Thursday, January 29, 2009
Thurs-Day 2
AP Chem- be sure to keep apace of the descriptive chemistry practice problem sets; we were going to have a descriptive chem quiz tomorrow but I will give that on Monday.
We reviewed how to write a rate law for an elementary step of a proposed mechanism; we then saw how to relate the EXPERIMENTALLY DETERMINED rate law to the expected rate law from the SLOW STEP of a proposed mechanism. However, when there is not a direct match between the proposed and expected rate laws, one must SUBSTITUTE for one of the reactants (the one that is NOT in the experimentally determined rate law) by solving for that reactant in a prior FAST elementary step that has reached EQUILIBRIUM i.e. the forward and reverse rates are equal in that step. We applied this method to two problems to see that the proposed mechanism rate law actually does agree with the experimentally determined rate law.
We then informally saw how rate laws are actually determined/inferred from the experimental data. Skill with exponents and multiplication is the main requirement!
Bio: PLEASE NOTE! Though we had no school yesterday AND even though there was a Math A Regents exam for most of the class, our UNIT EXAM on the circulatory, respiratory, and excretory systems is STILL ON MONDAY as decreed by the Biology Department.
We will cover the excretory system in its entirety on Friday. I will post the notes AND videos on Blackboard so that you can preview tomorrow's lesson and worksheets (especially if you are in Period 8 because we only have 40 minutes!).
The hw objectives are due tomorrow EXCEPT for the excretory system and the combined systems objectives, specifically objectives 9 through 13 will NOT be graded, though you should look at them before tomorrow.
I will post my complete answers to all objectives tomorrow afternoon so make sure that you study those answers as part of your preparation for Monday's exam.
We reviewed how to write a rate law for an elementary step of a proposed mechanism; we then saw how to relate the EXPERIMENTALLY DETERMINED rate law to the expected rate law from the SLOW STEP of a proposed mechanism. However, when there is not a direct match between the proposed and expected rate laws, one must SUBSTITUTE for one of the reactants (the one that is NOT in the experimentally determined rate law) by solving for that reactant in a prior FAST elementary step that has reached EQUILIBRIUM i.e. the forward and reverse rates are equal in that step. We applied this method to two problems to see that the proposed mechanism rate law actually does agree with the experimentally determined rate law.
We then informally saw how rate laws are actually determined/inferred from the experimental data. Skill with exponents and multiplication is the main requirement!
Bio: PLEASE NOTE! Though we had no school yesterday AND even though there was a Math A Regents exam for most of the class, our UNIT EXAM on the circulatory, respiratory, and excretory systems is STILL ON MONDAY as decreed by the Biology Department.
We will cover the excretory system in its entirety on Friday. I will post the notes AND videos on Blackboard so that you can preview tomorrow's lesson and worksheets (especially if you are in Period 8 because we only have 40 minutes!).
The hw objectives are due tomorrow EXCEPT for the excretory system and the combined systems objectives, specifically objectives 9 through 13 will NOT be graded, though you should look at them before tomorrow.
I will post my complete answers to all objectives tomorrow afternoon so make sure that you study those answers as part of your preparation for Monday's exam.
# posted by C @ 10:31 AM 
