Question

	Wavelength1= 230.0569	Wavelength 2 =272.9629
Absorbance of U1	0.926408	0.417250
Absorbance of U2	0.538657	0.393728

I have to create a simultaneous equation to find the concentration of benzoic acid and caffeine. How do I set it up and solve it? My values are way to high. Please help. Thank you!

Answer 1

There is no information on what U1 and U2 are, but the way to solve this problem is to determine the molar absorptivity of both caffeine and benzoic acid at the given wavelengths (you can do this by doing a calibration curve). And then, at both wavelengths you will have an absorbance given by;

Which means that you will have two equations (one with each wavelength) and two unknowns (the concentrations), so you will be able to solve it.

If you need any further help, please give me more information on what U1 and U2 are, and any other information you might have in the comments section and I'll try to help you!