34. Solution to Chemistry Problem

11(2). When determining the copper content in the alloy by the addition method, a sample of the alloy (mспл) was transferred to the solution and the volume of the solution was brought to 50.0 ml in a measuring flask. Aliquots of the solutions (10.0 ml) were transferred to two 50.0 ml measuring flasks. A standard solution containing 100 μg of copper was added to one of them. The required amount of aqueous ammonia was introduced into both flasks and the solutions in the flasks were brought to the mark with distilled water:
Cu2 4NH3→[Cu(NH3)4]2
Determine the mass fraction of copper in the alloy if the following data were obtained during photometry: Ах= 0.57, Ахст=0.60, (mспл) = 0.5022 g.