topic 6 - introduction - alkanes

Topic 6Topic 6

HydrocarbonsHydrocarbons

What are Hydrocarbons?What are Hydrocarbons?

• A A hydrocarbonhydrocarbon is a molecule which is a molecule which contains only the elements contains only the elements CarbonCarbon and and Hydrogen.Hydrogen.

• Hydrocarbons are obtained from the Hydrocarbons are obtained from the FractionalFractional DistillationDistillation of crude oil. of crude oil.

• We use them for We use them for fuelsfuels in cars in cars (octane) and in cookers (methane). (octane) and in cookers (methane).

How Do We Group All These How Do We Group All These Hydrocarbons Together?Hydrocarbons Together?

Hydrocarbons Hydrocarbons

•Homologous SeriesHomologous Series• a group of chemically similar compounds a group of chemically similar compounds

which can be represented by a general which can be represented by a general formula. formula.

• Physical properties change gradually through Physical properties change gradually through the series the series

• Alkanes Alkanes

• AlkenesAlkenes

• CycloalkanesCycloalkanes

AlkanesAlkanes

• MethaneMethane MonstersMonsters• EthaneEthane Eat Eat • PropanePropane PupilsPupils• ButaneButane ButBut• PentanePentane PreferPrefer• HexaneHexane HairyHairy• HeptaneHeptane HaggisHaggis• OctaneOctane oror• NonaneNonane Nice Nice • DecaneDecane DinnersDinners

Alkanes - MethaneAlkanes - Methane

• 3D Full Structural 3D Full Structural 2D Full 2D Full Structural Structural

Formula Formula FormulaFormula

AlkanesAlkanes

• Each member can be represented in Each member can be represented in three different ways:three different ways:

MethaneMethane PropanePropane• Full Structural Full Structural

Formula Formula • Shortened Structural Shortened Structural

FormulaFormula• Molecular FormulaMolecular Formula

AlkanesAlkanes

• The Alkanes are a family of The Alkanes are a family of hydrocarbons and all share the hydrocarbons and all share the same chemical properties:same chemical properties:• Single Carbon to carbon bonds ( - C – Single Carbon to carbon bonds ( - C –

C - )C - )• All end in -‘ane’All end in -‘ane’• Saturated hydrocarbonsSaturated hydrocarbons• All share a General Formula All share a General Formula

AlkanesAlkanes

AlkaneAlkane

(Carbon (Carbon Atoms)Atoms)

MoleculaMolecular Formular Formula

Shortened Shortened Structural Structural FormulaFormula

Full Full Structural Structural FormulaFormula

Boiling Boiling

PointPoint

MethaneMethane

(1)(1)-164-164

EthaneEthane

(2)(2)CC22HH66 CHCH33CHCH33 - 89- 89

PropanePropane

(3)(3)

AlkanesAlkanes

AlkaneAlkane





Boiling Boiling

PointPoint

MethaneMethane

(1)(1)CHCH44 CHCH44 -164-164

EthaneEthane

(2)(2)CC22HH66 CHCH33CHCH33 - 89- 89

PropanePropane

(3)(3)CC33HH88 CHCH33CHCH22CHCH33 - 42- 42

AlkanesAlkanes

AlkaneAlkane





Boiling Boiling

PointPoint

ButaneButane (4)(4)

PentanePentane

(5)(5)

HexaneHexane

(6)(6)

AlkanesAlkanes

AlkaneAlkane





Boiling Boiling

PointPoint

ButaneButane (4)(4)

CC44HH1010 CHCH33CHCH22CHCH22

CHCH33

-1-1

PentanePentane

(5)(5)CC55HH1212 CHCH33CHCH22CHCH22

CHCH22CHCH33

3636

HexaneHexane


CHCH22CHCH22CHCH33

6969

AlkanesAlkanes

AlkaneAlkane





Boiling Boiling

PointPoint

HeptaneHeptane

(7)(7)

OctaneOctane

(8)(8)

AlkanesAlkanes

AlkaneAlkane





Boiling Boiling

PointPoint

HeptaneHeptane


CHCH2 2

CHCH22CHCH22CHCH33

9898

OctaneOctane


CHCH2 2

CHCH22CHCH22CHCH33

126126

AlkanesAlkanes

General Formula for alkanes is CGeneral Formula for alkanes is CnnHH2n+22n+2

The number of Hydrogen atoms = 2 times the number of Carbon atoms plus 2

topic 6 - introduction - alkanes

Documents

alkanesgeneral formula

family of hydrocarbons

number of carbon atoms

hydrocarbons homologous

single carbon

elements carbon

carbon bonds c c

ethane 2c2h6ch3ch3