Step 1: Identify the longest continuous chain of carbon atoms in the molecule. In this case, there are 4 carbon atoms.
Step 2: Determine the type of bond present. The molecule has a double bond (indicated by '=') between the third and fourth carbon atoms.
Step 3: Count the total number of carbon atoms. There are 4 carbon atoms, which corresponds to the prefix 'but-' in IUPAC nomenclature.
Step 4: Since there is a double bond, we need to indicate its position. The double bond starts at the first carbon in the chain, so we use '1-' to indicate this.
Step 5: Combine the prefix and the suffix for alkenes. The suffix for a double bond is '-ene'.
Step 6: Put it all together. The IUPAC name is 'but-1-ene', but it is commonly referred to simply as 'butene'.
