Thursday, April 26, 2007
Thurs-Day 1
AP: we went nuclear today and discussed the five types of nuclear decay and the proximate reason for said decay: the neutron to proton ratio of the nucleus. We discussed nuclear decay kinetics (always first order) and applications thereof: carbon dating. We will briefly discuss other nuclear applications, tomorrow. I explained the strong force of nature and nuclear binding energy per nucleon. The isotope with the greatest binding energy per nucleon is Fe-56. All lighter isotopes tend to undergo fusion in order to form more strongly bound, more stable nuclei; all heavier isotopes tend to undergo fission reactions to form more stable nuclei.
We then looked at "penetrating power" and particle energies. Gamma rays are the most penetrating (can only be stopped by thick slabs of lead and/or concrete) but have the least energy per particle (though each gamma photon has a relatively high energy compared to the energy of a visible photon); beta particles have intermediate penetrating power (can be stopped by wood or thick cardboard) and intermediate energy per particle; alpha particles have the least penetrating power (can be stopped by paper or clothing) but have the highest energy per particle.
Honors: we did some qualitative "common ion" Le Chatelier problems. We then looked at the last part of our current unit: predicting spontaneity of a reaction or process by considering the change in enthalpy, entropy (chaos/randomness), and Gibbs Free Energy.
We defined entropy and considered various ways of predicting the entropy change of a process or reaction. We looked at the four possible combinations of enthalpy change and entropy change at a given temperature and considered the net change in Gibbs Free Energy in order to predict whether a given reaction or process is spontaneous.
Tomorrow, we will finish this part of the unit and get a jump on the Acids, Bases, and Salts unit.
Regents: we had our kinetics/equilibrium/Le Chat exam today...class average: 82
:(
We then looked at "penetrating power" and particle energies. Gamma rays are the most penetrating (can only be stopped by thick slabs of lead and/or concrete) but have the least energy per particle (though each gamma photon has a relatively high energy compared to the energy of a visible photon); beta particles have intermediate penetrating power (can be stopped by wood or thick cardboard) and intermediate energy per particle; alpha particles have the least penetrating power (can be stopped by paper or clothing) but have the highest energy per particle.
Honors: we did some qualitative "common ion" Le Chatelier problems. We then looked at the last part of our current unit: predicting spontaneity of a reaction or process by considering the change in enthalpy, entropy (chaos/randomness), and Gibbs Free Energy.
We defined entropy and considered various ways of predicting the entropy change of a process or reaction. We looked at the four possible combinations of enthalpy change and entropy change at a given temperature and considered the net change in Gibbs Free Energy in order to predict whether a given reaction or process is spontaneous.
Tomorrow, we will finish this part of the unit and get a jump on the Acids, Bases, and Salts unit.
Regents: we had our kinetics/equilibrium/Le Chat exam today...class average: 82
:(
# posted by C @ 2:05 PM 
