LABORATORY EXERCISE 7: Baking Powder Stoichiometry
PART I: Memo to Lab Groups
Consumer Research, Inc.
Food Quality Section
Washington, D.C.
TO: GenChemCo - Colorado Mountain College
Glenwood 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 Industries
COLORADO 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"
All contents copyrighted (c) 1998
Peter Jeschofnig, Ph.D., Professor of Science, Colorado Mountain College
All Rights reserved