Test 2 Flashcards
Hydrocarbons
Composed of hydrogen and carbon
Saturated hydrocarbons
No pi bonds, alkanes
IUPAC step 1
Identify the parent chain
IUPAC step 2
Name the parent chain
1 carbon
Methane, meth-
2 carbon
Ethane, eth-
3 carbons
Propane, prop-
4 carbons
Butane, but-
5 carbons
Pentane, pent-
6 carbons
Hexane, hex-
7 carbons
Heptane, hept-
8 carbons
Octane, oct-
9 carbons
Nonane, non-
10 carbons
Decane, dec-
Cyclie alkanes
And cyclo- to beginning of name based off number of carbons.
IUPAC step 3
Identify side chains, branches. Use -yl instead of -ane for ending
IUPAC step 4
Identify where branch or side chain is coming off of parent chain. Number from end with first branch.
IUPAC step 5
List numbered substitutes before the parent name alphabetically (ignore the prefixes)
Naming bicyclic compounds
- count the total carbons in the fused rings
- bicyclo- prefix
- bracketed numbers
Constitutional isomers
Same structure that differ in connectivity
More stable
Give off less energy
Staggered confirmation
Lowest energy, spread out, most stable
Eclipsed confirmation
Highest energy , over lapping, least stable
Anti conformation
Staggered, methyl groups are farthest apart
Gauche configuration
Staggered, methyl groups experience being next to each other so less stable.
Cyclohexane
- zero ring strain
- lowest energy confirmation “chair”
- no torsional strain (H staggered)
Axial atoms
Point up straight
Equatorial atoms
Slightly up or down atoms
Chair flips
The result of C-C single bonds rotate
Día I al interactions
Like a gauche interaction
Cis isomers
Two groups on the same side of the ring
Trans isomers
Two groups are on opposite side of a ring
stereoisomers
same molecular formula and constitution but different spatial arrangement of atoms
chiral atoms
bonded to 4 different groups of atoms
enantiomers
Two molecules that are mirror images but are non-identical and non-superimposable.
clockwise
R
counterclockwise
S
dash
lowest priority group
fisher projections horizontal lines
forward, wedge
fisher projections vertical lines
back, dash
diastereomers
stereoisomers that are not mirror images.
E
Going different ways from the double bond, walk like an Egyptian.
Z
going same directions from double bond, zame zide.
breaking a bond
cost energy
creating a bond
releases energy
+ΔH
- endothermic reaction
- must take energy from the environment
- surroundings cool off
-ΔH
- exothermic reaction
- gives energy off
- surroundings heat up
entropy
Δs, disorder, randomness, or freedom
spontaneous favors
the forward direction
if ΔStot is positive
the process is spontaneous
ΔG=
ΔHsys-TΔSsys
-ΔG
is a spontaneous reaction
exergonic process
- -ΔG
- spontaneous favors products
endergonic process
- +ΔG
- nonspontaneous favors the reactants
reaction rate depends on
- reactant concentration
- activation energy
- temperature
- geometry & sterics
- any catalyst present
activation energy
energy needed to reach the transition state, want higher energy state
catalyst lower
activation energy
Transition states
peaks
intermediates
vallies
nucleophiles
an atom carrying a formal or partial negative charge and have an available pair of electrons.
electrophiles
an atom carrying a formal or partial positive charge and can accept a pair of electrons.
nucleophilic attack
- the tail of the arrow stars on the electrons
- head of the arrow ends on a nucleus
loss of a leaving group
a bond breaks and one atom takes both electrons
proton transfers
an electron pairs steals an H+, arrow points to H+.
carbocation rearrangment
moved over one step to become more stable. Can only occur from an adjacent carbon.
secondary carbocation
- H
- R
- R
tertiary carbocation
- R
-R - R
(most stable form)
hydride shift
H moves one step over and + moves.
methide shift
methyl group take one step over, positive charge moves.
rule 1 of arrow pushing
the arrow starts on a pair of electrons ( a bond or a lone pair)
rule 2 of arrow pushing
the arrow ends on a nucleus ( a lone pair forms) or between two nuclei ( a bond forms)
rule 3 of arrow pushing
never give C,N,O, or F more than 8 valence electrons
rule 4 of arrow pushing
draw arrows that follow the four key patterns we outlined.
nucleophilic attack case 1, have a good leaving group
reversible
nucleophilic attack case 2, has a poor leaving group
irreversible
loss of a leaving group
virtually always reversible
proton transfers
reversible
carbocation rearrangements
irreversible
chiral compounds
both chiral atoms are either R or S
Meso compounds
one chiral atom is S while one is R
enantiomers
everything flips
diastereomers
at least one flips but not all
