exam prep

What is the name of this molecule?

• 3-ethyl-2,4-methylheptane

• 2,4-dimethyl-3-ethylheptane

• 3-ethyl-2,4-dimethylheptane

• 5-ethyl-4,6-dimethylheptane

Name this molecule. Spelling and proper use of commas/dashes matter.

Which direction would you number the carbons in the main chain?

• Left to Right

• Right to Left

• It doesn't matter here since both directions would be carbon #2

Name this molecule. Spelling and proper use of commas/dashes matter.

Name this molecule. Spelling and proper use of commas/dashes matter.

Name this molecule. Spelling and proper use of commas/dashes matter.

Name this molecule. Spelling and proper use of commas/dashes matter.

What is the name of this molecule?

• 4-ethyl-6-methyloctane

• 5-ethyl-3-methyloctane

• 2-ethyl-4-methylheptane

• 2,4-diethylheptane

How many carbons are in the main carbon chain in this molecule?

• 8

• 6

• 7

• 9

Answer explanation

If a double bond is present, the main chain must include this double bond, even if there is a longer continuous chain of carbons

Type the name of this molecule. Spelling and proper use of dashes/commas matter!

Answer explanation

Remember that you want the lowest possible numbers when identifying the position of each branch. Left to right, branches would be located at carbons 3, 4, and 6. Right to left, branches would be located at carbons 3, 5, and 6. This tells us to go left to right when numbering.

As a reminder, alphabetical order does NOT influence priority when it comes to numbering. Alphabetical order is only relevant when actually writing out the name.