Download Hydrocarbons

Hydrocarbons
The basis for organic chemistry
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)
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
Drawing Hydrocarbons
CH
H3C
CH3CH2CH2CH3
Hydrocarbon Root Names
# of Carbons
1
2
3
4
5
6
7
8
9
10
Root Name
methethpropbutpenthexheptoctnondec-
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. 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
Examples
Cyclic Alkanes
Cyclopropane, C3H6
Cyclobutane, C4H8
Cyclopentane, C5H10
Cyclohexane, C6H12
Cycloheptane, C7H14
Remember, explicit hydrogens are left out
Examples
Practice
• P. 11-16 #1, 2
• Naming Alkanes Worksheet
• Alkane Challenge Worksheet
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
Structural Isomers
• Structural isomers are compounds with the
same molecular formula but different
structural arrangements
• They will have different physical and
chemical properties
• Example:
– pentane
– 2-methylbutane
– 2,2-dimethylpropane
Cis-Trans Isomers
• Cis-trans isomers occur when different groups of
atoms are arranged around a double bond
• Unlike a single C-C bond that can rotate, the
double C=C bond is fixed
Same
side
Opposite
side
cis-1,2-dichloroethene
trans-1,2-dichloroethene
Cis-Trans Isomers
Examples:
• cis-3-pentene
• trans-2-hexene
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