145. Solving a chemistry problem

24. To determine nickel with dimethylglyoxime, the weight of the steel is dissolved and the solution is diluted to 100.0 ml. The necessary reagents are added to 5.0 ml of the solution, diluted with water to 50.0 ml and photometric at l = 1.0 cm, λeff. = 470 nm (ελ = 1.30.10 ^ 4). Calculate the mass of steel for
analysis, if the optimum value of optical density is 0.435 and the approximate mass fraction of nickel in steel is a) 0.5% b) 1% c) 5%