Experiment 11 - Kinetics of Food Dyes >> Step 4: Putting it all together

Experiment 11 - Kinetics of Food Dyes

Step 4. Putting it all together.

At the end of the experiment, in order to assemble the rate law, Rate = k [dye]^m[bleach]ⁿ, we need to convert the absorbance values to concentrations. To achieve this, we will perform the Beer's law calibration for the dye we used and obtain the proportionality constant (εl, the slope of the Beer's law plot). With this proportionality constant, we will be able to determine the concentration for any absorbance value we collected in Steps 1 and 3.

Preparing a set of dilutions of the standard dye

This part of the experiment, creating a calibration plot for the standard dye, has been done in Exp.3, the Analysis of Dyes, in Chem 121 and is provided here as a refresher. We will first prepare a set of dilutions of the standard Yellow 6 dye (using the tutor below) and then run an absorbance measurement of each solution.

Now collect the absorbance vs % dilution data and record the slope of the straight line in the feedback form. Include the units.

Note that the value of the slope of the Beer's Law plot depends on the units in which concentration is measured and its units are the reciprocal of that concentration unit. Record this value on your feedback form with the correct units.