Everything Science Grade 12

CHAPTER 1. ORGANICMOLECULES 1.7

Carbon atoms prefix

1 meth(ane)

2 eth(ane)

3 prop(ane)

4 but(ane)

5 pent(ane)

6 hex(ane)

7 hept(ane)

8 oct(ane)

9 non(ane)

10 dec(ane)

Table 1.2: The prefix ofa compound’s name isdetermined by the number of carbon
atoms in the longest chain

See video: VPmqb at http://www.everythingscience.co.za

Example 1: Naming the alkanes

QUESTION

Give the IUPAC name for the following compound:

H C(1)

H

H

C(2)

H

H

C(3) C(4)

H

H

H

H

H

Note: The numbers attached to the carbon atoms would not normally be

shown. The atoms havebeen numbered to helpyou to name the compound.

SOLUTION

Step 1 : Identify the functionalgroup

The compound is a hydrocarbon with single bonds between the

carbon atoms. It is an alkane and will have a suffix of -ane.

Step 2 : Find the longest carbonchain

There are four carbon atoms in the longest chain. The prefix of

the compound will be ’but’.