Wednesday, April 18, 2007
Wednes-Day 2
Honors: we began the most important topic of the remainder of the year: Le Chatelier's Principle as applied to chemical equilibrium. We covered the proper arrow labelling, exoHOT and endoCOOL, and listing the total number of moles of gas on each side of the chemical equation.
We then invoked the three Le Chat questions: 1. What is the stress? 2. What is the opposite or reverse of the stress? and 3. Which direction/shift (towards products or reactants) will cause the opposite or reverse of the stress to occur?
We applied this principle to several stresses on the reversible reaction of nitrogen with hydrogen to form ammonia.
We will continue this example, tomorrow.
Regents: we began the most important topic of the remainder of the year: Le Chatelier's Principle as applied to chemical equilibrium. We covered the proper arrow labelling, exoHOT and endoCOOL, and listing the total number of moles of gas on each side of the chemical equation.
We then invoked the three Le Chat questions: 1. What is the stress? 2. What is the opposite or reverse of the stress? and 3. Which direction/shift (towards products or reactants) will cause the opposite or reverse of the stress to occur?
We applied this principle to several stresses on the reversible reaction of nitrogen with hydrogen to form ammonia.
We started another example and will continue with it tomorrow.
Organic Test Average: 79
AP: we backtracked a bit and showed how the units work and cancel in the Eo =(RT/nF) lnK equation . We then did some qualitative and quantitative redox predictions using the table of standard reduction potentials. We used a shortcut: connect the two reactant particles; if the connecting line slopes down, the reaction is spontaneous under standard conditions and if the connecting line has a positive (uphill) slope, the reaction is not spontaneous under standard conditions.
We then began to look at "concentration cells" in which the anode and cathode are the same metal and the solutions are made from the same salt; the potential difference is caused solely by the difference in concentration of the solutions between the cells. The pH meter is a concentration cell, which we'll discuss more tomorrow.
We then invoked the three Le Chat questions: 1. What is the stress? 2. What is the opposite or reverse of the stress? and 3. Which direction/shift (towards products or reactants) will cause the opposite or reverse of the stress to occur?
We applied this principle to several stresses on the reversible reaction of nitrogen with hydrogen to form ammonia.
We will continue this example, tomorrow.
Regents: we began the most important topic of the remainder of the year: Le Chatelier's Principle as applied to chemical equilibrium. We covered the proper arrow labelling, exoHOT and endoCOOL, and listing the total number of moles of gas on each side of the chemical equation.
We then invoked the three Le Chat questions: 1. What is the stress? 2. What is the opposite or reverse of the stress? and 3. Which direction/shift (towards products or reactants) will cause the opposite or reverse of the stress to occur?
We applied this principle to several stresses on the reversible reaction of nitrogen with hydrogen to form ammonia.
We started another example and will continue with it tomorrow.
Organic Test Average: 79
AP: we backtracked a bit and showed how the units work and cancel in the Eo =(RT/nF) lnK equation . We then did some qualitative and quantitative redox predictions using the table of standard reduction potentials. We used a shortcut: connect the two reactant particles; if the connecting line slopes down, the reaction is spontaneous under standard conditions and if the connecting line has a positive (uphill) slope, the reaction is not spontaneous under standard conditions.
We then began to look at "concentration cells" in which the anode and cathode are the same metal and the solutions are made from the same salt; the potential difference is caused solely by the difference in concentration of the solutions between the cells. The pH meter is a concentration cell, which we'll discuss more tomorrow.
# posted by C @ 4:22 PM 
