Home > Chemistry, Organic chemistry, Uncategorized > Chemistry 51A Lecture 16 Notes 11/11/09

Chemistry 51A Lecture 16 Notes 11/11/09

Overview

Today is a 51 minute lecture on understanding organic reactions.

Details

Now we begin to build molecules.

Reactions overcome activation energies to go from reactants to intermediates to products.

CH3CH2I + NaCN =(EtOH) CH3CH2CN + NaI

Organic chemists will often just focus on the organic product.  Here NaI would be a byproduct.  All organic reactions occur in a solvent which is under the arrow.

This is a substitution reaction.  A sigma bond is broken, a C-CN bond is formed.

CH3CH2-I  + CN- = CH2CH2-CN + I-

The usual chemistry arrow doesn’t say anything about the equilibrium, just that we go from reactants to products.  An arrow from right to left implies equilibrium.  A small right to left arrow implies that the equilibrium is to the right.

Curved arrows show the making and breaking of bonds.  The flow of electron pairs.  From the lone pair on the nitrile to the CH2, then electrons onto the iodine atom.  The curved arrow has a double head.

Fishhook arrows show the movement of single electron flow.  It has a single head.

There are two energies associated with breaking bonds.  One is bond strength, breaking bonds homolytically where an electron goes to each atom.  He does not mention the second energy.

The addition reaction breaks a pie bond to make two new sigma bonds.

A Grignard reaction is say methyl magnesium bromide.  It acts as a nucleophile. Add one reagent, then add another.  This is an addition reaction.

Elimination reactions are the opposite of an addition reaction.  We break two sigma bonds to create a pi bond.  Recall that making bonds releases energy and breaking bonds cost energy.

Reactive intermediates form as a transition state from reactants to products.  Carbocations are cations of carbons.  Cations are positive, anions are negative.  Cations do not have a complete octet.

Radicals have an odd electron.  They are unhappy.  Carbocation reactions differ from radical reactions.  Radicals need 1 electron, carbocations need 2.  Radical reactions involve stealing, carbocations involve sharing.

Carbanions are negatively charged.  Carbon isn’t that electronegative.

Concerted reactions have no intermediates.  Other reactions happen in step.

Double headed arrows indicate resonance.

Review

Aging: oxygen, UV light, water, heat

A = a l c

Electronegativity: NOF Cl Kr

Alkane CnH2n+2

Alkene CnH2n

Alkyne CnH2n-2

Most important cyclic molecules: Benzene C6H6/Naphthalene C10H8

Moving formations: column line wedge vee eschelon

When not moving: herring bone and coil

Transversing Terrain: traveling, traveling overwatch, bounding overwatch

breaking bonds takes energy, making bonds releases energy

Loads on average were: – fighting load: 63 lbs – approach march load: 101 lbs – emergency approach march load: 132 lbs

One well-established norm is that a soldier cannot sustain a load greater than one-third of his body weight over time.

Noble gases: He, Ne, Ar, Kr, Xe, Rd

Types of bonding: ionic >1.7, polar covalent between, non polar <0.5

PV = nRT

METT TC mission enemy troops terrain time civilians

SALUTE size activity location unit time equipment

2s 6p 10d 14f

KE electron = E photon – Ionization Energy

Tissue: epithelial, connective, nervous, muscular

Epithelial: simple/stratified/pseudostratified cuboidal/columnar/squamous

  • single covalent bond – 1 shared pair
  • double covalent bond – 2 shared pairs
  • triple covalent bond – 3 shared pairs

Bond energy: single < double < triple

Bond length: single < double < triple

pKa’s:

Alkanes (50)

CH4/CH3-

Alkene (44)

Alkyne (25

HF +3.2

HCl -7

HBr -9

HI -10 NH3 38 L

RCOOH (4-5)

HF (3.2)

NH4+ (9.26)

H2O (15.7)

ROH (17)

RSH (11)

H30+ (-1.7)

pKa = – log Ka

Spectroscopy: emission/absorption

A = e l c

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

6 strong acids:

  • HCl
  • H2SO4
  • HNO3
  • HClO4
  • HBr
  • HI

The stronger the acid, the higher the Ka, the weaker the conjugate base.

hydrogen helium

lithium beryllium boron carbon nitrogen oxygen fluorine neon

sodium magnesium aluminum silicon phosphorus sulfur chlorine argon

potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton

rubidium strontium yttrium zirconium niobium molybdenum technicium ruthenium rhodium palladium silver cadmium indium antimony tin tellurium iodine xenon

cesium barium lutium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon

SWAT – snipers, entry team, inner perimeter/gas people

AOR = area of responsibility

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