Monday, September 22, 2008
Mon-Day 1
AP Chem- HERE are the hw problem types that we have covered in class and thus are due tomorrow. We will NOT have time to go over these in class. Use the Blackboard resources or see me just before 3rd period tomorrow in Room 308 if you have problems with the hw:
I will look at and grade questions: 19, 28, 38, 45 (use DeBroglie's formula from today's class BUT all masses must be converted to kg, otherwise the units will not cancel- see representative problems in files on Blackboard), 50, 108, 110 (b).
So that's it - 7 problems.
Your test on Wednesday will cover all material from Chapter 2 and the Chapter 7 material that we cover through tomorrow. I'll let you know in class the exact subtopic that will be tested.
Today, we finished the hydrogen emission spectrum procedure in order to see which specific energy visible photon were emitted from an excited sample of hydrogen atoms.
We then looked at an animation that illustrated the Bohr model of the atom; this model, showing the specific "quantized" energies that are allowed for an electron in a hydrogen atom, accounts for the specific electron "transitions" in which an electron loses a specific quantity of energy; that energy is converted to the energy of a photon/quantum that is emitted from the atom to the surroundings. In our case, the emitted photons were seen as specific colored lines as the photons hit the viewing screen.
We discussed how different elements, which have a different number of protons than hydrogen, have NOT ONLY different (and lower) energy levels for their electrons, BUT ALSO different DIFFERENCES in energy between any two corresponding energy levels. So the n=2 to n=1 electron transition in Hydrogen will give rise to a DIFFERENT energy photon than a n=2 to n=1 electron transition in a Helium (1+) ion because He (1+) has two protons attracting its electron.
So, in calculating electron energy levels, He (1+) has a different Rydberg constant than H.
We then discussed the flaws of the Bohr model: he could not account for many of the observed emission lines in (multi-electron) atoms other than H.
This is because Bohr did not:
1) factor in the electron-electron repulsion interactions in his energy calculations
AND
2) consider (he had NO evidence of this!) the electrons "WAVE" nature.
We discussed how Louis DeBroglie speculated that particles, such as electrons, might have a wave nature and a possibly measurable wavelength. By combining Einstein and Planck's equations for energy, he determined that the wavelength of a moving particle should equal h/mv,
that is, Planck's constant divided by the momentum of the moving particle.
This speculation was CONFIRMED when G.N. Thomson, J.J. Thomson's SON, discovered the wave nature of the electron. His famous experiment showed an INTERFERENCE PATTERN emerges when electrons are fired through microscopic slits in an Aluminum crystal - the SAME pattern observed when X-RAY electromagnetic WAVES are sent through the same Aluminum crystal.
This all led to the alteration of the Bohr model because you could NO LONGER claim that an electron was purely a particle.
The science of QUANTUM MECHANICS was born and the equations that solved for the allowed energies of electrons, EVEN in atoms of multi-electron elements, were developed from emission spectra and physics equations by Erwin Schroedinger. We will discuss the solutions to his equations and see the modern quantum mechanical model of the atom, tomorrow.
In the meantime, USE THE RESOURCES on Blackboard. There are practice problems, practice tests, tutorials, and animations.
HW is due tomorrow; you are responsible ONLY for the material covered in class so far.
I will post the question numbers soon.
Your test on Wednesday will cover the material from class through TUESDAY, INCLUDING the extensive number of review topics that we did (see your notes).
Bio 6/7- we reviewed the structure and functions of simple and complex carbohydrates. We then discussed the structure and function of fats/lipids and their building blocks (3 fatty acids + glycerol per fat molecule). We saw how PHOSPHOlipids are the major component of cell membranes; the phospholipid molecule naturally keeps water/solutions on the inside and outside of the cell because fats/lipids do NOT dissolve in water; instead, they form a separate layer/barrier/MEMBRANE.
We then discussed the most important and versatile class of molecules: PROTEINS.
Proteins are assembled via the (dehydration) synthesis of many amino acids that get bonded together (peptide bonds); the term "polypeptide" is synonymous with protein.
Proteins can function as enzymes/catalysts that speed up biochemical reactions so that they occur quickly enough to keep an organism alive. Proteins function in recognition and transport of certain molecules; they are embedded throughout the phospholipid bilayer of the cell membrane.
Antibodies are proteins that bind to harmful invading organisms called pathogens by having the specific SHAPE to lock onto part of the pathogens' cell surface; antibodies can also bind to toxins.
We finished the microscope procedure and we'll finalize that writeup on Wednesday.
Bio 8- we reviewed the structure and functions of simple and complex carbohydrates. We then discussed the structure and function of fats/lipids and their building blocks (3 fatty acids + glycerol per fat molecule). We saw how PHOSPHOlipids are the major component of cell membranes; the phospholipid molecule naturally keeps water/solutions on the inside and outside of the cell because fats/lipids do NOT dissolve in water; instead, they form a separate layer/barrier/MEMBRANE.
I will look at and grade questions: 19, 28, 38, 45 (use DeBroglie's formula from today's class BUT all masses must be converted to kg, otherwise the units will not cancel- see representative problems in files on Blackboard), 50, 108, 110 (b).
So that's it - 7 problems.
Your test on Wednesday will cover all material from Chapter 2 and the Chapter 7 material that we cover through tomorrow. I'll let you know in class the exact subtopic that will be tested.
Today, we finished the hydrogen emission spectrum procedure in order to see which specific energy visible photon were emitted from an excited sample of hydrogen atoms.
We then looked at an animation that illustrated the Bohr model of the atom; this model, showing the specific "quantized" energies that are allowed for an electron in a hydrogen atom, accounts for the specific electron "transitions" in which an electron loses a specific quantity of energy; that energy is converted to the energy of a photon/quantum that is emitted from the atom to the surroundings. In our case, the emitted photons were seen as specific colored lines as the photons hit the viewing screen.
We discussed how different elements, which have a different number of protons than hydrogen, have NOT ONLY different (and lower) energy levels for their electrons, BUT ALSO different DIFFERENCES in energy between any two corresponding energy levels. So the n=2 to n=1 electron transition in Hydrogen will give rise to a DIFFERENT energy photon than a n=2 to n=1 electron transition in a Helium (1+) ion because He (1+) has two protons attracting its electron.
So, in calculating electron energy levels, He (1+) has a different Rydberg constant than H.
We then discussed the flaws of the Bohr model: he could not account for many of the observed emission lines in (multi-electron) atoms other than H.
This is because Bohr did not:
1) factor in the electron-electron repulsion interactions in his energy calculations
AND
2) consider (he had NO evidence of this!) the electrons "WAVE" nature.
We discussed how Louis DeBroglie speculated that particles, such as electrons, might have a wave nature and a possibly measurable wavelength. By combining Einstein and Planck's equations for energy, he determined that the wavelength of a moving particle should equal h/mv,
that is, Planck's constant divided by the momentum of the moving particle.
This speculation was CONFIRMED when G.N. Thomson, J.J. Thomson's SON, discovered the wave nature of the electron. His famous experiment showed an INTERFERENCE PATTERN emerges when electrons are fired through microscopic slits in an Aluminum crystal - the SAME pattern observed when X-RAY electromagnetic WAVES are sent through the same Aluminum crystal.
This all led to the alteration of the Bohr model because you could NO LONGER claim that an electron was purely a particle.
The science of QUANTUM MECHANICS was born and the equations that solved for the allowed energies of electrons, EVEN in atoms of multi-electron elements, were developed from emission spectra and physics equations by Erwin Schroedinger. We will discuss the solutions to his equations and see the modern quantum mechanical model of the atom, tomorrow.
In the meantime, USE THE RESOURCES on Blackboard. There are practice problems, practice tests, tutorials, and animations.
HW is due tomorrow; you are responsible ONLY for the material covered in class so far.
I will post the question numbers soon.
Your test on Wednesday will cover the material from class through TUESDAY, INCLUDING the extensive number of review topics that we did (see your notes).
Bio 6/7- we reviewed the structure and functions of simple and complex carbohydrates. We then discussed the structure and function of fats/lipids and their building blocks (3 fatty acids + glycerol per fat molecule). We saw how PHOSPHOlipids are the major component of cell membranes; the phospholipid molecule naturally keeps water/solutions on the inside and outside of the cell because fats/lipids do NOT dissolve in water; instead, they form a separate layer/barrier/MEMBRANE.
We then discussed the most important and versatile class of molecules: PROTEINS.
Proteins are assembled via the (dehydration) synthesis of many amino acids that get bonded together (peptide bonds); the term "polypeptide" is synonymous with protein.
Proteins can function as enzymes/catalysts that speed up biochemical reactions so that they occur quickly enough to keep an organism alive. Proteins function in recognition and transport of certain molecules; they are embedded throughout the phospholipid bilayer of the cell membrane.
Antibodies are proteins that bind to harmful invading organisms called pathogens by having the specific SHAPE to lock onto part of the pathogens' cell surface; antibodies can also bind to toxins.
We finished the microscope procedure and we'll finalize that writeup on Wednesday.
Bio 8- we reviewed the structure and functions of simple and complex carbohydrates. We then discussed the structure and function of fats/lipids and their building blocks (3 fatty acids + glycerol per fat molecule). We saw how PHOSPHOlipids are the major component of cell membranes; the phospholipid molecule naturally keeps water/solutions on the inside and outside of the cell because fats/lipids do NOT dissolve in water; instead, they form a separate layer/barrier/MEMBRANE.
# posted by C @ 10:29 AM 
