MidtermReview

# MidtermReview - Chem 1a Midterm Review Sheet Please Note...

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Chem 1a Midterm Review Sheet Page 1 of 5 Please Note: This sheet is intended to assist students in reviewing for the midterm exam. It is not intended to be comprehensive (i.e. there may be errors or omissions). Absorption and emission Spectra of Atomic Hydrogen 1. E = h ν = hc λ = hc ν 2. Rydberg equations a ) E = R H Z 2 1 n f 2 1 n i 2 , R H = 13.6 eV = 2.18 × 10 18 J b) ∆ν = R H Z 2 h 1 n f 2 1 n i 2 Hz and = E hc (preferred units cm -1 ) c) For emission: Lyman n f = 1; Balmer n f = 2; Paschen n f = 3 Bohr Theory 1. Works only for 1 electron atoms and ions. 2. Bohr used the classical equations for a negatively charged particle revolving around a heavier positive particle; i.e. that the electrostatic force on the electron equals the centripetal force on the electron in an orbital: F ele = Ze 2 4 πε 0 r 2 ; and F cent = m e v 2 r where m e is the mass of the electron, ν the velocity of the electron and r the radius of the orbit. 3. Bohr postulated that only specific values of the angular momentum are allowed: π 2 h n n vr m e = = h , where n is an integer This gives e m a a Z n r e n 0 2 0 0 2 4 and h = = 4. The orbital energy is given by the classical equations: E = KE + PE = 1 2 mv 2 Ze 2 4 0 r =− Z 2 n 2 R H Quantum Mechanics 1. DeBroglie Wave: = h mv = h p 2. Heisenberg Uncertainty Principle: 2 or ; 2 h h t E x p p = mv p= m v and = h p ∆λ h p 2 p

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Chem 1a Midterm Review Sheet Page 2 of 5 3. 1D Wave Standing wave Not a standing wave with one node ends not tied down not allowed Boundary conditions: Ends tied down standing wave More nodes Î higher energy 4. 2D waves for a square or round drum have degenerate sets (i.e. two or more waves have the same energy.
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## This note was uploaded on 06/05/2008 for the course CH 1a taught by Professor Lewis during the Fall '08 term at Caltech.

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MidtermReview - Chem 1a Midterm Review Sheet Please Note...

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