Organic Chemistry With Biological Applications International Edition 2nd Edition by John E. McMurry - Test Bank

Organic Chemistry With Biological Applications International Edition 2nd Edition by John E. McMurry – Test Bank

 

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Sample Questions Are Posted Below

 

Chapter 7 – Alkenes and Alkynes

 

1. 1. The following group is a substituent on a molecule. What is an accepted IUPAC name for this group?

 

1. propenyl
2. allyl
3. vinyl
4. propylene
5. either a or b

 

ANS: e

 

2. 2. What is the IUPAC name of the following compound?
3. (E)-3-methylpent-3-ene
4. (Z)-3-methylpent-3-ene
5. (E)-3-methylpent-2-ene
6. (Z)-3-methylpent-2-ene

 

ANS: d

 

3. Name this compound.

 

 

 

 

 

 

 

 

ANS: 1-ethynyl-2-methylcyclopentane

 

4. 4. Choose substituents X and Y (listed in order below) for the following compound so as to make a Z isomer.

 

 

1. –Br, –NHCH₃
2. –F, –CHO
3. –I, –OCH₃
4. –COOH, –CH₂NH₂
5. –Br, –COOH

 

ANS: b

 

 

 

 

MATCH each definition to the term it describes. Place the letter corresponding to the term in the blank to the left of the definition.

 

1. Hammond Postulate
2. Cahn-Ingold-Prelog Rules
3. Markovnikov’s Rule
4. Degrees of Unsaturation

 

5.  Predicts that the more stable carbocation intermediate is formed in electrophilic additions to alkenes.

 

ANS: c

 

6.  Predicts that the transition state of an exergonic reaction step structurally resembles the reactant.

 

ANS: a

 

7.  Predicts the total number of multiple bonds and rings.

 

ANS: d

 

 

8. 8. A molecule has three degrees of unsaturation. In this molecule there would be

 

1. three rings
2. three double bonds
3. two rings and one double bond
4. one ring and two double bonds
5. any of the above

 

ANS: e

 

9. 9. For a compound containing substituents other than hydrogen, the number of hydrogen atoms in the equivalent hydrocarbon formula is determined by______________from the number of hydrogen atoms present.

 

1. subtracting the number of halogens atoms
2. adding two hydrogen atoms for each oxygen
3. subtracting the number nitrogen atoms
4. adding the number of oxygen atoms

 

ANS: d

 

 

10. 10. A compound with the following molecular formula contains two double bonds. What is the correct subscript for H in the formula?

 

C₁₀H_?ClN₂O

 

1. 19
2. 22
3. 18
4. 20
5. 21

 

ANS: a

 

 

11. Calculate the degree of unsaturation in the formula below. Show your calculations.

caffeine, C₈H₁₀N₄O₂

 

ANS:          Oxygen does not affect the base formula. One hydrogen is subtracted for each nitrogen, so the base formula for caffeine is C₈H₆. A saturated 8 carbon compound should have 18 hydrogens, so the number of degrees of unsaturation for caffeine is: (18 – 6) / 2 = 6

 

 

Dieldrin, C₁₂H₈Cl₆O, is a pentacyclic (five-ring) compound formerly used as an insecticide.

 

12. Calculate the degree of unsaturation for Dieldrin.

 

ANS:          Oxygen does not affect the base formula. One hydrogen is added to the base formula for each halogen, so the base formula for dieldrin is C₁₂H₁₄. A saturated 12 carbon compound should have 26 hydrogens, so the number of degrees of unsaturation for dieldrin is:

(26 – 14) / 2 = 6

 

13. How many double bonds does dieldrin have?

 

ANS:          Dieldrin has 6 degrees of unsaturation and it is pentacyclic. Therefore, dieldrin must have one double bond.

 

Draw structures corresponding to each name below.

 

14. (3E)-3,7-dimethylocta-1,3,6-triene

 

ANS:

15. trans-4,4-dimethylpent-2-ene

 

ANS:

 

 

Pent-2-ene is an example of a disubstituted alkene.

 

16. Draw the cis and trans isomers of pent-2-ene and label them.

 

ANS:

 

 

17. Circle the isomer of pent-2-ene that is most stable.

 

ANS:

 

Provide names for each structure below. Be sure to include the cis,trans or E,Z designations where applicable.

 

 

 

18.

 

 

ANS: trans-2-methylhex-3-ene or (E)-2-methylhex-3-ene

 

 

 

 

 

19.

 

 

 

ANS: 3-methylcyclopentene

 

 

 

 

 

20.

 

 

 

 

ANS: cis-3,3-dimethyl-4-propylocta-1,5-diene or (Z)-3,3-dimethyl-4-propylocta-1,5-diene

 

 

21. Rank each set of substituents using the Cahn-Ingold-Prelog sequence rules by numbering the highest

priority substituent 1 and numbering the lowest priority substituent 4. Place the number in the blank below

the substituent.

 

 

 

 

 

 

ANS:

 

 

 

 

 

 

 

22. 22. Which of the following substituents has the highest priority according to the Cahn-Ingold-Prelog system?
23. –COOH
24. –CHO
25. –CH₂OH
26. –CH₃

ANS: a

 

23. 23. Which of the following substituents has the highest priority according to the Cahn-Ingold-Prelog system?
24. –NH₂
25. –NHCH₃
26. –CH₂NH₂
27. –CH₂NHCH₃

ANS: b

 

 

Assign E or Z configurations to each alkene below.

 

24.

 

 

ANS: Z

 

25.

       

 

ANS: E

 

 

26. Rank the carbocations below in order of increasing stability (least stable = 1; most stable = 3). Place the number corresponding to the carbocation’s relative stability in the blank below the structure.

 

 

 

 

 

 

ANS:

 

 

27. 27. Alkene chemistry is dominated by what type of reaction?

 

1. substitution
2. electrophilic addition
3. nucleophilic addition
4. elimination
5. both b and c

 

ANS: b

 

28. 28. Hydride shifts

 

1. occur to form less highly substituted carbocations.
2. occur by transfer of an H⁺ between adjacent carbon atoms.
3. are observed only in single step reactions.
4. transfer positive charge to a more highly substituted carbon atom.

 

ANS: d

 

 

29. 29. Which of the following would have the smallest DH^o_hydrog?

 

 

 

ANS: d

 

 

 

 

 

 

 

 

30. Below are all the chemical structures and intermediates involved in a reaction. On the structures provided, show all electron flow using the arrow formalism for the complete stepwise mechanism.

 

ANS:

 

31. Why does the rearrangement that results in the formation of product B occur?

 

ANS:          The 1,2-alkyl shift is the rearrangement of a secondary carbocation to a more stable tertiary carbocation.

 

 

32. Predict the major organic product(s) in the reaction below. If more than one major organic product is

expected, draw each one.

 

 

 

 

 

 

 

 

 

 

 

ANS:

 

33. Predict the major organic product(s) in the reaction below. If more than one major organic product is

expected, draw each one.   Explain the significance of “35^oC” and “ether” shown in the reaction.

 

 

 

 

ANS:

 

 

 

35^oC and ether are notes related to the reactions conditions.  The reaction is carried out at 35^oC and the solvent is ether.

 

 

 

 

34. The following reaction is carried out in cyclohexane with the application of heat. Write the complete

equation for the reaction below. If more than one major organic product is expected, draw each one.

 

 

 

 

 

 

 

ANS:

 

 

 

 

 

 

35. 35. What alkene would you use to prepare the following alkyl halide?

ANS:  Only one alkene would be possible:

 

 

 

 

 

 

36. 36. Using curved arrows, write a mechanism for the following reaction. If carbocations are formed, specify if they are primary, secondary or tertiary.

 

 

 

ANS:

 

tertiary

secondary