4. (14 points) A soil sample (4.00 g) is digested and analyzed for Cd by atomic absorption analysis. The digestion results in 25.0 mL of extract. Because there is concern of matrix effects, standard addition is used. A portion of the extract is analyzed directly by AA and gives an absorbance of 0.211. Another 10.0 mL portion of the extract is spiked with 50.0 ug of Cd (ignore any added volume from Cd spiking) and gives an absorbance of 0.539. a) Calculate the Cd concentration in the (unspiked) extract (in ug/mL). (8 pts) b) Calculate the Cd concentration in the soil in ppm (by mass). (3 pts) c) A Cd standard prepared in dilute nitric acid to a concentration of 1.00 µg/mL is analyzed and gives an absorbance of 0.191. Was the standard addition justified? (3 pts)

4. (14 points) A soil sample (4.00 g) is digested and analyzed for Cd by atomic absorption analysis. The digestion results in 25.0 mL of extract. Because there is concern of matrix effects, standard addition is used. A portion of the extract is analyzed directly by AA and gives an absorbance of 0.211. Another 10.0 mL portion of the extract is spiked with 50.0 ug of Cd (ignore any added volume from Cd spiking) and gives an absorbance of 0.539. a) Calculate the Cd concentration in the (unspiked) extract (in ug/mL). (8 pts) b) Calculate the Cd concentration in the soil in ppm (by mass). (3 pts) c) A Cd standard prepared in dilute nitric acid to a concentration of 1.00 µg/mL is analyzed and gives an absorbance of 0.191. Was the standard addition justified? (3 pts)

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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