistry, and environmental science.
Tips: Enter absorbance (unitless), concentration in molarity (M), and path length in centimeters (cm). All values must be positive numbers greater than zero.
Q1: What are typical values for molar absorption coefficients?
A: Molar absorption coefficients vary widely depending on the compound and wavelength, ranging from near zero to over 100,000 M⁻¹·cm⁻¹ for highly absorbing compounds.
Q2: When is Beer's Law valid?
A: Beer's Law is valid for dilute solutions where the absorbing species do not interact with each other and when monochromatic light is used.
Q3: What factors can cause deviations from Beer's Law?
A: Deviations can occur due to high concentrations, chemical associations, scattering, fluorescence, or polychromatic light sources.
Q4: How is absorbance measured experimentally?
A: Absorbance is measured using a spectrophotometer, which compares the intensity of light passing through a sample to the intensity of light passing through a reference.
Q5: Can this calculator be used for any wavelength?
A: Yes, the molar absorption coefficient is wavelength-dependent, so the calculation applies to measurements made at any specific wavelength.