The third page demonstrates the practical applications of the Loi de Beer-Lambert in determining concentrations and calculating masses of substances in solution. It provides methods for applying the law using both graphical and numerical approaches.
For graphical analysis, the page explains how to read concentrations directly from the calibration curve. For numerical analysis, it presents the formula for calculating the constant k:
k = (Amax - Amin) / (Cmax - Cmin)
Formula: The concentration of an unknown sample can be calculated using C = A₀ / k, where A₀ is the measured absorbance and k is the slope of the calibration curve.
The page also covers how to calculate the mass of a substance present in a solution:
m = n × M = C × V × M
Where C is the concentration obtained from the Beer-Lambert law, V is the volume of the solution, and M is the molar mass of the substance.
Example: If you have determined the concentration C of a solution using the Loi de Beer-Lambert, and you know its volume V and the molar mass M of the dissolved substance, you can calculate the mass m present in the solution.
This final section ties together the theoretical aspects of the Beer-Lambert law with its practical applications in quantitative analysis, demonstrating its importance in fields such as chemistry and biochemistry.