In Chemistry this block, we have been studying physical chemistry through a combination of interactive lecture/discussion and problem solving.

We began the block with intermolecular forces, a topic we started last block, and spent more time thinking about how they relate to phase transitions and transition temperatures such as boiling points. This fit well with a deeper look at gases, including interpreting several types of experimental evidence, since intermolecular forces are a main cause of non-ideal gas behavior.

Next, we studied kinetics, the field that deals with rates (and often mechanisms) of chemical reactions. First we introduced some approaches to determining rates and rate laws. Then I told students that they needed to come up with an experimental plan to determine the rate and rate law for the bleaching of crystal violet dye by sodium hydroxide using our spectrophotometers. For homework, students thought about three questions related to the lab planning: essentially, I suggested some of the planning considerations and asked what they would do. In class, we talked through it and combined the students’ ideas into a functional plan. We spent the next week doing the lab. In the first session, students figured out the details, and in the second, they knew what they were doing and were able to quickly collect the data they needed.

Finally, in the last two weeks we are studying thermodynamics. We reviewed some thermochemistry from Block 1, introduced entropy and free energy, debated the most important part of a power plant, and grappled with conceptual questions that are difficult for both the students and me. We will finish developing these ideas about free energy, equilibrium, and work during Build Week, when we study electrochemistry.

-- Emily Eames