Introduction to Organic Chemistry: Hydrocarbons (Chapter 11)

Flashcards covering key vocabulary, definitions, and concepts from the Introduction to Organic Chemistry lecture, focusing on hydrocarbons, functional groups, reactions, and nomenclature.

Organic Chemistry

The study of carbon compounds.

Organic compounds

Compounds that contain carbon, most of the time hydrogen, and sometimes oxygen, nitrogen, halogens, or sulfur.

Covalent bonds (in organic compounds)

Chemical bonds formed by electron sharing between atoms.

Carbon

An element in Group 14 or 4A of the periodic table, possessing 4 valence electrons.

Valence electrons

Electrons in the highest energy level of an atom, used in chemical bonding.

Hydrocarbons

Organic compounds composed only of carbon and hydrogen.

Methane (CH4)

The simplest hydrocarbon.

Octet Rule (carbon)

Carbon wants to achieve 8 valence electrons.

Octet Rule (hydrogen)

Hydrogen wants to achieve 2 valence electrons.

Single Bond

The sharing of 2 electrons between two atoms, counting for both atoms.

VSEPR theory (tetrahedral shape)

Predicts that a molecule or compound with four bonds and no lone pairs around the central atom has a tetrahedral shape.

Alkanes

Hydrocarbons that contain only carbon-carbon single bonds.

IUPAC system

International Union of Pure and Applied Chemistry, used for naming organic compounds.

Naming Alkanes

Alkanes are named with an -ane ending.

Straight-chained or Continuous Alkanes

Alkanes where all carbon atoms are connected in a row.

Pentane

A continuous alkane with 5 carbon atoms.

Hexane

A continuous alkane with 6 carbon atoms.

Heptane

A continuous alkane with 7 carbon atoms.

Octane

A continuous alkane with 8 carbon atoms.

Nonane

A continuous alkane with 9 carbon atoms.

Decane

A continuous alkane with 10 carbon atoms.

Expanded Structural Formula

A structural formula that shows the bonds between all of the atoms in a compound.

Condensed Structural Formula

A structural formula that shows the arrangement but each carbon atom and its attached hydrogen atoms are written as a group.

Skeletal Structures

The simplest structural formulas drawn, where carbon atoms are found where lines intersect or end, and hydrogen atoms are implied to satisfy carbon's four bonds.

Cycloalkanes

Hydrocarbons where carbon atoms bond to form rings with only carbon-carbon single bonds.

Simplest cycloalkane

Cyclopropane (C3H6), a ring of three carbon atoms.

Branch or substituent

A group not attached to the longest continuous carbon chain in an alkane.

Branched alkane

An alkane with at least one branch or substituent.

Isomers

Two compounds that have the same chemical formula but different arrangements of atoms.

Alkyl groups

Alkanes that are missing one hydrogen atom, named with a -yl ending.

Methyl group

A one-carbon alkyl group (CH3-).

Ethyl group

A two-carbon alkyl group (CH3-CH2-).

Propyl group

A three-carbon alkyl group (CH3-CH2-CH2-).

Isopropyl group

A branched three-carbon alkyl group (CH3-CH-CH3).

Main chain (parent chain)

In the IUPAC system, the longest continuous carbon chain, which defines the base name of the compound.

Haloalkane

An alkane in which halogen atoms (F, Br, Cl, I) replace one or more hydrogen atoms.

Fluoro (F)

The IUPAC name for a fluorine substituent in a haloalkane.

Chloro (Cl)

The IUPAC name for a chlorine substituent in a haloalkane.

Bromo (Br)

The IUPAC name for a bromine substituent in a haloalkane.

Iodo (I)

The IUPAC name for an iodine substituent in a haloalkane.

Solubility of Alkanes in water

Alkanes are nonpolar, making them insoluble in water (polar) but soluble in nonpolar solvents.

Alkenes

Hydrocarbons that contain at least one double bond between carbon atoms.

Alkynes

Hydrocarbons that contain at least one triple bond between carbon atoms.

Unsaturated hydrocarbons

Alkenes and alkynes, which have fewer hydrogen atoms than their corresponding alkanes because of double or triple bonds.

Saturated hydrocarbons

Alkanes, which contain only single bonds and have the maximum number of hydrogen atoms.

Double bond (alkene)

Forms when two adjacent carbon atoms share two pairs of valence electrons.

Shape of carbons in a double bond

Planar or flat.

Triple bond (alkyne)

Forms when two carbon atoms share three pairs of valence electrons.

Shape of carbons in a triple bond

Planar.

Rigid double bond (alkenes)

Prevents rotation around the carbons, keeping groups connected to it fixed on one side or the other.

Cis isomer

An isomer where two hydrogen atoms, one on each alkene carbon, are on the same side of the double bond.

Trans isomer

An isomer where two hydrogen atoms, one on each alkene carbon, are on opposite sides of the double bond.

Trans isomers (stability)

Generally more stable than their cis counterparts because large groups attached to the double bond are further apart.

Absence of Cis-trans isomerism

Does not occur if one of the carbons in the double bond has identical atoms or groups of atoms attached to it.

Addition Reactions (alkenes/alkynes)

Characteristic reactions where atoms or groups of atoms add to the carbons of the double or triple bond, typically breaking the multiple bond.

Hydrogenation

An addition reaction where hydrogen atoms add to the carbons in a double or triple bond to form alkanes, requiring a catalyst (Pt, Ni, Pd).

Hydration

A reaction where alkenes react with water (HOH) catalyzed by a strong acid (e.g., H2SO4), adding H- and -OH to the double bond.

Benzene (C6H6)

A hydrocarbon consisting of a ring of 6 carbon atoms with one hydrogen atom attached to each, featuring alternating single and double bonds.

Aromatic compounds

Compounds containing a benzene ring, often characterized by distinct odors.

Reactivity of Benzene

Much less reactive than typical alkenes and does not undergo typical alkene reactions.

Toluene

The common and IUPAC-accepted name for 1-methylbenzene.

Aniline

The common and IUPAC-accepted name for 1-aminobenzene.

Phenol (compound)

The common and IUPAC-accepted name for 1-hydroxybenzene.

Alcohol

An organic compound in which a hydroxyl group (-OH) replaces one or more hydrogen atoms in an alkane or cycloalkane.

Ether

An organic compound containing an oxygen atom that is attached by single bonds to two carbon groups (alkyls or aromatic rings) (C-O-C).

Thiol

A group of sulfur-containing organic compounds that have a sulfhydryl (-SH) group.

Hydroxyl group

The -OH functional group found in alcohols and phenols.

Sulfhydryl group

The -SH functional group found in thiols.

Naming Alcohols (IUPAC)

Named with an -ol ending, replacing the -e in the corresponding alkane name, with the chain numbered from the end closest to the -OH group.

Naming Ethers (common names)

Involves writing the names of each alkyl or aromatic group attached to the oxygen atom alphabetically, followed by the word 'ether'.

Primary (1°) alcohol

An alcohol where one carbon group is attached to the carbon bonded to the -OH group.

Secondary (2°) alcohol

An alcohol where two carbon groups are attached to the carbon bonded to the -OH group.

Tertiary (3°) alcohol

An alcohol where three carbon groups are attached to the carbon bonded to the -OH group.

Electronegativity

The ability of an atom to attract electrons towards itself.

Hydrogen Bonding

The attraction between a polarized hydrogen atom in one molecule and a polarized oxygen, nitrogen, or fluorine atom in another molecule.

Solubility of Alcohols (1-4 carbons)

Very soluble in water because the polar -OH group can hydrogen bond with water molecules.

Solubility of Alcohols (5+ carbons)

Not very soluble in water because the nonpolar alkyl portion diminishes the effect of the polar -OH group.

Solubility of Phenol in water

Soluble in water because the -OH group dissociates slightly as a weak acid, forming a water-soluble phenoxide ion.

Carbonyl group

A functional group consisting of a carbon-oxygen double bond (C=O), which is polar.

Aldehyde

An organic compound where the carbon of the carbonyl group is bonded to at least one hydrogen atom.

Ketone

An organic compound where the carbonyl group is bonded to two alkyl groups or aromatic rings.

Naming Aldehydes (IUPAC)

Named with an -al ending by replacing the -e of the corresponding alkane; the carbonyl carbon is always carbon 1.

Benzaldehyde

A benzene derivative where an aldehyde group is directly attached to the benzene ring.

Naming Ketones (IUPAC)

Named with an -one ending by replacing the -e of the corresponding alkane; the main chain is numbered from the end nearest the carbonyl group.

Solubility of Aldehydes and Ketones in water

Carbonyl compounds with one to four carbons are soluble; those with five or more carbons are not very soluble due to the diminishing effect of the polar carbonyl group.

Dehydration of Alcohols

A reaction where alcohols lose a water molecule when heated with an acid catalyst (e.g., H2SO4) to produce an alkene.

Oxidation (in organic chemistry)

Refers to an increase in the number of carbon-oxygen bonds, often by removing hydrogens.

Reduction (in organic chemistry)

Refers to an increase in the number of carbon-hydrogen bonds.

Oxidation of primary alcohols

Usually produces an aldehyde, but can be oxidized further to carboxylic acids.

Oxidation of secondary alcohols

Forms ketones.

Oxidation of tertiary alcohols

Do not oxidize readily because there are no hydrogen atoms on the alcohol carbon.

Oxidation of aldehydes

Aldehydes readily oxidize to carboxylic acids.

Oxidation of ketones

Ketones do not undergo further oxidation.

Reduction of Aldehydes and Ketones

Aldehydes are reduced to primary alcohols, and ketones are reduced to secondary alcohols (e.g., using NaBH4).

Carboxylic acid

An organic compound containing a hydroxyl group attached to a carbonyl group, forming a carboxyl group.

Carboxyl group

A functional group consisting of -COOH (-C(=O)OH).

Naming Carboxylic Acids (IUPAC)

The names end in -oic acid, replacing the -e of the corresponding alkane, with the carboxyl carbon designated as carbon 1.

Benzoic Acid

A benzene derivative where a carboxyl group is directly attached to the benzene ring.

Polarity of Carboxylic Acids

Among the most polar organic compounds because the carboxyl group consists of two polar groups: a -OH group and a C=O group.

Solubility of Carboxylic Acids (1-4 carbons)

Very soluble in water because the carboxyl group can form multiple hydrogen bonds with water molecules.