111. Solving a chemistry problem

22. Equal volumes of waste water containing copper were poured into two 100 ml volumetric flasks. The necessary amounts of ammonia and solutions of rubeanic acid were also introduced there. 10.00 ml of copper sulfate standard solution (T CuSO4/Cu=0.001) was added to one of the flasks, the contents of both flasks were brought to the mark. After filtration, the solutions were photometered, obtaining the values of the optical density Dx and Dx st. determine the concentration of copper in wastewater (g/l) according to the following data: V, ml = 30.00; Dx=0.32; Dх st = 0.47.