Chapter 11: Nomenclature Flashcards
What groups can hydrocarbons be classified into?
- Aliphatic
- Alicyclic
- Aromatic
What is an aliphatic compound?
- A compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings
What is an alicyclic compound?
- An aliphatic compound arranged in non-aromatic rings with or without side chains
What is an aromatic compound?
- A compound containing a benzene ring
What are alkanes?
- Hydrocarbons containing single carbon-carbon bonds
What are alkenes?
- Hydrocarbons that contain at least one carbon-carbon double bond
What are alkynes?
- Hydrocarbons that contain at least one carbon-carbon triple bond
What is an alkyl group?
- A side chain formed by removing a hydrogen atom from an alkane parent chain
- It has the formula CnH2n+1
- It is often shown as R
What is an aryl group?
- A group containing a benzene ring
What does the stem of a molecule’s name show?
- The number of carbon atoms in the largest continuous chain
What do prefixes show about a molecule?
- The presence of side chains or functional groups
What does the suffix of a molecule show?
- Functional groups
List the 5 main rules for nomenclature.
- Identify the suffix
- Identify the longest continuous chain
- Number the carbons
- Identify which number carbon the side chains and functional groups are on
- Combine the suffix, stem and side chains to name the compound
What do you do if there are 2 continuous chains of the same length?
- The one with more branches is the longest
Which end do you number the carbons from?
- The side that will give side chains/ functional groups the lowest number
- If the numbers would be the same either way, you give higher priority functional groups the lowest numbers
List the 9 main functional groups in order of decreasing priority.
- Carboxylic acids
- Amides
- Aldehydes
- Ketones
- Alcohols
- Alkenes
- Benzene
- Alkanes
- Haloalkanes
How do you indicate that there are multiple of the same side chain/ functional group?
- You use the prefixes di, tri and tetra
How do you bring the prefixes, suffixes and stems of molecules together?
- You write the side chains/ other functional groups in front of the stem in alphabetic order (ignoring prefixes such as di, tri and tetra)
- You put commas between numbers and dashes between numbers and letters
- If there are 2 suffixes that need to go after the stem, the lower priority one becomes a prefix instead
Since the stem is mostly the alkane’s name: - If the stem is followed by a vowel, it loses its e (propanol)
- If it is followed by a consonant, it keeps the e (ethanenitrile)
How are alicyclic alkanes named?
- In the same way as alkanes, but the prefix ‘cyclo’ is added
- When a cycloalkane is the shorter chain, it is named like an alkyl group, and the prefix ‘cyclo’ is still used
How are haloalkanes named?
- The following prefixes are added:
- chloro
- bromo
- iodo
How are alkenes named?
- In the same way way as alkanes, but with the suffix ‘ene’
- If the longest chain has 4 or more carbons, the position of the double bond has to be shown
- Di, tri or tetra are used if there are multiple double bonds
- E.g. but-2-ene/ penta-1,3-diene
How are alcohols named?
- With the suffix ‘ol’, and a number before it to show where the hydroxyl group is
- However, if a higher priority functional group is present, it is shown using the prefix ‘hydroxy’ instead
What is a ketone?
- Carbon-oxygen double bond (in the middle of a chain), which is known as a carbonyl group
How are ketones named?
- With the suffix ‘one’, and the number before it
- If necessary, with the prefix ‘oxo’
What are aldehydes?
- They have the functional group CHO (carbon-oxygen double bond)
How are aldehydes named?
- With the suffix ‘al’
- A number is not needed as they can only go at the end of a chain, and therefore would be on carbon number 1
How are carboxylic acids named?
- With the suffix ‘oic acid’
- They do not need a number as they would always be on carbon 1
