135. Solving a chemistry problem

20. When determining bismuth in an alloy containing up to 0.02% bismuth, a photometric reaction with thiourea is used. Calculate the ratio of the optimal weighing values (in mg) of the alloy and the final volume (in ml) of the photometric solution, es-
Is it known that the molar absorption coefficient of the complex of bismuth with thiourea Bi[SC(NH2)2]3 is 35,000, the thickness of the absorbing layer is l=5 cm, the optimal value of the optical density is D=0.43. Photometry is carried out at λ=322 nm; the molar absorption coefficient of the thiourea solution at 322 nm is 3000.