|
Unit 5.2 Stoichiometry
Stoichiometry, always a difficult concept for chemistry
students, can be introduced by familiar processes like baking.
In this segment students bake cakes by varying the proportion
of ingredients.
Video program cues: 4:45-15:20
Designing chemicals
"We, as organic chemists, are molecular
engineers. Our tools, instead of wood and steel and hammers
and nails, are atoms and molecules. And we have learned
how to put these together to build molecules… so when
we design, it’s no different than when an architect
designs. You ask yourself which atoms you want placed where,
what the ultimate architecture of the molecule is, and then
you design a route to build it. Then you…actually make
the molecule."
Dr. Kevin Chapmann
Medicinal Research Chemist
Links
Reading
Dagani, R(1999)' Green Winners, 'Chemical & Engineering
News, Vol. 77, No. 27, pp: 30-32.
The tools of chemistry
Teachers’ forum
"It is all new to them. It is
novel for them to think that cooking has anything to do
with chemistry."
Caryn Galatis
Thomas Edison High School, Virginia
"Here’s a challenge that we have
then: If we are going to talk about household chemicals
as a basis for their understanding of chemistry, we also
have to teach students how to apply some of the techniques
and tools that chemists use in the lab to working with these
materials. So that is how we begin to quantify and measure
and compare things, and this really is a challenge because
we don’t find too much help in the books and lab manuals
that we get. What we are trying to do is to use everyday
substances with mathematics and modern techniques that traditionally
chemists use."
Dr. Leslie Pierce
Thomas Edison High School, Virginia
Links
Reading
Gimenez, S.M.N.; Yabe, M.J.S.; Kondo, N.K.; Mourino, R.O.;
Moura, G.C.R.(2000)' Linking the Lab Experience with Everyday
Life: An Analytical Chemistry Experiment for Agronomy Students,
'Journal of Chemical Education, Vol. 77, pp: 181-182.
Stoichiometry
Students’ ideas
"I’m guessing something to do with
how stuff works, I don’t know."
"Mathematical terms? I don’t know."
"Sounds like something you eat for dinner."
Links
Reading
Ault, A. (2001)' How to Say How Much: Amounts and Stoichiometry,
'Journal of Chemical Education, Vol. 78, No. 10,
pp: 1347-1349.
The stoichiometry of cooking
Lisa Morine teaches stoichiometry using the chemical composition
of the ingredients of cakes as an analogy.
Activity
Links
- An extensive site from the University
of Utah on food science.
- A unit
converter for the kitchen. Will convert SI and English
units. Convenient for anyone adapting a recipe for class
use.
Readings
JCE Editorial Staff (2000)' Flat as a Pancake? Exploring
Rising in Baked Goods, 'Journal of Chemical Education,
Vol. 77, No. 10, pp: 1264A-1264B and supplements1-3
McCamish, M. (1987)' The Rise of Self-Rising Flour: A Recipe
for Success, 'Journal of Chemical Education, Vol.
64, pp:710.
| Proceed
to Unit 5.3 |
 |
|
