Chapter 5

Question 1

Having the property of handiness, i.e., the case where mirror images of an object are not superposable

Answer 1

Chiral

Question 2

Two objects are superposable if, when one object is placed on top of the other, all parts of each coincide

Answer 2

Superposable

Question 3

Different molecules that have the same molecular formula

Answer 3

Isomers

Question 4

Compounds that have the same molecular formula but that differ in their connectivity (i.e., molecules that have the same molecular formula but have their atoms connected in different ways)

Answer 4

Constitutional isomers

Question 5

Compounds with the same molecular formula that differ only in the arrangement of their atoms in space

Answer 5

Stereoisomers

Question 6

Chemical studies that take into account the spatial aspects of molecules

Answer 6

Stereochemistry

Question 7

Stereoisomers that are mirror images of each other

Answer 7

Enantiomers

Question 8

Stereoisomers that are not mirror images of each other

Answer 8

Diastereomers

Question 9

A molecule that is not super possible on its mirror image; have handedness and are capable of existing as a pair of enantiomers

Answer 9

Chiral molecule

Question 10

A molecule that is superposable on its mirror image; lacks handedness and are incapable of existing as a pair of enantiomers

Answer 10

Achiral molecule

Question 11

An atom bearing groups of such nature that an interchange of any two groups will produce a stereoisomer

Answer 11

Chiral center

Question 12

When the exchange of two groups bonded to the same atom produces stereoisomers, the atom is said to be a stereogenic atom, or stereogenic center

Answer 12

Stereogenic center

Question 13

A single tetrahedral carbon with four different groups attached to it; also called an asymmetric carbon, a stereocenter, or a chirality center

Answer 13

Stereogenic carbon

Question 14

An imaginary plane that bisects a molecule in a way such that the two halves of the molecule are mirror images of each other. Any molecule with a plane of symmetry will be achiral

Answer 14

Plane of symmetry

Question 15

A method for designating the configuration of a tetrahedral chiral centers

Answer 15

R, S-system

Question 16

The particular arrangement of atoms (or groups) in space that is characteristic of a given stereoisomer

Answer 16

Configuration

Question 17

A compound that rotates the plane of polarization of plane-polarized light

Answer 17

Optically active compound

Question 18

Light in which the oscillations of the electrical field occur in one plane

Answer 18

Plane-polarized light

Question 19

A device used for measuring optical activity

Answer 19

Polarimeter

Question 20

A compound that rotates plane-polarized light clockwise

Answer 20

Dextorotatory

Question 21

A compound that rotates plane-polarized light in a counterclockwise direction

Answer 21

Levorotatory

Question 22

A physical constant calculated from the observed rotation of a compound using the following equation: [a]D = ac^xl where a is the observed rotation using the D line of a sodium lamp, c is the concentration of the solution or the density of a neat liquid in grams per milliliter, and l is the length of the tube in decimeters

Answer 22

Specific rotation

Question 23

An equimolar mixture of enantiomers; is optically inactive

Answer 23

Racemic mixture (racemate or racemic form)

Question 24

A percentage calculated for a mixture of enantiomers by dividing the moles of one enantiomers by the moles of both enantiomers and multiplying by 100; equals the percentage optical purity

Answer 24

Enantiomers excess (enantiomeric purity)

Question 25

A percentage calculated for a mixture of enantiomers by dividing the observed specific rotation for the mixture by the specific rotation of the pure enantiomers and multiplying by 100; equals the enantiomeric purity or enantiomeric excess

Answer 25

Optical purity

Question 26

I’m reactions where chiral centers are altered or created, a stereoselective rotation produces a preponderance of one stereoisomer; this type of reaction can either be enantioselective, in which case the reaction produces a preponderance of one enantiomer, or diastereoselective, in which case the reaction produces a preponderance of one diastereomer

Answer 26

Stereoselective reaction

Question 27

A process in which the rate of a reaction with one enantiomer is different than the other, leading to a preponderance of one produce stereoisomer. This process is said to be “stereoselective” in that is leads to the preferential formation of one stereoisomer over other stereoisomers that could possibly be formed

Answer 27

Kinetic resolution

Question 28

An optically inactive compound whose molecules are achiral even though they contain tetrahedral atoms with four different attached groups

Answer 28

Meso compound

Question 29

A two-dimensional formula for representing the three-dimensional configuration of a chiral molecule. They are written with the main carbon chain extending from top to bottom with all groups eclipsed. Vertical lines represent bonds that project behind the plane of the page (or that lie in it). Horizontal lines represent bonds that project out of the page

Answer 29

Fischer projection

Question 30

The relationship between the configurations of two chiral molecules. Molecules are said to have the same relative configuration when similar or identical groups in each occupy the same position in space. The configurations of molecules can be related to each other through reactions of known stereochemistry, for example, through reactions that cause no bonds to a stereogenic center to be broken

Answer 30

Relative configuration

Question 31

The actual arrangement of groups in a molecule; can be determined by X-ray analysis or by relating the configuration of a molecule, using reactions of known stereochemistry, to another molecule whose absolute configuration is known

Answer 31

Absolute configuration

Question 32

The process by which the enantiomers of a racemic form are separated

Answer 32

Resolution

Question 33

Conformational isomers that are stable, isolable compounds

Answer 33

Atropisomers