Schedule for Second Summer Session

Date Day Topics
7/13MonDiscussed class syllabus.
7/14TueChapter 16 sections 10 and 11. Heating curves.
7/15WedEquilibrium is a dynamic process. Can be described 2 ways: (1) Kinetically. The rates of the 2 opposing processes (forward rxn and reverse rxn) are equal at equilibrium. (2> Thermodynamically. ΔG = 0. Free energy of the system is at a minimum. Vapor pressure is a manifestation of an equilibrium process between evaporation and condensation. Discussed the Claussius-Clapeyron Equation which compares 2 vapor pressures at 2 different temperatures. Also discussed phase diagrams and how to interpret them.
7/16ThuChapter 17 - dissolution of solids into solution. Thermodynamics of dissolution. How the crystal lattice energy and the enthalpy of hydration combine to give the enthalpy of solution. Introduced Colligative properties.
7/17FriWent over more on solubility. Likes dissolve likes. Solubility of gases in water. Temperature dependence of solubility. Henry's Law. Colligative properties. van Hoff factor - we will only consider complete ionization of salts. Quick Exam overview - its 20 questions.
7/20MonEXAM 1
7/21TueChapter 6 - chemical equilibrium. The mass action expression.
7/22WedCloser look at Q vs K relationships. Le Chatlier's Principle - system at equil will respond to stress so as to relieve the stress. "Stress" is moving Q away from K by changing conc or press. You can move K away from Q by changing the T. Showed how to set up ICE Tables for solving equilibrium questions. Showed that you can write equilibrium constants with concentration terms (Kc) or with pressures (Kp).
7/23ThuThe relationship of Kp and Kc. Temperature dependence of K. Finish chapter 6 and intro Chapter 7 - Acid/Base equilibria.
7/24FriChapter 7 solving pH problems (Type 1)
7/27MonChapter 7 - finish - Exam 2 recap of material
7/28TueEXAM 2
7/29WedChapter 8. Defined what a buffer is. These are Type 2 problems in my way of thinking (and on my helpsheets). Also defined fraction of species and how the pH of a solution affects the RATIO of the conjugates. Showed the solution to the ICE tables for a buffer problem (type2). Took -log and got the Henderson-Hasselbalch equation for buffers.
7/30ThuShowed how to calculate points on a pH curve or a titration curve. How do you know when to stop a titration? When the indicator changes color (aka: the end point). Indicators are just special weak acids (or bases) themselves that happen to have different colors for the two conjugates. All indicators transition from one visual color to the other through about 2 pH units which are centered on the pKa value. PICK an indicator that changes color at the pH where you want to stop (this should be the equivalence point).
7/31FriFinished up titrations and indicators. Introduced Solubility equilibria. Now we use Ksp for our equil constant. You can calculate the molar solubility (x) from Ksp. The formula varies with the type of ratio salt you have. 1:1, 1:2, 1:3, 2:3 salts each have their own "formula" to solve to get x. Solubilities come in many different units - we need MOLAR solubility to go into the solubility product equation. "ppm" is parts-per-million which you need to switch to mg/L for aqueous solutions - then switch to mol/L for the solving for Ksp part.
8/3MonMore Chapter 8 on solubility equilibria. Showed that you can still calculate Q and compare to K, then predict the direction of the shift in equilibria. Remember that a LEFT shift in this section corresponds to a precipitation reaction. Showed the concept and the way a fractional precipitation works (called selective precipitation in your book). Showed how to predict the order of precipitation. Showed how you can dissolve hydroxide salts by adding acid. Introduced complex ions.
8/4TueFinishing Chapter 8 - more details on complex ion formation and dissociation. Plus some more dissolving precipitates. Will discuss exam also.
8/5WedEXAM 3
8/6ThuChapter 11. "Reviewed" redox reactions. Defined reduction and oxidation. LEO says GER. 1/2 rxns are written and tabulated as reductions - the TABLE you get is called a Standard Potential table. The potentials are given in volts and volts is really just a measure of the tendency of a reaction to want to go forward. Big + potentials want to really go forward (large -ΔG value). Negative potentials (-E) are NON-spontaneous as written. The overall potential for a redox reaction is just the reduction potential plus the oxidation potential. So this is just the difference between two numbers off the standard potential table. Which one do you substract from which? Leave the reduction alone (straight off the table), "flip" the reaction that is to be the oxidation. That "flip" puts the electrons on the RIGHT side of the equation (which will cancel out with the ones on the left in the other rxn) AND changes the sign of the potential. That new "flipped" potential is an oxidation potential.
8/7FriMore on cell notation. Non-standard conditions - the Nernst Equation. Electrolysis calculations using the faraday constant: I(t)/n(F) = mol of stuff.
8/10MonRecap of electrochem up to now. Showed my "cartoony" looking Electrochemistry help sheet. Talked about batteries, types, examples. Told you to know the reactions for a lead-storage battery. Introduced chemical reaction rates, how we write a reaction rate and what the units are.
8/11TueHow to write the rate law. How to use the Method of Initial Rates to find the rate law. This is basically solving a table full of concentration and rate data. Then did an integration of a rate law and got the integrated rate law equations for 1st, 2nd, and zero order reactions. Defined 1/2 life and how to calculate it.
8/12WedTemp dependence of rate. Reaction mechanisms.
8/13ThuEXAM 4
8/14FriCOOL Chemistry DEMOS!! Come one - come all. Course Overview - Final Exam discussion
8/17MonFINAL EXAM