when 200 ml of lead(II) nitrate solution of an unknown concentration had an excess of sodium chloride added, 3.48 g of solid was filtered out of the solution. what was the molar concentration of the lead(II) nitrate solution?

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.