36. Solving a chemistry problem

1. In two volumetric flasks with a capacity of 100.0 ml, 20 ml of waste water were placed. To one flask was added 10.00 ml of a copper sulfate standard solution with a copper titer of 0.0010 g/ml. In both flasks were introduced solutions of ammonia, rubeanic acid and diluted with water to the mark. When photometry solutions received optical densities Ah = 0.28 and Ah St = 0.32. Determine the concentration (g/l) of copper in waste water.