Friday, November 4, 2011
Fri-Day 1
AP Chem - we reviewed the photoelectric effect experiment, detailing the reasons that for the electron ejection rate, and the identical KE's of the ejected electrons for a given color of laser used on the sample.
We then related the quantum/particle nature of EMR to the emission spectra of atoms i.e. the spectral lines are caused by the emission of specific energy photons of the exact same energy that was lost by an electron as it lost potential (positional) energy as it got closer to the nucleus due to electrostatic attraction. Overall, the energy of an emitted photon is exactly equal to the magnitude of the energy lost by the electron; no net energy is created or destroyed.
From Coulomb's Law, Bohr calculated the possible levels of energy than an electron has depending on its distance from the nucleus; the DIFFERENCES in energy that an electron can have PERFECTLY matched the observed energies of the photons emitted from Hydrogen, or any one electron ion i.e. He + and Li 2+. However, Bohr's calculated electron energy differences did not match up with the emitted photon energies for ANY atom/element other than Hydrogen. Bohr did not account for the potential energy raising effect of electron-electron repulsion in any multi-electron atom i.e. any atom except for H.
Bio - we started our new unit on Transcription, Translation, and Genetic Mutation with an overview animation of the process of transcribing the DNA base code/sequence of a gene to an RNA base code/sequence in the nucleus (this way, the chromosomes never leave the nucleus - it would take way too much energy/ATP to transport the chromosomes every time a protein was synthesized). We then saw how the RNA base code/sequence was translated to a chain of a specific sequence of amino acids that form the specific protein that was coded for originally by the DNA gene.
We then related the quantum/particle nature of EMR to the emission spectra of atoms i.e. the spectral lines are caused by the emission of specific energy photons of the exact same energy that was lost by an electron as it lost potential (positional) energy as it got closer to the nucleus due to electrostatic attraction. Overall, the energy of an emitted photon is exactly equal to the magnitude of the energy lost by the electron; no net energy is created or destroyed.
From Coulomb's Law, Bohr calculated the possible levels of energy than an electron has depending on its distance from the nucleus; the DIFFERENCES in energy that an electron can have PERFECTLY matched the observed energies of the photons emitted from Hydrogen, or any one electron ion i.e. He + and Li 2+. However, Bohr's calculated electron energy differences did not match up with the emitted photon energies for ANY atom/element other than Hydrogen. Bohr did not account for the potential energy raising effect of electron-electron repulsion in any multi-electron atom i.e. any atom except for H.
Bio - we started our new unit on Transcription, Translation, and Genetic Mutation with an overview animation of the process of transcribing the DNA base code/sequence of a gene to an RNA base code/sequence in the nucleus (this way, the chromosomes never leave the nucleus - it would take way too much energy/ATP to transport the chromosomes every time a protein was synthesized). We then saw how the RNA base code/sequence was translated to a chain of a specific sequence of amino acids that form the specific protein that was coded for originally by the DNA gene.
# posted by C @ 8:04 PM 
