Question

By Beer’s Law, determine the molar absorptivity of the iron (II) phenanthroline complex using maximum absorbance, the molar concentration of the standard iron solution, and the cell path length.

I'm confused because on this lab we have calculated the max Wavelenth (497nm) and used a spectroscopy instrument to measue the max Absorbance at that wavelength for the other samples and unknown. Beers law seem simple, But how would I use it to find the molar absorptivity?

SAMPLE (in ppm)	Max (nm)	A Max (Lmol-1 cm-1)
2.5	497	1.150
2.0	497	1.080
1.5	497	.9850
1.0	497	.8550
0.5	497	.7340
Unknown	497	.8850

here's the data we collected. I'm stumped

Answer 1

for this experiment first u have to draw beers lamberts plot by taking concentration on x-axis and absorbance on y -axis. u will get a straight line after that for unknown, pointout the absorbance on y axis draw straight line to the slope, u will get concentration on x axis of unkown.when u got the unkown concentration by using beers lamberts law u can calculate molar absorbivity(= A/cl

molar absobvity()=( Absorbance)/ concentration *pathlength

u have A= 0.885 , cuvvetpathlength l=1cm, concentration c= got by graph