Transcript Hydrocarbons - mccormack-sch4u-2013

Organic Chemistry
 Organic chemistry is the
study of carbon containing
compounds derived from living
organisms.
Organic Compounds
• Contain C bonded to other elements,
commonly H, O, N, S, and halogens
• Carbon
– Can form many different compounds due to its
hybrid orbitals
– Has intermediate electonegativity, so its most
likely to form molecular compounds (Recall:
molecular compounds have diverse properties)
– Can make single, double, and triple bonds
– Can form isomers (same molecular formula but
different arrangement of atoms)
Isomers
• Structural Isomers have the same
molecular formula but the atoms are
bonded together in a different sequence
• Stereoisomers are molecules with the
same molecular formula, a same
sequence of atoms but they have
different 3D orientations
Stereoisomers
• Diastereomers form around a double
bond and each carbon atom involved in
the bond must have different types of
atoms bonded to it
• Enantiomers are mirror images of each
other
Types of Hydrocarbons
• Saturated: Contain the maximum number of
hydrogens, single bonds between all carbons
• Unsaturated: Contain 1+ double or triple
bonds
Types of Hydrocarbons
• Aliphatic Carbons are arranged in chains
• Cyclic: Carbons are arranged in rings
• Aromatic: Contain a benzene ring
Types of Hydrocarbons
Name
Alkane
Alkene
Alkyne
Definition
Hydrocarbon with only
single bonds between
carbon atoms.
Hydrocarbon with at
least one double bond.
Hydrocarbon with at
least one triple bond.
General
Formula
CnH2n+2
CnH2n
CnH2n-2
• Homologous series
• This is a series of compounds which all contain the
same functional group, and have similar chemical
properties.
• ALKANES
ALKENES
ALCOHOLS
• CH4
CH2 =CH2
CH3OH
• CH3-CH3
CH2 =CH –CH3
CH3CH2OH
• Each has a general formula:
• ALKANES: CnH2n+2
• The members of the series differ by the number of
CH2 units.
• CH3-CH3, CH3-CH2-CH3, CH3-CH2-CH2-CH3
• Graduation in physical properties: eg: boiling
points.
• CH4 (GAS), C8H18 (LIQUID), C30H62 (SOLID)
Rules for Naming Alkanes
(Nomenclature)
For a branched hydrocarbon, the longest continuous chain
of carbon atoms gives the root name for the hydrocarbon
H3C1
2
H3C
3
4
CH3
4 carbon chain = butane
Naming Alkanes
Based off the number of C atoms in the
longest chain
1. Count the number of C’s in the longest chain
2. Determine the appropriate root
3. Add the suffix “ane”
Hydrocarbon Root Names
# of Carbons
1
2
3
4
5
6
7
8
9
10
Root Name
methethpropbutpenthexheptoctnondec-
Examples
• Butane
• Heptane
Naming Branched Alkanes
Based off the number of C atoms in the
longest chain
1. Count the number of C’s in the longest chain
2. Determine the appropriate root
3. Use the numbered C’s to give the branches a
position number add “yl” suffix
4. Add the suffix “ane”
Naming Branched Alkanes
Important Rules:
1. Start numbering from the end that will give you
the lowest number of branches
2. If there is more than one type of branch, name
the branches in alphabetical order
3. If there is more than two of the same type of
branch, give the branch a position number and
prefixes “di”, “tri” “tetra” etc.
4. Put commas between numbers and hyphens
between numbers and letters
Rules for Naming Alkanes
(Nomenclature)
When alkane groups appear as substituents, they
are named by dropping the -ane and adding -yl.
—CH3 Methyl
—CH2CH3 Ethyl
—CH2CH2CH3 Propyl
—CH2CH2CH2CH3 Butyl
H3C
H3C
Methyl
CH3
Rules for Naming Alkanes
(Nomenclature)
The positions of substituent groups are specified
by numbering the longest chain of carbon atoms
sequentially, starting at the end closest to the
branching.
H3C1
2
3
H3C
Methyl
4
CH3
Rules for Naming Alkanes
(Nomenclature)
The location and name of each substituent are
followed by the root alkane name. The substituents
are listed in alphabetical order (irrespective of any
prefix), and the prefixes di-, tri-, etc. are used to
indicate multiple identical substituents.
H3C1
2
3
H3C
Methyl
4
CH3
Name: 2-methylbutane
Nomenclature Practice
Name this compound
CH3
H3C1 2
Cl
3 4
5
CH3
6
7
9 carbons = nonane
8
H3C9
Step #1: For a branched hydrocarbon, the longest
continuous chain of carbon atoms gives the root name
for the hydrocarbon
Nomenclature Practice
Name this compound
CH3
H3C1 2
Cl
3 4
5
CH3
6
7
8
9 carbons = nonane
CH3 = methyl
chlorine = chloro
H3C9
Step #2: When alkane groups appear as substituents, they
are named by dropping the -ane and adding -yl.
Nomenclature Practice
Name this compound
CH3
H3C1 2
Cl
3 4
5
6
7
9 carbons = nonane
CH3
CH3 = methyl
chlorine = chloro
8
H3C9
1
9 NOT
9
1
Step #3: The positions of substituent groups are
specified by numbering the longest chain of carbon
atoms sequentially, starting at the end closest to the
branching.
Nomenclature Practice
Name this compound
CH3
H3C1 2
Cl
3 4
5
CH3
6
7
9 carbons = nonane
CH3 = methyl
8
chlorine = chloro
H3C9
2-chloro-3,6-dimethylnonane
Step #4: The location and name of each substituent are
followed by the root alkane name. The substituents are
listed in alphabetical order (irrespective of any prefix),
and the prefixes di-, tri-, etc. are used to indicate
multiple identical substituents.
Cyclic Alkanes
Cyclopropane, C3H6
Cyclobutane, C4H8
Cyclopentane, C5H10
Cyclohexane, C6H12
Cycloheptane, C7H14
Remember, explicit hydrogens are left out
Practice
• P. 11-16 #1, 2
Structural Shorthand
Explicit hydrogens (those required to complete
carbon’s valence) are usually left off of
drawings of hydrocarbons
H
CH3
H
H
H
H3C
H
C1 C2 C3 C4
H
H
H
H
H
C1 C2 C3
C4
Line intersections represent carbon atoms
Different Methods of
Displaying Compounds
• Molecular Formula
• Expanded Molecular
Formula
• Condensed
Structural Formula
• Structural Formula
• Line Formula
Naming Alkenes & Alkynes
1. Count the number of C’s in the longest chain
containing the double/triple bond.
•
•
This is the parent chain, determine the root
Number the parent chain so that the double/triple bond has the
lowest possible position number
2. Identify the position numbers of branches
•
Same rules as before
3. Write the branches in alphabetical order
4. Write the root, including a prefix that identifies the
position of the double/triple bond
•
Add the prefix “cyclo” if its cyclic
5. Add the suffix “ene” or “yne”
Naming Alkenes & Alkynes
Naming Aromatics
1. Same rules
2. If benzene is the parent chain “benzene” suffix
3. If benzene is a branch group “phenyl”
Practice
•
•
•
•
P. 16-22 #3-7, 8abc
Naming Alkenes/Alkynes Worksheet
Isomer Challenge Worksheet
Naming Hydrocarbons Worksheet