1.2 Hydrocarbons
Hydrocarbons are the simplest type of organic compounds composed of Carbon and Hydrogen only
They are non-polar because they have only single bonds
2 types of Hydrocarbons
1. Aliphatic
a. Carbon atoms that are bonded in one or more chains and rings
b. contain single, double or triple bonds
2. Aromatic
a. Based on the aromatic benzene group
b. Benzene is the simplest aromatic compound
Alkanes, Alkenes and Alkynes
Alkane
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has only single bonds
do not contain rings
general formula is CnH2n+2
Example
Cycloalkane
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ring shape connected by single bonds
Example
Alkene
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Has at least one double bond
general formula CnH2n
a double bond contains 2 bonds (1 strong and 1 weak) these are more reactive
Example
Alkyne
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Has at least one triple bond
General formula CnH2n-2
even more reactive than alkenes
Example
Functional Groups
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a reactive group of bonded atoms that appears in all members of a chemical family
these groups determine physical and chemical properties
Common Functional Groups
Rules For Naming Organic Compounds
Three parts to an Organic compound name
Prefix
+
Root
+
Suffix
Root
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indicates the # of Carbon atoms in the longest chain that contains the functional group
root names see tale 1.2 page 13
Suffix
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indicates the type of compound according to the functional groups present
ane = alkane
ene = alkene
yne = alkyne
Prefix
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indicates the name and location of each branch and/or functional groups attached to the main
chain
table 1.3 page 14 and your cheat sheets
Steps to Naming Hydrocarbons
1. Find the root
a. longest chain containing the functional groups
b. count # of C’s obtain the root using table
c. if cyclic add the prefix “cyclo” before the root
2. Find the suffix
a. functional groups determine the suffix. Use your common organic families sheet here
b. if more than one functional group use prefix di(2) and tri(3) to indicate the number of
them
3. # the Main Chain
a. # from the end that is closest to any functional groups
b. # so any branches have the lowest position
4. Find the Prefix
a. Name each branch as an alkyl group and give its position #
b. if more than one branch put in alphabetical order
Examples
Steps to drawing hydrocarbons
1. Draw the main chain according to the root name # of carbons
2. add double or triple bonds according to the suffix
3. add branches according to the prefix
4. add H atoms so each carbon has 4 bonds
Examples
Aromatic Compounds
hydrocarbons that have a benzene ring
Naming Aromatic compounds
1.
# the Carbons in the benzene ring if more than 1 branch attached to the ring start numbering at
the Carbon with highest priority (page 18)
2. Name any branches attached to Benzene ring and give position #’s. if only one branch this is not
necessary
3. Place the position #’s and names of these branches before the root name benzene
Worksheets:
Extra practise Questions
BLM 1-2
BLM 1-3