Tuesday, October 4, 2011
Tues-Day 1
AP Chem - we continued stoichiometry in our new unit that focuses on solutions. In order to calculate the number of moles of reactants or products in solutions, we typically will have to use the concentration and volume data about the solutions.
We saw how to properly prepare and/or dilute a solution in a "volumetric flask".
We looked at the "trick" question (really just a question that requires some thought i.e. a good question)
involving a saturated solution of a salt, and noting that the CONCENTRATION of dissolved solute does not change as solvent evaporates from the open solution container; naturally, the quantity of dissolved solute proportionally decreases via precipitation as the quantity of solvent decreases via vaporization.
Basically, the molarity of a saturated solution does not change as solvent evaporates because some solute precipitates out at the same time; otherwise the solution would become "beyond saturated", which does not normally happen in any stable solution.
We will be balancing equations by mass AND charge in this unit that contains many REDOX reactions that occur in solution.
We saw how to properly prepare and/or dilute a solution in a "volumetric flask".
We looked at the "trick" question (really just a question that requires some thought i.e. a good question)
involving a saturated solution of a salt, and noting that the CONCENTRATION of dissolved solute does not change as solvent evaporates from the open solution container; naturally, the quantity of dissolved solute proportionally decreases via precipitation as the quantity of solvent decreases via vaporization.
Basically, the molarity of a saturated solution does not change as solvent evaporates because some solute precipitates out at the same time; otherwise the solution would become "beyond saturated", which does not normally happen in any stable solution.
We will be balancing equations by mass AND charge in this unit that contains many REDOX reactions that occur in solution.
Bio - did some Biochem review, focusing on the main problems that I saw in the hw questions.
Posted, on Edline, the answers to our in-class practice test.
Study hard; good luck tomorrow!# posted by C @ 10:38 PM 
