2010 Answers PDF

Preview

Summary

practice exam with answers...

Description

Chemistry 2213a Midterm Test, Fall 2010

1.

Page 1

Which one of the following Lewis structures has a net negative charge? O H H C C C H

A)

H O

B)

N

2.

C)

N

H O

H H D)

H C C N H H H

H H O C C H

E)

H O C C N H H

H C C N H H

How many of the following molecules are non-polar? CO2

CH2F 2

C 2H2

CH2O

CH 3OCH3

Shown on the right is the sedative phenobarbital. Which statements about phenobarbital are correct?

O

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

H N O

1. It contains exactly one sp3-hybridized carbon. 2

2. It contains two sp -hybridized nitrogens. 3. All carbon-carbon bond angles in the aromatic ring are 120°. A) All statements are correct B) 1 only C) 1 and 3 only D) 2 and 3 only E) 2 only

N O

H

Chemistry 2213a Midterm Test, Fall 2010

4.

Page 2

The ball-and-stick model shown below corresponds to which one of A – E?

A)

B)

C)

D)

E)

Chemistry 2213a Midterm Test, Fall 2010

5.

Page 3

The correct use of arrows is shown in which one of A – E?

O O

A)

B)

CH3OH

2

H Cl

O

CH3OH 2 + Cl

O

O C)

O

O

D)

+ H 2O

H OH2

O

O

E) O

H

+ NH3 O NH4

Chemistry 2213a Midterm Test, Fall 2010

6.

Page 4

Arrange the following in the order of increasing pKa, from lowest to highest. CH3 CH2OH 2

I3CCH 2OH

F3CCOOH

1

2

3

lowest

7.

Br3CCOOH 4

highest

A)

1

3

4

2

B)

3

1

2

4

C)

1

2

4

3

D)

2

4

3

1

E)

3

4

2

1

Which one of the following equilibria lies furthest to the left?

A)

CH3COOH + NH2

B)

CH3COO

+ H3 O

C)

CH3COO

+ HCl

D)

CH3COO

+ CH3 CH2 OH

E)

CH3COOH + OH

CH3COO

+ NH 3

CH3 COOH + H2 O

CH3 COOH + Cl

CH3 COOH + CH3CH2O

CH3COO

+ H 2O

Chemistry 2213a Midterm Test, Fall 2010

8.

Page 5

When aspartame, shown below, is placed in an acidic environment, such as that of the stomach, which atom is protonated first? A) 1

4

B) 2 C) 3 D) 4

2

3 O

CH3 O 5

NH2 O

H N

OH O

E) 5

9.

What is a correct IUPAC name for the following compound? F

Cl

A) 3-chloro-7-fluoro-9,10-dimethylundecane B) 8-chloro-4-fluoro-2-isopropyldecane C) 9-chloro-5-fluoro-2,3-dimethylundecane D) 1,2-dimethyl-4-fluoro-8-chloroundecane E) trans-3-chloro-7-fluoro-9,10-dimethylundecane

1

Chemistry 2213a Midterm Test, Fall 2010

10.

Page 6

Which one of the following is a different constitutional isomer from the others?

CH3

CH3 CH2CH3

H 3C A)

B) H

C)

CH3 H

H

CH3

H

CH3 CH2CH3

CH(CH 3) 2 D)

H 3C

C

H

E)

CH2CH3

11.

Which one of the following shows cis-4-isopropyl-1,1,3-trimethylcyclohexane in its most stable conformation?

A)

B)

C)

D)

E)

Chemistry 2213a Midterm Test, Fall 2010

12.

Page 7

How many of the compounds listed below can exhibit cis-trans isomerism? •

1,1,3-trichlorocyclohexane

•

2-chloro-2-butene

•

3-chloropropyne

•

2,3-difluoropentane

A) None B) 3 C) 4 D) 1 E) 2

13.

The compound epi-aristolochene is found in pepper and tomato plants. It has 15 carbon atoms. How many hydrogen atoms does it contain? A) 24 B) 32 C) 20 D) 18 E) 16

Chemistry 2213a Midterm Test, Fall 2010

14.

Page 8

Which of the alkenes below have an E configuration?

CH2OH

H 2N

CH2CBr3 CF3

HO 2

1

HOH 2C

4

3

B) 2, 3, and 4 only C) 1 and 4 only D) All of them E) 3 only

Which statements about retinal, shown below, is/are correct? O H

1. It has a total of 2 5 cis-trans isomers. 2. It contains exactly four isoprene units. 3. The carbon atom of carbon-oxygen double bond has an oxidation number of +1. A) 2 and 3 only B) 1 and 2 only C) All statements are correct D) 2 only E) 3 only

CH2NH2

NC

A) 1 and 3 only

15.

CN

Chemistry 2213a Midterm Test, Fall 2010

The overall rate for the forward reaction depicted in the energy diagram below is determined by which energy difference?

5

2

1

energy

16.

Page 9

3 4

reactants

products

reaction coordinate A) 5 B) 1 C) 4 D) 2 E) 3 17.

Which one of the following alkenes reacts the fastest with HBr?

O

Br A)

B)

D)

E)

C)

O

Chemistry 2213a Midterm Test, Fall 2010

18.

Page 10

What is the major product of the following reaction?

+ Cl2

?

A) trans-1,2-dichlorocyclopentane B) 1-chlorocyclopentane C) 1,2-dichloropentane D) 2-chlorocyclopentane E) cis-1,2-dichlorocyclopentane

19.

Which one of A – E correctly shows a 1,2-hydride shift?

H

A)

B)

D)

E) H

C)

H O

Chemistry 2213a Midterm Test, Fall 2010

20.

Page 11

Which reaction does not give the product shown as the major product?

Br

A)

Br

+ Br2

OH

1. BH3

B)

2. H 2O2, NaOH

C)

+ H2 O

H2SO4 OH

+ HCl

D)

Cl

HO E)

+

KMnO4

H H 3C

OH CH 3 H

Chemistry 2213a Midterm Test, Fall 2010

21.

Page 12

Which one of A – E is a major product of the following reaction sequence?

+ H2

Cl2

H

Cl A)

B)

H

Cl Cl

Cl

Cl C)

Lindlar's catalyst

Cl

H

H (racemic) Cl Cl

E) Cl Cl

H

Cl

D)

Cl

H

?

Chemistry 2213a Midterm Test, Fall 2010

22.

One mole of C7 H12 decolourized only one mole of bromine. The same compound reacted completely with ozone followed by dimethylsulfide to give the product shown below. What is the structure of C7H12?

C7H 12

23.

Page 13

O

1. O3

O

2. (CH3) 2S

A)

B)

D)

E)

H

C)

How many chiral centres are present in prostaglandin E1, shown below?

A) 1

O

O

B) 4

OH

C) 5 D) 3 E) 2

HO

OH

Chemistry 2213a Midterm Test, Fall 2010

24.

Page 14

Xylose is a sugar commonly added to chewing gum because it causes less tooth decay than sucrose. Assign an R or S configuration to each of the three chiral centres.

OH H 1 O

25.

OH 2

OH

3

OH

1

2

3

A)

S

R

S

B)

S

S

R

C)

R

R

R

D)

R

S

S

E)

R

S

R

The five structures shown below represent how many different compounds? COOH H H3C

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

OH

H

OH CH3

CH3

CH3

COOH HO

H COOH

H

COOH

OH COOH

H

CH3 OH

Chemistry 2213a Midterm Test, Fall 2010

26.

Page 15

Which statements about the four structures shown below are correct? CH2OH

CH2OH

CH2OH

CH2OH

H

OH

H

OH

HO

H

H

OH

H

OH

H

OH

HO

H

HO

H

H

OH

HO

H

HO

H

HO

H

CH2OH

CH2OH

CH2OH

CH2OH

A

B

C

D

1. A and C represent a pair of enantiomers. 2. B and C represent a pair of diastereomers. 3. A 1:1 mixture of A and D will be optically inactive. A) All statements are correct B) 1 and 2 only C) 3 only D) 1 only E) 2 only

Chemistry 2213a Midterm Test, Fall 2010

27.

Page 16

Which one of the following reactions does not give a mixture of diastereomers?

F H2

A)

KMnO4

Lindlar's catalyst

Br 2

B)

1. BH3

C)

2. H2 O2, NaOH

D)

E)

28.

H2 Pt

Cl2

The 13C-NMR spectrum of the compound shown below contains how many signals? A) 2 B) 3 C) 5 D) 4 E) 1

CH2 COOH HO C

COOH

CH2 COOH

Chemistry 2213a Midterm Test, Fall 2010

29.

30.

Page 17

The IR spectrum shown below corresponds to which one of A – E?

A)

B)

D)

E)

C)

A compound with the molecular formula C6 H10 reacts with H2SO 4/H 2 O in the presence of HgSO4 to give a single product with a sharp, strong IR absorption at 1775 cm−1 . What is a possible structure of C6H10?

A)

B)

D)

E)

C)

Chemistry 2213a Midterm Test, Fall 2010

31.

Page 18

Which amino acid has the IR and 13C-NMR spectra shown below?

180

160

140

120

100 PPM

80

60

40

20

NH2

A)

COOH

B) N

COOH

COOH

C)

D) NH2

E)

COOH

COOH NH2

NH2

0

Chemistry 2213a Midterm Test, Fall 2010

32.

In a vacuum filtration procedure, the recrystallized solid is collected in which one of A – E?

A

33.

Page 19

B

C

D

E

The three possible unknown compounds in Experiment #1 were benzoic acid (literature mp = 121–122 °C), benzoin (literature mp = 132–133 °C), and salicylic acid (literature mp = 156–158 °C). If you believe that your unknown is benzoic acid, which one of the following procedures would confirm that? A) You mix your unknown with salicylic acid, and obtain a melting point of 150–154 °C for the mixture. B) You mix your unknown with benzoic acid, and obtain a melting point of 120–121 °C for the mixture. C) You mix your unknown with benzoic acid, and obtain a melting point of 112–114 °C for the mixture. D) You mix your unknown with benzoin, and obtain a melting point of 116–121 °C for the mixture. E) You obtain a melting point of 119–121 °C for your unknown.

Chemistry 2213a Midterm Test, Fall 2010

34.

Page 20

Aqueous solutions of which one of the following compounds will form a precipitate upon the addition of concentrated HCl?

O

O A)

OCH 3

B)

O

C)

E)

35.

D)

O Na

OH

NH4 Cl

Which one of A – E is not a requirement for an extraction solvent? A) It must not react irreversibly with the compound being extracted. B) It must be less dense than water. C) It must selectively extract one substance from a mixture. D) It must be immiscible with the original solution being extracted. E) It must dissolve the substance being extracted.

End of test… answers will be posted on WebCT on Monday....