Deck 4: Alkanes

Question 1

Which of the following compounds has primary, secondary and tertiary hydrogen atoms?

A) Pentane
B) Hexane
C) 2-Methylpentane
D) 2,2-Dimethylpentane

Answer 1

2-Methylpentane

Question 2

How many constitutional isomers are there with the molecular formula C₅H₁₂?

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

Answer 2

3

Question 3

What is the parent chain for the following compound?

A) Heptane
B) Octane
C) Nonane
D) Decane

Answer 3

Nonane

Question 4

What is the IUPAC name for the following compound?

A) 4-Ethyl-5-methyloctane
B) 4-Methyl-5-ethyloctane
C) 4-Methyl-3-propylheptane
D) 4-Methyl-5-propyloctane

Question 5

Which of the following compounds has only primary, secondary and quaternary carbon atoms?

A) Pentane
B) 2-Methylpentane
C) 2,2-Dimethylpentane
D) 2,2,3-Trimethylpentane

Question 6

How many constitutional isomers are there with the molecular formula C₆H₁₄?

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

Question 7

Which of the following compounds has primary, secondary, tertiary and quaternary carbon atoms?

A) Pentane
B) 2-Methylpentane
C) 2,2-Dimethylpentane
D) 2,2,3-Trimethylpentane

Question 8

What is the parent chain for the following compound?

A) Hexane
B) Heptane
C) Octane
D) Nonane

Question 9

Which of the following statements about alkanes is not true?

A) Alkanes are aliphatic hydrocarbons.
B) Alkanes contain only C-C and C-H  bonds.
C) Alkanes are acyclic or cyclic.
D) Acyclic alkanes have two fewer H atoms than cyclic alkanes with the same number of carbons.

Question 10

What is the approximate C-C-C bond angle in propane?

A) 90°
B) 109.5°
C) 120°
D) 180°

Question 11

Which of the following compounds has only primary, secondary and tertiary carbon atoms?

A) Pentane
B) 2-Methylpentane
C) 2,2-Dimethylpentane
D) 2,2,3-Trimethylpentane

Question 12

Which of the following compounds has only primary and secondary carbon atoms?

A) Pentane
B) 2-Methylpentane
C) 2,2-Dimethylpentane
D) 2,3,3-Trimethylpentane

Question 13

What is the hybridization of a carbon atom in an alkane?

A) sp³
B) sp²
C) sp
D) p

Question 14

What is the molecular formula of an alkane that has twenty-three carbon atoms?

A) C₂₃H₄₆
B) C₂₃H₄₈
C) C₂₃H₅₀
D) C₂₃H₄₄

Question 15

Which of the following is not another representation for 2-methylbutane?

A) I
B) II
C) III
D) IV

Question 16

What is the name of the alkyl group that contains two carbons in a straight chain and one-carbon branch?

A) Ethyl
B) Propyl
C) Isopropyl
D) None of the above

Question 17

How many cycloalkane constitutional isomers (excluding stereoisomers) are there with molecular formula C₅H₁₀?

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

Question 18

Which of the following compounds has only primary and secondary hydrogen atoms?

A) 2-Methylpentane
B) 2,2,3-Trimethylpentane
C) 3-Methylpentane
D) 2,2-Dimethylpentane

Question 19

Which of the following statements about alkanes is true?

A) Alkanes are aliphatic hydrocarbons having only C-C and C-H  bonds.
B) Cyclic alkanes have two fewer H atoms than acyclic alkanes with the same number of carbons.
C) Acyclic alkanes contain carbons joined in one or more rings.
D) Acyclic alkanes have general molecular formula C_nH_2n.

Question 20

What is the molecular formula of a cycloalkane that has six carbon atoms?

A) C₆H₁₄
B) C₆H₁₀
C) C₆H₁₂
D) C₆H₁₆

Question 21

What is the IUPAC name for the following compound?

A) 1-Butyl-3-methylcyclohexane
B) 1-sec-Butyl-3-methylcyclohexane
C) 1-Methyl-3-sec-butylcyclohexane
D) 1-sec-Butyl-3-methylhexane

Question 22

What is the IUPAC name for the following compound?

A) 2,3,5-Trimethylhexane
B) 2,4,5-Triethylhexane
C) 2,4-Diethyl-5-methylheptane
D) 4-Ethyl-3,6-dimethyloctane

Question 23

What is the IUPAC name for the following compound?

A) 3,5-Diethyl-6-methylheptane
B) 3,5-Diethyl-2-methylheptane
C) 3-Ethyl-5-isopropylheptane
D) 5-Ethyl-3-isopropylheptane

Question 24

What is the IUPAC name for the following compound?

A) 1-sec-Butyl-4-isopropyl-2-methylcyclohexane
B) 1-Isopropyl-3-methyl-4-sec-butylcyclohexane
C) 4-Isopropyl-2-methyl-1-sec-butylcyclohexane
D) 1-sec-Butyl-3-isopropyl-2-methylcyclohexane

Question 25

What is the IUPAC name for the following compound?

A) 3-Ethyl-1-methylcyclohexane
B) 1-Ethyl-3-methylcyclohexane
C) 1-Ethyl-3-methylhexane
D) 3-Ethyl-1-methylhexane

Question 26

Which of the following are gauche conformers?

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

Question 27

What is the IUPAC name for the following compound?

A) Hexylcyclopentane
B) 1-Hexylcyclopentane
C) 1-Cyclopentylhexane
D) 1-Cyclopentylheptane

Question 28

Which of the following statements about the conformations of acyclic alkanes is true?

A) Conformations are the same arrangements of atoms that cannot be interconverted by rotation about single bonds.
B) In the eclipsed conformation, the C-H bonds on one carbon bisect the H-C-H bond angle on the adjacent carbon.
C) In the staggered conformation, the C-H bonds on one carbon are directly aligned with the C-H bonds on the adjacent carbon.
D) Rotating the atoms on one carbon by 60° converts an eclipsed conformation into a staggered conformation, and vice versa.

Question 29

What is the IUPAC name for the following compound?

A) 1,4-Dimethylcyclohexane
B) 1,3-Dimethylcyclohexane
C) 1,3-Dimethylcyclopentane
D) 1,4-Dimethylcyclopentane

Question 30

Rank the following alkanes in order of decreasing boiling point, putting the alkane with the highest boiling point first.

A) I > II > III
B) I > III > II
C) II > III > I
D) III > II > I

Question 31

What is the IUPAC name for the following compound?

A) 2,3-Dimethyl-4-sec-butylheptane
B) 4-sec-Butyl-2,3-dimethylheptane
C) 3,5,6-Trimethyl-4-propylheptane
D) 2,3,5-Trimethyl-4-propylheptane

Question 32

Which of the following statements about the conformations of acyclic alkanes is not true?

A) The staggered and eclipsed conformations are equally stable.
B) The staggered conformations are more stable than the eclipsed conformations.
C) An energy minimum and maximum occur every 60° as the conformation changes from staggered to eclipsed.
D) Conformations that are neither staggered nor eclipsed are intermediate in energy.

Question 33

What is the IUPAC name for the following compound?

A) 5-Ethyl-3,6-dimethylheptane
B) 3-Ethyl-2,5-dimethylheptane
C) 3-Ethyl-2,5-dimethyloctane
D) 5-Ethyl-3,6-dimethyloctane

Question 34

What is the IUPAC name for the following compound?

A) 1-Butylcyclohexane
B) Cyclohexanebutane
C) 1-Cyclohexylbutane
D) Butylcyclohexane

Question 35

Which of the following is not a conformer of butane?

A) I
B) II
C) III
D) IV

Question 36

What is the common name of the following alkyl group?

A) Isopropyl
B) Isobutyl
C) sec-Butyl
D) tert-Butyl

Question 37

What is the IUPAC name for the following compound?

A) 3-Ethyl-2,7-dimethyl-5-sec-butyldecane
B) 5-sec-Butyl-3-ethyl-2,7-dimethyldecane
C) 2,7-Dimethyl-3-ethyl-5-sec-butyldecane
D) 3-Ethyl-2,7-dimethyl-5-isobutyldecane

Question 38

Rank the following alkanes in order of increasing melting point, putting the alkane with the lowest melting point first.

A) I < III < II
B) I < II < III
C) II < III < I
D) III < II < I

Question 39

Which of the following statements about the conformations of acyclic alkanes is true?

A) A staggered conformation with two larger groups 180° from each other is called gauche.
B) Staggered conformations are at energy maxima and eclipsed conformations are energy minima.
C) A staggered conformation with two larger groups 60° from each other is called anti.
D) Gauche conformations are generally higher in energy than anti conformations.

Question 40

What is the common name of the following alkyl group?

A) Isobutyl
B) sec-Butyl
C) Isopropyl
D) tert-Butyl

Question 41

Which of the following is the most stable conformation of trans-1-isopropyl-3-methylcyclohexane?

A) I
B) II
C) III
D) IV

Question 42

Which of the following is the highest energy conformer of 2,3-dimethylbutane?

A) I
B) II
C) III
D) IV

Question 43

Which of the following chair conformations represents trans-1,3-dimethylcyclohexane?

A) I
B) II
C) III
D) IV

Question 44

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

A) I
B) II
C) III
D) IV

Question 45

Which of the following cycloalkanes has the most angle strain?

A) Cyclopropane
B) Cyclobutane
C) Cyclopentane
D) Cyclohexane

Question 46

Which of the following conformers has the highest energy?

A) I
B) II
C) III
D) IV

Question 47

Which of the following is the most stable conformation of cis-1-ethyl-3-isopropylcyclohexane?

A) I
B) II
C) III
D) IV

Question 48

What are the products of the combustion of alkanes?

A) Carbon and hydrogen
B) Carbon and water
C) Carbon dioxide and hydrogen
D) Carbon dioxide and water

Question 49

Which of the following cycloalkanes has the least angle strain?

A) Cyclopropane
B) Cyclohexane
C) Cyclopentane
D) Cycloheptane

Question 50

Rank the conformers of 1,2,4-trimethylcyclohexane in order of decreasing stability, putting the most stable first.

A) I > II > III > IV
B) III > II > IV > I
C) III > IV > II > I
D) I > II > IV > III

Question 51

Which of the following chair conformations represents trans-1,4-dimethylcyclohexane?

A) I
B) II
C) III
D) IV

Question 52

Which of the following are anti conformers?

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

Question 53

Select the most stable conformer of cis-1,3-cyclohexanediol.

A) I
B) II
C) III
D) IV

Question 54

Rank the conformers of butane in order of decreasing stability, putting the most stable first.

A) IV > I > II > III
B) IV > I > III > II
C) II > III > I > IV
D) I > IV > II > III

Question 55

Which of the following is the lowest energy conformer of 2,3-dimethybutane?

A) I
B) II
C) III
D) IV

Question 56

What is the alternate chair conformation of the following compound?

A) I
B) II
C) III
D) IV