In addition to other items commonly required in a laboratory report, calculate the concentration of your unknown both (1) by reading the concentration directly off the calibration curve and (2) by using the average of the molar absorptivities (actually εb) calculated from each of the five standard solutions. If the plot is linear the values should be the same, and the slope of the absorbance vs. concentration (in M) plot should be equal to εb according to Beer’s Law: A = εbc. Assuming the pathlength of the cuvette used is 1.00 cm, calculate the molar absorptivity, ε, of the ferrous o-Phen complex and compare with the literature value of 11,100 L/mol-cm. Comment on the reasons for any difference.