nguyen (jn9225) – H02: Gas Laws – mccord – (50950)
1
This printout should have 23 questions.
Multiplechoice questions may continue on
the next column or page – fnd all choices
beFore answering.
001
10.0 points
A gas is enclosed in a 10.0 L tank at 1200
mm Hg pressure. Which oF the Following is
a reasonable value For the pressure when the
gas is pumped into a 5.00 L vessel?
1.
2400 mm Hg
correct
2.
24 mm Hg
3.
0.042 mm Hg
4.
600 mm Hg
Explanation:
V
1
= 10.0 L
V
2
= 5.0 L
P
1
= 1200 mm Hg
Boyle’s law relates the volume and pressure
oF a sample oF gas:
P
1
V
1
=
P
2
V
2
P
2
=
P
1
V
1
V
2
=
(1200 mm Hg)(10
.
0 L)
5 L
= 2400 mm Hg
002
10.0 points
A sample oF gas in a closed container at a
temperature oF 66
◦
C and a pressure oF 5 atm
is heated to 352
◦
C. What pressure does the
gas exert at the higher temperature?
Correct answer: 9
.
21829 atm.
Explanation:
T
1
= 66
◦
C + 273 = 339 K
P
1
= 5 atm
T
2
= 352
◦
C + 273 = 625 K
P
2
= ?
Applying the GayLussac law,
P
1
T
1
=
P
2
T
2
P
2
=
P
1
T
2
T
1
=
(5 atm) (625 K)
339 K
= 9
.
21829 atm
003
10.0 points
IF I have 44.8 liters oF nitrogen gas at standard
temperature and pressure, how much will it
weigh?
1.
56 g
correct
2.
28 g
3.
56 u
4.
44.8 g
5.
28 kg
Explanation:
P
= 1 atm
V
= 44
.
8 L
T
= 273 K
P V
=
n RT
n
=
P V
RT
n
=
(1 atm)(44
.
8 L)
(
0
.
08206
L
·
atm
K
·
mol
)
(273 K)
·
28 g
1 mol
= 55
.
9941 g
004
10.0 points
At 80.0
◦
C and 12.0 Torr, the density oF cam
phor vapor is 0
.
0829 g
·
L
−
1
.
What is the
molar mass oF camphor?
1.
243 g
·
mol
−
1
2.
34
.
5 g
·
mol
−
1
3.
20
.
3 g
·
mol
−
1
4.
3490 g
·
mol
−
1
5.
152 g
·
mol
−
1
correct
Explanation:
T
= 80
◦
C + 273.15 K = 353.15 K
P
= (12 Torr)
1 atm
760 Torr
= 0
.
0157895 atm
ρ
= 0
.
0829 g/L
The ideal gas law is
P V
=
n R T
n
V
=
P
R T
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Documentnguyen (jn9225) – H02: Gas Laws – mccord – (50950)
2
with unit of measure mol/L on each side.
Multiplying each by molar mass (MM) gives
n
V
·
MM =
P
R T
·
MM =
ρ ,
with units of g/L.
MM =
ρ RT
P
=
(0
.
0829 g
/
L)
(
0
.
08206
L
·
atm
mol
·
K
)
0
.
0157895 atm
×
(353
.
15 K)
= 152
.
152 g
/
mol
005
10.0 points
What is the density of nitrogen gas at STP?
1.
0.625 g/L
2.
2.50 g/L
3.
1.25 g/L
correct
4.
4.00 g/L
5.
0.500 g/L
Explanation:
006 (part 1 of 3) 10.0 points
A chemist has synthesized a greenishyellow
gaseous compound that contains only chlorine
and oxygen and has a density of 7.71 g/L
at 36.0 degrees Celsius and 2188.8 mm Hg.
What is the molar mass of the compound?
1.
51.5 g/mol
2.
25.8 g/mol
3.
67.9 g/mol
correct
4.
86.9 g/mol
5.
109 g/mol
Explanation:
T
= 36
◦
C + 273 = 309 K
P
= 2188
.
8 mm Hg
atm
760 mm Hg
= 2
.
88 atm
P V
=
n RT
n
V
=
P
R T
=
(2
.
88 atm)
(309 K)(0
.
08206
L
·
atm
molK
)
= 0
.
1136
mol
L
MW =
7
.
71 g
/
L
0
.
1136
mol
L
= 67
.
87 g
/
mol
007 (part 2 of 3) 10.0 points
What is the molecular formula of the com
pound?
1.
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '07
 Fakhreddine/Lyon

Click to edit the document details