Monday, February 12, 2007
Monday, Day 1
We started our very abbreviated week (which may be further truncated by snow on Wednesday: good for vacation; bad for cramming all of the required material in an ever-shortening year).
AP: we did problems involving predicting the direction of a Bronsted acid- base reaction as it goes towards the equilibrium state. We took into account the relative strengths of the conjugate acids and conjugate bases in the reaction and then made the logical prediction that the reaction would always proceed from "strong" to "weak", i.e. higher Ka and Kb value side to the lower Ka and Kb value side.
We also proved that, given the Ka of an acid, the Kb of the acid's conjugate base is Kw/Ka. We showed this from combining the two ionization equations to show that they add up to the ionization of water equation, which has the K = 10^-14 at 298 K.
By the same logic, given the Kb of a base, the Ka of the base's conjugate acid is Kw/Kb.
Tomorrow's lesson is REEE-diculously important. We will be doing equilibrium concentration calculations for weak acids and bases. Remember, since these substances do NOT ionize 100% at equilibrium, you will need to set up an ICE table (for now) to calculate the final equilibrium concentration of H+ from which you will also know the pH. Eventually, you will see the pattern and this will be a 5 SECOND PROBLEM (no DOUBT).
Honors: we revisited and summarized stoichiometry problems of each type and then we moved on to the next Math of Chem topic: Molarity and the "strength"/concentrations of solutions.
So far, the first math of chem tests look generally GREAT... not just good but GREAT. I am pleasantly surprised how well some of you followed the methods used in class, which automatically help you to avoid errors; in turn, there are two 100's and several high 90's already. That is not only without ANY grade inflation, curve, boost but also with extreme prejudice and scrutiny for the slightest errors that I warned about regarding units, formulas, and sig figs. There is hope!
Regents: we had our first Math of Chem exam. Results pending...
Now the results are in:
Class AVERAGE: 67...absolutely PATHETIC! Keep up with the lack of extra help (only THREE people all week! almost NO questions from anybody at anytime even though everything on this test could NOT have been more CLEARLY spelled out!), ignoring the homework, not taking notes, not downloading the notes and you will get what you are preparing for: summer school. That is not a threat, just a sad fact. The Regents exam is NOT EASIER than the exams you have been taking. The next test will involve similar math skills and an even greater variety of problems. Most of you will fail that test also if you do not drastically deviate from your poor work ethic. I can't possibly be more available to answer your questions and I am getting very little in return from most of you. How about putting in some effort to make my effort worthwhile?
AP: we did problems involving predicting the direction of a Bronsted acid- base reaction as it goes towards the equilibrium state. We took into account the relative strengths of the conjugate acids and conjugate bases in the reaction and then made the logical prediction that the reaction would always proceed from "strong" to "weak", i.e. higher Ka and Kb value side to the lower Ka and Kb value side.
We also proved that, given the Ka of an acid, the Kb of the acid's conjugate base is Kw/Ka. We showed this from combining the two ionization equations to show that they add up to the ionization of water equation, which has the K = 10^-14 at 298 K.
By the same logic, given the Kb of a base, the Ka of the base's conjugate acid is Kw/Kb.
Tomorrow's lesson is REEE-diculously important. We will be doing equilibrium concentration calculations for weak acids and bases. Remember, since these substances do NOT ionize 100% at equilibrium, you will need to set up an ICE table (for now) to calculate the final equilibrium concentration of H+ from which you will also know the pH. Eventually, you will see the pattern and this will be a 5 SECOND PROBLEM (no DOUBT).
Honors: we revisited and summarized stoichiometry problems of each type and then we moved on to the next Math of Chem topic: Molarity and the "strength"/concentrations of solutions.
So far, the first math of chem tests look generally GREAT... not just good but GREAT. I am pleasantly surprised how well some of you followed the methods used in class, which automatically help you to avoid errors; in turn, there are two 100's and several high 90's already. That is not only without ANY grade inflation, curve, boost but also with extreme prejudice and scrutiny for the slightest errors that I warned about regarding units, formulas, and sig figs. There is hope!
Regents: we had our first Math of Chem exam. Results pending...
Now the results are in:
Class AVERAGE: 67...absolutely PATHETIC! Keep up with the lack of extra help (only THREE people all week! almost NO questions from anybody at anytime even though everything on this test could NOT have been more CLEARLY spelled out!), ignoring the homework, not taking notes, not downloading the notes and you will get what you are preparing for: summer school. That is not a threat, just a sad fact. The Regents exam is NOT EASIER than the exams you have been taking. The next test will involve similar math skills and an even greater variety of problems. Most of you will fail that test also if you do not drastically deviate from your poor work ethic. I can't possibly be more available to answer your questions and I am getting very little in return from most of you. How about putting in some effort to make my effort worthwhile?
# posted by C @ 11:44 AM 
