1. What do these have in common?

2. Hydrocarbons – organic compounds that contain
only atoms of hydrogen and carbon.
As the number of carbons in a hydrocarbon increases,
its boiling point (bp) increases. This is because bigger
molecules attract each other with greater dipole-dipole
forces. This holds them together better in a liquid and
makes it harder to break them apart
into gases. H C
bp = C
bp = -89 0C
bp = 36 0C

4. The alkanes are a homologous series of
saturated (only single bonds) hydrocarbons
that release energy when burned.
methane CH4
ethane C2H6
propane C3H8
butane C4H4
ETC.

5.  Each next heavier member of the alkanes
is formed by adding a CH2 unit. See
Ex. ethane + CH2 unit  propane
General formula for alkanes: CnH2n+2 (see Table Q)
n = 1: CnH2n+2 = C1H2•1+2 = C1H4 = CH4  methane
n = 2: CnH2n+2 = C2H2•2+2 = C2H  ethane
n = 3: CnH2n+2 = C3H2•3+2 = C3H  propane
n = 4: CnH2n+2 = C4H2•4+2 = C4H  butane H C

6. Compounds in which each member differs from the
one before it by the same additional unit are called
a homologous series.
Ex. What is the molecular formula for the alkane that has 8 carbon atoms?
alkane formula: CnH2n+2
n = 8: CnH2n+2 = C8H2•8+2 = C8H18
Sketch its structural
formula:
Ball and stick view:
Skeletal view:
Note how the actual shaped is bent or kinked.

7. Use Table P to name them.
Each alkane is named by
adding the prefix to –ane.
Ex. What is the name of the
alkane of the last example?
Ex. What is the name of the
alkane that has five C atoms?
What is its molecular formula?
Sketch its structural formula.
octane
pentane
C5H12

8. B. The alkenes are a homologous series of
unsaturated (not all single bonds) hydrocarbons
that contain one double bond.
 There must be at least 2 carbon atoms to
form an alkene. The simplest member is
ethene (also known as ethylene and olefin).
ethene:
structural
formula:
C2H4
Other views:

10. Many ethylenes = polyethylene
Polyethylene or polythene (IUPAC name polyethene or poly(methylene)) is the most widely used plastic, with an annual production of approximately 80 million metric tons.[1] Its primary use is within packaging (plastic bag, etc.).

12. HDPE is used in products and packaging such as milk jugs, detergent bottles, margarine tubs, garbage containers and water pipes. One third of all toys are manufactured from HDPE. In 2007 the global HDPE consumption reached a volume of more than 30 million tons.[6

13. Next alkene after ethene:
propene
molecular formula:
C3H6
Other
views:
structural formula:
How many carbon atoms does it have? 3
How many double bonds? 1

14. The next alkenes are: butene, pentene, etc.
Alkenes are named using the same prefixes
that are used for alkanes.
The general formula for
alkenes is in Table Q:
CnH2n
Ex. What are the name and
general formula for the alkene
that has nine carbon atoms?
C9H18

15. C. The alkynes are a homologous series of
unsaturated (not all single bonds) hydrocarbons
that contain one triple bond.
As with the alkenes, there must be at least 2
carbon atoms to form an alkyne. The simplest
member is ethyne (also known as acetylene):
molecular formula:
structural formula:
Other views:
C2H2

16. Next alkyne after ethyne:
propyne
molecular formula:
C3H4
Other
views:
structural
formula:
How many C atoms does it have? 3
How many double bonds? 1

17. The next alkynes are: butyne, pentyne, etc.
Alkenes are named using the same prefixes
that are used for alkanes and alkenes.
The general formula for
alkenes is in Table Q:
CnH2n-2
Ex. What are the name and
general formula for the alkyne
that has seven carbon atoms?
heptyne

18. Ex. Name and give the molecular formula of the…
…alkane with 6 carbon atoms:
…alkene with 10 carbon atoms:
…alkyne with 5 carbon atoms:
Ex. Circle all alkanes, star all alkenes and box all
alkynes in the list below. (Some are not possible.)
CH4 C3H8 C2H2
C5H10 CH2 C3H8
C4H10 C6H10 C7H12
C20H42 C3H6 C9H20
C3H10 C2H4 C8H14
hexane
decene
pentyne

19. double +2
double
double - 2

20. Ex. Name and give the molecular formula of the…
…alkane with 6 carbon atoms:
…alkene with 10 carbon atoms:
…alkyne with 7 carbon atoms:
Ex. Circle all alkanes, star all alkenes and box all
alkynes in the list below. (Some are not possible.)
Mark with an S for saturated and a U for unsaturated.
CH4 C3H8 C2H2
C5H10 CH2 C3H8
C4H10 C6H10 C7H12
C20H42 C3H6 C9H20
C3H10 C2H4 C8H14
hexane
decene
heptyne S S U U U S S U U S U S U U

21. Ex. Put in order of increasing boiling points
from left to right:
decane, ethane, nonane, pentane,
Ex. What are the names of the following? 1. 2. 3.
ethane,
pentane,
nonane,
decane
butyne
heptane
hexene

22. What is this ring of
hydrocarbons, which is
produced in volcanoes,
forest fires and cigarette
smoke…?
Very useful,
very toxic.

23. D. The examples so far are open hydrocarbons.
Other types include cyclic hydrocarbons. Two
examples of these are shown here:
structural
skeletal
structural
skeletal
cyclo
_______ hexane
a _________ “ring”
benzene
Are the above two compounds alkanes,
alkenes or alkynes?
cyclohexane is an alkane
benzene is in a class by itself