Chapter 4 Flashcards
define hydrocarbon
a hydrocarbon is a compound comprised of carbon and hydrogen atoms only
what is a saturated hydrocarbon?
a saturated hydrocarbon contains no pi bonds
(saturated = as many hydrogens as possible)
IUPAC stands for?
IUPAC nomenclature
international union of pure & applied chemistry
standardized words for describing chemicals
describe an alkane (in words)
an alkane is a saturated hydrocarbon
it is H & C, with no pi bonds
1 (prefix)
meth
2 (prefix)
eth
3
(prefix)
prop
4
(prefix)
but
5
(prefix)
pent
6
(prefix)
hex
7
(prefix)
hept
8
(prefix)
oct
9
(prefix)
non
10
(prefix)
dec
11
(prefix)
undec
12
(prefix)
dodec
13
(prefix)
tridec
14
(prefix)
tetradec
15
(prefix)
pentadec
20
(prefix)
eicos
30
(prefix)
triacont
40
(prefix)
tetracont
50
(prefix)
pentacont
100
(prefix)
hect
meth?
1
eth?
2
prop?
3
but?
4
pent?
5
hex?
6
hept?
7
oct?
8
non?
9
dec?
10
undec?
11
dodec?
12
tridec?
13
tetradec
14
pentadec
15
eicos
20
triacont
30
tetracont
40
pentacont
hect
100
cyclo means?
cyclo means ring
alkane with 1 carbon atom in parent chain is called?
methane
alkane with 2 carbon atom in parent chain is called?
ethane
alkane with 3 carbon atom in parent chain is called?
propane
alkane with 4 carbon atom in parent chain is called?
butane
alkane with 5 carbon atom in parent chain is called?
pentane
alkane with 6 carbon atom in parent chain is called?
hexane
alkane with 7 carbon atom in parent chain is called?
heptane
alkane with 8 carbon atom in parent chain is called?
octane
alkane with 9 carbon atom in parent chain is called?
nonane
alkane with 10 carbon atom in parent chain is called?
decane
alkane with 20 carbon atom in parent chain is called?
eicosane
alkane with 50 carbon atom in parent chain is called?
pentacontane
alkane with 100 carbon atom in parent chain is called?
hectane
what are substituents?
substituents are groups connected to the parent chain
naming of alkanes – base
find the longest parent (might be a ring)
if multiple possibilities, find the one with the most substituents
cyclopropane
cyclobutane
cyclopentane
what are alkyl groups?
substituents on an alkane
ethyl group
methyl group
cyclopropyl
propyl
common name for:
isopropyl
common name for:
sec-butyl
common name for:
isobutyl
common name for:
tert-butyl
common name for:
isopentyl
OR
isoamyl
common name for:
neopentyl
draw a neopentyl group
draw an isopentyl group
draw a tert-butyl group
draw an isobutyl group
draw an isoamyl group
draw a sec-butyl group
draw an isopropyl group
what is a locant?
a locant is the # assigned to a carbon in a parent or substituent
how do you name a bicyclic compound?
- count the total number of carbons – this gives you the bicycloXane
- place a #1 at a bridgehead and number the rest of the carbons from there
- count how many carbons are on either side of the bridgeheads (not counting the bridgeheads!) –> both sides and the bridge!
- from largest # to smallest number,
bicyclo[Y,W,Z]Xane
(ex: bibcyclop(3,1,1)heptane)
what is a bicyclic compound?
a bicylic compound is a compound containing two fused rings
(bi = two, cyclic = ring)
(ex: bicyclo[1,1,1]pentane)
as molecular size (weight) of alkanes increases, the number of constitutional isomers possible ________
increases
describe COMBUSTION for an alkane
combustion:
alkane + oxygen –> CO2 + water
(compresion –> heat)
during combustion, a more stable isomer of an alkane gives off ________ heat energy
less
during combustion, a less stable isomer of an alkane gives off ________ heat energy
more
branched alkane isomers are ________ stable than straight-chain isomers
more
what is the heat of combustion?
it is the heat given off to the surrounding environment during combustion (burning)
what is petroleum?
petroleum is a complex mixture of hundreds of hydrocarbons, most of which are alkanes
a.k.a. crude oil
what is refining?
refining is the process of separating crude oil (pretroleum) into commercially available products
what is cracking?
cracking is the process of breaking C-C bonds in larger alkanes, to produce smaller alkanes (more suitable for gasoline)
what are the 2 types of cracking?
thermal cracking (high temp)
catalyst cracking (aid of catalysts)
what is reforming?
reforming is converting straight-chain alkanes into branched hydrocarbons and aromatic compounds
what is knocking?
knocking happens in the engine when there are too many straight-chain hydrocarbons in the gasoline. branched & aromatic hydrocarbons are mixed in to reduce the likelihood of knocking.
draw a Newman Proejction with a staggered conformation
draw a Newman projection with an eclipsed conformaion
if two conformations have the same energy level, they are said to be __________
degenerate
what is torsional strain?
torsional strain is the the difference in energy between the staggered and eclipsed conformations
Newman Projections
what is the energy cost of an eclipsed H-H?
4 kJ/mol
Newman Projections
what is the energy cost of an eclipsed H-CH3?
6 kJ/mol
Newman Projections
what is the energy cost of an eclipsed CH3-CH3?
11 kJ/mol
Newman Projections
what is the energy cost of a gauche CH3-CH3?
3.8 kJ/mol
draw the chair conformations of cyclohexane
draw the chair conformation of cyclohexane and note with positions are axial and which are equatorial
what does cis mean with respect to cyclohexane?
both of the identical groups are on the same face
what does trans mean with respect to cyclohexane?
the identical groups are on opposite faces
draw the chair conformation of cyclohexane and mark one cis face. which positions are on the cis face & which positions would be opposite that side (trans)?
CHART
