Deck 11: Alkanes

Question 1

Compounds which contain a carbon-carbon triple bond are classified as which of the following?

A) alkanes
B) alkenes
C) alkynes
D) arenes

Answer 1

C

Question 2

Which of the following represents the molecular formula for a noncyclic alkane?

A) C₁₅H₃₀
B) C₁₉H₄₀
C) C₂₀H₄₀
D) all of them

Answer 2

B

Question 3

Dodecane is a 12 carbon alkane. How many hydrogen atoms are in dodecane?

A) 12
B) 24
C) 26
D) 28

Answer 3

C

Question 4

Compounds which contain a carbon-carbon double bond are classified as which of the following?

A) alkanes
B) alkenes
C) alkynes
D) arenes

Question 5

Which of the following is the correct molecular formula for hexane?

A) C₆H₆
B) C₆H₁₀
C) C₆H₁₄
D) C₆H₁₆

Question 6

Which of the following explains why alkanes are called saturated hydrocarbons?

A) They are good solvents for most organic compounds.
B) They are the most highly reactive organic compounds.
C) They contain the maximum possible number of hydrogen atoms bonded to each carbon.
D) They are found in animal fats and plant oils.

Question 7

Compounds which contain only carbon-carbon single bonds are classified as which of the following?

A) alkanes
B) alkenes
C) alkynes
D) arenes

Question 8

Which of the following is the correct molecular formula for heptane?

A) C₅H₁₂
B) C₆H₁₄
C) C₇H₁₆
D) C₈H₁₈

Question 9

Which of the following is not the molecular formula of a noncyclic alkane?

A) C₁₅H₃₂
B) C₁₉H₃₈
C) C₂₀H₄₂
D) C₂₂H₄₆

Question 10

Alkanes belong to which class of hydrocarbons?

A) alkali
B) aromatic
C) saturated
D) unsaturated

Question 11

Which of the following is the correct molecular formula for nonane?

A) C₇H₁₆
B) C₉H₂₀
C) C₁₁H₂₄
D) none of these

Question 12

Which of the following is not the molecular formula of an alkane?

A) C₁₅H₃₂
B) C₁₉H₄₀
C) C₂₀H₄₂
D) None of them, these are all alkanes.

Question 13

Unbranched hydrocarbons are also called straight chain hydrocarbons. Which of the following is true of unbranched hydrocarbons?

A) The C−C−C angle is 180°.
B) No carbon atom is connected to more than two other carbon atoms.
C) both a and b
D) neither a nor b

Question 14

Unbranched hydrocarbons are also called straight chain hydrocarbons. Which of the following is true of unbranched hydrocarbons?

A) Each carbon has bond angles of 120^°.
B) Every carbon atom is connected to two other carbon atoms.
C) both a and b
D) neither a nor b

Question 15

Of the hydrocarbons given here, which contains the most carbon atoms?

A) butane
B) pentane
C) ethane
D) propane

Question 16

Compounds which contain one or more benzene-like rings are classified as which of the following?

A) alkanes
B) alkenes
C) alkynes
D) arenes

Question 17

Eicosane is a 20 carbon alkane. How many hydrogen atoms are in eicosane?

A) 38
B) 40
C) 42
D) 44

Question 18

Which of the following represents the molecular formula for an unbranched alkane?

A) C₅H₁₀
B) C₆H₁₀
C) C₇H₁₈
D) C₈H₁₈

Question 19

What is the name given to a −CH₂− group?

A) methane
B) methylane
C) methylene
D) methyl

Question 20

Which of the following correctly describes the relationship between butane and 2-methylpropane?

A) They have the same molecular formula.
B) They have the same chemical properties.
C) They have the same physical properties.
D) All of the above are true.

Question 21

Which of the following are representations of the same molecule? (i)
CH₃CH₂CH₂CH₂CH₂CH₂CH₃(ii) (iii)

A) only (i) and (ii)
B) only (i) and (iii)
C) only (ii) and (iii)
D) none of them

Question 22

What is the molecular formula for the following compound?

A) C₇H₁₆
B) C₈H₁₆
C) C₈H₁₇
D) C₈H₁₈

Question 23

When naming a branching substituent in an alkane, which of the following is the correct procedure?

A) Add the suffix -yl to the name of the parent hydrocarbon.
B) Replace the suffix -ane with the suffix -yl.
C) Replace the suffix -ane with the suffix -anyl.
D) Insert -yl before the suffix -ane.

Question 24

Which of the following is a constitutional isomer of butane, CH₃(CH₂)₂CH₃?

A)
B)
C)
D) all of these

Question 25

Which of the following is(are) constitutional isomer(s) of hexane, CH₃(CH₂)₄CH₃?

A)
B)
C) both a and b
D) neither a nor b

Question 26

How many different substituent groups can obtained by removing a hydrogen atom from butane?

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

Question 27

The formula of a particular compound can be written as (i)
C₄H₁₀(ii)
CH₃CH₂CH₂CH₃(iii)
CH₃(CH₂)₂CH₃Which of the following is true?

A) All of these provide exactly the same amount of information.
B) Formula (ii) provides more information than formulas (i) or (iii).
C) Formulas (ii) and (iii) provide exactly the same amount of information.
D) No two of these provide exactly the same amount of information.

Question 28

How many different substituent groups can be obtained by removing a hydrogen atom from propane?

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

Question 29

Which of the following is true of branched chain hydrocarbons?

A) The longest carbon chain becomes the root name
B) The longest carbon chain is always written horizontally
C) both a and b
D) neither a nor b

Question 30

The butyl group is obtained by doing which of the following?

A) removing a hydrogen atom from C-1 of butane
B) removing a hydrogen atom from C-2 of butane
C) removing a hydrogen atom from C-1 of 2-methylpropane
D) removing a hydrogen atom from C-2 of 2-methylpropane

Question 31

Which of the following compounds are constitutional isomers? (i) (ii) (iii)

A) (i) and (ii)
B) (i) and (iii)
C) (ii) and (iii)
D) all of them

Question 32

Of the compounds listed here, which one is not a constitutional isomer of the other three?

A) 2,3-dimethylpentane
B) 3-methylhexane
C) 3-ethylpentane
D) 2,2-dimethylbutane

Question 33

Given the compounds 2,3-dimethylpentane, 3-ethylpentane and 3-methylhexane, which are constitutional isomers of one another?

A) only 2,3-dimethylpentane and 3-ethylpentane
B) only 2,3-dimethylpentane and 3-methylhexane
C) only 3-ethylpentane and 3-methylhexane
D) They are all constitutional isomers of one another.

Question 34

Which of the following are representations of the same molecule? (i)
CH₃CH₂CH₂CH₂CH₂CH₂(ii) (iii)

A) only (i) and (ii)
B) only (i) and (iii)
C) only (ii) and (iii)
D) all of them

Question 35

How many different substituent groups can be obtained by removing a hydrogen atom from ethane?

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

Question 36

Which of the following are representations of the same molecule? (i)
CH₃CH₂CH₂CH₂CH₂CH₂CH₃(ii) (iii)

A) only (i) and (ii)
B) only (i) and (iii)
C) only (ii) and (iii)
D) none of them

Question 37

The isobutyl group is obtained by doing which of the following?

A) removing a hydrogen atom from C-1 of butane
B) removing a hydrogen atom from C-2 of butane
C) removing a hydrogen atom from C-1 of 2-methylpropane
D) removing a hydrogen atom from C-2 of 2-methylpropane

Question 38

Which of the following is(are) constitutional isomer(s) of hexane, CH₂(CH₂)₄CH₃?

A)
B)
C) both a and b
D) neither a nor b

Question 39

Which of the following are representations of the same molecule? (i)
CH₃CH₂CH₂CH₂CH₂CH₂CH₃(ii) (iii)

A) only (i) and (ii)
B) only (i) and (iii)
C) only (ii) and (iii)
D) none of them

Question 40

How many constitutional isomers are there with the formula C₆H₁₄?

A) 4
B) 5
C) 6
D) 7

Question 41

A student gave the name of a compound as 2,2-diethylpentane. Although this correctly represented the connectivity of the compound, it was not a valid IUPAC name. What is the correct IUPAC name for this compound?

A) 3-ethyl-3-methylhexane
B) 3-methyl-3-propylpentane
C) 2-ethyl-2-propylbutane
D) 4,4-diethylpentane

Question 42

The tert-butyl group is obtained by doing which of the following?

A) removing a hydrogen atom from C-1 of butane
B) removing a hydrogen atom from C-2 of butane
C) removing a hydrogen atom from C-1 of 2-methylpropane
D) removing a hydrogen atom from C-2 of 2-methylpropane

Question 43

What is the common name of 2-methylbutane?

A) isopentane
B) neopentane
C) 2-methylisopropane
D) none of these

Question 44

When deriving an IUPAC name, which of the following prefixes should be ignored during the alphabetizing of substituents?

A) di-
B) sec-
C) tri-
D) all of these

Question 45

On an exam, students were shown the structure of an alkane and asked to give the IUPAC name of the compound. Of the following answers which were given, which corresponds to the correct IUPAC name of a real compound?

A) 2-ethyl-2-methylbutane
B) 2,2-dimethylbutane
C) 2,2-diethylbutane
D) none of them

Question 46

What is the IUPAC name of the compound below?

A) 4-ethyl-4-methyloctane
B) 3-methyl-3-propylheptane
C) 2-ethyl-2-propylhexane
D) none of these

Question 47

A student gave the name of a compound as 2-methyl-2-ethylbutane. Although this correctly represented the connectivity of the compound, it was not a valid IUPAC name. What is the correct IUPAC name for this compound?

A) 2-ethyl-2-methylbutane
B) 2,2-dimethylpentane
C) 2,2-diethylpropane
D) none of these

Question 48

What is the correct IUPAC name for the following compound?

A) 3,3-diethyl-6-methylheptane
B) isododecane
C) 5,5-diethyl-2-methylheptane
D) 1,1,1-triethyl-4-methylpentane

Question 49

Pentane and 2-methylbutane have third isomer, neopentane. What is the IUPAC name of this isomer?

A) 2,2-dimethylpropane
B) 2-methylisobutane
C) 2-ethylpropane
D) none of these

Question 50

Which of the following line-angle structures is 4-isopropyloctane?

A)
B)
C)
D)

Question 51

What is the correct IUPAC name for the following compound?

A) 1,1-dimethylpentane
B) 2,2-dimethylpentane
C) 1,1,1-trimethylbutane
D) 4,4,4-trimethylbutane

Question 52

Which of the following is a correct IUPAC name?

A) 1-methylpentane
B) 2-ethylpentane
C) 3-ethylpentane
D) None, they are all incorrect.

Question 53

Which of the following is a correct IUPAC name?

A) 1-methylhexane
B) 2-ethylhexane
C) 3-propylhexane
D) None, they are all incorrect.

Question 54

Which of the following is the correct line-angle structure for 3-ethylheptane?

A)
B)
C)
D)

Question 55

The sec-butyl group is obtained by doing which of the following?

A) removing a hydrogen atom from C-1 of butane
B) removing a hydrogen atom from C-2 of butane
C) removing a hydrogen atom from C-1 of 2-methylpropane
D) removing a hydrogen atom from C-2 of 2-methylpropane

Question 56

Which is the correct IUPAC name for the following compound?

A) 2,2-diethylpentane
B) 4-ethyl-4-methylhexane
C) 4-methyl-4-ethylhexane
D) 3-ethyl-3-methylhexane

Question 57

When deriving an IUPAC name, which of the following prefixes should not be ignored during the alphabetizing of substituents?

A) iso
B) di-
C) sec-
D) All three should be ignored.

Question 58

Which of the following is a correct IUPAC name?

A) 2-ethyl-3-methylpentane
B) 2,2-dimethylpentane
C) 2,2-diethylpentane
D) all of them

Question 59

What is the IUPAC name of the compound below?

A) 2-ethyl-2-methylpropane
B) 2,2-dimethylbutane
C) 3,3-dimethylbutane
D) none of these

Question 60

Which of the following is a correct IUPAC name?

A) 2-ethylpropane
B) 2-ethylbutane
C) 2-ethylpentane
D) None, they are all incorrect.

Question 61

Which of the following are perpendicular to the imaginary plane through the six carbon atoms of cyclohexane?

A) only the axial bonds
B) only the equatorial bonds
C) both the axial and equatorial bonds
D) neither the axial nor the equatorial bonds

Question 62

Which of the following is a correct IUPAC name?

A) 1-methylcyclohexane
B) cis-1,3-dimethylcyclohexane
C) cis-1,1,2-trimethylcyclohexane
D) trans-1,1-diethylcyclobutane

Question 63

Which of the following is the most stable conformation of cyclohexane?

A) boat
B) chair
C) envelope
D) twist

Question 64

Which of the following compounds has the common name isohexane?

A) CH₃(CH₂)₄CH₃
B)
C) CH₃(CH₂)₂CH(CH₃)₂
D) none of these

Question 65

How many cycloalkanes have the molecular formula C₅H₁₀?

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

Question 66

Which of the following is true of the axial positions in cyclohexane?

A) Each carbon atom of the ring has two groups bonded to it in axial positions.
B) Each carbon atom of the ring has one group bonded to it in an axial position.
C) The axial positions are all on the same side of the ring.
D) The axial and equatorial positions on each carbon atom are on the same side of the ring.

Question 67

Which of the following is true when there is a single substituent on cyclohexane?

A) This substituent will prefer to be in the axial position.
B) This substituent will prefer to be in the equatorial position.
C) This substituent has no particular preference for either the axial or equatorial position.
D) The situation will vary, depending on the identity of the substituent.

Question 68

Which of the following statements about the conformation shown below are true?

A) The ethyl and methyl groups are both axial.
B) All three alkyl substituents are equatorial.
C) The ethyl group is axial and the methyl group is equatorial.
D) The ethyl and methyl groups are both equatorial and the propyl group is axial.

Question 69

What is the IUPAC name of the following compound?

A) 1,1-dipropylcyclohexane
B) 1-isopropyl-1-propylcyclohexane
C) isopropylpropylcyclohexane
D) none of these

Question 70

Which size rings of carbon atoms are especially abundant in nature?

A) 3 and 4 carbon atom rings
B) 4 and 5 carbon atom rings
C) 5 and 6 carbon atom rings
D) 6 and 7 carbon atom rings

Question 71

What is the IUPAC name of the following compound?

A) diethylcyclopentane
B) butylcyclopentane
C) 1,1-diethylcyclopentane
D) none of these

Question 72

Different conformations of an alkane are the result of which of the following?

A) rotation around C−H bonds
B) rotation around C−C bonds
C) the existence of cyclic compounds
D) all of the these

Question 73

What is the most abundant alkane present in natural gas?

A) butane
B) propane
C) ethane
D) methane

Question 74

When organic chemists draw the structure of a cycloalkane, which of the following do they most frequently write?

A) all the C and H atoms
B) only the C atoms
C) only the polygon with as many sides as there are carbon atoms
D) the appropriate polygon and all the C and H atoms

Question 75

Which of the following is true about conformations of cycloalkanes?

A) They are constitutional isomers of one another.
B) They are obtained from one another by rotation around carbon-carbon bonds.
C) They are obtained from one another by breaking and reforming carbon-carbon bonds.
D) They are equally stable.

Question 76

What is the IUPAC name of the compound below?

A) 2-sec-butyl-2-propylbutane
B) 4-ethyl-3,4-dimethylheptane
C) 3,4-dimethyl-3-propylhexane
D) none of these

Question 77

What is the IUPAC name of the following compound?

A) 1-propylcyclohexane
B) isopropylcyclohexane
C) 1-propylhexane
D) propylcyclohexane

Question 78

Which of the following is the most stable conformation of cyclopentane?

A) boat
B) chair
C) envelope
D) twist

Question 79

Which of the following is true of the equatorial positions in cyclohexane?

A) Each carbon atom of the ring has two groups bonded to it in equatorial positions.
B) Each carbon atom of the ring has one group bonded to it in an equatorial position.
C) The equatorial positions are all on the same side of the ring.
D) The axial and equatorial positions on each carbon atom are on the same side of the ring.

Question 80

What is the IUPAC name of the compound below?

A) 2-isopropyl-2,3-dimethylpentane
B) 2-sec-butyl-2-isopropylpropane
C) 2,3,3,4-tetramethylhexane
D) none of these