A standard solution was put through appropriate dilutions to give the concentrations of iron shown below. The iron(II)-1,10,phenanthroline complex was then formed in 25.0·mL aliquots of these solutions, following which each was diluted to 50.0 mL. The following absorbances (1.00-cm cells) were recorded at 510 nm:
(a) Plot a calibration curve from these data.
(b) Use the method of least squares to find an equation relating absorbance and the concentration of iron(II).
(c) Calculate the standard deviation of the slope and intercept.