Tuesday, February 06, 2007
Tuesday, Day 4
Regents: we applied the definition of the word "percent", which is (part divided by whole) times 100%, to percent composition (by mass) of each element in a given compound.
We then began our shortcut path to all mole to gram to molecule calculations via the "Magic Triangle", which simply relates how the number of moles of a given substance can be converted to the number of grams, molecules/ion/or atoms, or liters of gas of the given substance.
We will further develop that tomorrow.
Honors: we completed forwards AND backwards, a molecular formula to empirical formula to percent composition to empirical formula to molecular formula problem. As you practice these problems, you should double-check your work forwards and backwards until you know how to do these problems no matter what the starting point.
We then talked about Avogadro and the MOLAR VOLUME (number of LITERS per MOLE) of ANY gaseous substance (behaving ideally) at STP, which is 22.4 liters per mole.
We then completed the final vertex of the magic triangle which converts moles of a gaseous substance at STP to liters and vice-versa.
AP: we qualitatively explained Le Chatelier's Principle and then explained the much more detailed kinetics/particle-level explanation that OBVIATES the need for any kind of human conceptual shortcut principle; that is, we explained what is ACTUALLY occurring when a given stress is applied to a system that is already AT EQUILIBRIUM. Today, we covered (1) the stresses of inc/dec concentration or partial pressure of reactants or products and (2) inc/dec volume or total pressure on the system. Tomorrow, we will cover the stresses of adding an inert gas at constant volume (no effect) or at constant pressure (dilution/increasing volume effect); we will also cover the "stress" of adding a catalyst and the NON-EFFECT of adding ANY SOLIDS or LIQUIDS (one exception, though) or INC/DEC SURFACE AREA of a liquid or solid.
We then began our shortcut path to all mole to gram to molecule calculations via the "Magic Triangle", which simply relates how the number of moles of a given substance can be converted to the number of grams, molecules/ion/or atoms, or liters of gas of the given substance.
We will further develop that tomorrow.
Honors: we completed forwards AND backwards, a molecular formula to empirical formula to percent composition to empirical formula to molecular formula problem. As you practice these problems, you should double-check your work forwards and backwards until you know how to do these problems no matter what the starting point.
We then talked about Avogadro and the MOLAR VOLUME (number of LITERS per MOLE) of ANY gaseous substance (behaving ideally) at STP, which is 22.4 liters per mole.
We then completed the final vertex of the magic triangle which converts moles of a gaseous substance at STP to liters and vice-versa.
AP: we qualitatively explained Le Chatelier's Principle and then explained the much more detailed kinetics/particle-level explanation that OBVIATES the need for any kind of human conceptual shortcut principle; that is, we explained what is ACTUALLY occurring when a given stress is applied to a system that is already AT EQUILIBRIUM. Today, we covered (1) the stresses of inc/dec concentration or partial pressure of reactants or products and (2) inc/dec volume or total pressure on the system. Tomorrow, we will cover the stresses of adding an inert gas at constant volume (no effect) or at constant pressure (dilution/increasing volume effect); we will also cover the "stress" of adding a catalyst and the NON-EFFECT of adding ANY SOLIDS or LIQUIDS (one exception, though) or INC/DEC SURFACE AREA of a liquid or solid.
# posted by C @ 4:26 PM 
