Chapter 2 Glossary Terms

Front 1

acid chloride

Back 1

An acid derivative with a chlorine atom in place of the hydroxyl group.

Front 2

alcohol

Back 2

A compound that contains a hydroxyl group; R-OH. (p. 71)

Front 3

aldehyde

Back 3

A carbonyl group with one alkyl group and one hydrogen; (p. 72)

Front 4

alkanes

Back 4

Hydrocarbons containing only single bonds. (p. 68)

Front 5

alkenes

Back 5

Hydrocarbons containing C=C double bonds. (p. 69)

Front 6

alkynes

Back 6

Hydrocarbons containing C≡C triple bonds. (p. 70)

Front 7

alkyl group

Back 7

A hydrocarbon group with only single bonds; an alkane with one hydrogen removed, to allow bonding to another group; symbolized by R. (p. 69)

Front 8

amide

Back 8

An acid derivative that contains an amine instead of the hydroxyl group of the acid. (p. 74)

Front 9

amine

Back 9

An alkylated analogue of ammonia; R - NH₂, R₂NH, or R₃N. (p. 73)

Front 10

aromatic

Back 10

hydrocarbons (arenes) Hydrocarbons containing a benzene ring, a six-membered ring with three double bonds. (p. 70)

Front 11

bond dipole moment

Back 11

A measure of the polarity of an individual bond in a molecule (p. 58)

Front 12

carbonyl group

Back 12

The functional group, as in a ketone or aldehyde. (p. 72)

Front 13

carboxyl group

Back 13

The -COOH functional group, as in a carboxylic acid. (p. 72)

Front 14

carboxylic acid

Back 14

A compound that contains the carboxyl group; (p. 72)

Front 15

cis-trans isomers (geometric isomers)

Back 15

Stereoisomers that differ in their cis-trans arrangement on a ring or a double bond. The cis isomer has similar groups on the same side, and the trans isomer has similar groups on opposite sides. (p. 57)

Front 16

constitutional isomers (structural isomers)

Back 16

Isomers whose atoms are connected differently; they differ in their bonding sequence. (p. 56)

Front 17

cyano group

Back 17

The -C≡N functional group, as in a nitrile. (p. 74)

Front 18

dipole-dipole forces

Back 18

Attractive intermolecular forces resulting from the attraction of the positive and negative ends of the molecular dipole moments of polar molecules. (p. 62)

Front 19

dipole moment

Back 19

See bond dipole moment and molecular dipole moment. (p. 58)

Front 20

double bond

Back 20

A bond containing four electrons between two nuclei. One pair of electrons forms a sigma bond, and the other pair forms a pi bond. (p. 44)

Front 21

ester

Back 21

An acid derivative with an alkyl group replacing the acid proton. (p. 73)

Front 22

ether

Back 22

A compound with an oxygen bonded between two alkyl groups; R-0-R'. (p. 71)

Front 23

functional group

Back 23

The reactive, non-alkane part of an organic molecule. (p. 69)

Front 24

hybrid atomic orbital

Back 24

A directional orbital formed from a combination of s and p orbitals on the same atom. Two orbitals are formed by sp hybridization, three orbitals by sp² hybridization, and four orbitals by sp³ hybridization. (p. 45)

Front 25

sp hybrid orbitals give a bond angle of

Back 25

180° (linear geometry).

Front 26

sp² hybrid orbitals give bond angles of

Back 26

120° (trigonal geometry).

Front 27

sp³ hybrid orbitals give bond angles of

Back 27

109.5° (tetrahedral geometry).

Front 28

hydrocarbons

Back 28

Compounds composed exclusively of carbon and hydrogen.

Front 29

alkanes

Back 29

Hydrocarbons containing only single bonds. (p. 68)

Front 30

alkenes

Back 30

Hydrocarbons containing C=C double bonds. (p. 69)

Front 31

alkynes

Back 31

Hydrocarbons containing C≡C triple bonds. (p. 70)

Front 32

cycloalkanes, cycloalkenes, cycloalkynes

Back 32

Alkanes, alkenes, and alkynes in the form of a ring. (p. 68)

Front 33

aromatic hydrocarbons

Back 33

Hydrocarbons containing a benzene ring, a six-membered ring with three double bonds. (p. 70)

Front 34

hydrogen bond

Back 34

A particularly strong attraction between a nonbonding pair of electrons and an electrophilic O-H or N-H hydrogen. Hydrogen bonds have bond energies of about 5 kcal/mol (21 kJ/mol), compared with about 100 kcal/mol (about 400 kJ/mol) for typical C-H bonds. (p. 63)

Front 35

hydroxyl group

Back 35

The -OH functional group, as in an alcohol. (p. 71)

Front 36

isomers

Back 36

Different compounds with the same molecular formula. (p. 56)

Front 37

constitutional isomers (structural isomers)

Back 37

are connected differently; they differ in their bonding sequence.

Front 38

stereoisomers

Back 38

differ only in how their atoms are oriented in space.

Front 39

cis-trans isomers (geometric isomers) are

Back 39

stereoisomers that differ in their cis-trans arrangement on a ring or a double bond.

Front 40

stereochemistry is

Back 40

the study of the structure and chemistry of stereoisomers.

Front 41

ketone

Back 41

A carbonyl group with two alkyl groups attached. (p. 72)

Front 42

linear combination of atomic orbitals (LCAO)

Back 42

Wave functions can add to each other to produce the wave functions of new orbitals. The number of new orbitals generated equals the original number of orbitals. (p. 41)

Front 43

London dispersion forces

Back 43

Intermolecular forces resulting from the attraction of correlated temporary dipole moments induced in adjacent molecules. (p. 62)

Front 44

molecular dipole moment

Back 44

The vector sum of the bond dipole moments (and any nonbonding pairs of electrons) in a molecule; a measure of the polarity of a molecule. (p. 60)

Front 45

molecular orbital (MO)

Back 45

An orbital formed by the overlap of atomic orbitals on different atoms. MOs can be either bonding or antibonding, but only the bonding MOs are filled in most stable molecules. (p. 41)

Front 46

A bonding molecular orbital

Back 46

places a large amount of electron density in the bonding region between the nuclei. The energy of an electron in a bonding MO is lower than it is in an atomic orbital.

Front 47

An antibonding molecular orbital

Back 47

places most of the electron density outside the bonding region. The energy of an electron in an antibonding MO is higher than it is in an atomic orbital.

Front 48

nitrile

Back 48

A compound containing a cyano group, -C≡N. (p. 74)

Front 49

node

Back 49

In an orbital, a region of space with zero electron density. (p. 40)

Front 50

pi bond ( π bond)

Back 50

A bond formed by sideways overlap of two p orbitals. A pi bond has its electron density in two lobes, one above and one below the line joining the nuclei. (p. 44)

Front 51

sigma bond ( σ bond)

Back 51

A bond with most of its electron density centered along the line joining the nuclei; a cylindrically symmetrical bond. Single bonds are normally sigma bonds. (p. 41)

Front 52

stereochemistry

Back 52

The study of the structure and chemistry of stereoisomers. (p. 57)

Front 53

stereoisomers

Back 53

Isomers that differ only in how their atoms are oriented in space. (p. 57)

Front 54

structural isomers (IUPAC term - constitutional isomers)

Back 54

Isomers whose atoms are connected differently; they differ in their bonding sequence. (p. 56)

Front 55

triple bond

Back 55

A bond containing six electrons between two nuclei. One pair of electrons forms a sigma bond and the other two pairs form two pi bonds at right angles to each other. (p. 52)

Front 56

valence-shell electron-pair repulsion theory (VSEPR theory)

Back 56

Bonds and lone pairs around a central atom tend to be separated by the largest possible angles — about 180° for two, 120° for three, and 109.5° for four. (p. 45)

Front 57

van der Waals forces

Back 57

The attractive forces between neutral molecules, including dipole-dipole forces and London forces. (p. 62)

Front 58

dipole-dipole forces

Back 58

The forces between polar molecules resulting from attraction of their permanent dipole moments.

Front 59

London forces

Back 59

Intermolecular forces resulting from the attraction of correlated temporary dipole moments induced in adjacent molecules.

Front 60

wave function (ψ)

Back 60

The mathematical description of an orbital. The square of the wave function (ψ²) is proportional to the electron density. (p. 39)