Home > Chemistry > Chemistry 51A: Lecture 4 Notes

Chemistry 51A: Lecture 4 Notes

Overview

Today is a 50 minute lecture on acids and bases.  If you’ve been following along, this ought to be an old topic for you.

Details

sp3 orbitals have bond angles of 109.5 degrees with a tetrahedral geometry.

Methane, CH4, has tetrahedral geometry, all bond angles are 109.5.

Ammonia, NH3, has a long pair on top.  This had a tetrahedral geometry, but the lone pair pushes the hydrogens down because they take up alot of space.  Thus, the new structure is a pyramid.  The new bond angles are 107.3

Water also had a tetrahedral geometry, but the oxygen has two lone pairs.  These push the hydrogens down for a new bond angle of 104.5 and a bent geometry.

sp2 atoms have a trigonal planar arrangement with a 120 degree angle.  Ethylene has these hybrid orbitals.

Methyl carbocation is CH3+.  120 degree bond angles.

sp hybrized atoms have 180 degree bond angles and linear arrangements.

Acetonitrile

H3C-C-=N

Allene

H2C=C=CH2

Acids and bases are central to the creation of reactive species like electrophiles and nucleophiles.

Bronsted acids donate protons, bronsted bases accept protons.

Lewis acids accept electrons, lewis bases donate electrons.

HCl + H2O = H3O+ + Cl-

Acid + Base = Conjugate Acid + Conjugate Base

A lone pair on oxygen attacks H of Hcl makes H3O+ and Cl-.  Chloride has 8 electrons.

Degree of Acidity

pKa = -log Ka

HA + H2O = H3O+ + A-

Ka= [H+][A-]/[HA]

Strong acids fully dissociate, weak acids only partially dissociate.

HCl    pKa = -7            Ka = 10^7

CH4            50                      10^-50

Lone pairs are donated from the lewis base to the lewis acid.

Review

OIL RIG – oxidation is loss, reduction is gain.

dEo cell = Eo cathode – Eo anode

IGL: point source, random motion, elastic collisions, high temperatures, low pressure

anode oxidation, cathode reduction

C-H   1.1 A C-C   1.54 C=C   1.34 C_=C 1.20 C-F  1.40 C-Cl 1.79 C-Br  1.97 C-I   2.16 C-C  1.54 C-N  1.47 C-O  1.43 C-F   1.40

Fatigue: reassure, rest, replenish, restore

Combat forces: armored/light/special

Infantry: light/ranger/mechanized/airborne/air assault

F_d, =, tfrac12, rho, v^2, c_d, A

PV = nRT

Diffusion solute moves; osmosis water moves

Electronegativity – NOF Cl Kr

pKa = -log Ka

SALUTE size activity location unit time equipment

Advertisements
  1. No comments yet.
  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: