Chem 40 – Theme 2 | Designing food pH indicators

Preamble

Using real food to design your own pH indicator.

In this project, you are to create your own pH indicator with actual food that are present. A pH indicator is a substance that will change its color depending on the pH of the solution. There are many natural foods that exhibit this phenomenon, and a good place to start are these websites: 

https://www.thoughtco.com/home-and-garden-ph-indicators-601971

https://www.scientificamerican.com/article/bring-science-home-cabbage-chemistry/

http://www.tuxgraphics.org/npa/litmus-redcabbage-tumeric-radish-ph-indicator/

You and you group are to create a pH indicator with 3 different kinds of food and package it well like you are ‘selling” the product. A proper MSDS must be created for each with any chemical concerns of your indicator. If the 3 different kinds of indicators cannot be combined, then you can make 3 separate pH indicators with 3 different packaging and MSDS sheets. 

In addition to creating your own pH indicator, you also need to make 2 solution of a known concentration. Once you have created your solution, your solution will be tested with its accuracy of its concentration by your peers via titration. Your grade is based on the accuracy of your concentration. 

 

What you need to learn

Specific Outcomes

  1. Identifying an acid and base through various definitions (Arrhenius, and Bronsted-Lowry theories. (C12-05-01)
  2. Write an acid and base reaction with neutralization (C12-01-04, C12-05-02)
  3. Describing the relationship of the hydronium ion and hydroxide ion in water (C12-05-03, )
  4. Calculating pH, pOH, Kw, [H+], and [OH-] (C12-05-06)
  5. Performing titration to calculate the concentration of an unknown acid or base (C12-01-05, C12-01-06)
  6. Explain how pH Indicators work with Le Chatelier’s principle (C12-05-05, C12-04-06)

How you are assessed

Deliverables

  1. Group design of food pH indicator including the packaging, the presentation, and the chemistry behind the indicator. 
  2. Quizzes on Acid and base definitions, calculating pH, pOH, [H+], [OH-], and neutralization calculations.
  3. Accuracy of your 2 solutions. (Acid and base)

Schedule 

Tutorial Videos

Watch these to help and guide you along. You are expected to watch all of these videos and complete the workbook required.

  1. Definitions of Acid and base. (Arrhenius, Bronsted-Lowry)
  2. Neutralization reactions
  3. Calculating Neutralization reactions
  4. Calculating [H+] and [OH-]
  5. Calculating Kw, pH and pOH
  6. Calculating weak acids and weak bases
  7. What is titration?
  8. How to perform a titration?
  9. Titration calculations

Other notes

Notes:

    Review:

    • Unit Acids and Bases: Review