Polymer and pH Indicator (In Person)

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VIDEO LINKS:

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

  1. Extracting the Polymer
  2. Making Indicator Solution
  3. Polymer with Indicator
  4. Determining pH Using Indicator Solution
  5. Determining pH Using pH Paper
 

Data analysis and calculations (Use these if you need help with your data and interpretations)

  1. Absorbed Water
  2. pH
 

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

(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.  

Data Processing

  1. (Representation) Complete the table below with the results of your tests for each material with the purple cabbage indicator solution, the indicator-soaked polymer and using the pH paper. Classify the substances you tested in your pH experiment as acidic, basic, or neutral.
Tested substance Color of indicator solution (descriptive) Color of indicator with polymer (descriptive) pH from the pH paper Acidic/Basic/Neutral
 
  1. (Analysis) Evaluate your results by comparing the descriptive colors associated with materials that are acidic, basic, or neutral.
  2. (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 ...
The indicator is not affected by the presence of the polymer. Compare the color of the indicator solution and the soaked polymer.
 

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 polymers and identify what kind of polymers are found in diapers.
  2. (Analysis) Describe what happened when you added water to your polymer and use your observation to explain how a diaper works.
  3. (Existing knowledge, research, and views) Look up the water uptake of this superabsorbent polymer in the literature. Describe how your result compares to that number.
  4. (Existing knowledge, research, and views) Name at least 3 other applications for these super absorbent polymers and describe how they are used. Describe what makes these applications interesting to you.
  5. (Analysis) Describe what happened when you added salt to your polymer. Identify at least one other substance that you expect to produce the same effect and provide an argument for the similar results.
  6. (Existing knowledge, research, and views) Define pH and describe what it is used for.
  7. (Existing knowledge, research, and views) Describe the pH indicator used in this experiment and how it was prepared. If the indicator wasn’t the whole red cabbage, identify the specific compound.
  8. (Analysis) Predict the color of the indicator and the pH of the solution if a strong acid like HCl is used in place of the vinegar. Provide an explanation for your choice.
  9. (Analysis) Predict the color of the indicator and the pH of the solution if a strong base like NaOH is used instead of sodium bicarbonate. Provide an explanation for your choice.
  10. (Analysis) Predict the color of the indicator and the pH of the solution if a higher concentration of the acetic acid was used instead of the 5% vinegar. Provide an explanation for your choice.
  11. (Analysis) Identify the method that is most sensitive among the 3 different methods you tested in this experiment and provide a supported argument for your choice.
  12. (Experimental design) Describe a practical application that requires you to determine the pH and provide a convincing argument why the red-cabbage indicator may or may not work for that purpose.