Which factor influences the absorbance of a colored substance?

The absorbance of a colored substance is primarily influenced by the concentration of the compound in accordance with Beer-Lambert Law. This law states that absorbance is directly proportional to the concentration of the absorbing species. Therefore, as the concentration of the colored substance increases, the absorbance increases correspondingly, assuming that the path length and wavelength of light remain constant.

Other factors, while they can affect absorbance measurements, do not have the same direct and consistent relationship. For example, the temperature of the solution might influence the color intensity and stability of a compound, but it does not directly change the absorbance in a predictable manner. Similarly, the volume of solvent affects the final solution and can dilute the analyte, but it is the concentration that directly impacts absorbance measurements. The type of light source can determine the wavelengths available for absorption but does not influence the fundamental relationship between concentration and absorbance itself. Thus, the concentration of the compound is the key factor that dictates the absorbance of the colored substance.