A Carolina Exclusive! Addresses AP® Chemistry Big Idea 1 and Learning Objective 1.16. Determine the concentration of food dyes in powdered drink mixes using Beer-Lambert's law. Prepare standard solutions of 2 food dyes, plot calibration curves of absorbance as a function of concentration for each dye, and determine the concentration of each dye in its unknown solution. Procedure does not use toxic thiocyanate salts. For 30 students working in teams of 3.