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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 the absorbance of a solution is directly proportional to the concentration of the absorbing species in the solution and the path length.
The calculator uses Beer's Law equation:
Where:
Explanation: The equation calculates the concentration of a solution based on its absorbance at a specific wavelength, the molar absorptivity coefficient, and the path length of the light through the solution.
Details: Accurate concentration determination is crucial in analytical chemistry, pharmaceutical analysis, environmental monitoring, and biochemical research for quantifying substances in solution.
Tips: Enter absorbance (typically between 0.1-1.0 for best accuracy), molar absorptivity (specific to the compound and wavelength), and path length (usually 1.0 cm for standard cuvettes). All values must be positive.
Q1: What is the valid absorbance range for Beer's Law?
A: Beer's Law is typically valid for absorbance values between 0.1 and 1.0. Outside this range, deviations may occur due to various factors.
Q2: How do I determine molar absorptivity?
A: Molar absorptivity is determined experimentally by measuring absorbance of solutions with known concentrations at a specific wavelength.
Q3: What units should I use for the calculation?
A: Use consistent units: absorbance (dimensionless), molar absorptivity (L/mol·cm), path length (cm), concentration (mol/L).
Q4: When does Beer's Law not apply?
A: Beer's Law may not apply at high concentrations, with polychromatic light, in scattering solutions, or when chemical associations occur.
Q5: Can I use this for mixtures?
A: For mixtures, additional calculations are needed as absorbance is additive, and each component may absorb at the measured wavelength.