146. Solving a chemistry problem

23. The molar coefficient of light absorption of the complex [MoO (SCN) 5] 2- in isoamyl alcohol at λeff = 475 nm is equal to 1.50 * 10 ^ 4. Calculate the minimum mass fraction (%) of molybdenum in the soil, which can be determined by this method, if from the sample of soil weighing 20.00 g, molybdenum is recovered in 200.0 ml of oxalate buffer solution. 150.0 ml of filtrate are taken and, after appropriate treatment, the resulting [MoO (SCN) 5] 2 - 15.00 ml of isoamyl alcohol is extracted. The extract is photometered in a cuvette with l = 3.0 cm. The minimum optical density is 0.020.