Practice Chapter 3 Conformations of Alkanes and Cycloalkanes

Organic Chemistry

Carey/Giuliano8th edition

Chapter 3

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Question 1What is the relationship between the Newman

representations shown?

A) identicalB) constitutional isomersC) different conformations of the same compoundD) stereoisomers

Question 2What is the relationship between the Newman

representations shown?

A) identicalB) constitutional isomersC) different conformations of the same compoundD) stereoisomers

Question 3

Select the least stable conformation of ethylene glycol.

A) B)

C) D)

Question 4

Select the most stable conformation of butanoic acid.

A) B)

C) D)

Question 5

Which compound has the greatest torsional strain in the planar conformation?A) cyclopropaneB) cyclobutaneC) cyclopentaneD) cyclohexane

Question 6

Rank the conformations of cyclohexane in order of decreasing stability.A) chair > half-chair > twist-boatB) chair > twist-boat > half-chairC) twist-boat > half-chair > chairD) half-chair > twist-boat > chair

Question 7

The most stable conformation of cis-1-tert-butyl-4-methylcyclohexane hasA) both groups equatorialB) both groups axialC) the tert-butyl group axial and the methyl

equatorialD) the tert-butyl group equatorial and the

methyl axial

Question 8

The most stable conformation of trans-1-isopropyl-3-methylcyclohexane is:

A) B)

C) D)

Question 9What is the relationship between the two chair

conformations below?

A) conformational isomersB) constitutional isomersC) different compoundsD) stereoisomers

Question 10

What is the relationship between the two cyclohexane chairs below?

A) conformational isomersB) constitutional isomersC) stereoisomersD) different compounds

Question 11

Which of the following statements is not true concerning the chair-chair interconversion oftrans-1,2-diethylcyclohexane?A) An axial group will be changed into the equatorial position.B) The energy of repulsions present in the molecule will be changed.C) Formation of the cis substance will result.D) One chair conformation is more stable than the other

Question 12

Which of the listed terms best describes the relationship between the methyl groups in the chair conformation of the substance shown? A) eclipsedB) transC) antiD) gauche

Question 13

Which of the following has an equatorial methyl group in its most stable conformation?

A) B)

C) D)

Question 14

The structure shown is the carbon skeleton of adamantane, a hydrocarbon having astructure that is a section of the diamond lattice. Adamantane is: A) bicyclicB) tricyclicC) tetracyclicD) pentacyclic

Question 15

Which structure has the most strain?A) the eclipsed conformation of ethaneB) the gauche conformation of butaneC) the boat conformation of cyclohexaneD) the skew boat conformation of

cyclohexane

Question 16What is the IUPAC name for the compound

represented by the Newman projection?

A) 1-tert-Butyl-1-isopropylethaneB) 1-tert-Butyl-3-methylbutaneC) 2-isopropyl-3,3-dimethylbutaneD) 2,2,3,4-tetramethylpentane

Question 17Which one of the following statements is true?

A) Van der Waals strain in cis-1,2-dimethylcyclopropane is the principal reasonfor its decreased stability relative to the trans isomer.

B) Cycloalkanes larger than cyclodecane rarely occur naturally because they are too strained.

C) One mole of cyclohexane gives off less heat on being burned in air than one mole of any other cycloalkane.

D) The principal source of strain in the gauche conformation of butane is torsional strain.

Question 18

Which of the following statements best describes the most stable conformation oftrans-1,3-dimethylcyclohexane?A) Both methyl groups are axial.B) Both methyl groups are equatorial.C) One methyl groups is axial, the other

equatorial.D) The molecule is severely strained and

cannot exist.

Question 19What is the relationship between the two

structures shown?

A) Constitutional isomersB) StereoisomersC) Different drawings of the

same conformation of the same compound.

D) Different conformations of the same compound.

Question 20The most stable conformation of the compound

to the right has A) an axial methyl group and

an axial ethyl group.B) an axial methyl group and

an equatorial ethyl group.C) an equatorial methyl group and an

equatorial ethyl group.D) an equatorial methyl group and an axial

ethyl group.

Answer Key Chapter 31. C2. B3. C4. B5. D6. B7. D8. B9. A10. C

11. C12. D13. D14. B15. C16. D17. A18. C19. A20. D

Organic Chemistry Question 1Question 2Question 3Question 4Question 5Question 6Question 7Question 8Question 9Question 10Question 11Question 12Question 13Question 14Question 15Question 16Question 17Question 18Question 19Question 20Answer Key Chapter 3