Compounds in which each member differs from the one before it by the same additional unit are called a homologous series. Ex: methane, ethane, propane, etc.

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.

Use the table shown 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 thealkane that has five C atoms?

What is its molecular formula?

Sketch its structural formula.

octane

pentane

C5H12

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 isethene (also known as ethylene and olefin).

ethene: structuralformula:

Other views:

C2H4

Ethene is the chemical that causes fruits to ripen.

They produce it naturally or it can be artificially applied.

Many geologists and scholars believe that the famous Greek Oracle at Delphi went into her trance-like state as an effect of ethylene rising from ground faults.

Next alkene after ethene: ___________

Other views:

molecular formula:

structural formula:

C3H6

propene

How many carbon atoms does it have?

How many double bonds?

3

1

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:

CnH2n

Ex. What are the name and general formula for the alkene that has nine carbon atoms?

C9H18

nonene

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

Ethene = acetyleneCombustion of acetylene with

oxygen produces a flame of over 3600 K (3300 °C, 6000 °F),

Oxyacetylene is the hottest burning common fuel gas

Demonstration:

CaC2 + 2H2O → Ca(OH)2 + C2H2

Carbide lamps:

In carbon-14 dating, the object to be datedhas carbon C. It is allowed to come intocontact with lithium metal to form lithiumcarbide.

LiC2 + 2H2O → 2CaOH + C2H2

Next alkyne after ethyne:

Other views:

molecular formula:

structural formula:

C3H4

propyne

How many C atoms does it have?

How many triple bonds?

3

1

The next alkynes are: butyne, pentyne, etc.Alkynes are named using the same prefixes that are used for alkanes and alkenes.

The general formula for alkynes is:

CnH2n-2

Ex. What are the name and general formula for the alkyne that has seven carbon atoms?

heptyne

misprint!!!

Ex. Name and give the molecular formula of the…

…alkane with 6 carbon atoms:

…alkene with 10 carbon atoms:

…alkyne with 7 carbon atoms:

hexane

decene

heptyne

In sum:

C6H14

C10H20

C7H12

D. The examples so far are _______ hydrocarbons.

Other types include ________ hydrocarbons. Two

examples of these are shown here:

_______ hexane A _________ “ring”

structural skeletal structural skeletal

Hydrocarbons with __________ single & double bonds

are called _______. Benzine itself is a colorless, highly

flammable liquid found in _______. It is ____________.

It is used to make solvents, dyes, and ____________.

cyclo benzene

open

cyclic

alternating

aromaticscrude oil carcinogenic

polymers

Steroids – 3 cyclohexanes and 1 cyclopentane fused together

Examples: Cholesterol the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone, as well ashundreds of others found inplants, animals and fungi.They differ from each other by the functional groups attached to this four ring core and by the oxidation state of the rings.

What is this ring of hydrocarbons, which isproduced in volcanoes,forest fires and cigarettesmoke…?

Very useful,very toxic.