Blue Food Dye Kinetics (in person)

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VIDEO LINKS:

Lab Experiments (Write protocols and perform experiments based on these):

  1. Making the Blue Dye #1 Solution
  2. Making the Bleach Solution
  3. Calibrating the Spectrophotometer
  4. Recording Full Spectrum of Blue Food Dye #1
  5. Monitoring the Kinetics
  6. Monitoring the Kinetics Part 2
  7. Monitoring the Kinetics Part 3

The prelab must include Experimental Protocol, Chemical Table, and Equipment Table.

The lab report requires all sections (including prelab sections) to be completed in one document.

Experimental Protocol

(Analysis) Watch the experiment videos.  Take notes on the protocol.  Stop the video and re-watch as necessary to acquire the details of the procedure.  Write out the protocol for each part of the experiment.  (It can be written in sequential steps.  Complete sentences are not necessary.)  This is the protocol you will follow, so be detailed.

Chemical Table

(Representation) Prepare your chemical table including the materials you will use in the experiment.  Here is a general template that you may use.
Chemical Name Chemical Formula Molar Mass (g/mol) Hazards reference PPE
Sodium Chloride NaCl 58.5 Skin irritation https://fscimage.fishersci.com/msds/21105.htm  
         
         
         

Equipment Table

(Analysis) Identify the equipment (type AND size) needed for the experiment and include the name and an image of each.  Be sure to describe the equipment, how to use it, and why it is suitable for this use.
Equipment Name Equipment Picture Intended Purpose

Data Collection

  1. (Acquiring competencies) Following your detailed protocol based on the videos, perform all the experiments. Record your observations and take pictures of your key steps in the process. Your observations and images need to be incorporated in your data section and this section should be as detailed as possible as you will use this information to complete your discussion.
  2. (Acquiring competencies) Perform the following 3 experiments using the amounts indicated in the table. Repeat each experiment to test the reproducibility of your measurements.
Experiment Temperature Volume of Dye solution (mL) Volume of H2O (mL) Volume of Bleach (mL)
1 Room temperature 1.5 0 1.5
2 Room temperature 0.75 0.75 1.5
3 Room Temperature 1.5 0.75 0.75
  1. (Representation) Record the maximum wavelength, that you used for data acquisition__________________________
  2. (Representation) Experiment 1 at room temperature_________ oC, data
Time (trial 1) (s) Absorbance (trial 1) Time (trial 2) (s) Absorbance (trial 2)
  1. (Representation) Experiment 2 at room temperature_________ oC, data
Time (trial 1) (s) Absorbance (trial 1) Time (trial 2) (s) Absorbance (trial 2)
  1. (Representation) Experiment 3 at room temperature__________ oC, data
Time (trial 1) (s) Absorbance (trial 1) Time (trial 2) (s) Absorbance (trial 2)

Data Processing

  1. (Manipulation) Calculate the initial molarity of the bleach (NaClO) solution you used, if 5 ml of the commercial bleach is diluted in a 100ml volumetric flask.
  2. (Existing knowledge, research, and views) Find the molar absorptivity value for the blue dye #1, Brilliant Blue FCF. Indicate the value with the associated unit and include the reference.
  3. (Manipulation) Calculate the initial molarity of blue dye #1, in the 100ml volumetric flask using the equation, where A is the absorbance value recorded at the maximum absorbance wavelength, l = 1.0 cm and  has the value you identified in the previous literature search.
  4. (Manipulation) Calculate the initial moles of each component, from mixing the solutions in the cuvettes, for each experiment (use the average of the two trials):
Experiment Volume blue dye solution Volume bleach solution Moles of blue dye Moles of bleach Total cuvette volume
1
2
3
  1. (Manipulation) Calculate the initial concentrations of each component in the cuvette, and then the rate of reaction for each experiment:
Experiment Initial concentration blue dye Initial concentration bleach Reaction time (s) Rate
1
2
3
  1. (Manipulation) Using the method of initial rates, write the differential rate law for the reaction of blue food dye with bleach. Include the order of each reactant, overall order and the calculated value for the rate constant with units.
  2. (Manipulation) Complete the following table using the experiment 1 data:
Time (x axis) Absorbance Concentration (Y axis) ln Concentration (Y axis) 1/ Concentration (Y axis)
8. (Graphical Representation) Plot time vs concentration, ln concentration, and 1/concentration for experiment 1. (You may use Excel or graphing paper for your plots.)
  1. (Manipulation) Complete the following table using the experiment 2 data:
Time (x axis) Absorbance Concentration (Y axis) ln Concentration (Y axis) 1/ Concentration (Y axis)
 
  1. (Graphical Representation) Plot time vs concentration, ln concentration, and 1/concentration for experiment 2. (You may use Excel or graphing paper for your plots.)
  2. (Manipulation) Complete the following table using the experiment 3 data:
Time (x axis) Absorbance Concentration (Y axis) ln Concentration (Y axis) 1/ Concentration (Y axis)
  1. (Graphical Representation) Plot time vs concentration, ln concentration, and 1/concentration for experiment 3. (You may use Excel or graphing paper for your plots.)
  2. (Representation) Write the differential rate equation for the reaction between the NaClO and blue food dye based on the integrated rate law relationships.
  3. (Interpretation) Based on the appropriate graph, find the order of reaction as well as the rate constant for the reaction at room temperature.
  4. (Assumptions and Analysis) Fill in the following table using the observations and data from your experiments.
Assumptions made Testing the assumption If assumptions are wrong ...
Only the blue dye has color. Perform the experiment with another food coloring. Changes will be apparent.
There are no colorful products formed in the reaction between the blue dye and the bleach.
 

Discussion

Write a minimum one-page (12 font, single spaced) discussion on the experiment conducted this week. Address at least one question in each category as fully as possible integrating the collected data, providing explanations for the observed trends, and evaluating whether your original assumptions about the experiment were validated by the results. The assignment will be graded on completeness, clarity of the explanations and the meaningful integration of the collected and calculated data. Correct grammar and appropriate format for the chemical formulae and chemical reactions is expected. You may use the outline included at the end of this document on how to build your essay to address each category.  
  1. (Existing knowledge, research, and views) Define chemical kinetics, and discuss the influence of collisions and energy.
  2. (Existing knowledge, research, and views) List the factors that affect the rate of a reaction. (HINT: there are 5.)
  3. (Analysis) Identify the variable that is changed in each of our experiments (blue food dye #1 and bleach).
  4. (Analysis) Provide a supported argument for the color change during the bleach/ food dye (Hint: connect to the chemical equations describing the experiment)
  5. (Interpretation) Describe how the different graphs were used to determine the order of the reaction as a function of the blue food dye concentration.
  6. (Interpretation) Describe how you derived the rate equation for the experiment and use your data as supporting argument.
  7. (Analysis) Compare the rates of your three experiments. Include your values and evaluate whether your values are consistent with expectations.
  8. (Analysis) Compare the rate constants of your three experiments. Include your values and evaluate whether your values are consistent with expectations.
  9. (Analysis) Compare the rate law derived from the method of initial rates to that derived from the graphing of the absorption data. Give a supported argument to explain the comparison.
  10. (Experiment design) In the experiment we are tracking the change in the absorption of the blue dye in its reaction with bleach. Propose a modification to the materials and predict how the modification could impact the outcome of the experiment.
  11. (Experimental Design) Predict the effect on the rate constant, rate of reaction, and rate law expression, if the temperature of the room is colder by 10o
  12. (Analysis) Predict the effect on the activation energy of lowering the reaction temperature by 10o