Question

What is the best name for this molecule? Explain your naming process. (4 points) A hydrocarbon with seven total carbons single bonded together. There is a straight chain of five carbons across the bottom with one ethyl group (two carbons) branching off of the third carbon.

Answer 1

3-ethyl pentane is the hydrocarbon

Answer 2

Answer:

3-ethyl pentane

Explanation:

1       2       3       4      5

CH₃-CH₂-CH₂-CH₂-CH₃

This is the 5 C straight chain (main chain).  The main chain is called pentane.

1       2       3       4      5

CH₃-CH₂-CH₂-CH₂-CH₃

                |

               C₂H₅

There is one ethyl group (side chain) from the third C atom. And there are a total of 7 C atoms.

So the nomenclature of this molecule is 3-ethyl pentane.