24. Solving a chemistry problem

4. Find the optimal thickness of the absorbing layer for photometry of a colored solution of the complex of eriochrome cyanine with beryllium with a molar absorption coefficient εmax equal to 15000 at a compound concentration of 0.04 mg in 25 cm3. The optimal optical density value is 0.425. The ratio of beryllium and eriochrome cyanine C23H15Na3O9S in the complex compound is 1:2.