Everything Science Grade 12

1.7 CHAPTER 1. ORGANICMOLECULES

There are no branched groups in this molecule.

Step 5 : Name the compound

The name of this compound is but-2-ene.

Example 6: Naming the alkenes

QUESTION

Draw the structural formula for the organic compound 3-methyl-butene

SOLUTION

Step 1 : Identify the functionalgroup

The suffix -ene means that this compound is an alkene and there

must be a double bondin the molecule. Thereis no number

immediately before thesuffix which means thatthe double bond

must be at the first carbon in the chain.

Step 2 : Determine the numberof carbons in the longest chain

The prefix for the compound is ’but’ so there must be four carbons

in the longest chain.

Step 3 : Look for any branchedgroups

There is a methyl groupat the third carbon atomin the chain.

Step 4 : Combine this information to draw the structural formula for this

molecule.

C

H

H

C

H

C

H

H C

H

H

C

H

H

H