Functional Group Chemistry and Hydrocarbons

Vocabulary flashcards covering key functional groups, hydrocarbon families, substituents, and common examples discussed in the lecture.

Functional group

A recognizable group of atoms within a molecule that determines its characteristic reactions and properties.

Connectivity

The pattern of how atoms are bonded within a functional group, influencing reactivity and shape.

Alcohol

A compound with an OH group attached to an sp3-hybridized carbon (R–OH); primary, secondary, or tertiary based on attached carbons.

Primary alcohol

An alcohol where the OH-bearing carbon is attached to one other carbon.

Secondary alcohol

An alcohol where the OH-bearing carbon is attached to two other carbons.

Tertiary alcohol

An alcohol where the OH-bearing carbon is attached to three other carbons.

Alkane

A saturated hydrocarbon with only single bonds and sp3 carbons; ends with -ane (e.g., propane).

Saturated

Contains only single bonds with maximum hydrogens; no double or triple bonds.

Unsaturated

Deficient in hydrogen due to double bonds or rings (e.g., alkenes, alkynes, aromatics).

Alkene

An unsaturated hydrocarbon with a carbon–carbon double bond (sp2); undergoes addition reactions.

Alkyne

An unsaturated hydrocarbon with a carbon–carbon triple bond (sp); highly unsaturated with hydrogen deficiency of four per triple bond.

Cycloalkane

Cyclic alkanes (rings) that are named with cyclo- and -ane; ring closure reduces hydrogens by two per ring.

Benzene

A classic aromatic ring with a planar, cyclic structure and delocalized pi electrons; typically represented with resonance and six pi electrons.

Aromatic

Planar, cyclic, conjugated systems with delocalized electrons that follow the Huckel 4n+2 rule.

Huckel rule

A rule stating that planar cyclic systems with 4n+2 pi electrons are aromatic.

Delocalization

Spread of electrons across multiple atoms (as in conjugated pi systems), increasing stability.

Resonance

The concept that a molecule is described by multiple contributing Lewis structures; the real structure is a resonance hybrid.

Resonance hybrid

The actual molecule is a blend of resonance structures with bonds of intermediate order.

Alkyl group

A hydrocarbon substituent attached to the main chain by removing one hydrogen (e.g., methyl, ethyl).

Methyl

CH3 group derived from methane; attached to a main chain by replacing a hydrogen.

Ethyl

CH2–CH3 group derived from ethane; attached via loss of a hydrogen from ethane.

Propyl

A three-carbon alkyl group; attached through a terminal carbon (n-propyl).

Isopropyl

A three-carbon branched alkyl group attached through the middle (secondary) carbon.

tert-Butyl

A four-carbon tert-butyl group attached to a tertiary carbon; bulky, highly branched substituent.

Arene group

An aromatic ring (aryl) attached as a substituent to a main chain.

Phenyl group

A benzene ring directly attached to a chain (aryl group, not the same as benzyl).

Benzyl group

A benzene ring attached to a –CH2– linker to the main chain (C6H5–CH2–).

Ether

An functional group with an oxygen atom bound to two carbon substituents (R–O–R′).

Dimethyl ether

An ether with two methyl groups on oxygen (CH3–O–CH3).

Diethyl ether

An ether with two ethyl groups on oxygen (CH3CH2–O–CH2CH3); common solvent and historically anesthetic.

THF

Tetrahydrofuran, a cyclic ether (oxacyclopentane) used as a common solvent.

Haloalkane (alkyl halide)

An alkyl group bearing a halogen substituent (R–X); halogenated hydrocarbons.

Primary alkyl halide

A halogenated carbon attached to the main chain that is bonded to only one other carbon.

Secondary alkyl halide

A halogenated carbon attached to the main chain that is bonded to two other carbons.

Tertiary alkyl halide

A halogenated carbon attached to the main chain that is bonded to three other carbons.

Alkenyl halide (vinyl halide)

A halogenated carbon attached to a carbon of a carbon–carbon double bond.

Amine

A nitrogen-containing group derived from ammonia by substituting hydrogens with R groups; classified as primary, secondary, or tertiary by number of R groups on N.

Primary amine

An amine where nitrogen is bonded to one R group (NH2 attached to one carbon).

Secondary amine

An amine where nitrogen is bonded to two R groups.

Tertiary amine

An amine where nitrogen is bonded to three R groups.

Quaternary carbon

A carbon bonded to four other carbons; cannot bear an additional bond (no tertiary alkyl halide possible at this center).

Phenol

An alcohol where the OH group is attached directly to an aromatic ring; more acidic than regular alcohols due to resonance with the ring.

__ are specific groupings of atoms within molecules that exhibit characteristic chemical reactions and properties.

Functional Groups

Functional groups are defined by atom ___; different atoms (O, N, etc.) create distinct groups with characteristic properties.

connectivity

Alkenes contain an sp^2-hybridized carbon and a C=C double bond, enabling reactions that change hybridization from sp^2 to sp^3.

addition

Alkanes consist solely of sp^3-hybridized carbon atoms and single bonds, and primarily undergo reactions or combustion.

substitution

Alkanes are saturated hydrocarbons with the general formula CnH{2n+2}, composed entirely of __ carbons and hydrogen atoms linked by single bonds.

sp^3-hybridized

Alkenes are unsaturated hydrocarbons containing at least one __ double bond. Their carbons are sp^2-hybridized and planar.

carbon-carbon

Cycloalkanes are alkanes that form a closed ring structure, with a general formula of __.

CnH{2n}, reflecting the loss of two hydrogens upon ring formation compared to an open-chain alkane

Alkynes are unsaturated hydrocarbons containing at least one carbon-carbon triple bond (C\equiv C), and their carbons are __-hybridized and linear.

sp

Aromatic compounds are cyclic, planar molecules that exhibit special stability due to the delocalization of __ electrons.

\pi

According to Hückel's Rule, a compound is aromatic if it is cyclic, planar, fully conjugated, and contains __ \pi electrons (where n is a non-negative integer).

(4n+2)

The delocalization of \pi electrons in benzene imparts significant __ stabilization, making aromatic compounds much more stable.

resonance

In benzene, each of the six carbon atoms is __-hybridized, with an unhybridized p-orbital creating a continuous \pi-electron cloud.

sp^2

Benzene cannot be accurately represented by a single Lewis structure, but is best described as a __ hybrid of two equivalent Kekulé structures.

resonance

All carbon-carbon bond lengths in benzene are __ (1.39 \mathring{A} or 0.139 \text{ nm}), an experimental observation supporting resonance.

identical

In IUPAC nomenclature for alkanes, the __ carbon chain determines the parent name.

longest continuous

Alkyl groups are formed by removing one hydrogen atom from an alkane and are named by replacing the '-ane' suffix with '__'.

-yl

is an aromatic substituent derived directly from benzene (C6H5-), while (C6H5CH*2-) includes a methylene group connecting the phenyl ring to the main chain.

Phenyl, benzyl

A __ haloalkane is one where the carbon atom bonded to the halogen is attached to only one other carbon atom.

primary (1^\circ)

A __ haloalkane is one where the carbon atom bonded to the halogen is attached to two other carbon atoms.

secondary (2^\circ)

A __ haloalkane is one where the carbon atom bonded to the halogen is attached to three other carbon atoms.

tertiary (3^\circ)

Quaternary carbons cannot form halides as there are no __ left to be replaced by a halogen.

hydrogens

An alcohol contains a hydroxyl (-OH) functional group attached to an __ carbon atom.

sp^3-hybridized

A __ alcohol has the carbon bearing the -OH group attached to only one other carbon atom.

primary (1^\circ)

A __ alcohol has the carbon bearing the -OH group attached to two other carbon atoms.

secondary (2^\circ)

A __ alcohol has the carbon bearing the -OH group attached to three other carbon atoms.

tertiary (3^\circ)

Phenols are compounds where a hydroxyl (-OH) group is directly attached to an __ ring.

aromatic

Phenols are significantly more acidic than typical aliphatic alcohols because their conjugate base (phenoxide ion) is stabilized by __.

resonance

Ethers have the general formula __, where R and R' are alkyl or aryl groups.

R-O-R'

__ are three-membered cyclic ethers that are highly strained and thus more reactive than other ethers.

Epoxides (oxiranes)

Fluorinated ethers have polarity due to C-F bonds and volatility due to stronger dipole-dipole interactions.

higher, reduced

Amines are organic derivatives of ammonia (NH_3), where one or more hydrogen atoms are replaced by __ or aryl groups.

alkyl

A __ amine has the nitrogen attached to one R group (RNH_2).

primary (1^\circ)

A __ amine has the nitrogen attached to two R groups and one hydrogen (R_2NH).

secondary (2^\circ)

A __ amine has the nitrogen attached to three R groups (R_3N).

tertiary (3^\circ)

Amines are the most common organic bases due to the __ of electrons on the nitrogen atom, which can accept a proton from an acid.

lone pair