Organic Chemistry

Question 1

Isomers that can convert by changing the location of a proton.

Answer 1

Tautomers

Question 2

A type of diastereomers with different arrangements of substituents about an immovable bond.

Answer 2

Cis-Trans Isomers

Question 3

A species that tends to donate electrons to another atom. With the same attacking atom (OH^‐, CH3O^‐) in aprotic solvents, nucleophile strength correlates to basicity. In protic solvents and in situations where the attacking atom is different (OH^‐, SH^‐), nucleophile strength correlates to smaller size.

Answer 3

Nucleophile

Question 4

Stereoisomers that are not mirror images of each other. Diastereomers differ in their configurations at at least one chiral center and share the same configuration at at least one chiral center. They have similar chemical properties but different physical properties.

Answer 4

Diastereomers

Question 5

Describes groups on a cyclic molecule that are perpendicular to the plane of the molecule, pointing straight up or down.

Answer 5

Axial

Question 6

Increased energy that results when molecules assume eclipsed or gauche staggered conformations.

Answer 6

Torsional Strain

Question 7

A functional group containing a nitrile (−C≡N) and a hydroxyl group.

Answer 7

Cyanohydrin

Question 8

A method of synthesizing amino acids that uses potassium phthalimide and diethyl bromomalonate followed by an alkyl halide; two substitution reactions are followed by hydrolysis and decarboxylation.

Answer 8

Gabriel (Malonic-Ester) Synthesis

Question 9

Describes two solvents that will not mix with or dissolve each other.

Answer 9

Immiscible

Question 10

Describes groups that pull electron density away from another atom; stabilizes negative charges and destabilizes positive charges while increasing acidity.

Answer 10

Electron-Withdrawing

Question 11

The phenomenon of atoms pushing electron density towards surrounding atoms; in NMR spectroscopy, pulls the group further upfield on the spectrum. Deshielding is the opposite - the pulling of electron density by surrounding atoms; in NMR, pulls a group further downfield on the spectrum.

Answer 11

Shielding

Question 12

Molecules that have the same molecular formula but different connectivity; also called constitutional isomers.

Answer 12

Structural Isomers

Question 13

A compound that has a carbonyl group bonded to nitrogen. Amides are named by dropping the -oic acid in the corresponding carboxylic acid and adding -amide. Substituents attached to nitrogen are listed as prefixes and are preceded by N-.

Answer 13

Amide

Question 14

A molecule that either does not contain a chiral center or contains chiral centers and a plane of symmetry; as such, it has a superimposable mirror image.

Answer 14

Achiral

Question 15

Characteristics of compounds that do not change chemical composition, such as melting point, boiling point, solubility, odor, color, and density.

Answer 15

Physical Properties

Question 16

A type of bond that links the sugar moieties of adjacent nucleotides in DNA.

Answer 16

Phosphodiester Bond

Question 17

A stereoisomer with an internal plane of symmetry. Meso compounds are optically inactive.

Answer 17

Meso Compound

Question 18

Compounds consisting of only carbons and hydrogens bonded with σ bonds. As chain length increases, boiling point, melting point, and density increase. However, chain branching decreases both boiling point and density.

Answer 18

Alkanes

Question 19

Molecules that have the same molecular formula but different connectivity; also called structural isomers.

Answer 19

Constitutional Isomers

Question 20

Nonsuperimposeable stereoisomers that are mirror images of each other. Enantiomers differ in configuration at every chiral center but share the same chemical properties in a nonstereospecific environment. Their optical activities are exactly opposites of each other.

Answer 20

Enantiomers

Question 21

A method used to separate a component in a mixture by exploiting its solubility properties. Two solvents are usually used (one aqueous and one organic), and the component of interest will be soluble in one phase, while the impurities will be soluble in the other.

Answer 21

Extraction

Question 22

A type of chromatography that uses silica gel or alumina on a card as the medium for the stationary phase.

Answer 22

Thin-Layer Chromatography (TLC)

Question 23

A functional group containing two carbonyls separated by an oxygen atom (RCOOCOR); often the condensation dimer of a carboxylic acid.

Answer 23

Anhydride

Question 24

A method of visualizing a compound in which the line of sight is down a carbon-carbon bond axis.

Answer 24

Newman Projection

Question 25

Describes groups that push additional electron density toward another atom; stabilizes positive charges and destabilizes negative charges while decreasing acidity.

Answer 25

Electron-Donating

Question 26

Describes the orbital in which an electron is found; possible values range from -l to +l.

Answer 26

Magnetic Quantum Number (m{l})

Question 27

The complete loss of a carboxyl group as carbon dioxide.

Answer 27

Decarboxylation

Question 28

Configurational isomers that have different spatial arrangements of substituents, which affects the rotation of plane-polarized light.

Answer 28

Optical Isomers

Question 29

An -OH group; seen in alcohols, hemiacetals and hemiketals, carboxylic acids, water, and other compounds.

Answer 29

Hydroxyl Group

Question 30

A technique that measures the alignment of magnetic moments from certain molecular nuclei with an external magnetic field; can be used to determine the connectivity and functional groups in a molecule.

Answer 30

Nuclear Magnetic Resonance (NMR) Spectroscopy

Question 31

A double bond between a carbon and an oxygen.

Answer 31

Carbonyl

Question 32

A functional group that contains a carbon atom bonded to two -OR groups, an alkyl chain, and a hydrogen atom.

Answer 32

Acetal

Question 33

A standardized measure of a compound's ability to rotate plane-polarized light.

Answer 33

Specific Rotation ([α])

Question 34

A separation technique that uses the retention time of a compound in the mobile phase as it travels through the stationary phase two separate compounds with different chemical properties.

Answer 34

Chromatography

Question 35

A compound that has a nonterminal carbonyl group. Ketones are named by replacing the -e in the corresponding alkane with -one.

Answer 35

Ketone

Question 36

A compound that has a carbonyl as a terminal group. Aldehydes are named by replacing the -e in the corresponding alkane with -al. Formaldehyde, acetaldehyde, and propionaldehyde are common names used for the simplest aldehydes.

Answer 36

Aldehyde

Question 37

A compound that has a -COOH terminal group. Carboxylic acids are named by replacing the -e in the corresponding alkane with -oic acid. Formic acid and acetic acid are common names for the simplest carboxylic acids: methanoic acid and ethanoic acid, respectively.

Answer 37

Carboxylic Acid

Question 38

A technique that measures molecular vibrations at different frequencies, from which specific bonds can be determined; functional groups can be inferred based on this information.

Answer 38

Infrared (IR) Spectroscopy

Question 39

Describes groups on a cyclic molecule that are in the plane of the molecule.

Answer 39

Equatorial

Question 40

Isomers that can only interconvert by breaking bonds; include enantiomers, diastereomers, and cis-trans isomers.

Answer 40

Configurational Isomers

Question 41

A cyclic ester; named according to the number of carbon atoms other than the carbonyl carbon and for the straight-chain form of the compound.

Answer 41

Lactone

Question 42

A compound that has a -COOR group. Esters are named as alkyl or aryl alkanoates.

Answer 42

Ester

Question 43

Derived from phosphoric acid, the molecule that forms high-energy bonds for energy storage in nucleotide triphosphates like ATP; also used for enzyme regulation.

Answer 43

Inorganic Phosphate (P{i})

Question 44

The resonance form of a carbonyl that has a carbon-carbon double bond (ene) and an alcohol (-ol).

Answer 44

Enol

Question 45

The exact spatial arrangement of atoms or groups in a chiral molecule around a single chiral atom, designated by (R) or (S).

Answer 45

Absolute Conformation

Question 46

Compounds with the same molecular formula and connectivity but different arrangements in space. Stereoisomers include cis-trans isomers, diastereomers, enantiomers, conformational isomers, and meso compounds.

Answer 46

Stereoisomers

Question 47

Stereoisomers that differ by rotation about one or more single bonds, usually represented using Newman projections.

Answer 47

Conformational Isomers

Question 48

An arbitrary variable used to plot NMR spectra; measured in parts per million (ppm).

Answer 48

Chemical Shift (δ)

Question 49

"Electron-loving" atoms with a positive charge or positive polarization; can accept an electron pair when forming new bonds with a nucleophile.

Answer 49

Electrophiles

Question 50

The bonding molecular orbital formed by head-to-head or tail-to-tail overlap of atomic orbitals; all single bonds are σ bonds.

Answer 50

Sigma (σ) Bond

Question 51

A technique that measures absorbance of ultraviolet light of various wavelengths passing through a sample.

Answer 51

Ultraviolet (UV) Spectroscopy

Question 52

An analog of frequency used for infrared spectra instead of wavelength.

Answer 52

Wavenumber

Question 53

The process that transforms one ester to another when an alcohol acts as a nucleophile and displaces the alkoxy group on an ester.

Answer 53

Transesterification

Question 54

Describes the shell in which an electron is found; values range from 1 to ∞.

Answer 54

Principal Quantum Number (n)

Question 55

The pull of electron density across σ bonds.

Answer 55

Induction

Question 56

A liquid (or a gas in gas chromatography) that is run through the stationary phase in chromatography.

Answer 56

Mobile Phase

Question 57

A type of chromatography used to separate vaporizable compounds; the stationary phase is a crushed metal or polymer and the mobile phase is a nonreactive gas.

Answer 57

Gas Chromatography (GC)

Question 58

A functional group that contains a carbon atom bonded to one -OR group, one -OH group, and two alkyl chains.

Answer 58

Hemiketal

Question 59

In an IR spectrum, the region of 1400 to 400 cm^‐1 where more complex vibration patterns, caused by the motion of the molecule as a whole, can be seen; it is characteristic of each individual molecule.

Answer 59

Fingerprint Region

Question 60

The prevention of a reaction at a particular location in a molecule by substituent groups around the reactive site.

Answer 60

Steric Hindrance

Question 61

A functional group that contains a carbon atom bonded to one -OR group, one -OH group, an alkyl chain, and a hydrogen atom.

Answer 61

Hemiacetal

Question 62

A mixture that contains equal amounts of (+) and (-) enantiomers. Racemic mixtures are not optically active.

Answer 62

Racemic Mixture

Question 63

The carbon adjacent to a carbonyl; in amino acids, the chiral stereocenter in all amino acids except glycine.

Answer 63

α-Carbon

Question 64

A double bond between a carbon and a nitrogen.

Answer 64

Imine

Question 65

A form of chromatography in which a small sample is put into a column that can be manipulated with sophisticated solvent gradients to allow very refined separation and characterization; formerly called high-pressure liquid chromatography.

Answer 65

High-Performance Liquid Chromatography (HPLC)

Question 66

The lowest-energy molecular orbital that does not contain electrons; in UV spectroscopy, electrons are excited from the HOMO to the LUMO.

Answer 66

Lowest Unoccupied Molecular Orbital (LUMO)

Question 67

Describes the intrinsic spin of the two electrons in an orbital by arbitrarily assigning one of the electrons a spin of +1/2 and the other a spin of -1/2.

Answer 67

Spin Quantum Number (M{s})

Question 68

A ratio used in thin-layer chromatography to identify a compound; calculated as how far the compound traveled relative to how far the solvent front traveled.

Answer 68

Retardation Factor (R{f})

Question 69

The bonding molecular orbital formed when two parallel p-orbitals share electrons; exists as electron clouds above and below the σ bond between the two nuclei.

Answer 69

Pi (π) Bond

Question 70

The highest-energy molecular orbital containing electrons; in UV spectroscopy, electrons are excited from the HOMO to the LUMO.

Answer 70

Highest Occupied Molecular Orbital (HOMO)

Question 71

A reaction in which an aldehyde or ketone acts as both the electrophile and nucleophile, resulting in the formation of a carbon-carbon bond in a new molecule called an aldol.

Answer 71

Aldol Condensation

Question 72

An indication of the hypothetical charge that an atom would have if all of its bonds were completely ionic.

Answer 72

Oxidation State

Question 73

Increased energy that results when nonadjacent atoms or groups compete for the same space; also called steric strain.

Answer 73

Nonbonded Strain

Question 74

A molecule or carbon atom bonded to four different groups and without a plane of symmetry; thus, it is not superimposable upon its mirror image and has an enantiomer.

Answer 74

Chiral

Question 75

A compound that can be created from a carboxylic acid by nucleophilic acyl substitution; includes anhydrides, esters, and amides.

Answer 75

Carboxylic Acid Derivative

Question 76

The prevention of the formation of alternative products using a protecting group such as a mesylate or tosylate.

Answer 76

Steric Protection

Question 77

The phase over which the mobile phase runs during chromatography; usually a solid material. Also called the absorbent.

Answer 77

Stationary Phase

Question 78

In NMR spectroscopy, a phenomenon that occurs when there are protons in such close proximity to each other that their magnetic moments affect each other's appearance in the NMR spectrum by subdividing their peaks into subpeaks; also called splitting.

Answer 78

Coupling

Question 79

Describes the subshell in which an electron is found; possible values range from 0 to n - 1, with l = 0 representing the s subshell, l = 1 representing p, l = 2 representing d, and l = 3 representing f.

Answer 79

Azimuthal Quantum Number (l)

Question 80

A separation technique used to separate liquids with different boiling points. The mixture is heated slowly, and as the liquid with the lower boiling point changes to its gaseous form, it passes through a condenser, where it cools back into its liquid form.

Answer 80

Distillation

Question 81

Atoms or groups that can dissociate from the parent chain to form a stable species after accepting electron pairs. Weak bases tend to be good leaving groups.

Answer 81

Leaving Group

Question 82

The spatial arrangement of groups in a chiral molecule compared to another chiral molecule.

Answer 82

Relative Configuration

Question 83

Laboratory technique that relies on measurement of the energy differences between the possible states of a molecular system by determining the frequencies of electromagnetic radiation (light) absorbed by the molecules or their response to a magnetic field.

Answer 83

Spectroscopy

Question 84

A method of synthesizing amino acids that uses condensation between an aldehyde and hydrogen cyanide, followed by hydrolysis.

Answer 84

Strecker Synthesis

Question 85

Characteristics of compounds that change chemical composition during a reaction; determines how a molecule will react with other molecules.

Answer 85

Chemical Properties

Question 86

Energy created in a cyclic molecule by angle strain, torsional strain, and nonbonded strain; determines whether a ring is stable enough to stay intact.

Answer 86

Ring Strain

Question 87

A cyclic amide; named according to the number of carbon atoms other than the carbonyl carbon.

Answer 87

Lactam

Question 88

A reaction that combines two molecules into one, with the loss of a small molecule.

Answer 88

Condensation Reaction

Question 89

Alternating single and multiple bonds that create a system of parallel unhybridized p-orbitals; thus, electrons can be shared between these orbitals, forming electron clouds above and below the plane of the molecule and stabilizing it.

Answer 89

Conjugation

Question 90

An alcohol with an aromatic ring; has slightly more acidic hydroxyl hydrogens than other alcohols.

Answer 90

Phenol