11. A sample of ore weighing m g was transferred to the solution and brought to 50.0 ml. Two samples of 20.00 ml each were taken from the resulting solution. 10.00 ml of a standard rhenium solution (T = 0.02 mg/ml) were added to one of the samples, and 10.00 ml of water were added to the other. Rhenium was repeatedly extracted from both samples with toluene in the presence of methyl violet. The extracts were collected in two 50.0 ml flasks, the volume was brought up to the mark with toluene, and the optical densities Ax and Ax+st were measured. Determine the mass fraction (%) of rhenium in the ore using the following data:
Option 1 2 3

m, g 1.250 2.000 2.500
Ax 0.210 0.340 0.420
Ax+st 0.450 0.560 0.700
Solution for option 1

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