Spectroscopic Measurements

This text discusses the use of spectroscopy to measure the concentration of an analyte in a sample. The text includes two problems, one involving the analysis of phosphorus and the other involving the analysis of copper.

Questions

1. What is the relative uncertainty in concentration if the blank is 1.0 × 10–4 M in analyte?
2. What is the purity of a sample that contains 2.469 g of Na2HPO4 and has an absorbance of 0.135?
3. What is the concentration of copper in a sample with an absorbance of 0.027?

Answers

1. The relative uncertainty in concentration is 0.9%.
2. The purity of the sample is 95.5%.
3. The concentration of copper in the sample is 0.346 mg/L.