Thursday, February 26, 2009
Thurs-Day 1
AP Chem- used quantitative Ka values to predict the favored side of a Bronsted acid-base reaction.
The side that has the higher value Ka acid (will also have the higher value Kb base) and will form more of the substances on the other side of the equation.
We then launched into weak acid equilibrium problems involving calculation of pH, Ka, or various species concentrations at equilibrium.
We discovered the NOTORIOUSLY important "approximation" method in which the amount of acid ionized is negligible RELATIVE TO the initial concentration of the acid whenever there is a large (about a thousand or five hundred times) difference between the Ka value and the initial acid concentration. Under these conditions, one may NEGLECT the amount of acid ionized and subtracted from the original acid concentration when doing the Ka value calculation.
This is GENERALLY a legitimate approximation and will get you the SAME two sig fig pH value as doing the "exact" calculator method whenever:
1. Ka is very small (about 10^-5 or smaller) and
2. the initial acid concentration is 0.10 M or higher (i.e. relatively concentrated acid).
Remember, as we saw on the graph, ONLY in very DILUTE solutions is the %ionization of the weak acid very significant, so, in concentrated solutions, a very low (less than 5%) percentage of the weak acid ionizes (i.e. a negligible amount).
We then saw the reason that ammonia and amines are Bronsted bases (the lone pair of electrons on the N). We did an equilibrium pH calculation of a given concentration aqueous solution of an amine by setting up an ICE table, as we did for the acid equilibrium problems.
Bio 6/7 - we reviewed the locations of the central and peripheral nervous system and then discussed specific examples of actions or behaviors that are controlled by the somatic and autonomic nervous systems. We showed the opposite effects of a sympathetic autonomic response and a parasympathetic autonomic response.
We then looked at the structure of the brain and discussed the function of its three broad main parts: the cerebrum, the cerebellum, and the medulla oblongata.
We then did a review worksheet for reinforcement.
We briefly discussed four disorders/diseases of the brain and/or nervous system.
We finished our "Making Connections" lab project.
Bio 8- we discussed the mechanism and did an example of a "reflex arc". We then discussed the structure and function of the parts of the central nervous system, starting with the brain.
The side that has the higher value Ka acid (will also have the higher value Kb base) and will form more of the substances on the other side of the equation.
We then launched into weak acid equilibrium problems involving calculation of pH, Ka, or various species concentrations at equilibrium.
We discovered the NOTORIOUSLY important "approximation" method in which the amount of acid ionized is negligible RELATIVE TO the initial concentration of the acid whenever there is a large (about a thousand or five hundred times) difference between the Ka value and the initial acid concentration. Under these conditions, one may NEGLECT the amount of acid ionized and subtracted from the original acid concentration when doing the Ka value calculation.
This is GENERALLY a legitimate approximation and will get you the SAME two sig fig pH value as doing the "exact" calculator method whenever:
1. Ka is very small (about 10^-5 or smaller) and
2. the initial acid concentration is 0.10 M or higher (i.e. relatively concentrated acid).
Remember, as we saw on the graph, ONLY in very DILUTE solutions is the %ionization of the weak acid very significant, so, in concentrated solutions, a very low (less than 5%) percentage of the weak acid ionizes (i.e. a negligible amount).
We then saw the reason that ammonia and amines are Bronsted bases (the lone pair of electrons on the N). We did an equilibrium pH calculation of a given concentration aqueous solution of an amine by setting up an ICE table, as we did for the acid equilibrium problems.
Bio 6/7 - we reviewed the locations of the central and peripheral nervous system and then discussed specific examples of actions or behaviors that are controlled by the somatic and autonomic nervous systems. We showed the opposite effects of a sympathetic autonomic response and a parasympathetic autonomic response.
We then looked at the structure of the brain and discussed the function of its three broad main parts: the cerebrum, the cerebellum, and the medulla oblongata.
We then did a review worksheet for reinforcement.
We briefly discussed four disorders/diseases of the brain and/or nervous system.
We finished our "Making Connections" lab project.
Bio 8- we discussed the mechanism and did an example of a "reflex arc". We then discussed the structure and function of the parts of the central nervous system, starting with the brain.
# posted by C @ 2:59 PM 
