Tuesday, March 20, 2007
Tues-Day 3
AP: we did a "suppression of dissociation via common ion" problem complete with comparison of % dissociation with and without the common ion in solution. We then did a "competitive equilibrium" problem in which two or more cations are in solution, one of which is "selectively" precipitated by added just enough of a salt that has an anion that will more readily form a precipitate with one of the cations in solution. We then did the common follow-up question about the % of the mostly precipitated ion that is still in solution JUST WHEN the other cation is ABOUT to precipitate.
We then moved on to discuss/explain which salts can have their solubility influenced by the pH of the solution. ALL SALTS will become more soluble in acidic solution EXCEPT: ALL chlorides, bromide, iodides, nitrates, and perchlorates; END OF LIST! Notice the connection: these ions are all the conjugate "bases" of strong acids.
p.s. hydrogen sulfate salts can be made more soluble in BASIC solutions because the HSO4- will react with the excess OH-.
Honors: we finished general characteristics of solids, liquids, and gases; then we began our final math of chem subtopic: heating and cooling curves. More on that on Thursday. Tomorrow is the Math of Chem 3 exam which focuses on the behavior and laws of gases.
Follow the test-taking advice that was listed after the last test so that you do not make careless errors tomorrow. Make sure that EVERYTHING is explicitly labelled.
Regents: we had our Gas Laws exam today. I will return them by Thursday. That was probably the last test of the third quarter so you can calculate your third quarter average before the weekend.
We then moved on to discuss/explain which salts can have their solubility influenced by the pH of the solution. ALL SALTS will become more soluble in acidic solution EXCEPT: ALL chlorides, bromide, iodides, nitrates, and perchlorates; END OF LIST! Notice the connection: these ions are all the conjugate "bases" of strong acids.
p.s. hydrogen sulfate salts can be made more soluble in BASIC solutions because the HSO4- will react with the excess OH-.
Honors: we finished general characteristics of solids, liquids, and gases; then we began our final math of chem subtopic: heating and cooling curves. More on that on Thursday. Tomorrow is the Math of Chem 3 exam which focuses on the behavior and laws of gases.
Follow the test-taking advice that was listed after the last test so that you do not make careless errors tomorrow. Make sure that EVERYTHING is explicitly labelled.
Regents: we had our Gas Laws exam today. I will return them by Thursday. That was probably the last test of the third quarter so you can calculate your third quarter average before the weekend.
# posted by C @ 5:40 PM 
