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Chemistry 211
Name:__________________________________
General Chemistry I
Fall 2006
Exam II
All questions must be answered on a Scantron form.
Multiple choice questions are provided with answers ae, and only
one
answer is correct.
You must sign the honor statement on the exam form below
to receive credit for the exam.
Turn
your Scantron form in to correct envelope and the exam to the box in front of the classroom.
The exam total is 100 points,
with each question worth 100/35.
I have abided by all aspects of the GMU honor code on this exam.__________________________________
1. What is the ratio of the root mean square molecular (average) speed of CH
4
molecules to that of SO
2
molecules at 298
K?
a.
2:1
b
.
1
:
2
c.
1:1
d.
1:2
e.
2
:
1
u CH
4
/u SO
2
= [1/
√
(M
m
CH
4
)]/[1/(
√
M
m
SO
2
)] = (1
√
16)/(1/
√
64) = 2, thus, 2:1
2. Which of the following graphs does
NOT
correctly describe the ideal gas law:
a.
a
b.
b
c.
c
d.
d
e.
All the above graphs correctly represent the ideal gas law.
PV = nRT, V
∝
T, V
∝
n, R = constant, P
∝
1/V, and all graphs correctly depict these relationships.
3.
How many moles of sulfate ions are there in a 0.20L solution of 0.030 M Al
2
(SO
4
)
3
?
a.
0.018
b.
0.024
c.
0.0060
d.
0.0030
e.
0.012
M SO
4
2
= 0.20 L x 0.030 M Al
2
(SO
4
)
3
x 3 (SO
4
2
ions/formula unit) = 0.018 M
4.
Which of the following gases would occupy the smallest volume at 25ºC and 1.00 atm pressure?
1.
100 g C
3
H
8
2.
100 g CO
2
3.
100 g N
2
O
a.
1 only
b.
2 only
c.
3 only
d.
1 and 2 only
e.
1, 2, and 3
All three gases have same mass and Mm, thus, all occupy same volume.
5. The complete combustion of phenylhydrazine, C
6
H
5
NHNH
2
, with the oxidizer dinitrogen tetraoxide is shown in the
equation below.
When balanced, the sum of all the coefficients (using smallest whole numbers) is
_
1
_ C
6
H
5
NHNH
2
+ _
4
_ N
2
O
4
→
_
6
_ CO
2
+ _
4
_ H
2
O + _
5
_ N
2
a.
b.
c.
d.
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a.
10
b.
15
c.
20
d.
25
e.
30
6. When solutions of barium chloride and sodium sulfate are mixed, the spectator ions in the resulting reaction are
a.
only Ba
2+
b.
only Na
+
c.
both Na
+
and Cl

d.
only Cl

e.
only SO
4
2
Ba
2+
+ 2 Cl

+ 2 Na
+
+ SO
4
2
→
BaSO
4
(s) + 2 Na
+
+ 2 Cl

; thus, Na
+
and Cl

are spectator ions
7. What is the ratio of the average rate of effusion of NOF(g) to that of HBr(g) at 400 K?
a.
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This note was uploaded on 07/08/2009 for the course CHEM 211 taught by Professor Papanastasiou during the Spring '07 term at George Mason.
 Spring '07
 Papanastasiou
 Chemistry

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