Home > Chemistry, Organic chemistry > Chemistry 51A 10/30/09 Lecture 14 Notes

Chemistry 51A 10/30/09 Lecture 14 Notes

Overview

Today is a 53 minute lecture on assigning tetrahedral stereocenters.

Details

There are two stereoisomers, R and S.

R = rectus/right/clockwise

S = sinister/left/counterclockwise

Begin by identifying the center.  It’s usually a carbon atom with 4 different substituents.  Then rank the substituents.

2-butanol.  The carbon is connected to OH, H, CH3, C2H5.  This carbon is the only tetrahedral stereogenic center.

1) Rank them by weight.  Higher atomic number, higher priority.

2) If the weight is the same, move outwards.

3) Find the lowest priority atom.  Find the direction of 1 2 3, is it CW or CCW?

4) You can also invert the stereocenter, get the result, and conclude the opposite.  Swapping two substituents swaps the stereochemistry.

Tetrahydrofuran is a 6 membered ring with one oxygen inside.  The priority is Cl, O, CH2, H.  Pick it up and flip it over, then the 1 is pointing back.  CCW, S.  (S)-2-chlorotetrahydrofuran.

Double bonds and triple bonds.  Pretend that structure is a carbon bonded to two different carbons.  (R)-3-methyl-1-pentene.  Treat double bonds as two C-C bonds.  Treat triple bonds as three C-C bonds.

Treat CCOH as C-O, C-O, C-H.

Two isotopes like D deuterium and H hydrogen.  D is heavier than H.  It’s used as a label.

Review

Aging: oxygen, UV light, water, heat

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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