ppt 3 Flashcards
different connectivity of atoms
constitutional
different functional groups
functional
different positions of the functional groups
positional
different carbon skeleton
skeletal
same connectivity but different spatial orientation of atoms
stereoisomers
- different, NON-INTERCONVERTING spatial arrangement of atoms
- NOT the result of rotation about single bonds
- DIFFERENT compounds
configurational
result from restricted rotation around a double bond or on cyclic alkanes
Geometric
around a chiral carbon
optical
nonsuperimposable mirror images
enantiomers
nonmirror images
Diastereomers
- different, INTERCONVERTING spatial arrangements of atoms
- the RESULT of rotation about single bonds
- SAME compound
Conformational
Usually uses the name given when it was discovered
common
Names compound as a derivative of a parent compound
derived
- Most systematic
- Based on the longest continuous chain of carbon atoms
IUPAC (International Union of Pure and Applied Chemistry)
position and name of functional group
suffix
position/s, number, & name/s of substituents; number of C of parent functional group
prefixes
where and what are the substituents?
prefixes
how many carbons?
parent
where is the primary functional group?
locant
what is the primary functional group?
suffix
Contain carbon and hydrogen only
HYDROCARBONS
types of hydrocarbons
- Aliphatic, Cyclic, and Aromatic
- Saturated and Unsaturated
- Alkanes, Alkenes, and Alkynes
- open chain (acyclic)
- Straight chain
- Branched
aliphatic
has a closed ring but no aromaticity
alicyclic
has a benzene ring
aromatic
contain C-C bonds
saturated
contain at least one C=C or C ≡C bond
unsaturated
formula for alkane
CnH2n+2
formula for alkene
CnH2n
formula for alkyne
CnH2n-2
molecular geometry for:
alkane
alkene
alkyne
tetrahedral
trigonal planar
linear
- Saturated hydrocarbons
- Single bonds (sigma)
- sp3 hybridized C atoms
- Bond angles approximate 109.5°
- Tetrahedral geometry
- CnH2n+2
alkane
a.k.a. paraffins
- derived from L. parum affinis, meaning “slight affinity”
- describes LITTLE CHEMICAL AFFINITY for other substances and are inert to most
laboratory reagents - relatively unreactive and are rarely involved in chemical reactions
- react under appropriate conditions with oxygen, chlorine, and a few other
substances
alkanes
*occur naturally in the plant and animal world
*most common sources: natural gas and petroleum deposits
*derived from the decomposition ofplant andanimal matter, primarily of marine origin
alkane
found in the waxy coating on cabbage leaves
nonacosane (C29H60)
found in wood oil of the Jeffrey pine common to the Sierra Nevada mountains of California
heptane (C7H16)
consists chiefly of methane but also contains ethane, propane, and butane
natural gas
a complex mixture of hydrocarbons that must first be separated into various fractions and then further refined before it can be used
petroleum
PROPERTIES OF ALKANES
Combustion Reaction
- form H2O and CO2
Reaction with Chlorine
- occurs when irradiated with ultraviolet light (hv)
same molecular formula of alkane but different structural formula (different connectivity of atoms).
constitutional isomers
C atoms
* ____ – bonded to 1 C
* ____ – bonded to 2Cs
* ____ – bonded to 3Cs
* ____ – bonded to 4Cs
H atoms
* ____ – bonded to primary C
* ____ – bonded to a secondary C
* ____ – bonded to a tertiary C
primary
secondary
tertiary
quaternary
primary
secondary
tertiary
abbreviation for secondary
sec-butyl
abbreviation for tertiary
tert-butyl
methyl group attached to the 2nd C
4 methyl groups attached to one C
unbranched chains
iso
neo
n (normal)
Alkanes with 2 or more C can be twisted into a number of different 3D arrangements of their atoms by rotating about1 or more C-C bonds.
CONFORMATIONALISOMERS
oblique view of C-C bond
Sawhorse
along a C-C bond
Newman Projection
C-H bonds are as far away from each other; more stable
Staggered
C-H bonds are as close as possible; less stable
Eclipsed
- Contain two fewer hydrogen atoms than an aliphatic alkane with the same
numberofcarbonatoms(CnH2n) - Usually represented by skeletal formulas
ALICYCLIC ALKANES (CYCLOALKANES)
- sp3 carbons have bond angles of 109.5°
- But cycloalkanes, assuming they are planar, have different bond angles = ___
180*
strain that arises when atoms separated by four or more bonds are forced abnormally close to one another
steric strain
vertical; alternating up and down
axial
outward; parallel to the lines of the ring
equatorial
isomer:
_____ on the same side
_____ across from
cis
trans
alkyl halide
______ released in large amounts by ocean kelp, forest fires and volcanoes
have a vast array of industrial applications, including use as:
* solvents
* inhaled anesthetics
* refrigerants
* pesticides
chloromethane
- a.k.a. olefins
- occur abundantly in nature
- ____ –plant hormone that induces ripening in fruit
- ____ –the major component of turpentine
- ____ – a poly alkene that contains 11 double bonds; the orange pigment responsible for the color of carrots; and a valuable dietary source of vitamin
alkene
Ethylene
a-pinene
b-carotene
much less common than alkenes
alkynes
ALKENES WITH MULTIPLE BONDS
separated by at least 2 single bonds
adjacent
alternating with single bonds
isolated
cumulative
conjugated
For disubstituted alkenes
CIS-TRANS SYSTEM
for tri‐ and tetrasubstituted alkenes
E/Z SYSTEM
E/Z SYSTEM
E - From the German _____, meaning opposite; specifies that groups of higher priority on the carbons of a double bond are on opposite sides
Z - From the German _____, meaning together; specifies that groups of higher priority on the carbons of a double bond are on the same side.
entgegen
zusammen
E/Z SYSTEM
priority rules is based on _________. The higher the atomic no, the higher the priority
atomic number
