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CHE 131 Exam 3, Fall 2006
Multiple Choice, 4 points each
Identify the letter of the choice that best completes the statement or answers the question.
1.
Which of the following is true regarding the Van der Waals
a
and
b
constants for argon and neon?
Recall that
a
has units of L
2
atm/mol
2
and
b
has units of L/mol.
A. a(Ne) < a(Ar) and b(Ne) < b(Ar)
B. a(Ne) < a(Ar) and b(Ne) > b(Ar)
C. a(Ne) > a(Ar) and b(Ne) > b(Ar)
D. a(Ne) > a(Ar) and b(Ne) < b(Ar)
E. a(Ne) = a(Ar) and b(Ne) < b(Ar)
2.
A 2.00 L flask of nitrogen (N
2
) gas at a pressure of 1.00 atm is separated by a stopcock from a 3.00 L
flask of nitrogen gas at a pressure of 2.00 atm. Both compartments are at the same temperature. What is
the pressure in the flasks if the stopcock is opened, assuming the temperature remains the same?
A. 1.60 atm
B. 1.50 atm
C. 0.60 atm
D. 1.00 atm
E. 2.60 atm
3.
In a mixture of Ar and Kr in a container of 2.00 L at a pressure of 0.900 atm the ratio of the partial
pressures
P
Ar
/
P
Kr
is 1.89. What is the molar fraction of Kr in the mixture?
A. 0.529
B. 0.346
C. 0.471
D. 0.654
E. 0.476
4.
Which of A through D are
not
true for plots of the ratio PV/nRT versus pressure P for neon and argon
gases at several temperatures? If all are true, answer E.
A. At moderate pressures and low temperatures, negative deviations from ideality are
greater for argon than for neon.
B. At high pressure and temperature, positive deviations from ideality are greater for
argon than for neon.
C. At very low pressures, the ratio PV/nRT is close to 1.
D. As both neon and argon are real gases, ideal behavior will never be seen.
E. All the above are true.
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View Full Document 5.
Analysis of a compound revealed that it was 85.7% C and 14.3% H by mass. A 1.77 gram gas sample
of the compound exerted a pressure of 0.668 atm in a 1.500 L flask at a temperature of 17
°
C. What is
the molecular formula of the compound?
A. CH
2
B. CH
4
C. C
2
H
4
D. C
3
H
4
E. C
3
H
6
6.
Which of the following noncovalent interactions is found in pure acetone?
C
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This note was uploaded on 04/20/2008 for the course CHE 131 taught by Professor Kerber during the Spring '08 term at SUNY Stony Brook.
 Spring '08
 Kerber

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