How do you explain the difference in Cr(III) content in the product, when you are sure that your solution contains the same analyte as the pure Cr(NO3)3 solution?

Question

anonymous · Answer

So we produced a product containing chromium, approximately 4 grams of it. We then took 0.5grams of it, diluted it, purfied it, reacted it with nitric acid, and measured the absorbance of the solution at a wavelength of 575nm.

anonymous · Answer

We then had to compare the accepted absorption spectrum of CR(NO3)3 and the absorption spectrum created from synthesizing our own CR(NO3)3. So basically the question is asking, we the only chemical species of concern is Cr3+, but the absorption spectrum differs from each other, how would you explain the difference in conentration of Cr+3.

anonymous · Answer

Which is what i don't know how to answer... b/c if the concentration differed due to loss of reacant during transfer, which would cause the production of the product containing chromium to be less.. and thus the concentration of chromium to be less...
but if the total product is 4g and you only use 0.5g how would the concentration differ?

anonymous · Answer

also, How do you explain the difference in Cr(III) content in the product, when you know that the solution contains at least one other different analyte absorbing light in the VIS range of the spectrum (so the spectrum is different)?