2. Naming Alkanes

7/28/2019 2. Naming Alkanes

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HYDROCARBONS


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Hydrocarbons

C C C C

C C

C

C

C

C

C

C

H

H

H

H

H

H

C C C C C

H

H

H

H

H H

H

H

H

H

H

H

Alkanes Alkenes

Alkynes Aromatics

C C C C C

H

H

H

H

H

H

H

H

H

H

C C C C CH

H

H

H

H

H

H

H

CnH2n+2 CnH2n

CnH2n-2

REACTIVE!

REACTIVE!
http://www.youtube.com/watch?v=mAjrnZ-znkYhttp://www.youtube.com/watch?v=mAjrnZ-znkY


3/18

Alkanes and Alkenes and Alkynes

oh my!

Identify each of the following hydrocarbon formulas

as alkane, alkene or alkyne.

C2H6

C5H8

C4H10

C25H52

C14H28 C10H18


4/18

Alkanes and Alkenes and Alkynes

oh my!

Identify each of the following hydrocarbon formulas

as alkane, alkene or alkyne.

C2H6 alkane (CnH2n+2)

C5H8 alkyne (CnH2n-2)



C14H28 alkene (CnH2n) C10H18 alkyne (CnH2n-2)


5/18

Naming Hydrocarbon Molecules

Common names used in the 1800s are still used for some

compounds today:

H C C H

Acetylene

O

C

CH3CH3

AcetoneFormic acid

C

O

OHH

The International Union of Pure and Applied

Chemistry (IUPAC) was established in 1900s

Systematic method allows an infinite number of

compounds to be named given a few rules


6/18

First Ten Hydrocarbons

Name

Methane

Ethane

Propane

Butane

Pentane

Hexane

Heptane

Octane

Nonane

Decane

1

2

3

4

5

6

7

8

9

10

CH4

C2H6

C3H8

C4H10

C5H12

C6H14

C7H16

C8H18

C9H20

C10H22

CH4

CH3CH3

CH3

CH2CH

3

CH3CH2CH2CH3

CH3CH2CH2CH2CH3

CH3CH2CH2CH2CH2CH3

CH3CH2CH2CH2CH2CH2CH3

CH3CH2CH2CH2CH2CH2CH2CH3

CH3CH2CH2CH2CH2CH2CH2CH2CH3

CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3

Number of

Carbon Atoms

Molecular

Formula

Condensed Structural

Formula
http://en.wikipedia.org/wiki/Hydrocarbonhttp://en.wikipedia.org/wiki/Hydrocarbon


7/18

Mnemonic for First Four Prefixes

First four prefixes

Meth-

Eth-

Prop-

But-

Monkeys

Eat

Peeled

Bananas


8/18

?Decade

Decimal

Decathalon

Other Prefixes

Pent-

Oct-

Dec-

Hex-, Hept-, Non-


9/18ane

Naming Alkane Molecules

Rule 1: choose the correct ending

CH3 CH2 C

CH2

CH2 C

CH2

CH3

CH3

CH3

CH3
http://www.youtube.com/watch?v=mAjrnZ-znkYhttp://www.youtube.com/watch?v=mAjrnZ-znkYhttp://www.youtube.com/watch?v=mAjrnZ-znkYhttp://www.youtube.com/watch?v=mAjrnZ-znkYhttp://www.youtube.com/watch?v=mAjrnZ-znkY


10/18

ane


Rule 2: determine the longest carbon chain

CH3 CH2 C

CH2

CH2 C

CH2

CH3

CH3

CH3

CH3


11/18ane


Rule 3: circle all branches

CH3 CH2 C

CH2

CH2 C

CH2

CH3

CH3

CH3

CH3


12/18

CH3 CH2 C

CH2

CH2 C

CH2

CH3

CH3

CH3

CH3

ane


Rule 4: Number each carbon on the parent chain so that the

first branch is the lowest number.

1 2 3 4 56 7


13/18

CH3 CH2 C

CH2

CH2 C

CH2

CH3

CH3

CH3

CH3

ane


Rule 4: Number each carbon on the parent chain so that the

first branch is the lowest number.

7 6 5 4 32 1


14/18heptane


Rule 5: Name the parent chain

1 2 3 4 56 7

CH3 CH2 C

CH2

CH2 C

CH2

CH3

CH3

CH3

CH3


15/18heptane


Rule 5: Name the branches

1 2 3 4 56 7

CH3 CH2 C

CH2

CH2 C

CH2

CH3

CH3

CH3

CH3ethyl

methyl

methyl


16/18heptane


Rule 6: attach name of branches alphabetically

1 2 3 4 56 7

CH3 CH2 C

CH2

CH2 C

CH2

CH3

CH3

CH3

CH3ethyl

methyl

methyl

3-ethyl- 5-methyl5-methyl-


17/18heptane


Rule 7: group similar branches

1 2 3 4 56 7

CH3 CH2 C

CH2

CH2 C

CH2

CH3

CH3

CH3

CH3ethyl

methyl

methyl

3-ethyl- 5-methyl- 5-methyl5,5-dimethyl


18/18

CH3

CH

CH

CH2

CH3

CH3

CH2CH3

3-ethyl-2-methylpentane

CH3 CH2

CH CH3

CH2CH2

CH3

3-methylhexane

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2. Naming Alkanes