Ch. 3: An Introduction to Organic Compounds Flashcards
What is an alkane?
a compound composed only of carbon and hydrogen atoms and contain only single bonds
What is a hydrocarbon?
compounds that contain only carbon and hydrogen atoms
What is a straight-chain alkane?
alkanes in which the carbons form a continuous chain with no branches
CH4
methane
CH4
C2H6
ethane
CH3CH3
C3C8
propane
CH3CH2CH3
C4C10
butane
CH3CH2CH2CH3
C5H12
pentane
CH3(CH2)3CH3
C6H14
hexane
CH3(CH2)4CH3
C7H16
heptane
CH3(CH2)4CH3
C8H18
octane
CH3(CH2)6CH3
C9H20
nonane
CH3(CH2)7CH3
C10H22
decane
CH3(CH2)8CH3
What is a homologous series?
a family of compounds in which each member differs from the one before it in the series by one methylene (CH2) group. the members of a homologous group are called homologues.
What’s the general molecular formula for an alkane?
CnH2n+2, where n is any positive integer
How many possible structures are there for methane, ethane, and propane?
one possible structure for each
How many possible structures are there for butane?
two possible structures
What are constitutional isomers?
compounds such as butane and isobutane that have the same molecular formula but differ in the way atoms are connected
What is an “iso” structural unit?
How many possible structures are there for pentane?
three possible structures
How many possible structures are there for hexane?
five constitutional isomers with molecular formula C6H14
How many possible structures are there for heptane?
nine alkanes with molecular formula C7H16
How are alkyl groups named?
Alkyl groups are named by replacing the “ane” ending of the alkane with “yl”
What is an alkyl subsituent?
the result of removing a hydrogen from an alkane
What happens if an H in an alkane is replaced by an OH?
the compound becomes an alcohol
What happens if an H in an alkane is replaced by an NH2?
the compound becomes an amine
What happens if an H in an alkane is replaced by a halogen?
the compound becomes an alkyl halide
What happens if an H in an alkane is replaced by an OR?
the compound becomes an ether
What is a propyl group?
the result of when a H is removed from a primary carbon of propane
What is a primary carbon?
a carbon bonded to only one other carbon
What is an isopropyl group?
the result of when a H is removed from the secondary carbon of propane
What is a secondary carbon?
a carbon bonded to two other carbons
What is a butyl group?
have a hydrogen removed from a primary carbon
What is an isobutyl group?
have a hydrogen removed from a primary carbon
What is a sec-butyl group?
has a hydrogen removed from a secondary carbon
What is a tert-butyl group?
has a hydrogen removed from a tertiary carbon
What is a tertiary carbon?
A carbon bonded to three other carbons
What is a primary hydrogen?
a hydrogen attached to a primary carbon
What is a secondary hydrogen?
a hydrogen attached to a secondary carbon
what is a tertiary hydrogen?
a hydrogen attached to a tertiary carbon
Can you use the prefix “sec” like with “sec-butyl” for other compounds that have a CH3 group on the secondary C?
No! Besides sec-butyl, using “sec” wouldn’t be correct terminology because other compounds like pentane may have multiple secondary carbons
What can the prefix “tert” be used for?
both tert-butyl and turt-pentyl compounds because each of these substituent names describes only one alkyl group. With that in mind, tert-hexyl cannot be used because it would describe two different alkyl groups
What is the only isoalkyl compound without the substituent on the primary C?
isopropyl alcohol, it has its substituent on a secondary carbon
methyl
ethyl
propyl
isopropyl
butyl
isobutyl
sec-butyl
tert-butyl
pentyl
isopentyl
hexyl
isohexyl
Draw the structure of a compound with no secondary carbons.
Draw the structures and name the four constitutional isomers with molecular formula C4H9Br
What is a parent hydrocarbon and how does it affect the name of an alkane?
The number of carbons in the longest continuous carbon chain. The name that indicates the number of carbons in the parent hydrocarbon becomes the alkane’s “last name.”
Where is the name of the alkyl substituent placed in relation to the parent hydrocarbon?
The name of any alkyl substituent attached to the parent hydrocarboin is placed in front of the name of the parent hydrocarbon. Both names are joined into one word, preceded by a hyphen that connects the substituent’s number with its name.
How does the alkyl substituent affect the numbering of the carbons in the parent chain?
The carbons in the parent chain are numbered in the direction that gives the substituent as low a number as possible.