"We continued our discussion of Equilibrium Chemistry. We reviewed the main concepts we had established before, and developed an understanding of the 2nd Law of Thermodynamics. We then reviewed the Gibbs function, and introduced a new equation that related it to the balance of Q and K-eq. From there, we derived the equation for the standard free energy change by discussing the difference between STP and standard conditions. Next, we moved on to solution equilibria as our first specific case of applying equilibrium to various types of chemical systems. I showed the parallels between K-eq and K-sp, and those between Q and IP. We discussed molar solubility, and showed how to use a "common pathway" of problem-solving to simplify the process of relating the K-sp and the molar solubility, applying it to two questions, one of which incorporated the Common Ion Effect.
The student did not correctly remember what a supersaturated solution was, and therefore had some difficulty grasping how saturation was the equilibrium condition for the dissociation of ionic salts. A discussion of how to prepare a supersaturated solution reminded her of the correct definition, and the discussion became smoother from there. She did successfully internalize many, if not all, the main points of our discussion about the nature of equilibrium. Mostly, it was the definition of thermodynamic terms, so I reminded her that I had already uploaded a document for her which listed them all.
She will take a full-length practice test this weekend, which I will review Sunday night to see if there are themes in the questions she is getting wrong. She will abstract a topic list as well. In addition to those topics, we will pursue our discussion of equilibrium chemistry and apply it to acid-base systems. She has asked me to create a study schedule for her, and to export our whiteboards from the session. I will finish these tasks this weekend."