125. Solving a chemistry problem

2. The analyzed aqueous ammonia solution with a volume of 50 ml contains cobalt (II) and nickel (II) salts. To this solution was added a solution of sodium diethyldithiocarbamate in an amount sufficient to completely convert cobalt (II) and nickel (II) into diethyldithiocarbamate complexes, which were then almost completely extracted with carbon tetrachloride and 10 ml of an extract containing diethyldithiocarbamate complexes of cobalt (II) and nickel ( II). The light absorption of the extract was measured at two wavelengths of 328 and 367 nm in a cuvette with an absorbing layer thickness of 1 cm with respect to pure carbon tetrachloride (reference solution) and the following optical density values ​​were obtained: A328=0.698 and A367=0.737. The molar extinction coefficients under the conditions of the experiment at the indicated wavelengths are found to be equal, l*mol-1*cm-1: for cobalt (II) complexes ε328=3910, ε367=14340; for nickel(II) complex ε328=35210, ε367=21820. Using the optical density additivity law, calculate the concentrations c(Co2 ) c(Ni2 ) in mol/l and the mass m(Co2 ) , m(Ni2 ) of cobalt (II) and nickel (II) in the analyzed ammonia aqueous solution.