LABORATORY EXERCISE 7: Baking Powder Stoichiometry

PART I: Memo to Lab Groups

Consumer Research, Inc.Food Quality SectionWashington, D.C.

TO: GenChemCo - Colorado Mountain CollegeGlenwood Springs, CO Re: Analysis of three brands of baking powder (using stoichiometry)

As you know, the main active ingredient in baking powder is sodium bicarbonate. When it decomposes, carbon dioxide is released which makes the dough rise. In the laboratory, we can release carbon dioxide from sodium bicarbonate through the following reaction: Sodium bicarbonate reacts with hydrochloric acid to form sodium chloride, water and carbon dioxide. Using your experience with stoichiometry, we would like you to examine the enclosed three brands of baking powder and determine their respective sodium bicarbonate content.
Please, rank the brands with regards to their sodium bicarbonate content from highest to lowest, and compare the sodium bicarbonate content with price to determine which brand is the best buy. We expect to include your results in the next edition of "Best Values in Baking Powder."
We are looking forward to the results of your study.
Sincerely yours,
R. Meckelsburger
Director
Food Research Department

PART II: InterLab Memo

GenChemCo IndustriesCOLORADO MOUNTAIN COLLEGE

InterLab Memo:

As you can see from the attached letter, our group was asked to analyze and rank three brands of baking powder.
I would like the class as a whole to brainstorm on the following ideas:
1) How can we determine the mass of sodium bicarbonate (NaHCO3) in the baking powder based on our knowledge of stoichiometry (and the reaction provided by Consumer Research, Inc),
NaHCO3 + (inert components) + HCl --> NaCl + inert components + H2O + CO2
2) How can we calculate the strength and amount of HCl needed. Remember, we should use excess HCl.
3) How should we design our experimental procedure to perform the desired analyses.
4) Brands of Baking Powder Used: Calumet $ 1.39/7 ox; Clabber Girl $ 1.19/10 oz; Red Star $ 1.97/10 oz.
5) Remember that CO2 is heavier than air.
Each group will need to conduct the analysis of one of the baking powder brands and share their data with the other groups so that each group can determine their own ranking and identify the "best buy".
Each work-group will submit a report (due two weeks from today) which should include the following sections:
1. Initial Working Hypothesis. (Include all hypotheses you plan to test)
2. Initial Working Plan. (Include specific procedures you use)
3. Your Data.
---Please show ALL measurements and calculations of your groups share of the project.
4. Analysis of the Data
---Does the data support your hypothesis? Why? Why not?
5. Further Steps Taken.
---Did you do anything beyond your initial working plan? Why? What did you find?
6. A Letter of Response.
---Each group should submit a response directed to the client outlining what you did, what you found, and how this addresses the questions proposed by the client.
ADDITIONAL QUESTION: 1. Explain in one or two paragraphs how this lab exercise can be used to demonstrate the "Scientific Method"