1. The problem statement, all variables and given/known data The problem involves a calibration curve which was created and where % T vs concentration was favored for use over the usual Absorbance vs concentration and a question of why would this be used in favor over the latter relationship curve was presented. other details: % concentration is from 0.35-0.05 with a 0.1 interval between points. Total points on graph = 7 Max transmitance occuring at the 0.05 % concentration is ~80%T Minimum transmittance at the 0.35% concentration is ~ 15%T Best fit line through the points is linear in relationship [exception for this is the highest concentration %T point which is somewhat above the line] 2. Relevant equations [itex]A= abc[/itex] [itex]A=-log (T) [/itex] [itex]T= [/itex]Exiting light intensity / Incident light intensity = I / Io 3. The attempt at a solution What I know: % Transmittance vs concentration plot usually has a negative sloping exponential relationship. (not talking about the one here which is linear in the range observed) Due to #1 above, it is preferential to plot calibrations curves using absorbance vs concentration. This is a result of the relationship A = abc which demonstrates that concentration is directly proportional to the absorbance of a solution. Generally it is linear within the working range of absorbance being ~ 0.10-0.82 from what I looked up. I was thinking that the reason that the % T vs concentration was used was that since the concentration range observed on the graph (0.05-0.3%) is small and as a result, in that area the relationship between %T and concentration is linear, it would not matter if one chose to use this calibration plot vs a abs vs concentration since the latter would be linear as well. But as to why % T was chosen over using Abs for the graph, I am unsure about since from what my thoughts on the subject tell me, they would be equivalent in this case (except for the positive slope in the abs vs concentration graph). In addition, all I could generally find around the web and in my text enlighten me on the benefits of using abs vs concentration as opposed to the cases in which %T would more favorable for use. I would appreciate any comments on whether my thoughts are correct or not. Thanks!