1. 1.1 Alkanes

2. ORGANIC CHEMISTRY: the study of carbon compounds
ORGANIC COMPOUND:
a molecular compound of carbon (not including CO (g) , CO2 (g) , and HCN (g))

3. Why Carbon? carbon can form 4 covalent bonds
carbon atoms bond to one another to form chains, rings or sheets
carbon can form single, double, or triple bonds
Catenation ability “chain making ability”

4. HYDROCARBONS
… are molecules consisting of a chain of carbon to which H’s are attached. They are useful as fuels. Hydrocarbons are the most basic type of molecule in organic chemistry.

5. ALKANES
Alkanes are saturated hydrocarbons meaning they contain only single bonds. All alkanes have a specific prefix and end in “ane”
The general formula for an alkane is
CnH2n+2

6. No. OF C ATOMS
NAME
CONDENSED FORMULA
STRUCTURAL FORMULA 1
methane
CH4 2
ethane
C2H6 3
propane
C3H8 4
butane
C4H10 5
pentane
C5H12 6
hexane
C6H14 7
heptane
C7H16 8
octane
C8H18 9
nonane
C9H20 10
decane
C10H22

7. EXAMPLE: OCTANE

8. CYCLIC ALKANES
… contain carbon atoms that can join to form a closed ring. They are also known as cycloalkanes.
ex. cyclopropane C3H6 is the simplest cycloalkane.
General formula is CnH2n

9. ALKYL GROUPS
An alkyl group is a hydrocarbon branch attached to the main chain.
Example: A methyl group (CH3) is a fragment of a methane molecule (CH4)
The -yl ending means “a fragment of an alkane formed by removing a hydrogen.”

10. No. OF C ATOMS
ALKYL GROUP
CONDENSED FORMULA 1
methyl
CH3 2
ethyl
C2H5 3
propyl
C3H7 4
butyl 5
pentyl 6
hexyl 7
heptyl 8
octyl 9
nonyl 10
decyl

11. ISOMERS OF ALKYL GROUPS
When alkyl groups have three or more C atoms, they may be attached to the parent chain either at the end C atom or at one of the middle C atoms.
and... k

12. RULES FOR NAMING ALKANES
ID the longest chain first
ID all groups attached to the parent chain (fig 7 p. 11)
number the parent chain so that substituents are attached to the C with the lowest number
if there is a tie, go alphabetically
if the same substituent is present more than once use a prefix to indicate this (di, tri, etc) and include a number to indicate location

13. FINAL NAME SHOULD INCLUDE:
substituents listed in alphabetical order, ignoring prefixes
words separated by hyphens
numbers separated by commas
simple possible arrangement used for parent chain

14. NAME THE FOLLOWING:

15. NAME THE FOLLOWING:

16. NAME THE FOLLOWING:
Could be called 5-tert-butyl-8-ethyl-3-methyldecane or
5-(butan-2-yl)-8-ethyl-3-methyldecane

17. NAME THE FOLLOWING:

18. RULES FOR DRAWING ALKANES
draw the parent chain from the last part of the compound name
identify the C atoms to which the substituents are attached
draw the substituents attached to the parent chain or ring

19. Draw the structural formula for 4-ethyl-3,5-dimethylnonane

20. Draw the structural formula for 7-ethyl-2-methyl-4(propan-2-yl)decane

21. Draw the structural formula for 1-ethyl-2-propylcyclobutane

22. PRACTICE TIME!
p & 2

23. PROPERTIES OF ALKANES C-H bonds are nonpolar (En = 0.4)
H bonds are evenly arranged so molecules also nonpolar
VDW are the main forces at work and since they are weak, they have low MP and BP
BP/MP directly related to the length of the chain

25. FRACTIONAL DISTILLATION

26. ALKYL HALIDES
This is an alkane where a halogen replaces a hydrogen as a substituent group. Alkyl halides are formed by a substitution reaction.
Named by writing the root of the halogen name first, followed by “o”, followed by the name of the parent alkane.

27. NAMING ALKYL HALIDES
a) b)

28. DRAWING ALKYL HALIDES c) 1,1,3-tribromobutane
d) 3-bromo-2,5-difluoro-4-ethylheptane

29. PROPERTIES OF ALKYL HALIDES
halogen atom attached to carbon makes for a very polar bond, so alkyl halides are very polar
dipole-dipole bonds make for higher boiling points
CFC’s (chlorofluorocarbons) used as coolants in refrigerators. They are nontoxic and unreactive. PROBLEM: they destroy the ozone layer!

30. REACTIONS OF ALKANES
generally unreactive at room temperature (ex. with acids, bases, oxidizing agents)
used as fuel b/c complete combustion releases a lot of energy
long chain vs short chain?
Undergo substitution reactions in the presence of UV light and halogens to turn into alkyl halides (or haloalkanes)
complete combustion of butane?
Substitution reaction between butane and chlorine gas?

31. HOMEWORK:
p. 17 # 1-7