Baking Soda/Cream of Tartar Titration Lab

Research Questions

How much baking soda and/or cream of tartar will dissolve in a saturated solution?

How can we insure that the solution has reached equilibrium?

How can the acid base properties of a salt be used to measure its solubility?

Learning Objectives:

  1. Correctly prepare saturated solutions and provide evidence that the solution has reached equilibrium

  2. Describe how a single compound can have multiple types of aqueous behavior

  3. Explain the limitations and assumptions present in electrochemical measurements of aqueous equilibrium

  4. Explain the connection between equilibrium calculations of pH and observed experimental results.

  5. Describe why similar experimental tools can be used in multiple contexts and list the strengths and limitations for the approach.

To Do List:

Step 1: Read lab background, watch videos, and visit links provided about experimental context on this page

Step 2: Read lab procedure

Step 3: Watch corresponding lab tutorial

Step 4: Answer pre-lab questions

Step 5: Perform lab experiment

Step 6: Answer post-lab questions


Food Deserts and the Right to Cook

Have you ever lived in an area where you’ve had to travel far to find food that is actually good for you? Are vegetables and fruits hard to find in your neighborhood uncanned? Do you have access to many corner stores, bodegas and fast food places but nowhere to find something healthy and inexpensive like the other food you can find easily? This is all too common in many areas in the United States. The term “food desert” is used to describe a geographic area where residents do not have sufficient access to healthy food options, mainly fresh produce, due to the lack of grocery stores within reasonable travelling distance.1 Food deserts disproportionately affect urban areas in minority and low-income communities.

Where Are Food Deserts Found?

In all but very dense urban areas, the higher the percentage of minority population, the more likely the area is to be a food desert. From a study conducted by the USDA, areas with higher levels of poverty are more likely to be food deserts. Except for other factors, such as vehicle availability and use of public transportation, the association with food desert status varies across very dense urban areas, less dense urban areas, and rural areas. Places with higher poverty rates are more likely to be food deserts regardless of rural or urban designation.2

The Overarching Problem and What You Can Do!

Residents of food deserts therefore lack the access to affordable nutritious foods within their communities. However, the overarching issue is not residents having a lack of nutrition (though they often do), but rather having a deficiency in personal freedoms to buy the foods they want, that many others have full access to. Instead of having the option to bake desserts or cook meals with quality ingredients of their choice, people living within food deserts are often left only with the option of processed, prepackaged foods.

If you would like to take action to combat the issues of food deserts listed above consider supporting any of the following organizations linked below:

  1. Produce for Better Health Foundation

  2. Community Food Lab

  3. Wholesome Wave

  4. Soul Fire Farm

  5. Food Empowerment Project

  6. Thrive Market

  7. Food Revolution Network

At a more local scale, consider donating to community food banks or by starting or contributing to a community garden. These actions increase accessibility to foods within your community. If you live in a food desert, the Food Empowerment Project recommends to start helping out your community by growing your own food, communicating with local retailers, and bringing up these issues to local representatives and government officials.1 On social media, supporting the #GiveHealthy movement which aims to enable people to donate healthy foods and raise public awareness.

Baking Soda Chemical Structure

Baking soda or sodium bicarbonate (NaHCO3) is added to recipes as a leavening agent. This means that it reacts in a recipe to produce gas and this gas is trapped in the dough and causes the cake or cookie to “rise” or puff up. Baking soda is used in doughs or mixes that are acidic (due to vinegar, lemon juice, buttermilk or the like). The following reaction details how baking soda (sodium bicarbonate) reacts with acid to produce carbon dioxide gas (CO2)

  1. H+(aq) + NaHCO3 (aq) → Na+ (aq) + H2CO3 (aq)

  2. H2CO3 (aq) → H2O(l) + CO2 (g)

Sodium bicarbonate is acting here as a base and accepting the proton from the acid. As you will see in your experiment, it can also act like an acid and donate a proton. This makes baking soda an amphoteric compound just like cream of tartar.

Cream of Tartar

So what do we do for leavening in batters that aren’t already acidic? In those cases, we need to add an acid into the batter react with the baking soda. Cream of tartar is an acid commonly used with baking soda in many cookie, pie and cake recipes. As shown in the following reaction, baking soda and cream of tartar react together to produce carbon dioxide gas.

  1. KHC4H4O6(aq) + NaHCO3 (aq) → NaKC4H4O6 (aq) + H2CO3 (aq)

  2. H2CO3 (aq) → H2O(l) + CO2 (g)4

In the case of cooking, we are interested in using cream of tartar’s acidic properties. The combination of the two is actually what baking powder consists of. Between the acidity of cream of tartar and the basicity of baking soda, a neutralization reaction occurs, and with the addition of heat, leavening can occur.4

Cream of Tartar Chemical Structure

Listen to or read this interview for information about Dr. Christy Haynes, the Elmore H. Northey Professor of Chemistry at the University of Minnesota who uses microfluidic devices for influential projects surrounding environmental matters and healthcare.

References

  1. FOOD DESERTS. “Food Empowerment Project.”
https://foodispower.org/access-health/food-deserts/ (accessed Jun 25, 2020).
  1. Dutko, P.; Ver Ploeg, M.; Farrigan, T. Characteristics and Influential Factors of Food
Deserts; Economic Research Report 140; United States Department of Agriculture, August 2012. https://www.ers.uswq da.gov/webdocs/publications/45014/30940_err140.pdf (accessed Jun 24, 2020).
  1. Cahn, L. “30 Recipes Whose Secret Ingredient is Cream of Tartar.”
https://www.tasteofhome.com/collection/recipes-with-cream-of-tartar/ (accessed 24 Jun 2020).
  1. Goodwin, J., Slusher, D., Gilbert, T., and Hanson, D. Solving Real Problems With
Chemistry, First Edition. Pacific Crest, 2009 (accessed 29 Jun 2020).
  1. Arumugam, Nadia. “Food Explainer: What’s Cream of Tartar, and Do I Have to Buy It?”
Slate, 29 Nov 2013. https://slate.com/culture/2013/11/what-is-cream-of-tartar-the-food-explainer-explains.html (accessed 29 Jun 2020).
  1. Greaves, V. Cream of Tartar: What It Is and How to Use It.
https://www.allrecipes.com/article/cream-of-tartar/ (accessed 24 Jun 2020).
  1. Cream, Maddie. “Cream of Tartar: What Is It, Anyway?” Huffington Post, 19 Dec 2012.
https://www.huffpost.com/entry/cream-of-tar-tar_n_2322569#:~:text=Potassium%20tartrate%20was%20first%20discovered,it%20frequently%20in%20their%20cooking (accessed 27 Jun 2020).
  1. Mad Food Science. “Cream of Tartar.”
https://www.madfoodscience.com/post/4338474877/cream-of-tartar#:~:text=Because%20it's%20an%20acid%2C%20cream,acts%20as%20a%20leavening%20agent.&text=Finally%2C%20cream%20of%20tartar%20is,reaction%20happen%20for%20inverting%20sugar (accessed 27 Jun 2020).
  1. Schwarcz, J. Cream of Tartar. McGill Office for Science and Society.
https://www.mcgill.ca/oss/article/general-science-history/cream-tartar (accessed 24 Jun 2020).
  1. SOLUBILITY AND THE SOLUBILITY PRODUCT CONSTANT. United States
Naval Academy March 7, 2018. https://www.usna.edu/ChemDept/_files/documents/112pdf/2018%20Documents/Exp-44-Ksp-lab-pot-acid-tartrate-FV-s18.pdf (accessed 24 Jun 2020).
  1. Solubility of Potassium Bitartrate. James Madison University.
https://www.jmu.edu/chemistry/132%20Lab/Exp%209--Solubility%20of%20Potassium%20Bitartrate.pdf (accessed 24 Jun 2020).