1. (1.2) Hydrocarbons - An Introduction

2. Organic Compounds Organic compounds are molecular compounds of carbon.
A hydrocarbon is an organic compound that contains only C and H atoms.
Ex. butane (C4H10) or benzene (C6H6)

3. Organic or Inorganic Sugar vs. Salt
C12H22O11
Sugar vs. Salt
Which is inorganic and which is organic?
Organic compounds are carbon based,
therefore sugar is organic, and salt is inorganic.
NaCl

4. Why Study Organic Chemistry?
When you study organic chemistry you are studying the substances that make up your body and much of the world around you.
We can use the knowledge of organic compounds and synthesize them from inorganic compounds.

5. Classifying Hydrocarbons
We classify hydrocarbons based upon their covalent bonds between carbon atoms and functional groups.
Hydrocarbons
Aliphatics
Alkanes
Alkenes
Alkynes
Aromatics
Derivatives
ex. Alcohols, esters, amino acids

6. Classification of Aliphatic Hydrocarbons
Recall: Carbon can share 4 electrons
There are 3 types of aliphatic hydrocarbons:
1. Alkanes: all carbon atoms are bonded to one another by single bonds
C-C
have maximum possible # of H atoms
referred to as saturated hydrocarbons

7. Classification of Aliphatic Hydrocarbons
2. Alkenes: at least 1 double bond between carbon atoms is present
C=C
have less than maximum possible # of H atoms
referred to as unsaturated hydrocarbons
3. Alkynes: at least 1 triple bond between carbon atoms is present
C  C
also referred to as unsaturated

8. Properties of Alkanes
Consider the properties of the following alkanes:
CH4 (natural gas) - methane
C3H8 (propane burner) - propane
C4H10 (fuel in a cigarette lighter) - butane
C8H18 (gasoline) - octane
C25H52 (paraffin wax)
Note the variety!

9. The “Backbone”
These carbon – carbon bonds are referred to as the backbone of organic compounds.
That is because they are the main structure from which the functional groups branch.
The backbone can be a straight chain, branched chain, or cyclic.

10. Representing Hydrocarbons
Molecular formula
e.x. pentane C5H12
Expanded molecular formula
e.x. CH3CH2CH2CH2CH3
Condensed Molecular formula
e.x. CH3(CH2)3CH3

11. Drawing Hydrocarbons – 4 Methods
Consider 3 hydrocarbons methane, butane, pentane
There are four methods used to draw these molecules
3-Dimensional sketch
show shape around C atoms
show all the atoms
use lines, dashes and wedges to represent the 3-D structure of the bonds between atoms.

12. Drawing Hydrocarbons – 4 Methods
Consider 3 hydrocarbons methane, butane, pentane
2) Complete Structural Diagram
show all the atoms
use lines to represent bonds between atoms

13. Drawing Hydrocarbons – 4 Methods
Consider 3 hydrocarbons methane, butane, pentane
3) Condensed Structural Diagram
show only C-C bonds
C-H bonds are assumed to be present but not shown

14. Drawing Hydrocarbons – 4 Methods
Consider 3 hydrocarbons methane, butane, pentane
4) Line Structural Diagram
show only C-C bonds
the ends of the lines, and points where they meet, represent C atoms

15. Naming Hydrocarbons Need to memorize the “root”.
# C atoms
Root 1
Meth 2
Eth 3
Prop 4
But 5
Pent 6
Hex 7
Hept 8
Oct 9
Non 10
Dec
Need to memorize the “root”.
We name hydrocarbons based upon how many carbon atoms are present.