Nomenclature

CH 4 o chem

Alcohols with 2 OH groups

glycols, diols. ex. 1, 2 - ethanediol

sec-butyl alcohol

tert-butyl alcohol

isobutyl alcohol

neopentyl alcohol

neopentyl

Only named alkyl group with 5 C

Identifying H

Attached to C bonded to 1 other C = primary

butyl

4 carbon group that is unbranched

sec-butyl

4 carbon group unbranched but H is taken off of center C instead of side C

tert-butyl

4 carbon group with 3 C attached to central C

Isobutyl

4 carbon group thats unbranched except for methyl group on 2nd C

unbranched alkane names

methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, etc.

homologous series

series of compounds where each member differs from the rest by a constant unit, ex. CH2 in alkanes

acetylenic hydrogen atom

H atom attached to terminal alkyne

ethynyl group

HC triple bond C - R

Vinyl group

ethenyl group, C=C-R

Allyl group

prop-2-ene-1yl C that attaches to R group is always C1. C=C-C-R

density of alkanes and cycloalkanes

least dense, lighter than water

conformational analysis

study changes in energy of molecule as rotate freely rotating single bonds

newman projection

See along 2 carbon axis, using circle and lines to represent location of H

Staggered conformation

dihedral angle is 60 and H of front and back C far apart as possible. Ethane spends most time staggered since lower energy.

Eclipsed conformation

H are overlaping and angle between them is 0

hyperconjugation

In staggered conformation, favorable filled and unfilled orbital to stabilize it

torsional barrier

small barrier to single bond rotation due to differnece in energy staggered vs ecliped conformation

torsional strain

causes barrier to rotating, caused by steric hinderance between e- groups. Butane has larger barrier to rotation than ethane.

guache conformation

Large CH3 groups on butane 60 degrees apart, higher energy than anti

anti conformation

Large CH3 groups on butane 180 degrees apart, lowest energy state

Semi-eclipsed conformation

CH3 group and H group fully overlaping, high energy since e- repulsion unstable

Fully-eclipsed conformation

Least stable, 2 CH3 fully on top of each other

Steric hinderence

dispersion forces between e- that are repulsive and slightly prohibit free rotation of single bonds

steroisomers

same formula and connectivity but different arangement of atoms in 3D space

conformational steroisomers

steroisomers that are related to each other by rotating single bonds