【Daily Question】Chemical Analysis Version, 2020.6.11
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This post was last edited by zjp on 2020-6-11 08:22. Multiple-choice question: There are two different colored solutions, both of which obey the Lambert-Beer law. If the thickness of the cuvette, the intensity of the incident light, and the concentration of the solution are all equal, which of the following statements is correct? A. The intensity of the transmitted light is equal. B. The absorbance is equal. C. The absorption coefficient is equal. D. None of the above statements are correct. D
This post was last edited by Song Yonggang15532757608 on 2020-6-11 at 16:50, version D. At a given wavelength, under conditions such as solvent and temperature, the absorbance of an absorbing substance per unit concentration and per unit thickness of the liquid layer is called the absorption coefficient. According to Beer’s law, the absorbance A is directly proportional to the product of the concentration c of the absorbing substance and the path length b of the absorption cell. When the unit of c is g/L and the unit of b is cm, then A=abc; the proportionality constant a is called the absorption coefficient, with units of L/g·cm-1 ； When the unit of c is mol/L and the unit of b is cm, then A = εbc; the proportionality constant ε is called the molar absorption coefficient, with units of L/mol·cm-1. Numerically, ε is equal to the product of a and the molar mass of the substance undergoing absorption.