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This in-class activity is designed to follow the linked lecture/demonstration on soapmaking. The soaps cure enough to be handled in 48 hours if kept warm, and the students can feel the difference in the canola/coconut oil soaps.
The calcuations go through the major reactions, functional groups, and physical properties of soap molecules, and ends with the calculation of molecular weight for a mixture of substances. This could be related to a later polymer unit.
I include "Team Cards" so that some of the calculations are divided into a class dataset that could be presented in the last 5-10 minutes of class.
For 2016, I will have students do more of calculations, and then report back to the class on their results in a subsequent class period; there was not enough time for the reporting last year.
| Attachment | Size |
|---|---|
| in class exercise on soap molecules | 301.99 KB |
| printable cards for dividing groups | 59.45 KB |
| updated exercise for 2016 | 235.85 KB |
1. Identify the major functional groups found in soap and used in soapmaking
2. Explain how soap works at the molecular level
3. Draw balanced chemical reactions for the soapmaking process
4. Calculate various metrics for soap and relate them to the soap’s properties
5. Compare different ways of calculating the molecular weight of soap and polymers
none
the students struggled with the MW calculations and I would appreciate input on how to change this to help them understand it better.
Evaluation
the exercises were evaluated according to the keys provided
This LO underwent a fairly significant update for Fall 2016. It covers the same material in much the same way, but now it is much more of a guided inquiry exercise (pre class) with in-class group calculations. I am uploading new versions (LOv2016) for you to look at and evaluate. Reading comes from Atkins, Jones, & Laverman, 7th ed, 2016.
Day 1 inclass was a powerpoint presentation reviewing organic chemistry and soap chemistry, followed by a demo as described previously.