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The simulation of peroxide reacting with red food dye was developed using the ChemCollective Kinetics Studies of the Bleaching of Food Dyes Activity simulations.
Monitoring the reaction
Monitoring the reaction
Experimental instructions:
Prepare three cuvettes that are identical to “cuvette A” from Part I (do not add any oxidant yet). Label these E, F, and G.
Prepare a syringe containing 0.50 mL of peroxide, and have a clean, dry glass stirring rod ready.
Set up the spectrometer for a kinetics run (see the spectrometer operating instructions – you will need to set the wavelength, sampling rate, etc.).
Carry out the first run with cuvette E, adding the peroxide exactly 10 s after the spectrometer has begun recording data.
Repeat this experiment using cuvettes F and G (identical reaction parameters).
Simulation: Watch the video for a simulation of monitoring the Red #40 + peroxide + catalyst reaction using absorption spectroscopy.
Analyzing the results
Analyzing the results
Compared to the "perfect" data obtained from the simulation, when performing the experiment in the lab you would see a plot like the one below - this one includes the "jump" when the peroxide was added and might exhibit fluctuations due to the stirring rod obstructing the light path.
Plot of absorbance versus time for the reaction of red number 40 with NaOCl. The absorbance is approximately 1.40 before the NaOCl is added. When the NaOCl is added, there is some variance or noise in the data due to the mixing process. Immediately after mixing, the absorption gradually decreases from approximately 1.00 to zero at 200 s as the reaction occurs. The reaction is 15% complete at approximately 30 s.
Use the buttons below to download experimental data to use for completing the lab report.
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