1022JDBOMIDTERMEXAMICHAPTERS10,11,12,13&15SPRING2010MAINCAMPUSVersionAAnswerKey

Dr. Jim Bloxton Name
CHEM 1022
Spring 2010 Recitation Day and Time
MIDTERM EXAM I
CHAPTERS 10, 11, 12, 13 & 15 Answer Key
Please place your name, recitation day and time on the front page of this exam.
Group Numbers: H, K IA; C IVA; N VA; O VIA; I VIIA
1. Write a Lewis structure for (CH
3
)
3
N and give the molecular geometry and predict the central
bond angle about the N atom in (CH
3
)
3
N.
The molecular geometry is trigonal pyramidal and the bond angle about the N atom is
107.3 ○ .
H H
│ .. │
H─C─N─C─H
│ │ │
H │ H
H─C─H
│
H
2. Write condensed structures for two compounds that are isomers and are both secondary
alcohols and have the formulas C
6
H
14
O.
Various answers are possible.
CH
3
CH
2
CH
2
CH
2
CHCH
3
(CH
3
)
2
CHCH
2
CHCH
3
│ │
OH OH
3. Draw an expanded structural formula of a compound that contains an aldehyde and an alkyne
and has the formula C
6
H
8
O.
H H H O
│ │ │ ║
H─C≡C─C─C─C─C─H
│ │ │
H H H
4. Identify the polar bonds in problem 3 and indicate the direction of polarity in the polar bonds
in problem 3.
+ ὁ ὁ -
C═O

5. Draw the Lewis structure for an ester with the formula C
2
H
4
O
2
. If this cannot be drawn then
explain why not.
:O: H
║ .. │
H─C─O─C─H
..
│
H
6. Write the structure of an alcohol that is an isomer of a carboxylic acid that has five carbons.
Various answers are possible.
CH
3
OCH
2
CH═CHCH
2
OH
7. What is the name of the following compound?
(CH
3
CH
2
)
2
C(CH
2
)
4
CH
3
│
CH
2
CH(CH
3
)
2
4,4-diethyl-2-methylnonane
8. Which compound would you predict has a higher boiling point and why: 2-methylnonane or
4-isopropyl-2-methylpentane?
2-Methylnonane will have the higher boiling point since it has a longer continuous chain of
carbon atoms and it has less branching and also has a higher molecular weight than 4-
isopropyl-2-methylpentane. All of these factors result in stronger London Dispersion
forces for 2-methylnonane and a higher boiling point.