Allura Red Dye Lab Report

From the best fit equations found in Graph 2, we were able to create a graph for the concentrations of the bleach and diluted dye solutions at each given reaction time. With this graph, we are able to calculate the half-lives for the bleaching reactions. A half-life is the specific time at which the concentration of the solution is exactly half of its starting value. Our starting concentration of the allura red dye was 0.000938 M, so our half-life occurred at 3 minutes and 20 seconds. Our starting concentration of the sunset yellow was 0.0009864 M, so our half-life occurred at 5 minutes and 15 seconds. The sunset yellow dye had a faster and more linear reaction time than allura red; this could be caused by incorrect dilutions of the dye and

Based on our results, sunset yellow had a smaller maximum wavelength than allura red, which means that allura red was able to absorb more light than the sunset yellow dye. When bleach was added to each dilution of dye, the allura red’s half-life was 3 minutes and 20 seconds while the sunset yellow’s half-life was 5 minutes and 15 seconds. We cannot make a justified conclusion on our results because the sunset yellow’s reaction had several errors

We then found the maximum wavelength at which each dye displayed the maximum absorbance based on the peaks in each curve. For allura red, this peak occurred at 500 nm. For sunset yellow, this peak occurred at 480 nm.
Using our data from the calibration curve (Table 2), we were able to find the extinction coefficient using Beer’s Law. Beer’s Law states . Epsilon ( represents the extinction coefficient, ‘A’ represents the absorbance, ‘l’ represents the length of the cuvette (1 cm), and ‘c’ represents the sample’s concentration. An example of how we found epsilon by using our data from the .0001 M concentration of allura dye at its maximum wavelength is shown below.
In this lab, we acquired 0.001, 0.0001, 0.00001, 0.00003, 0.00005, and 0.00008 M diluted solutions of allura red and sunset yellow dyes. With the 0.00001 M diluted dyes, we recorded its absorbance for wavelengths of 400-700 nm in increments of 20, found the value for each dye, and created a plot. Using the value as a parameter, we then found the absorbance values for each dye at the concentrations of 0.0001, 0.00001, 0.00005, 0.00008 M, created a calibration curve, and solved for the extinction coefficients. Lastly, we put 3 drops of an 8.25% solution of bleach into the 0.001 M solution of allura red dye and 3 drops of an 0.825% solution of bleach into the 0.0001 M solution of sunset yellow dye