GENERAL CHEMISTRY I
CHEM 1311.001
EXAM 4
Wednesday April 28, 1999


1. Charles' Law applies to processes in which the __________ remains constant.
a) temperatureb) pressurec) volume
2. Boyle's Law applies to processes in which the __________ remains constant.
a) temperatureb) pressurec) volume
3. Gay-Lussac's Law applies to processes in which the __________ remains constant.
a) temperatureb) pressurec) volume
4. What quantity must remain constant in ALL THREE of the laws above?
a) temperatureb) pressurec) volume
d) number of molese) none of these
5. When temperature does not change during a process, we say that process is
a) isobaricb) isochoricc) isothermal
6. When pressure does not change during a process, we say that process is
a) isobaricb) isochoricc) isothermal
7. When volume does not change during a process we say that process is
a) isobaricb) isochoricc) isothermal
8. When doing gas calculations, gas temperatures must be in units of
a) Celsiusb) Fahrenheitc) Kelvin
d) It makes no difference
9. In class, we discussed the fact that real gases do not always behave ideally, and we considered the conditions under which a gas behaves most ideally and the conditions under which it behaves least ideally. Under what conditions does a gas behave most ideally?

a) high temperature and high pressure

b) high temperature and low pressure

c) low temperature and high pressure

d) low temperature and low pressure

10. A sample of gas was confined in a cylinder fitted with a movable piston. Initially, the gas had a volume of 3.217 L, exerted a pressure of 2.818 atm and had a temperature of 21.9 oC. The gas was isothermally compressed to a volume of 2.102 L. What pressure did the gas exert under these conditions?
a) 1.841 atmb) 4.313 atmc) 6.907 atmd) 8.705 atm
11. A sample of gas was confined in a cylinder fitted with a movable piston. Initially, the gas had a volume of 1.168 L, exerted a pressure of 2.557 atm, and had a temperature of 25.5 oC. The gas was isobarically heated, causing its volume to increase to 3.985 L. What was the temperature of the hot gas?
a) 100.0 oCb) 472.6 oCc) 745.8 oCd) 1018.9 oC
12. A sample of gas was confined in a closed container having a volume of 3.500 L. The gas exerted a pressure of 1.308 atm at 27.3 oC. What pressure will the gas exert if the system is isochorically heated to a temperature of 99.2 oC?
a) 1.621 atmb) 4.753 atmc) 7.102 atmd) 9.338 atm
13. A sample of gas was confined in a cylinder fitted with a movable piston. Initially, the gas had a volume of 3.976 L, exerted a pressure of 1.408 atm, and had a temperature of 14.5 oC. The gas was simultaneously heated and compressed. After the heating and compression, the gas had a temperature of 92.7 oC and exerted a pressure of 3.659 atm. What was the volume of the gas after the heating and compression?
a) 1.017 Lb) 1.946 Lc) 2.503 Ld) 3.320 L
14. A sample of gas was confined in cylinder fitted with a movable piston. Initially, the gas had a volume of 2.893 L, exerted a pressure of 1.226 atm and had a temperature of 18.2 oC. The gas was simultaneously heated to a temperature of 84.6 oC and compressed to a volume of 1.558 L. What pressure did the gas exert after the heating and compression?
a) 1.778 atmb) 2.795 atmc) 4.006 atmd) 7.331 atm
15. A closed container having a volume of 6.113 L holds 19.82 g of ammonia gas, NH3 at a pressure of 4.552 atm. What is the temperature of the ammonia? Note that the gas constant R has a value of 0.08205783 L atm / K mol.
Atomic weights needed for this problem are as follows: N = 14.00674   H = 1.00794
a) 18.2 oCb) 72.5 oCc) 145.8 oCd) 291.4 oC
16. What pressure is exerted by 8.815 g of hydrogen gas, H2, when confined to a 7.331 L container at 11.8 oC?
Note that the gas constant R has a value of 0.08205783 L atm / K mol. The atomic weight of hydrogen is 1.00794.
a) 6.75 atmb) 13.95 atmc) 28.15 atmd) 35.80 atm
17. If a 7.340 L vessel contains nitrogen monoxide (NO) gas at 3.104 atm and 22.5 oC, what mass of nitrogen monoxide is in the vessel? Note that the gas constant R has a value of 0.08205783 L atm / K mol.
Atomic weights needed for this problem are as follows: N = 14.00674   O = 15.9994
a) 3.381 gb) 9.606 gc) 28.179 gd) 42.811 g
18. What is the density of carbon dioxide gas (CO2) at 5.153 atm and 31.8 oC? Note that the gas constant R has a value of 0.08205783 L atm / K mol.
Atomic weights needed for this problem are as follows: C = 12.011   O = 15.9994
a) 9.063 g / Lb) 15.114 g / Lc) 31.401 g / Ld) 48.483 g / L
19. An unknown gas has a density of 3.868 g / L when the pressure is 2.150 atm and the temperatue is 25.0 oC. What is the molecular weight of the gas? Note that the gas constant R has a value of 0.08205783 L atm / K mol.
a) 17.03 g / molb) 28.01 g / molc) 44.02 g / mold) 58.12 g / mol
20. If 5.282 g of methane gas, CH4, exerts a pressure of 3.108 atm when confined in a steel tank at 33.7 oC, what is the volume of the tank? Note that the gas constant R has a value of 0.08205783 L atm / K mol.
Atomic weights needed for this problem are as follows: C = 12.011   H = 1.00794
a) 2.667 Lb) 3.550 Lc) 7.192 Ld) 9.998 L
***   THE   END   ***


ANSWERS:

1 b      2 a      3 c      4 d      5 c     

6 a      7 b      8 c      9 b      10 b     

11 c      12 a      13 b      14 b      15 a     

16 b      17 c      18 a      19 c      20 a

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