Chem ch. 12-2 Flashcards
sigma bonds (signal carbon)
C can share valence with 4 different elements for single bond. the strongest.
can only be 1 bond (alpha 1)
sigma
aliphatic hydrocarbons (alpha is first) AND also known as…(parfin and alph)
open, no rings - also known as parafins - also known as saturated
olefin (ol’ fin is keen to be un)
alkenes - unsaturated
acetylenes
is ethyne. unsaturated hydrocarbons
aromatic (benz smells good)
benzene
constitutional isomers
same formula but different connections. alcohol and ethers are isomers.
only exists when there is a C-C bond. (conform to the carbon bonds)
conformation
When tetra = 0 it’s called…(tetra moon)
or on top of each other, it’s called eclipsed
tetra (or dihedral) (hide tetris)
is the angle from the H you see and the one behind it.
when tetra is about 60 degrees
it’s called staggered
primary carbon (1 with circle on top) (primarily last)
the carbon that is attached to only 1 other carbon. All the carbons at each end of the molecule
secondary carbon - (2 with a circle on top)
attached to 2 more other carbons.
tertiary carbon - (3 with a circle above it)
attached to 3 more carbon.
quaternary carbon - (4 with a circle at top)
attached to 4 more carbons.
C4H10 - format of formula? (you see the molecules)
molecular formula - you see the number and type
c-c-c-c - format of formula?
extended formula
CH3 - CH2 - CH2 - CH3 OR CH3 (CH)2 CH3 (these 2 are the same) format of formula?
condensed structure
/-/ = - format of formula?
line structure
line facing me
wedge
line projecting away
dashes
_____
ethane line structure
constitutional isomers
think butane - drawn as C-C-C-C and C-C-C and one C on top.
n-butane
normal butane - the butane isomer that is a straight chain
isobutane (isolate the branch in butane)
the butane isomer with the branch
in isomers, don’t add..
the extra carbon on the end. Only add it to carbons in the middle
any isomer that begins with “iso” (isolated branch)
has one branch in the middle
isomer that has a branch carbon on top and on bottom is called…
neo. ex- neo-pentane
conformers are not
isomers
can’t rotate conformation with carbons where there are..
double or triple bond. Visualize it and it will make sense. The bonds would wrap around each other.
conformation
just the view of the hydrogens. if the H rotate around the C, seeing them and not seeing them are the 2 conformations.
affects the property of the molecules (2 things)
isomer and conformation
eclipse (conformation) and the degrees (eclipse at 3 - one 120 min)
when the hydrogens are covering each other. at 0, 120, 240 degrees, you can’t see them individually.
staggered (conformation) and degrees (staggering after 3 a.m. - do a 180 now)
when the hydrogens are not covering each other. at about 60 degrees, 180, or 300 degrees.
tetrahydral structure (meth tetris)
methane - just one C.
dihedral structure (think di)
2 carbons (2 tetras)
newman projection
a type of planar (not 3 dimensional) projection along one bond - the projected bond
dihedral angle (di newman)
angle between hydrogens in newman projection
the most stable conformer
staggered
if asked to identify conformer on test…
ex. it would be straight chain of the same number of C, either zig zag, or straight across, etc.
can be branched or unbranched
alkanes
branches (or substituents) are called
alkyls
if you remove just one hydrogen from an alkane, it becomes an
alkyl
how to change the name for the branches?
methane becomes methyl - just change ending to hyl.
CH3 (alkyl)
methyl
CH3CH2 or C2H5 (alkyl)
ethyl
CH3CH2CH2 (alkyl) or CH3CHCH3
propyl. If the H is removed from the middle carbon, it’s called isopropyl
line groups for methyl and ethyl
methyl is like a straight line, ethyl is a little bent
CH3CH2CH2CH2 (alkyl)
butyl
line angle for isopropyl
Y-shaped
if you remove a middle hydrogen in butane - CH3CHCH2CH3 it’s called…
secbutyl or s-butyl
isobutyl (buty Y are you upside down)
in the shape of a cross, one on top, one on bottom and becomes isobutyl. The line structure is an upside down Y.
tert-butyl (tert the bird)
the lone H on the bottom is removed, leaving a middle C attached to 3 other carbons. (bird foot)
nomenclature - rule 1
1) longest chain and name it. if you have equal number going in 2 different directions, pick the option with more branches.
nomenclature - rule 2
name all the side chains, alkyl groups
nomenclature - rule 3
number the chain beginning with the end closest to the branches. IF both branches are the same distance from the end, name the alkyl group and go in alphabetical order.
nomenclature - if you have 2 or more side chains that are the same (ie methyl)
then number it, and use the one with smaller numbers. ie. if it’s 3, 8, 10 or 3, 5, 10 - use the 3, 5, 10 one.
nomenclature - rule 4
number to which the branch is attached separated by a hyphen. If there are 2 numbers following each other, use a comma between numbers.
nomenclature - if there are several of the same alkyl group
use di, tri, tetra (these prefixes do not change the alphabetical order)
with conformers, watch for…
the formulas that wrap around. Count the number of carbons like you’re naming it, and then check where any substituents are. It could be tricky.
tert-butyl
butyl (substituent) attached to 4th carbon
