AP CHEM

A student is given a sample of CuSO4 (s) that contains a solid impurity that is soluble and colorless. The student wants to determine the amount of CuSO4 in the sample and decides to use a spectrophotometer. First, the student prepares a calibration graph by measuring the absorbances of CuSO4 (aq) solutions of known concentrations. The graph is shown below.