Tuesday, March 24, 2009
Tues-Day 2
AP Chem- ATTENTION: THERE WILL BE A DESCRIPTIVE CHEM QUIZ DURING WEDNESDAY'S CLASS.
There are a number of Ksp/Salt Equilibria files posted so that you can practice a lot for the next exam.
We continued our salt equilibrium problem by calculating the "percent precipitation", which is just the percent formula. We divide the final concentration of a given ion still in solution (from the ICE table) by the INITIAL concentration of that ion (JUST AFTER the solutions were mixed BUT unreacted!); we multiply that fraction by 100 to get the percentage.
We then did our first (of two) problems on "selective precipitation". These problems are very difficult especially IF you do not draw out the potential reactions that are occurring in solution!
The problem involves two "competing" equilibria; you will be asked to calculate whether the ions of one element can be SELECTIVELY removed/precipitated from solution WHILE the ions of another element MOSTLY/COMPLETELY remain in solution.
You first must find the TWO DIFFERENT concentrations of an ion (assuming two possible precipitates) that can be added to solution that will JUST begin to cause precipitation of each ion. Whichever REQUIRED concentration is LOWER will be for the LESS SOLUBLE PRECIPITATE.
THEN, at the HIGHER concentration of added ion to JUST BEGIN to cause precipitation of the MORE soluble salt, the concentration of the ion that has ALREADY been precipitating is calculated by using its precipitate's Ksp expression.
Finally, we calculate whether one of the ions is "completely precipitated" at the point at which the OTHER ion JUST are ABOUT TO precipitate.
Bio 6- we defined Mendel's Law of Dominance (due to the suppression of the translation of one allele by the other allele on a homologous chromosome) and Law of Segregation (really due to anaphase I and II of meiosis). We saw that gamete formation causes segregation of alleles that can be re-combined during fertilization so that traits that do not show up in a given generation (due to DOMINANT/recessive alleles) WILL show up in the next generation.
We showed the modern understanding of Mendel's laws, which are caused by what occurs to chromosomes/alleles during meiosis/gamete formation. We saw that Punnet squares really just show the TWO possible gametes formed with respect to a given trait and how those gametes combine to form offspring with a particular combination of alleles for a given trait.
Bio 7/8 - we finished discussing Mendel's scientific process that led to his discoveries of patterns of inheritance. We defined Mendel's Law of Dominance (due to the suppression of the translation of one allele by the other allele on a homologous chromosome) and Law of Segregation (really due to anaphase I and II of meiosis). We saw that gamete formation causes segregation of alleles that can be re-combined during fertilization so that traits that do not show up in a given generation (due to DOMINANT/recessive alleles) WILL show up in the next generation. We showed the modern understanding of Mendel's laws, which are caused by what occurs to chromosomes/alleles during meiosis/gamete formation. We saw that Punnet squares really just show the TWO possible gametes formed with respect to a given trait and how those gametes combine to form offspring with a particular combination of alleles for a given trait.
There are a number of Ksp/Salt Equilibria files posted so that you can practice a lot for the next exam.
We continued our salt equilibrium problem by calculating the "percent precipitation", which is just the percent formula. We divide the final concentration of a given ion still in solution (from the ICE table) by the INITIAL concentration of that ion (JUST AFTER the solutions were mixed BUT unreacted!); we multiply that fraction by 100 to get the percentage.
We then did our first (of two) problems on "selective precipitation". These problems are very difficult especially IF you do not draw out the potential reactions that are occurring in solution!
The problem involves two "competing" equilibria; you will be asked to calculate whether the ions of one element can be SELECTIVELY removed/precipitated from solution WHILE the ions of another element MOSTLY/COMPLETELY remain in solution.
You first must find the TWO DIFFERENT concentrations of an ion (assuming two possible precipitates) that can be added to solution that will JUST begin to cause precipitation of each ion. Whichever REQUIRED concentration is LOWER will be for the LESS SOLUBLE PRECIPITATE.
THEN, at the HIGHER concentration of added ion to JUST BEGIN to cause precipitation of the MORE soluble salt, the concentration of the ion that has ALREADY been precipitating is calculated by using its precipitate's Ksp expression.
Finally, we calculate whether one of the ions is "completely precipitated" at the point at which the OTHER ion JUST are ABOUT TO precipitate.
Bio 6- we defined Mendel's Law of Dominance (due to the suppression of the translation of one allele by the other allele on a homologous chromosome) and Law of Segregation (really due to anaphase I and II of meiosis). We saw that gamete formation causes segregation of alleles that can be re-combined during fertilization so that traits that do not show up in a given generation (due to DOMINANT/recessive alleles) WILL show up in the next generation.
We showed the modern understanding of Mendel's laws, which are caused by what occurs to chromosomes/alleles during meiosis/gamete formation. We saw that Punnet squares really just show the TWO possible gametes formed with respect to a given trait and how those gametes combine to form offspring with a particular combination of alleles for a given trait.
Bio 7/8 - we finished discussing Mendel's scientific process that led to his discoveries of patterns of inheritance. We defined Mendel's Law of Dominance (due to the suppression of the translation of one allele by the other allele on a homologous chromosome) and Law of Segregation (really due to anaphase I and II of meiosis). We saw that gamete formation causes segregation of alleles that can be re-combined during fertilization so that traits that do not show up in a given generation (due to DOMINANT/recessive alleles) WILL show up in the next generation. We showed the modern understanding of Mendel's laws, which are caused by what occurs to chromosomes/alleles during meiosis/gamete formation. We saw that Punnet squares really just show the TWO possible gametes formed with respect to a given trait and how those gametes combine to form offspring with a particular combination of alleles for a given trait.
# posted by C @ 10:46 AM 
