4 - Intro

# 4 - Intro - Jim Heath 16 Noyes [email protected] 1 A few...

This preview shows pages 1–10. Sign up to view the full content.

1 Jim Heath 16 Noyes [email protected]

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
2 A few comments: 1. You won±t have to memorize much, if anything (this is not biology) 2. If you do your work with a solid effort, pass the big exams, and if your application to Caltech was legitimate, then you will pass 3. Lecture notes are VERY important!! For part 1 of this course, the powerpoint presentations of the lectures will be posted after each class (in pdf form). I may also occasionally post written lecture notes that should help focus your studying. OGN is a big, amorphous book ² it has good problem sets, but it covers too much material. 4. I will highlight many of our lectures by placing them into the context of real science that is being done at Caltech and elsewhere. I will cover what is important about these chemistry in context examples, and you will be asked about them regularly on quizzes.
3 Please ask questions!!! Stop me and raise your hand if you don±t understand something. If you have a question, chances are about 30-80% of the people in the room have the same question. The ones who fully understand this material are not present in this room because they are not taking this course.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
4 Fri & next week Today & tomorrow & Thursday Also, Mass spectrometry next week
5 Spectroscopy Units wavenumbers cm -1 A wavenumber is simply 1/ O , with O in cm±s. Recall that Energy = E = h Q = hc/ O , so 1/ O (= cm -1 ) is an energy Q , or frequency (cycles per second) is also an energy c § 3.0×10 10 cm·s -1 = 3.0e10 cm·s -1 = speed of light in vacuum h = 6.626e-34 J·s (kg m 2 s -1 ) = Planck±s constant B E Light is electromagnetic radiation O time (wavelength)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
6 Spectroscopy Units wavenumbers cm -1 A wavenumber is simply 1/ O , with O in cm±s. Recall that E = h Q = hc/ O , so 1/ O (= cm -1 ) is an energy Q , or frequency (cycles per second) is an energy Also, electron volts eV 1 eV § 8000 cm -1 = 1.6e-19 J 1 eV is the kinetic energy an electron has after being accelerated through a 1 volt electric field Visible light § 13000 ² 25000 cm -1 § 1.5 ² 3 eV eV±s are a manageable unit for describing visible & UV light and hence chemical bond energies c § 3.0×10 10 cm·s -1 = 3.0e10 cm·s -1 = speed of light in vacuum h = 6.626e-34 J·s (kg m 2 s -1 ) = Planck±s constant
7 The photon absorption or photon emission spectrum of a molecule is discreet, or quantized True for NMR, rotational spectroscopy, infrared spectroscopy, and electronic spectroscopy Absorbance or emission O , cm -1 , s -1 , or eV±s WHY? Discreet (or quantized) absorption or emission spectra

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
8 The pickle light bulb
9 A guitar string and its resonant frequen- cies. Notice that all frequencies are integral multiples of the funda- mental frequency, shown at the bottom of the drawing. e The particle is confined by these potential energy barriers ± like fingers on frets An electron will exist as a wave in between these two potential barriers The deBroglie Relationship O = h/mv L L Particle-in-a-Box Analogy (Guitar String) h = 6.626e-34 J·s (kg m 2 s -1 ) = Planck²s constant m e = mass of an electron = 9.109e-31 kg Louis DeBroglie 1892-1987 (was a Duke) Ph.D. Thesis: any moving particle or object has an associated wave.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 38

4 - Intro - Jim Heath 16 Noyes [email protected] 1 A few...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online