CHEM 120 Exam 2 Name:
,
Last First
Total of 137 exam points, adjusted to 100 course points.
ADJUSTED SCORE:
Part I: Multiple Choice (3 points each,
... [Show More] 60 pts total, No guessing correction, so answer ALL questions)
Note, only questions that are marked as such might have multiple correct answers.
Use the following answers for Numbers 1-24 (12 questions)
AA: Alkanes AB: Alkenes AC: Alkynes AD: Aromatics AE: Alkyl Halides
BA: 1o Alcohols BB: 2o Alcohols BC: 3o Alcohols BD: 1o Amines BE: 2o Amines
CA: 3o Amines CB: 4o Ammonium Salts CC: Aldehydes CD: Ketones
CE: Hemiacetals DA: Acetals DB: Carboxylic Acids DC: Esters DD: 1o Amides
DE: 2o amides EA: 3o Amides EB: Phenols EC: Ethers ED: Thiols
EE: Monosulfides EC: Disulfides
To answer these questions requires two lines on the Scantron, one for each letter of the answer. For example:
1-2. Which functional group results in the smelliest compounds?
The answer is ED: Thiols. Therefore, you would bubble in E on line 1 on the Scantron, and D on line 2.
The order matters (answering DE would be wrong, as that would indicate your answer is 2o amide which is
wrong), and both lines are graded together as a single question. Answer this question now on lines
1-2 to get credit for this question.
3-4. Which functional group has a carbonyl group attached to both a carbon and to a hydrogen? CC:
Aldehyde
5-6. Which functional group is made by the gentle oxidation of a thiol? EC: Disulfides
7-8. Which functional group is the condensation product of a 1o amine and a carboxylic acid? DE: 2o Amides -
a new group is added to the amine to become an amide!
9-10. Which functional group is the most acidic? DB: Carboxylic Acids - phenol common wrong answer
11-12. Which functional group undergoes saponification? DC: Esters
13-14. Which functional group give compounds the highest boiling point? DD: 1o Amides
15-16. Which functional groups has a set of carbon-carbon double bonds with unusual stability? AD: Aromatics
17-18. Which functional group promotes more soluble in aq NaOH than in water, but not more solubility in aq
NaHCO3? EB: Phenols - carboxylic acid common wrong answer, but they are more soluble in
NaHCO3 ; thiol would also be correct, and credit was given to those (who guess this?)
19-20. Reduction of which functional group gives a 1o alcohol? CC: Aldehydes (others we didn't learn)
21-22. Which functional group is most unstable in water? CE: Hemiacetals - I said in lecture you can't put
them in a bottle because they are in equilibrium with alcohol and aldehyde/ketone
23-24. Which of these functional groups reacts with acid to form a salt and does not self-hydrogen bond? CA: 3o
Amines - I should have seen the simple structures on many exam that would make this easier
Part I /60
Part II /39
Part III /3825. The compound on the right would be classified as
A) an aromatic amine
B) a primary amine
C) a secondary amine Good results!
D) a tertiary amine
E) a quaternary amine
H3C
H3C
CH3
N CH3
H
26. Which of the following is an alternate name for 2-methyl-1-propoxypropane?
A) butyl propyl ether
B)sec-butyl propyl ether
C) isobutyl isopropyl ether
D) sec-butyl sec-propyl ether
E) isobutyl propyl ether - only 1/2 got this right - WRITE DOWN THE STRUCTURE!
27. Which of the following is the best name for the compound on the right?
A) 3,4-dichlorobenzaldehyde
B) 4,5-dichlorobenzaldehyde
C) 3,4-dichlorophenylaldehyde
D) 1,2-dichlorobenzenaldehyde
E) 3,4-dichlorobenzenaldehyde
28. Which of the following structures is a hemiacetal derived from an ketone? Str C (B is from aldehyde)
29. For the following reaction, which of the following changes would shift the equilibrium to the right? Mark all
that apply.
CH3CH=CH2 + H2O D CH3CHOHCH3 + heat
A) Using a larger reaction flask
B) Decreasing the amount of CH3CHOHCH3
C) Decreasing the amount of CH3CH=CH2
D) Decreasing the amount water
E) Increasing the amount of water
30. The best name for the compound on the right is
A) 2,4-diethyl-2-methyl-3-pentanol - an equally common answer! CH3 CH2CH3
B) 3,3,5-trimethylheptanol don't rely on how it is written!
C) 5-ethyl-3,3-dimethyl-4-hexanol
D) 2-ethyl-4,4-dimethyl-3-hexanol
E) 3,3,5-trimethyl-4-heptanol
H3C C CH CH CH3
CH3CH2 OHO
OH
31. Hemiacetals are usually not stable and revert to the alcohol and the aldehyde or ketone they were made
from. Which of the following hemiacetals would be the most stable? Compound A (CYCLIC) Cmpd D
most common answer, but the aromatic ring is there in the aldehyde and hemiacetal.
32. What bond angles does VSEPR predict for the carbon in formaldehyde (H2C=O)?
A) 60o B) 90o C) 109.5o D) 120o E) 180o
Did you write down the structure?
Part II, Reactions (3 pts each, 39 pts total) For each of the following reactions, enter the necessary reagents
above/below the arrow or enter the structure for the starting material or product, whichever is missing from the
equation.
33.
H
2
Pt
(Showing new hydrogens optional)
Cl
34.
OH
Cr(VI)/water Cl OH
excess
35.
O
OH Cr(VI)/no water
H
excess
36.
O
Cr(VI)/no water
OH
excess
H2CrO4/water
37. NR
Q 34-37 had disappointing results - learn the reactions!
H
HNaBH4
O
For Question 38, give the starting material (reactant)
OH
H3O+
38.
Probably the most difficult question on the exam; Kudos to those who got it (almost) right.
39.
HS CH3
mild
oxidation CH3-S-S-CH3
H3O+
40. Cl NR (A [Show Less]