The Beers Law Calculator is a valuable tool used in chemistry to determine the concentration of a substance in solution based on its absorbance of light. This calculation relies on the principles outlined in Beer’s Law, which establishes a relationship between the absorbance of light by a substance, its concentration, and the path length of the light through the solution.
Formula of Beers Law Calculator
The formula used in the Beers Law Calculator is:

Where:
- A is the absorbance of the substance.
- ε is the molar absorptivity (or molar extinction coefficient), a constant specific to the substance and the wavelength of light being used.
- c is the concentration of the substance in solution, typically measured in mol/L (molarity).
- l is the path length of the cuvette or container through which the light passes, typically measured in centimeters (cm).
General Terms Table
Term | Description |
---|---|
Absorbance | Measure of how much light a substance absorbs at a particular wavelength. |
Molar Absorptivity | Constant specific to the substance and the wavelength of light. |
Concentration (c) | Amount of solute dissolved in a solvent, usually expressed in molarity (mol/L). |
Path Length (l) | Distance the light travels through the solution, typically in centimeters (cm). |
This table provides general terms and their descriptions, aiding users in understanding the concepts related to the Beers Law Calculator without the need for manual calculations.
Example of Beers Law Calculator
Suppose we have a solution with a molar absorptivity (εε) of 200 L/(mol*cm), a concentration (cc) of 0.02 mol/L, and a path length (ll) of 1 cm. To find the absorbance (AA) of the solution:
A=200 L/(mol*cm)×0.02 mol/L×1 cm
So, the absorbance of the solution is 4.
Most Common FAQs
A: According to Beer’s Law, absorbance is directly proportional to concentration. As the concentration of a substance increases, so does its absorbance of light.
A: Beer’s Law is applicable to solutions that follow ideal behavior, meaning there are no chemical reactions or interactions between solute particles that could alter the absorption of light.
A: The path length represents the distance light travels through the solution. Increasing the path length increases the amount of substance encountered by the light, resulting in higher absorbance values.