Chapter 4

Question 1

Hydrocarbons having only single (σ) bonds between carbon atoms

Answer 1

Alkanes

Question 2

Hydrocarbons having at least one double bond between carbon atoms

Answer 2

Alkenes

Question 3

Hydrocarbons having at least one triple bond between carbon atoms

Answer 3

Alkynes

Question 4

Alkanes in which some or all of the carbon atoms are arranged in a ring

Answer 4

Cycloalkanes

Question 5

A process used in the petroleum industry for breaking down the molecules of larger alkanes into smaller ones; may be accomplished with heat, or with a catalyst

Answer 5

Cracking

Question 6

Each carbon atom within the chain is bonded to no more than two other carbon atoms

Answer 6

Unbranched

Question 7

Compounds that have the same molecular formula but that differ in their connectivity

Answer 7

Constitutional isomers

Question 8

A set of nomenclature rules overseen by the Internal Union of Pure and Applied Chemistry (IUPAC) that allows every compound to be assigned an unambiguous name

Answer 8

IUPAC system (“systematic nomenclature”)

Question 9

The designation given to a fragment of a molecule hypothetically derived from an alkane by removing a hydrogen atom

Answer 9

Allyl group

Question 10

A system for naming compounds that uses two or more words for naming compounds that uses two or more words to describe the compound

Answer 10

Functional class nomenclature

Question 11

A system for naming compounds in which each atom or group, called a substituent, is cited as a prefix or suffix to a parent compound

Answer 11

Substitutive nomenclature

Question 12

Alcohols containing two hydroxyl groups

Answer 12

Glycol

Question 13

The carbon atoms common to both rings

Answer 13

Bridgeheads

Question 14

Each chain of atoms connecting the bridgehead atoms

Answer 14

Bridge

Question 15

Compounds with two fused or bridged rings

Answer 15

Bicyclic compounds

Question 16

The H2C=CH- group

Answer 16

Vinyl group

Question 17

The -CH2CH=CH2 group

Answer 17

Allyl group

Question 18

Substitutes on the same side

Answer 18

Cis compound

Question 19

Substitutents on opposite sides

Answer 19

Trans compound

Question 20

Monosubstituted acetylenes or 1-alkynes

Answer 20

Terminal alkynes

Question 21

A hydrogen atom attached to a carbon atom that is bonded to another carbon atom by a triple bond

Answer 21

Acetylenic hydrogen atom

Question 22

The anion obtained when the acetylenic hydrogen is removed

Answer 22

Alkynide ion or an acetylide ion

Question 23

A series of compounds in which each member differs from the next member by a constant unit

Answer 23

Homologous series

Question 24

A particular temporary orientation of a molecule that results from rotations about its single bonds

Answer 24

Conformation

Question 25

A particular staggered confirmation of a molecule

Answer 25

Conformer

Question 26

An analysis of the energy changes that a molecule undergoes as its groups undergo rotation (sometimes only partial) about the single bonds that join them

Answer 26

Conformational analysis

Question 27

A means of representing the spatial relationships of groups attached to two atoms of a molecule; imagine viewing the molecule from one end directly along the bond axis joining the atoms

Answer 27

Newman projection formula

Question 28

A temporary orientation of groups around two atoms joined by a single bond such that the bonds of the back atom exactly bisect the angles formed by the bonds of the front atom when shown in a Newman projection formula

Answer 28

Staggered conformation

Question 29

The angle between two atoms (or groups) bonded to adjacent atoms, when viewed as a projection down the bond between the adjacent atoms

Answer 29

Dihedral angle

Question 30

A temporary orientation of groups around two atoms joined by a single bond such that the groups directly oppose each other

Answer 30

Eclipsed conformation

Question 31

Electron delocalization (via orbital overlap) from a filled bonding orbital to an adjacent unfilled orbital; generally has a stabilizing effect

Answer 31

Hyperconjugation

Question 32

A graphical plot of the potential energy changes that occurs as molecules (or atoms) react (or interact). Potential energy is on the y-axis and the progress of the reaction on the x-axis

Answer 32

Potential energy diagram

Question 33

The barrier to rotation of groups joined by a single bond caused by repulsion’s between the aligned electron pairs in the eclipsed form

Answer 33

Torsional barrier

Question 34

The strain associated with an eclipsed confirmation of a molecule; it is caused by repulsions between the aligned electron pairs of the eclipsed bonds

Answer 34

Torsional strain

Question 35

An effect on relative reaction rates caused when the spatial arrangement of atoms or groups at or near the reacting site hinders or retards a reaction

Answer 35

Steric hinderance

Question 36

Doesn’t have torsional strain from steric hinderance because the groups are staggered and the methyl groups are far apart

Answer 36

Anticonformation

Question 37

The methyl groups are close enough to each other that the dispersion forces between them are repulsive

Answer 37

Gauche conformation

Question 38

Compounds with the same molecular formula that differ only in the arrangement of their atoms in space; they have the same connectivity

Answer 38

Stereoisomers

Question 39

Stereoisomers differing in space only due to rotations about single (σ) bonds

Answer 39

Conformational stereoisomers

Question 40

An analysis of the energy changes that a molecule undergoes as its groups undergo rotation (sometimes only partial) about the single bonds that join them

Answer 40

Conformational analysis

Question 41

The increased potential energy of the cyclic form of a molecule (usually measured by heats of combustion) when compared to its acyclic form

Answer 41

Ring strain

Question 42

The increased potential energy of a molecule (usually a cyclic one) caused by deformation of a bond angle away from its lowest energy value

Answer 42

Angle strain

Question 43

The strain associated with an eclipsed confirmation of a molecule; it is caused by repulsions between the aligned electron pairs of the eclipsed bonds

Answer 43

Torsional strain

Question 44

Rotations about the carbon-carbon single bonds of cyclohexane can produce different conformations which are interconvertible. The most important are the chair conformation, the boat conformation, and the twist conformation

Answer 44

Conformations of cyclohexane

Question 45

The all-staggered conformation of cyclohexane that has no angle strain or torsional strain and is, therefore, the lowest energy conformation

Answer 45

Chair conformation

Question 46

A conformation of cyclohexane that resembles a boat and that has eclipsed bonds along its two sides: it is of higher energy than the chair conformation

Answer 46

Boat conformation

Question 47

Molecules that are synthesized that have large rings threaded on chains and that have large rings threaded on chains and that have large rings that are interlocked like links in a chain

Answer 47

Catenanes

Question 48

The six bonds of a cyxlohexane ring that are perpendicular to the general plane of the ring, and that alternate up and down around the ring

Answer 48

Axial bond

Question 49

The six bonds of a cyclohexane ring that lie generally around the “equator” of the molecule

Answer 49

Equatorial bond

Question 50

The change in a cyclohexane ring (resulting from partial bond rotations) that converts one ring conformation to another; converts any equatorial substituent to an axial substituent and vice versa

Answer 50

Ring flip

Question 51

The interaction between two axial groups that are on adjacent carbon atoms

Answer 51

1,3-diaxial interaction

Question 52

Diastereomers that differ in their stereochemistry at adjacent atoms of a double bond or on different atoms of a ring

Answer 52

Cis-trans isomers

Question 53

An old name for an alkane

Answer 53

Paraffin

Question 54

A reaction in which hydrogen adds to a double or triple bond; often completed through the use of a catalyst such as platinum, palladium, rhodium, or ruthenium

Answer 54

Hydrogenation

Question 55

Equals the number of pairs of hydrogen atoms that must be subtracted from the molecular formula of the corresponding alkane to give the molecular formula of the compound under consideration

Answer 55

Index of hydrogen deficiency (IHD)