Nomenclature Flashcards
how would you write the number of carbon atoms for a molecule
- by using a letter code
- like meth = one carbon atoms or prop = three
what is the mnemonic for the first five number of carbon atoms
- Monkeys Eat Peeled Bananas (Partially)
- M = meth = one carbon atom
- E = eth = two carbon atoms
- P = prop = three carbon atoms
- B = but = four carbon atoms
- P = pent = five carbon atoms
why are suffixes and prefixes used when naming molecules
- to indicate the presence of atoms other than carbon and hydrogen
how would a suffix or prefix be written with 2 examples
- by adding other letters before or after the code for the number of carbon atoms
- like bromo = an atom of bromine, making bromoethane
- or ol = a hydoxyl group (OH) at the end of alcohols
why would you need to multiply prefixes and are the common ones
- to show the presence of two or more identical groups
- usually with di or tri = two or three
what are locants
where atoms and groups can have different positions in a molecule
what are used to show the positions of locants in the name of a molecule
numbers and hyphens
what do the numbers used to show locants specifically indicate
the carbon atom in the longest chain that the group is attached to
what would a locant of 2- be telling us
- that the group of atoms are attached to the second carbon atom
- in the longest chain of carbon atoms
what are the codes and prefixes for the number of carbon atoms up to 5
- meth = methyl
- eth = ethyl
- prop = propyl
- but = butyl
- pent = pentyl
what is the name of CH3-CH2-CH3
propane
what is the name of CH3-CH-CH3
|
CH3
methylpropane
why doesnt that methylpropane have a 2- at the beginning of it to show the locant
- if the methyl group was attached to the first or third carbon atom
- that would simply make a chain 4 carbon atoms long
- making it butane
- therefore the locant isnt needed at that is the only position the methyl could be in for the code to still be prop(ane)
what is the name of CH3-CH2-CH-CH2-CH3
|
CH3
and why
3-methlypentane
- the longest chain consists of 5 carbon atoms
- and the methyl is attached to the third carbon atom
- this time the locant can be shown because the code wouldnt change if it was bonded to the 2nd or 4th carbon atom
what is the name of CH3-CH2-CH2-CH-CH3
|
CH3
and why
2-methylpentane
- it is not 4-methyl as the lowest locant should be used
- considering 4 and 2 would both indicate exactly the same molecule
- just flipped over
what is the name of:
CH3
|
CH3-CH-CH-CH3
|
CH3
and why2,3-dimethylbutane
- there are two locants showing where two of the methyl molecules are
- the numbers should be in chronological order from the smallest if it is the same prefix
- because there are two you multiply the prefix to dimethyl
- and the longest chain that can be made consists of 4 carbon atoms so it is butane
what is the name of:
CH2-CH3
|
CH3-CH2-CH-CH-CH3
|
CH3
and why3-ehtyl-2methylpentane
- the prefixes must be in alphabetical order if they are different
- it is not 4methyl as that isnt the smallest number
- and 3 + 4 is higher than the number of carbon atoms making the longest chain(5) which would be 3 + 2
what is the name of CH3-CH2-OH
ethanol
what is the name of CH3-CH2-CH2-OH
propan-1-ol
what is the name of CH3-CH-CH-CH3
| |
OH CH3
3-methylbutan-2-ol
- it is not 2-methylbutan-3-ol because the lowest locant should be used for the suffix over the prefix
- as the suffix indicates the functional group
what is the name of:
CH3
|
CH3-C-CH2-CH2-OH
|
CH3
and why3,3-dimethylbutan-1-ol
- the use of prefixes, suffixes and a comma is kinda long
- the suffix comes first so its 1 going from right to left
- the two methyl molecules are bonded to the 3rd carbon atom in this direction
- so the multiplied prefix is dimethyl and you have one on the 3rd twice
- giving 3,3
what would dimethylpropane look like
CH3
|
CH3-C-CH3
|
CH3what would 3-methylbutan-1-ol look like
CH3-CH-CH2-CH2-OH
| |
CH3 (OH) or this
