Chapter 2 Flashcards

1
Q

conformations: different … of atoms that result from … about a single bond

A

spatial arrangements; rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

staggered conformation: atoms/ groups on adjacent carbons are as

A

far apart as possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

eclipsed conformation: atoms/groups on adjacent carbons are as

A

close as possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

compounds reside in … conformational state

A

lowest E

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

eclipsed conformation is less stable because of

A

hyperconjugation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

in staggered conformation, highest molecular orbital overlaps with

A

smallest antibonding molecular orbitals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

… conformation: all conformations between staggered and eclipsed

A

skew

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

anti conformation is when the groups are … apart

A

180 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

gauche: groups are

A

60 degrees apart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

torsional strain: resistance to …, non-bonded atoms separated by 3 bonds forced from … to …

A

rotation; staggered; eclipsed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

angle strain: bond angle is …/… compared to optimum values

A

expanded; compressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

steric strain: non-bonded atoms separated by 4+ bonds are

A

forced closer to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

strain: a measure of the energy stored in a compound due to a

A

structural distortion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

dihedral angle: the angle created by two …, each defined by … atoms

A

intersecting planes; three

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

the energy difference between the conformational extremes arise from the stabilization of the staggered conformation. This arises because of a small … interactinon between a filled C-H bonding MO of one carbon and the empty/unfilled C-H antibonding MO on the adjacent carbon with which it is aligned

A

donor-acceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

puckering of the ring alters the strain energy in two ways:

(1) it decreases the … associated with eclipsed interactions but
(2) it increases further the … caused by the compression of C–C–C bond angles

A

torsional strain; angle strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

a boat conformation is considerably less stable than a chair because of th e… associated with four pairs of eclipsed C-H interactions and the … between the two “flagpole” hydrogens

A

torsional strain; steric strain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

some of the strain in the boat conformation can be relieved by a slight twisting of the ring to a … conformation

A

twist-boat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

as the size of the alkyl substituent increases, the preference for conformations with the group … increases

A

equatorial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

alkanes are … hydrocarbons, containing only C-C …

A

saturated; single bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

alkanes are … hydrocarbons because the physical properties of the higher members of this class resemble those of the long C-chain molecules we find in … and …

A

aliphatic; animal fats; plant oils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

a hydrocarbon that contains one or more C-C double bonds, triple bonds, or benzene rings, is classified as an … hydrocarbon

A

unsaturated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q
alkane names (based on number of C): 
C: 
C2: 
C3: 
C4: 
C5: 
C6: 
C7: 
C8: 
C9: 
C10: 
C11: 
C12: 
C13: 
C14: 
C15: 
C16: 
C17: 
C18: 
C19: 
C20:
A

methane; ethane; propane; butane; pentane; hexane; heptane; octane; nonane; decane; undecane; dodecane; tridecane; tetradecane; pentadecane; hexadecane; heptadecane; octadecane; nonadecane; eicosane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

alkanes have the general molecular formula

A

CnH2n+2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

constitutional isomers are compounds that have the same … but different …

A

molecular formula; structural formulas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

by “different structural formulas” we mean that constitutional isomers differ in the kinds of … they have (.., ..,. or …) and/or in the … of their atoms

A

bonds; single; double; triple; connectivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

to determine whether two or more structural formulas represent constitutional isomers, write the … of each and then compare them. all compounds that have the same molecular formula but different … are constitutional isomers

A

molecular formula; connectivities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The IUPAC name of an alkane with an unbranched chain of carbon atoms consists of two parts: (1) a … that indicates the number of .. atoms in the chain and (2) the … -ane to show that the compound is a …

A

prefix; carbon; suffix; saturated hydrocarbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

The IUPAC name of an alkane with a branched chain consists of a … that indicates the longest chain of C atoms in the compound and … names that indicate the groups bonded to the parent chain

A

parent name; substitutent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

a substituent group derived from an alkane by the removal of a hydrogen atom is called an …; it is commonly represented by the symbol …

A

alkyl group; R–

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

We name alkyl groups by dropping the -ane from the name of the parent alkane and adding the suffix …

A

-yl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

(Rules of IUPAC system) the name for an alkane with an unbranched chain of C atoms consists of a prefix showing the number of … in the chain and the ending ..

A

C atoms; -ane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

(Rules of IUPAC system) for branched-chain alkanes, select the longest chain of C atoms as the … chain; its name becomes the root name

A

parent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

(Rules of IUPAC system) Give each substituent on the parent chain a name and a number. the number shows the … of the … to which the substituent is bonded. use a hyphen to connect the number to the name

A

carbon atom; parent chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

(Rules of IUPAC system) if there is one substituent, number the parent chain from the end that gives the substituent the

A

lower number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

(Rules of IUPAC system) if there are two or more identical substituents, number the parent chain from the end that gives the lower number to the substituent … The number of times the substituent occurs is indicated by a … A … is used to separate position numbers

A

encountered first; prefix (e.g. di, tri); comma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

(Rules of IUPAC system) if there are two or more different substituents, list them in … and number the chain from the end that gives the lower number to the substituent … if there are different substituents in equivalent positions on opposite ends of the parent chain, give the substituent of lower … the lower number

A

alphabetical order; encountered first; alphabetical order

38
Q

the prefixes di-, tri-, tetra-, and so on, are … in alphabetizing. Alphabetize the names of the substituents first and then insert prefixes

A

not included

39
Q

where there are two or more parent chains of identical length, choose the parent chain with the

A

greater number of substituents

40
Q

the fact that an alkane chain is unbranched is sometimes indicated by the prefix … (…)

A

n-; normal

41
Q

for branched chain alkanes beyond propane, … indicates that one end of an otherwise unbranched chain terminates in a … group, and … indicates that it terminates in -C(CH3)3

A

iso; (CH3)2CH; neo

42
Q

the name we give to any compound with a chain of carbon atoms consists of three parts: a …, an … and a …

A

prefix; infix; suffix

43
Q

the prefix indicates the number of carbon atoms in the parent chain; the infix indicates the … of the C-C bonds in the parent chain (whether they are …, …, or …)

A

nature; single; double; triple

44
Q

infixes:
- an: … bonds
- en: one or more … bonds
- yn: one or more …

A

single; double; triple

45
Q

the suffix indicates the class of compound to which the substance belongs:

  • e: …
  • ol: …
  • al: …
  • amine: …
  • one: …
  • oic acid: …
A

hydrocarbon; alcohol; aldehyde; amine; ketone; carboxylic acid

46
Q

cycloalkanes contain … fewer hydrogen atoms than an alkane with the same number of C atoms and have the general formula ..

A

two; CnH2n

47
Q

to name a cycloalkane, prefix the name of the corresponding open-chain alkane with … and name each substituent on the ring. if there is only one substituent on the cycloalkane ring, there is no need to …

A

cyclo-; give it a number

48
Q

if there are two substituents, number the ring by beginning with the substituent of lower … If there are three or more substituents, number the ring to give the substituents the lower set of … and list them in …

A

alphabetical order; numbers; alphabetical order

49
Q

an alkane that contains two rings that share two C atoms is classified as a … The shared C atoms are called … Cs, and the carbon chain connecting them is called a

A

bicycloalkane; bridgehead; bridge

50
Q

the general formula of a bicycloalkane is …

A

CnH2n-2

51
Q

difference between torsional and steric strain:
torsional is repulsion on … c atoms, when they are …
steric is when repulsion occurs between C/groups that are not … (e.g. … interactions)

A

neighboring; eclipsing; neighboring; diaxial

52
Q

the interconversion between the strained and relaxed structures results from … and .. motions

A

collisions; thermal

53
Q

in a newman projection, a molecule is viewed down the axis of a .. bond. the three lines in front represent bonds directed … you, whereas the three lines in back …

A

C-C; toward; point away from you

54
Q

different conformations are often called … or …

A

conformational isomers; conformers

55
Q

the lowest E (most stable) conformation is a … conformation; the highest energy (least stable) is an .. conformation

A

staggered; eclipsed

56
Q

torsional strain arises when nonbonded atoms achieve conformations via rotations around bonds where they are closer to one another than in a more stable

A

alternate conformation

57
Q

the two gauche conformations have equal … and are related by …

A

energies; reflection

58
Q

small ring strain: exists in ring sizes below .. carbons and is due to the C-C-C bond angles not being able to achieve the optimal …

A

six; tetrahedral angle

59
Q

nonplanar/puckered conformations are favored in all cycloalkanes larger than

A

cyclopropane

60
Q

In cyclopentane, the ring will form a … conformation, where four C are in a plane and the 5 bends out. This is an energetic compromise that balances a decreased … strain with an increased … strain

A

envelope; torsional; angle

61
Q

diaxial interaction is a kind of … strain that refers to the strain between an axial … and an axial … (or another group) on the same side of a cyclohexane group

A

steric; substituent; hydrogen

62
Q

the preference for the equatorial position among the halogens increases in the order … < …. < … < ..

A

F; I; Cl; Br

63
Q

stereoisomers are compounds that have (1) the same …

(2) the same … of their atoms
(b) but a different … of their atoms in space

A

molecular formula; connectivity; orientation

64
Q

cycloalkanes with substituents on two or more carbons of the ring show a type of stereoisomerism called …

A

cis, trans isomerism

65
Q

the prefix cis indicates that the substituents are on the … side of the ring

A

same

66
Q

the prefix trans indicates that they are on … sides of the ring

A

opposite

67
Q

the cis isomer cannot be converted to the trans isomer and vice versa without … and … one or more bonds

A

breaking; refomring

68
Q

the cis isomer is approximately higher in energy than the trans isomer because of the … of the methyl groups on adjacent carbons in the cis isomer

A

steric strain

69
Q

a stereocenter is an atom, most commonly carbon, about which …. produces a different

A

exchange of two groups; stereoisomer

70
Q

configuration refers to the arrangement of atoms about a …

A

stereocenter

71
Q

the most important property of alkanes and cycloalkanes is their almost complete lack of

A

polarity

72
Q

alkanes are nonpolar compounds and only weak interactions exist between their molecules. … are the weakest intermolecular attractive forces

A

dispersion forces

73
Q

the existence of dispersion forces accounts for the ability to … low-molecular weight, nonpolar substances

A

liquefy

74
Q

dispersion forces: at any instant, there is a nonzero probability that electron density will be … (shifted) more toward one part of the atom than toward another . this temporary polarization creates a temporary …, which in turn induces temporary dipole moments in …

A

polarized; dipole moment; adjacent atoms

75
Q

the small attraction referred to as dispersion forces is the source of … between temporary dipoles. the strength of dispersion forces depends on how easily an electron cloud can be …

A

electrostatic attraction; polarized

76
Q

electrons in smaller atoms and molecules are held closer to their nuclei, and, therefore, are not easily … The strength of dispersion forces tends to increase with increasing … and …

A

polarized; molecular mass; size

77
Q

the boiling points of alkanes are … than those of almost any other type of compound of the same molecular weight

A

lower

78
Q

both boiling and melting points of alkanes … as molecular weight increases, but the increase in melting points is not as regular as that observed for boiling points

A

increase

79
Q

alkanes containing 1 to 4 carbons are… at room temperature; those containing 5 to 17 carbons are … high molecular weight alkanes are …, …

A

gases; colorless liquids; white, waxy solids

80
Q

all liquid and solid alkanes are … dense than water

A

less

81
Q

alkanes that are constitutional isomers are … compounds and have … physical and chemical properties

A

different; different

82
Q

the more branching there is the … the boiling point. as branching increases, the shape of an alkane molecule becomes more … and its surface area …

A

lower; compact; decreases

83
Q

as surface area decreases, contact among adjacent molecules decreases, the strength of … decreases, and … decrease. thus, for any group of alkane constitutional isomers, the least branched isomer usually has the … boiling point and the most branched isomer usually has the … boiling point

A

dispersion forces; boiling points; highest; lowest

84
Q

alkanes and cycloalkanes are quite … toward most reagents

A

unreactive

85
Q

the … of alkanes by o2 to give … and … is by far their most economically important reaction. they act as energy sources for heat. the energy of the products is less than that of the reactants, with the difference in energy being given off as the …

A

oxidation; CO2; water; heat of combustion

86
Q

as branching increases, the … decreases. therefore, we conclude that branching .. the stability of an alkane

A

change in enthalpy; increases

87
Q

strain energy is the difference between the predicted and actual

A

heats of combustion

88
Q

natural gas consists of 90-95% methane with lesser amounts of … and other low weight hydrocarbons

A

ethane

89
Q

petroleum is a liquid mixture of literally … of different hydrocarbons. the most important processes in petroleum refining are …, …, and …

A

thousands; fractional distillation; catalytic cracking; catalytic reforming

90
Q

synthesis gas: a mixture of … and …, can be derived from natural gas or coal

A

carbon monoxide; H