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How to calculate molar absorption coefficient
The maximum absorption wavelength of potassium dichromate is 480nm, and the absorption cell with optical path b= 1cm is selected for determination.

The concentration of potassium dichromate solution is 200ug/ 100ml.

The molar mass of potassium dichromate is 294g/mol, and the solution concentration is converted into 200 times 0.00000 1/294/100/0.001= 6.8 times 0.000001per liter.

The absorbance of the solution was determined at the maximum absorption wavelength λ= 0.0 19.

According to Bill-Lambert law, A=εcb, and the molar absorption coefficient ε = a/CB = 0.019/6.8/0.000001= 2794L/mol.cm..

Extended data:

1 and the influencing factors of molar absorption coefficient

The molar absorption coefficient is related to the properties of the substance to be measured, the solvent and the wavelength of light.

The molar absorption coefficient is different for different substances to be measured, so the molar absorption coefficient can be used as the characteristic constant of the substance.

The molar absorption coefficient of the same substance in different solvents is different. Therefore, when explaining the molar absorption coefficient, the solvent should be indicated.

Different wavelengths of light have different absorption coefficients. The higher the purity of monochromatic light, the greater the molar absorption coefficient.

2. Applicable conditions of Bill-Lambert Law

(1) The incident light is parallel monochromatic light and irradiated vertically.

(2) The light-absorbing substance is a uniform non-scattering system.

(3) There is no interaction between absorbing particles.

(4) The interaction between radiation and matter is limited to the absorption of light, and fluorescence and photochemical phenomena do not occur.

(5) Scope of application: the absorbance is between 0.2 and 0.8.

Baidu Encyclopedia-Beer-Lambert Law

Baidu encyclopedia-molar absorption coefficient