Big Ideas in AP Chemistry: Connections Among Thermodynamics and Equilibrium

revamping a unit

I have a confession: thermodynamics is not my strong suit. The data set I got from the College Board confirmed my lack of confidence in the summer of 2015. With the hope of improvements, I spent some time revamping my thermo unit and I implemented it near the end of last school year. I will share an activity that I feel was quite formative for students and for me in making connections among thermodynamic principles and equilibrium.

 

As I restructured the thermo unit, I really wanted to help students make connections among the many abstract ideas they had learned and were still struggling with. I was browsing through chemistry teaching materials from the Royal Society of Chemistry and found this gem: http://www.rsc.org/learn-chemistry/resource/res00000651/thermodynamics

 

The prompt is short and elegant:

I gave my student giant whiteboards and sent them off to work and think. There were 20 students in the class and they were in groups of 2-3. After about 15-20 minutes, I stopped them off and we shared out our thoughts in a “board meeting” (a socratic seminar with whiteboards). To begin, I had them go around and share their observations of the work presented around the room. What are similarities? Differences? That alone got the conversation flowing.

 

There, quite a few misconceptions came out and we could tackle them. Many first tried to calculate the change in Gibb’s free energy and realized that they weren’t sure which formula to use (Big student question: Was this at standard state?). Some groups had found the change in entropy but had different signs (positive or negative). Students and I had to grapple with why the change in entropy was positive and talked about solvation effects. In hindsight, the calculations themselves were really easy, but the process of starting so small and getting quite deep was so amazing. Everyone had something to contribute to the board meeting, and I tried to make a point that even the groups that had inconsistencies in logic helped us deepen the collective understanding even more. Students had to grapple and convince each other of the logic, and authentically consider different perspectives. My students and I found much more success with thermodynamics content last year.

Thanks for reading. Do you have any gems in your thermodynamics unit you’d like to throw out there and share?

Note #1: If such an open ended activity is intimidating to you as it was to me, the link has a variety of sample possible methods to tackle this problem.
Note #2: Facilitating socratic seminars is difficult (or at least for me). It gets better with practice and norm setting!