Deck 26: Structures of Organic Compounds

Question 1

A conformation is a set of all possible optical isomers of an organic compound of a given molecular formula.

Answer 1

False

Question 2

Which of the following classes of organic compounds and their general structural formulas have been correctly matched?
I.ester:

II.aldehyde:

III.ketone:

IV.carboxylic acid:

V.amide:

A)I,II,and V
B)II,III,and V
C)III,IV,and V
D)I,IV,and V
E)II,IV,and V

Answer 2

I,IV,and V

Question 3

Replacing the acidic hydrogen of a carboxylic acid with an organic group produces an amide.

Answer 3

False

Question 4

Cis-trans isomerism is a type of isomerism generally known as stereoisomerism.

Question 5

How many primary,secondary,tertiary and quaternary carbon atoms are there in the structure of 2,4,6-trimetylheptane?

A)5 primary,2 secondary,2 tertiary and 1 quaternary carbon atoms
B)5 primary,3 secondary,2 tertiary and 0 quaternary carbon atoms
C)4 primary,4 secondary,2 tertiary and 0 quaternary carbon atoms
D)4 primary,2 secondary,2 tertiary and 2 quaternary carbon atoms
E)5 primary,2 secondary,3 tertiary and 0 quaternary carbon atoms

Question 6

Choose the INCORRECT statement.

A)Hydrocarbons are compounds of carbon and hydrogen.
B)Skeletal isomerism is also called chain isomerism.
C)Isomers have the same chemical formula but differ with respect to the arrangement of atoms.
D)Saturated hydrocarbons have only single bonds connecting each atom.
E)Organic compounds can be obtained only from living tissue.

Question 7

Different forms of isomerism in organic compounds can be summarized as follows:
"Isomers can be constitutional or stereoisomers.Constitutional isomers are further divided in enantiomers and diastereomers."

Question 8

In alkene nomenclature "trans" stands for "on the same side" while "cis" means "across."

Question 9

Choose the INCORRECT statement.

A)Latin prefixes provide information on the numbers of C atoms in a chain.
B)An alkane group used as a side chain group is called an alkyl group.
C)Di,tri,and tetra can be used to designate the number of side chain groups.
D)Positional isomers differ in the position on the main chain of the side chain group.
E)Functional groups are distinctive groupings of one or more atoms.

Question 10

Which compound is the lowest boiling?

A)methane
B)ethene
C)ethane
D)cyclopropane
E)ethyne

Question 11

Two structural features shared among all aromatic organic compounds are:
1)They all are flat,cyclic or linear molecules
2)They have a conjugated bonding system.

Question 12

When determining the priority of substituents is "A substituent atom of higher atomic number has higher priority over a substituent atom with lower atomic number."

Question 13

The IUPAC name of tert-butyl group is:

A)1,1-dimethylethyl
B)1,1-dimethylethane
C)1,2-dimethylethyl
D)1-methylpropyl
E)2-methylpropyl

Question 14

Constitutional isomers have different bond connectivities,and as a consequence they have different skeletal structures.

Question 15

In the rings of heterocyclic compounds we can find one or more atoms that are not carbon atoms.

Question 16

A solid wedge line denotes a bond that sticks back behind the plane of the paper.

Question 17

The compound with formula C₄H₉N has two degrees of unsaturation.

Question 18

Find the structure for 2,3,5,7-tetramethyloctane

A)
B)
C)
D)
E)

Question 19

Torsional or rotational energy is the difference in energy between the eclipsed and staggered conformations in alkane structure.

Question 20

What is the correct IUPAC name for the following structure?

A)2-ethyl-3-methylheptane
B)3,5-dimethyloctane
C)4-methyl-6-ethylheptane
D)4,6-dimethyloctane
E)3,5-dimethyloctyl

Question 21

Which of the following methods are used for the laboratory alkane synthesis?
I.catalytic addition of hydrogen to multiple carbon - carbon bonds
II.catalytic hydrogenation of aldehydes
III.from halogenated hydrocarbons and sodium
IV.from alkali metal salts of organic acids and alkali metal hydroxides
V.dehydrohalogenation of organic halogen compounds

A)I,II,and V
B)II,III,and V
C)I,III,and IV
D)II,III,and IV
E)III,IVand V

Question 22

What are skew conformations?

A)Skew conformations all possible conformations between the eclipsed and staggered extremes.
B)Skew conformations in which linear molecules get twisted.
C)Skew conformations are conformations that have the greatest energy.
D)Skew conformations are conformations that have the lowest energy.
E)Skew conformations are conformations that have the greatest energy barrier.

Question 23

Which of the following structures represent the structure of trans-1-bromo-2-methylcyclohexane?

A)
B)
C)
D)
E)

Question 24

Find the correct stereochemistries for the following four alkenes:

A)A is Z,B is Z,C is E,D is E
B)A is Z,B is E,C is Z,D is E
C)A is E,B is E,C is Z,D is E
D)A is E,B is E,C is Z,D is Z
E)A is Z,B is Z,C is E,D is Z

Question 25

Define "conformation."

A)Conformations are different arrangements of bonds in space.
B)Conformations are different structural representations of the same molecule.
C)Conformations are different spatial arrangements one structure can have.
D)Conformations are two enantiomers.
E)Conformations are all possible structural isomers for a given molecular formula.

Question 26

Reforming is:

A)a process that joins low molecular mass hydrocarbons into higher molecular mass hydrocarbons
B)a process that converts straight chain hydrocarbons to branched hydrocarbons
C)a process that converts unsaturated organic compounds to saturated ones
D)a process that breaks down high molecular mass hydrocarbons into low molecular mass hydrocarbons
E)a process that converts branched hydrocarbons to straight chain hydrocarbons

Question 27

Which of the following structures represents a structure of R isomer of 1-amino-2-propanol?

A)
B)
C)
D)
E)

Question 28

How many chiral carbon atoms can you find in the molecule below?

A)1
B)2
C)3
D)4
E)5

Question 29

Which statements regarding chiral compounds are correct?
I."Chiral carbon" is synonymous with "asymmetric carbon."
II.The presence of one chiral carbon in a structure results in two possible enantiomers.
III.Two enantiomers can be interconverted without breaking any bonds.
IV.Two chiral molecules are mirror images of each other.
V.Two chiral molecules have significantly different chemical properties.

A)II,III,and V
B)I,II,and IV
C)I,III,and IV
D)II,IVand V
E)III,and V

Question 30

Which of the following represent two different chair forms of methylcyclohexane?

A)
B)
C)
D)
E)

Question 31

Give the name for CH₃CH =CHCH₃.

A)3-butene
B)2-butene
C)2-propene
D)2-pentene
E)2-butane

Question 32

Choose the INCORRECT statement.

A)In thermal cracking large hydrocarbon molecules are broken down into smaller molecules,ideally,molecules in the gasoline range.
B)Reforming converts straight-chain hydrocarbons into branched-chain hydrocarbons.
C)Branched-chain hydrocarbons have higher octane numbers.
D)Alkylation is the joining of small hydrocarbon fragments to larger molecules.
E)Engine knocking is caused by the smooth firing of gasoline.

Question 33

You found an organic compound containing chiral carbon atom with the following four substituents: HC≡C-,Cl-,O=C- and H₂C=CH-.What would be the correct order of their priorities?

A)HC≡C- > O=C- > Cl- > H₂C=CH-
B)Cl- > HC≡C- > O=C- > H₂C=CH-
C)Cl- > O=C- > HC≡C- > H₂C=CH-
D)Cl- > O=C-> H₂C=CH- > HC≡C-
E)O=C- > Cl- > HC≡C- > H₂C=CH-

Question 34

There are three rules for assigning priorities:
Rule 1: A substituent atom of higher atomic number takes precedence over one of lower atomic number.
Rule 2: If two substituent atoms attached to the stereocenter have the same priority,the atom on the right of a hydrogen atom bonded to chiral carbon is a substituent of higher priority.
Rule 3: Double and triple bonds are treated as if they were single,and the atoms in them are duplicated or triplicated at each end by the particular atoms at the other end of the multiple bond.
Which rule(s)is/are stated incorrectly?

A)rule 2
B)rules 1 and 3
C)rule 3
D)rules 2 and 3
E)rules 1 and 2

Question 35

Can 1,3,5-hexatriene be considered an aromatic compound? Why do you think so?

A)Yes,because it contains alternating double and single bonds.
B)No,because the molecule is not a flat ring.
C)Yes,because its double bonds contain 4n+2 electrons (n = 1).
D)No,because the structure is not based on benzene ring.
E)Yes,because the molecule has a delocalized π electron cloud.

Question 36

Choose the INCORRECT statement.

A)Axial H atoms are directed above and below the cyclohexane ring.
B)A substitution reaction typically involves a functional group replacing a hydrogen atom on a chain or ring containing molecule.
C)A free radical is a compound with an unpaired electron.
D)LPG is linear polymerized gas.
E)Unsaturated usually means a double,triple or delocalized electron system is present in the molecule.

Question 37

Find the answer that has correct both the two structures of cis-1-isopropyl-4-methylcyclohexane and their relative stability (stability is indicated with ">" meaning "more stable than").

A)
B)
C)
D)

Question 38

How many chiral carbon atoms can you find in the molecule below?

A)0
B)1
C)2
D)3
E)4

Question 39

Why does benzene have a much higher boiling point (80 °C)than hexane (69 °C),even though they have the same number of carbons?

A)Benzene has fewer hydrogens than hexane.
B)Benzene is much more polar than hexane which enhances the attractive forces between molecules and raises the boiling point.
C)Benzene is planar and has delocalized electron density which increases the attractive forces between molecules and raises the boiling point.
D)Hexane has more Kekulé structures than benzene.
E)Benzene can covalently bond to another benzene molecule which increases its boiling point.

Question 40

Choose the best configuration assignments for the three double bonds,labeled A,B and C,in the following compound:

A)A is E,B is E,and C is E
B)A is E,B is E,and C is Z
C)A is Z,B is Z,and C is E
D)A is E,B is Z,and C is E
E)A is Z,B is E,and C is Z

Question 41

The diol,ethylene glycol,is used extensively as an antifreeze additive in automobile radiators.What properties of ethylene glycol make it a good antifreeze?

A)Ethylene glycol coats the radiator to prevent crystallization of ice at low temperatures.
B)Ethylene glycol has a higher boiling point than water and is soluble in water.
C)Ethylene glycol has a lower boiling point than water and is soluble in water.
D)Ethylene glycol forms a film on the surface of the water to prevent ice formation in the radiator.
E)Ethylene glycol will remain in the radiator after the water evaporates.This prevents freezing in cold climates.

Question 42

What is the IUPAC name for the following molecule?

A)2-bromo-4-isopropyl-3-methylbutane
B)2-bromo-3,5-dimethylhexane
C)3,5-dimethyl-2-bromohexane
D)2-bromo-3-methyl-4-propylbutane
E)2-bromo-5,5,3-trimethylpentane

Question 43

Compound A easily reacts with water to give compound B.Compound B can be oxidized to produce compound C.Both B and C can be further oxidized to produce D.To which classes of organic compounds A,B,C and D most likely belong to,respectively?

A)A is an alkane,B is an alcohol,C is an aldehyde and D is a carboxylic acid
B)A is an alkene,B is an ether,C is an aldehyde and D is a carboxylic acid
C)A is an alkene,B is an alcohol,C is a ketone and D is a carboxylic acid
D)A is an alkene,B is an alcohol,C is an aldehyde and D is an ester
E)A is an alkene,B is an alcohol,C is an aldehyde and D is a carboxylic acid

Question 44

Which class of compounds is the least reactive?

A)ethers
B)alcohols
C)ketones
D)alkyl halides
E)aldehydes

Question 45

How many skeletal isomers for C₆H₁₄ can be drawn?

A)6
B)3
C)8
D)5
E)2

Question 46

Name the functional groups in the molecule below:

A)ester,ether,amine,keto
B)carboxyl,ether,amine,keto
C)ester,ether,amine,aldehyde
D)ester,ether,amide,aldehyde
E)ester,carboxyl,amine,keto

Question 47

An alcohol of formula C₃H₈O in which there are only three different kinds of hydrogens is:

A)2-propanol
B)1-propanol
C)cyclopropanol
D)ethanol
E)None of the above

Question 48

CH₃(C=O)CH₃ is a(n):

A)ether
B)ketone
C)ester
D)aldehyde
E)carboxylic acid

Question 49

Provide names for compounds A,B and C:

A)A is 3-chloro-4-methylpentanal,B is meta-chlorophenol and C is 3-(2-methylcyclohexyl)cyclopentanecarboxylic acid
B)A is 3-chloro-4-methylpentanol,B is meta-chlorophenol and C is 3-(2-methylcyclohexyl)cyclopentanecarboxylic acid
C)A is 3-chloro-4-methylpentanal,B is ortho-chlorophenol and C is 3-(3-methylcyclohexyl)cyclopentanecarboxylic acid
D)A is 3-chloro-4-methylpentanone,B is meta-chlorophenol and C is 3-(2-methylcyclohexyl)cyclopentanal
E)A is 4-chloro-3-methylpentanal,B is para-chlorophenol and C is 3-(2-methylcyclohexyl)cyclopentanecarboxylic acid

Question 50

The terms ortho,meta and para are used to describe the substitution on benzene ring.What do they stand for?

A)Ortho stands for two adjacent substituents,meta for two substituents with one carbon between them and para for two substituents with two carbon atoms between them.
B)Ortho stands for two cis substituents,meta for two trans substituents and para for two opposite substituents.
C)Ortho stands for two adjacent substituents,meta for two different adjacent substituents and para for two substituents with one carbon atoms between them.
D)Ortho stands for two substituents with one carbon atom between them,meta for two substituents with two carbons between them and para for two substituents with three carbon atoms between them.
E)Ortho stands for two substituents with two carbon atoms between them,meta for two substituents with three carbons between them and para for two substituents with four carbon atoms between them.

Question 51

Calculate the degree of unsaturation for the following molecules:
Molecule I: C₃H₄
Molecule II: C₅H₁₀
Molecule III: C₄H₆

A)For molecule I the degree of unsaturation is 2,for molecule II the degree of unsaturation is 1 and for molecule III the degree of unsaturation is 1.
B)For molecule I the degree of unsaturation is 2,for molecule II the degree of unsaturation is 0 and for molecule III the degree of unsaturation is 2.
C)For molecule I the degree of unsaturation is 2,for molecule II the degree of unsaturation is 1 and for molecule III the degree of unsaturation is 2.
D)For molecule I the degree of unsaturation is 2,for molecule II the degree of unsaturation is 2 and for molecule III the degree of unsaturation is 2.
E)For molecule I the degree of unsaturation is 1,for molecule II the degree of unsaturation is 2 and for molecule III the degree of unsaturation is 1.

Question 52

Choose the INCORRECT statement.

A)CH₃CH₂CH₂CH₂CH₂NH₂ is an amine.
B)CH₃CH₂OCH₂CH₂CH₃ is an ether.
C)CH₃CH₂CH₂CH₂CH₂OH is an alcohol.
D)O CH₃CH₂CH₂CH₂CH is a ketone.
E)CH₃CH₂CH₂CH=CH₂ is an alkene.

Question 53

What are heterocyclic compounds?

A)They are cyclic compounds in which carbon has one or more substituents that are neither hydrogen or another carbon atom.
B)They are cyclic compounds in which two or more carbon rings are connected by C-C bonds (for example biphenyl).
C)They are cyclic compounds in which carbon ring is connected to another ring not containing carbon atoms.
D)They are cyclic compounds in which one or more atoms are not carbon atoms.
E)They are cyclic compounds that can have more than one stable conformation.

Question 54

Which of the following synthetic procedures are plausible?
I.synthesis of esters from alcohols and acids
II.synthesis of ethers from acids and alcohols
III.synthesis of amides from acids and amines
IV.synthesis of alcohols from alkanes and water
V.synthesis of aldehydes from alcohols and oxidizing agents

A)I,III,and IV
B)I,III,and V
C)II,III,and V
D)II,III,and IV
E)III,IV,and V

Question 55

C₃H₈O has how many skeletal isomers?

A)2
B)4
C)5
D)6
E)3

Question 56

Which two simple functional groups make carboxyl group?

A)aldehyde and keto groups
B)aldehyde and hydroxyl groups
C)keto and hydroxyl groups
D)ester and hydroxyl groups
E)ester and ether groups

Question 57

To produce an ether from methanol,one can use:

A)reacting alkene with water in a presence of a strong mineral acid
B)alcohol and concentrated H₂SO₄
C)KOH in alcohol
D)Cu,heat
E)reacting alcohol with sodium

Question 58

What is the degree of unsaturation for the following compounds?

A)For A the degree of unsaturation is 1,for B is 6 and for C is 5.
B)For A the degree of unsaturation is 1,for B is 5 and for C is 6.
C)For A the degree of unsaturation is 0,for B is 6 and for C is 5.
D)For A the degree of unsaturation is 1,for B is 6 and for C is 4.
E)For A the degree of unsaturation is 1,for B is 4 and for C is 5.

Question 59

Which class of compounds is most oxidized?

A)alkanes
B)alcohols
C)carboxylic acids
D)aldehydes
E)ketones

Question 60

Which methods can be used to prepare alcohols?
I.addition of H₂O to alkenes in the presence of H₂SO₄
II.reacting alkanes with a concentrated solution of CH₃OH
III.hydrolysis of alkyl halides
IV.methanol can be prepared from CO(g)and H₂(g)in the presence of a heterogeneous catalyst
V.removing one oxygen atom from a carboxylic acid

A)I,IIand IV
B)I,III,and IV
C)II,III,and V
D)I,II,and V
E)II,IVand V

Question 61

Give the condensed structural formula for 3-bromopentane.

A)CH₃CH₂CHBrCH₂CH₂CH₃
B)CH₃CHBrCH₂CH₂CH₃
C)(CH₃)₃CHBrCH₂CH₃
D)CH₃CH₂CHBrCH₂CH₃
E)CH₃CH₂CBr₃CH₂CH₃

Question 62

The burning of alkanes to produce carbon dioxide and water is known as what type of reaction?

A)thermal cracking
B)reforming
C)radical substitution
D)oxidation
E)alkylation

Question 63

The two benzene substituents of the common analgesic shown below are considered in what relation to one another?

A)ortho
B)para
C)meta
D)trans
E)1,3

Question 64

What is the condensed structural formula for 2-pentyne?

A)CH₂ CHCH₂CH₂CH₃
B)CH₃C CCH₂CH₃
C)CH₃CH CHCH₂CH₃
D)CH₃C CCH₃
E)CH₃CH CCH₂CH₂CH₃

Question 65

Which of the following has the lowest melting point: cyclohexane,hexane,benzene?

A)cyclohexane
B)hexane
C)benzene
D)They have approximately the same melting point.
E)There is not enough information to determine.

Question 66

What are the possible positions for hydrogen on the chair conformation of cyclohexane?

A)staggered and eclipsed
B)axial and equatorial
C)equatorial and apical
D)longitudinal and latitudinal
E)chair and boat

Question 67

Which of the following chiral compounds is(are)R enantiomer(s)?

A)I
B)II
C)III
D)II and III
E)I and II

Question 68

Which of the following compounds is(are)chiral?

A)I
B)II
C)III
D)I and II
E)II and III

Question 69

Which of the following compounds is(are)chiral?

A)I
B)II
C)III
D)I and II
E)II and III

Question 70

Combustion of 493 mg of a hydrocarbon gave 1549 mg CO₂ and 633.9 mg H₂O.What is the molecular formula if the molecular weight is subsequently found to be 42?

A)CO₂
B)CH₂
C)C₆H₁₂
D)C₂H₂O
E)C₃H₆

Question 71

If an ethyl group is substituted for one hydrogen of cyclohexane,what would be the preferred position of that ethyl substituent on the ring?

A)axial position
B)equatorial position
C)chair position
D)boat position
E)twist boat conformation

Question 72

Give the condensed structural formula for 3-methyl-3-hexene.

A)CH₃CH₂CH(CH₃)CH=CHCH₃
B)CH₃CH₂C(CH₃)₂CH=CHCH₃
C)(CH₃)₃CCH=CHCH₃
D)CH₃CH₂C(CH₃)=CHCH₂CH₃
E)(CH₃)₆CCH₂CH=CH₂

Question 73

Which of the following chiral compounds is(are)S enantiomer(s)?

A)I
B)II
C)III
D)I and II
E)I and III

Question 74

C₄H₁₀O has how many skeletal isomers?

A)11
B)12
C)8
D)7
E)6

Question 75

Which of the following compounds is(are)E configuration(s)?

A)I
B)II
C)III
D)I + II
E)II + III

Question 76

Give the name for CH₃CH₂CHBrCH₃.

A)2-bromobutane
B)3-bromobutane
C)2-bromopropane
D)3-bromopropane
E)3-bromylpentane

Question 77

How many different structural isomers are there of the compound dichlorobutane?

A)6
B)8
C)9
D)5
E)7

Question 78

Which of the following compounds is(are)Z configuration(s)?

A)I
B)II
C)III
D)I + II
E)I + II + III

Question 79

What is the complete systematic name for the following molecule?

A)3-pentene
B)3-hexene
C)cis-3-hexene
D)trans-3-hexene
E)cis-3-hexyne

Question 80

Provide IUPAC names for the following compounds:

A)A is (3S)-3-bromo-2,3-dimethylpentane,B is (2S)-1,2-dibromopentane and C is (3R)-3-fluoro-3-methylhexane
B)A is (3R)-3-bromo-2,3-dimethylpentane,B is (2S)-1,2-dibromopentane and C is (3R)-3-fluoro-3-methylhexane
C)A is (3S)-3-bromo-2,3-dimethylpentane,B is (2R)-1,2-dibromopentane and C is (3R)-3-fluoro-3-methylhexane
D)A is (3S)-3-bromo-2,3-dimethylpentane,B is (2S)-1,2-dibromopentane and C is (3S)-3-fluoro-3-methylhexane
E)A is (3R)-3-bromo-2,3-dimethylpentane,B is (2S)-1,2-dibromopentane and C is (3S)-3-fluoro-3-methylhexane