1. Chapter 11 Organic Chemistry
The study of the compounds of carbon

2. Some Properties Typical of Organic Compounds
Organic compounds form covalent bonds
have low melting points and boiling points
tend to be flammable
are soluble in non-polar solvents
are not very soluble in water
Oil and water
A Review of the Bonding in Carbon
Compounds of Carbon and Hydrogen
Carbon has 4 valence electrons, and hydrogen has 1;
to achieve an octet, C forms four bonds
We will use a line __ to indicate the sharing of 2 electrons

3. You may recall that when 4 groups are attached to a central atom, the groups arrange themselves so they point to the corners of a tetrahedron
The following illustrates 4 different but equivalent ways of illustrating the structure of methane:
Compound solely of carbon and hydrogen are called hydrocarbons;
if more than on carbon atom is present, then the molecule must have carbon-carbon bonds. The molecule shown below is called ethane
CH3CH different ways of writing ethane

4. If carbon can form stable bonds to itself, there is no reason why there can’t be hydrocarbon composed of more than 2 carbons

5. Butane (butane lighter) has the following structures:
Although the two forms of butane shown differ in the orientation of the CH3 groups circled, rotation of the groups as shown occurs quite rapidly
Butane, C4H10 has one other feature worth describing.
In the structure shown above, each carbon is either
attached to one or two other carbon atoms.
Consider a different way in which these four
carbon atoms can be attached
The lower molecule is called isobutane

6. If we consider hydrocarbons with 5 carbons, you can imagine a number of ways of putting the carbon backbone together
CH3-CH2-CH2-CH2-CH3
C – C – C
All of these compounds have a molecular formula of C5H12 are referred to as structural isomers. All are known compounds
Structural isomers have similar but different properties and can be distinguished from one another by identifying carbon atoms that have different number of carbon atoms attached
Are these structural isomers?
These are two different ways of drawing the same compound

7. butane
Some different ways of writing butane; all of then refer to the same compound because of rotation about the carbon-carbon bonds

8. A systematic way of naming alkanes and identifying identical structures
1. Locate the longest carbon chain in the molecule: this identifies the parent alkane
the longest carbon chain is 4:
butane
2. Identify the points of branching and count the number of carbons in each branch
2 points of branching at the same carbon: each 1 carbon
3. Name the branch on the basis of the number of carbons by dropping the ane of the parent and adding yl:
methane methyl
4. Give the first branch encountered the lowest number and use the prefix di, tri, tetra, ... for multiple groups
2 methyl groups both at carbon 2
2,2-dimethylbutane

9. Name the following:
hexane
parent:
groups
position of groups
both methyl
2 at carbons 2 and 4
2,4-dimethylhexane
parent:
groups
position of groups
heptane
2 chlorines and methyl
chlorine at positions 3 and 5, methyl at position 3
Cl as a group is named chloro
3,5-dichloro-3 methylheptane

10. Name this compound:
5, pentane
longest carbon chain
groups:
chloro, methyl
CH3 at C2 and Cl at C3
location:
3-chloro-2-methylpentane
CH3-CH2-CH2-CH2-CH2-CH2-CH-CH2-CH2-CH3 │
CH2CH3
longest carbon chain
groups:
10, decane
ethyl
4-ethyldecane
location:
ethyl at C4

11. What is a general molecular formula for these alkanes?
if n = the number of carbon atoms, note that the number of hydrogens is?
2n+2
The general formula for all the compounds is given by CnH2n+2
How many C?
How many H? 8 18
2*8+2 = 18

12. . Can we make an alkane with n C but less the 2n+2 hydrogens?
H-CH2CH2CH2CH2-H .
cycloalkanes can have less the (2n+2) H’s
C3H6
C4H8
C5H10
C6H12

13. parent: cyclohexane
groups: ethyl, chloro
location: 1, 3 
1-chloro-3-ethylcyclohexane
1-ethyl-3-chlorocylohexane
The textbook often draws hydrocarbons without all of the hydrogen shown. This is an abbreviated way of drawing the molecule. Please remember that carbon always has 4 bonds to it and if all the bonds are not designated, you need to assume there are hydrogens at these positions
parent:
groups:
cyclopentane
isopropyl
isopropylcyclopentane

14. Properties of n-alkanes
The properties of alkanes include being
nonpolar
insoluble in water
less dense than water
flammable in air
Alkanes with 1–4 carbon atoms are
methane, ethane, propane, and butane
all are gases at room temperature
all are used as heating fuels
Alkanes with 5–8 carbon atoms are liquids at room temperature
all are very volatile
all are found in gasoline
Alkanes with 9–17 carbon atoms are liquids at room temperature
all have higher boiling points
all are found in kerosene, diesel, and jet fuels
Alkanes with 18 or more carbon atoms
are waxy solids at room temperature
are used in waxy coatings of fruits and vegetables

15. The hydrocarbons in crude oil are often cracked to produce smaller hydrocarbons which are separated by their different boiling points
All hydrocarbons can be burned in oxygen to produce carbon dioxide and water
C8H O2 = CO H2O + Heat
C8H O2 = 8CO H2O + Heat
C8H /2O2 = 8CO2 + 9H2O + Heat
2C8H O2 = 16CO2 +18H2O + Heat

16. .. Compounds of carbon with other elements
Oxygen oxygen has 6 valence electrons; needs to form 2 bonds .. O
If a molecule contains a hydroxyl (–OH) group, it is called an alcohol.
The the oxygen atom is bonded to two carbon atoms it is called an ether (–C–O–C–) .
ethyl alcohol, ethanol hydroxyethane O
In both these cases, the oxygen is single bonded to carbon

17. Compounds of carbon with other elements
Nitrogen nitrogen has 5 valence electrons; needs to form 3 bonds .. N
In an amine, nitrogen is attached by a single bond to 1, 2, or 3 different carbon atoms
2 carbons

18. A Summary of the typical functional groups encountered in organic chemistry
are a characteristic feature of organic molecules that behave in a predictable way
are composed of an atom or group of atoms
are groups that replace a H in the corresponding alkane
provide a way to classify families of organic compounds