Monday, March 16, 2009
Mon-Day 2
AP Chem- NOTE: because we did not yet cover acid-base indicator selection in titrations, the hw questions involving such selection/calculation can be omitted.
Finished our quantitative titration of a weak acid by a strong base; the equivalence point pH calculation involves the most steps because we separated the events into the neutralization of the acid by the added titrant base (SRFC TABLE) during which the solution volume changes and then the back hydrolysis of water by the conjugate A- (ICE TABLE).
We saw that, JUST barely past the equivalence point (about 1.oo mL past), there is a drastic increase in pH because there is practically no more HA to react with the added base so the effect is practically the same as adding strong base to WATER.
The limiting/final pH is just due to the given initial (and ultimately final/limiting) concentration of the titrant/hydroxide i.e. just take the negative log of its concentration to get the pOH.
We then did the same routine but with a weak base titration by a strong acid; we will finish that up tomorrow after a brief descriptive chem quiz:
Possible reactions tested-
1. any of the four gas forming reactions
2. double replacement - with precipitation or acid-base neutralization
3. redox- cationic or anionic single replacement
4. Lewis acid-base: metal oxide with water, non-metal oxide with water, metal-ligand complex, boron compound reactions
5. organic reaction types: redox/combustion, substitution, addition, esterification
6. synthesis/redox- metal + non-metal forms a salt
Bio 6- reviewed the mechanism/sources of variety in meiosis I and the finished with meiosis II.
We noted that the sources of genetic variation/recombination occur mainly during PROPHASE I (crossing over of parts of homologous pairs of chromosomes during synapsis) and during METAPHASE I (each homologous pair lines up double file) INDEPENDENTLY of all other homologous pairs and can line up in either order (right-left or left-right).
The other major source of genetic recombination/variety occurs when the egg and sperm unite to form a genetically unique individual (the sperm and egg typically have many alleles that are not the same and they combine to give the individual a unique set of traits).
Bio 7/8- finished watching the animations of meiosis I and meiosis II. We then drew step-by-step to see that the sources of genetic variation/recombination occur mainly during PROPHASE I (crossing over of parts of homologous pairs of chromosomes during synapsis) and during METAPHASE I (each homologous pair lines up double file) INDEPENDENTLY of all other homologous pairs and can line up in either order (right-left or left-right).
The other major source of genetic recombination/variety occurs when the egg and sperm unite to form a genetically unique individual (the sperm and egg typically have many alleles that are not the same and they combine to give the individual a unique set of traits).
We did a first run of our gummy-worm meiosis simulation; I just wanted to get you used to manipulating the worms as chromosomes- we will discuss nondisjunction and then edit and refine the process on Wednesday.
Finished our quantitative titration of a weak acid by a strong base; the equivalence point pH calculation involves the most steps because we separated the events into the neutralization of the acid by the added titrant base (SRFC TABLE) during which the solution volume changes and then the back hydrolysis of water by the conjugate A- (ICE TABLE).
We saw that, JUST barely past the equivalence point (about 1.oo mL past), there is a drastic increase in pH because there is practically no more HA to react with the added base so the effect is practically the same as adding strong base to WATER.
The limiting/final pH is just due to the given initial (and ultimately final/limiting) concentration of the titrant/hydroxide i.e. just take the negative log of its concentration to get the pOH.
We then did the same routine but with a weak base titration by a strong acid; we will finish that up tomorrow after a brief descriptive chem quiz:
Possible reactions tested-
1. any of the four gas forming reactions
2. double replacement - with precipitation or acid-base neutralization
3. redox- cationic or anionic single replacement
4. Lewis acid-base: metal oxide with water, non-metal oxide with water, metal-ligand complex, boron compound reactions
5. organic reaction types: redox/combustion, substitution, addition, esterification
6. synthesis/redox- metal + non-metal forms a salt
Bio 6- reviewed the mechanism/sources of variety in meiosis I and the finished with meiosis II.
We noted that the sources of genetic variation/recombination occur mainly during PROPHASE I (crossing over of parts of homologous pairs of chromosomes during synapsis) and during METAPHASE I (each homologous pair lines up double file) INDEPENDENTLY of all other homologous pairs and can line up in either order (right-left or left-right).
The other major source of genetic recombination/variety occurs when the egg and sperm unite to form a genetically unique individual (the sperm and egg typically have many alleles that are not the same and they combine to give the individual a unique set of traits).
Bio 7/8- finished watching the animations of meiosis I and meiosis II. We then drew step-by-step to see that the sources of genetic variation/recombination occur mainly during PROPHASE I (crossing over of parts of homologous pairs of chromosomes during synapsis) and during METAPHASE I (each homologous pair lines up double file) INDEPENDENTLY of all other homologous pairs and can line up in either order (right-left or left-right).
The other major source of genetic recombination/variety occurs when the egg and sperm unite to form a genetically unique individual (the sperm and egg typically have many alleles that are not the same and they combine to give the individual a unique set of traits).
We did a first run of our gummy-worm meiosis simulation; I just wanted to get you used to manipulating the worms as chromosomes- we will discuss nondisjunction and then edit and refine the process on Wednesday.
# posted by C @ 10:36 AM 
