Answer Happy

17. (5 points) Suppose you are analyzing for lead in drinking water. You prepare a series of standard solutions containing known amounts of lead. You make up a calibration curve, and use linear regression to obtain the best-fit line for your data. For your data, you obtain an equation of the line of your plot to be y=0.0253 x +0.0024 where x is concentration in ppm Pb, and y is absorbance. You have a 500 mL solution that you need to know its concentration of Pb, in ppm. The solution is too concentrated to analyze by AA, so you take 20 mL of the solution and place it in 500 mL volumetric flask, and fill it to the line with water. You then analyze this solution by AA, and find it gives an absorbance reading of 0.527. a. What is the ppm concentration of Pb in dilute solution? b. What is the ppm concentration of Pb in the original solution?