Organic Chemistry Test Flashcards
Alkanes
bond: single
suffix: –ane
prefix: indicates the longest straight chain in the mlecule
Alkyl Branches
named with the prefix for the branch, followed by the suffix –yl
Naming Hydrocarbons
numerals are separated by commas
numerals and letters by hyphens
names of branches and parent chains are NOT separated
Steps of Naming an Alkane
- identify the LONGEST carbon chain (it may travel through branches)
- number the carbon atoms, starting with the end closest to the branch(es)
- name each branch and identify its location –branch name parent name
- write IUPAC name: number of location – branch nameparent name
- list branches in alphabetical order
Cyclic Hydrocarbons Prefix
cyclo–
Alkenes
bond: double
suffix: –ene
prefix: indicates the longest straight chain in the mlecule
Alkynes
bond: triple
suffix: –yne
prefix: indicates the longest straight chain in the mlecule
Steps of Naming an Alkene/Alkyne
SAME STEPS AS NAMING ALKANE
but when numbering carbon atoms in the parent chain, begin with the end closest to the multiple bond.
Insert hyphens between the branch chain and the parent chain to denote where the carbon double or triple bond is located
e.g. 3-methyl-1-butene OR 3-methylbut-1-ene
When there are multiple alkyl branches on an alkane…
there is a prefix in front of the side chain name
di– tri– tetra–…
When there are multiple double or triple bonds on an alkene/alkyne…
their locations are indicated by the prefixes di– tri– tetra–…
Aromatic Hydrocarbons
In simple aromatics, the benzene ring is the parent with alkyl groups named as branches
(YOU DO NOT HAVE TO NUMBER THE BRANCH IF THERE IS ONLY 1 PRESENT)
If the aromatic ring is considered the side chain…
the prefix phenyl– is used
Nomenclature of Hydrocarbons
No. of C Atoms Prefix Side Chain Prefix for Substituents
1 meth- meth-
2 eth- eth- di-
3 prop- prop- tri-
4 but- but- tetra-
5 pent- pent- penta-
6 hex- hex- hexa-
7 hept- hept- hepta-
8 oct- oct- octa
9 non- non-
10 dec dec
Nomenclature of Alkenes and Alkynes
when you reach 4 carbons, you must specify the location of the double or triple bond
Propyl Side Chain
can attach 2 different ways:
1. can attach in a line formation with an ending carbon
n-propyl
- with its middle carbon attached to the parent
isopropyl
Butyl
can attach four different ways:
1. with an ending carbon
n-butyl
- with the second carbon in the chain
sec-butyl / s-butyl - in an upper case “T”
isobutyl - in a lower case “t”
tert-butyl / t-butyl
Cyclic Hydrocarbons
are aliphatic hydrocarbon chains that form rings
–need at least 3 carbons to form a cyclic hydrocarbon
prefix: cyclo-
Aliphatic
means they do not contain benzene
Note about cyclic hydrocarbons
the cyclic hydrocarbon is considered a side group (cyclo__yl-) instead of the root if it is attached to a hydrocarbon chain with a greater number of carbons
Properties of Cyclic Hydrocarbons
- non-polar; are insoluble in water
- physical properties are similar to straight-chain counterparts with the same number of carbon atoms
- melting and boiling points are higher than straight-chain counterparts due to stronger intermolecular attractions (London Dispersion Forces)
Aromatic Hydrocarbons
are derived from a benzene ring
-hydrocarbon ring with 3 double bonds, 1 hydrogen atom bound to each carbon atom (C6H6)
Note
benzene is considered a side group (phenyl–) instead of the root if it is attached to a hydrocarbon chain with more than 6 carbons
Note
if there is only 1 substituent on the benzene ring, you do not specify the location
Properties of Aromatic Hydrocarbons
- non-polar; insoluble in water
- benzene is a liquid at standard temperature
- boiling points are similar to aliphatic hydrocarbons with the same number of carbon atoms because they have similar molar masses
- strong odours
Isomers
molecules with the same molecular formula, but with atoms in different arrangements
2 main classes: constitutional isomers and stereoisomers
Constitutional Isomers
molecules with the same molecular formula with atoms bonded together in a different sequence
AKA structural isomers
Properties of Constitutional Isomers
- those with more branches have lower boiling points due to a decrease in surface area and a decrease in attractive forces (London Dispersion Forces)
Stereoisomers
molecules with the same molecular formula and atoms bonded in the same sequence, but they differ in 3D orientations of atoms in space
2 types: diastereoisomers and enantiomers
Diastereoisomers
based on a double bond in which different types of atoms or group are bonded to each carbon in the double bond
AKA geometric isomers
Cis Isomer
when the larger atoms or groups are on the same side of the double bond
Trans Isomer
when the larger atoms or groups are on opposite sides of the double bond
Enantiomers
molecules that are mirror images of each other around a single carbon atom bonded to 4 different types of atoms or groups
- they cannot be superimposed on top of each other
Alcohols
hydrocarbon derivatives that contain a hydroxyl (–OH) functional group
1˚ Alcohols
the carbon atom bearing the –OH group is attached to ONE other alkyl group
2˚ Alcohols
the carbon atom bearing the –OH group is attached to TWO alkyl groups
3˚ Alcohols
the carbon atom bearing the –OH group is attached to THREE alkyl groups
Naming Alcohols
- Identify the root: how many carbons are in the longest chain
DROP THE “e” if a single –OH group is present - Identify the suffix: –ol
* ensure the alcohol has the lowest number when it is the parent chain* - Identify the side chain(s)
- Name the compound
Physical Properties of Alcohols
- hydroxyl group (–OH) is very polar which makes small alcohols polar and soluble in water
- polarity and solubility decrease as the length of the hydrocarbon chain increases
- boiling points of alcohols are much higher than alkanes with the same number of carbon atoms due to HYDROGEN BONDING and DIPOLE INTERACTIONS
- they are toxic
Ethers
hydrocarbon derivatives in which an oxygen atom is single bonded to 2 carbon atoms (–O– functional group)
Naming Ethers
alkoxy group: the –R group with LESS carbon atoms
- named in the prefix
- add “-oxy” after the name (ex. ethoxy)
parent chain: the –R group with MORE carbon atoms
- is named in the suffix (ex. butane)
- the first number in the name tells you which carbon of the parent is attached to the oxygen
alkoxy - side chains - parent chain
ex: 2-ethoxybutane, 1-methoxy-4-methylpentane
When numbering the carbons in an ether…
start numbering from the end closest to the oxygen
Physical Properties of Ethers
- bond angle makes ethers slightly polar (DIPOLE INTERACTIONS)
2-3 carbons: soluble in water
4-6 carbons: slightly soluble in water
7+: insoluble in water
longer carbon chain = less polar - ethers with a total of 2-3 carbons are gases at room temp while larger ether are liquids at room temp
Alcohol contains which functional group?
hydroxyl –OH
Hydroxyl –OH is in what?
Alcohol
What is the smaller carbon chain attached to an ether is called?
alkoxy group
An alkoxy group is in what?
Ethers
Aldehydes
contain the carbonyl (C=O) functional group
- carbon double bonded to oxygen
Where are aldehydes located?
aldehydes are ALWAYS found at the END of a hydrocarbon chain
Note
in aldehydes, the carbonyl group is part of the formyl functional group (–CHO)
Naming Aldehydes
- Identify the root: how many carbons are in the longest chain?
DROP THE “E: AT THE END OF THE PARENT ALKANE - Identify the suffux: –al
- Identify the side chains
- Name the compound