The method developed in Problem 14-11 was used for the routine determination of iron in 25.0-mL aliquots of groundwater. Express the concentration (as ppm Fe) in samples that yielded the accompanying absorbance data (1.00-cm cell). Calculate the relative standard deviation of the result. Repeat the calculation assuming the absorbance data are means of three measurements.
Problem 14-11
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.