Name___________________________

SSN____________________________

Note: Some (but not all) problems on this exam require the use of the universal gas constant R. For your information note that it's value is as follows:

R = 0.08205783 (L atm) / (K mol)

1. A gas was confined in a cylinder fitted with a movable
piston.
At 11.22 ^{o}C, the gas occupied a volume of 1.407 L and exerted a
pressure
of 1.179 atm. The gas was then isobarically heated, causing it to
expand (lifting the piston higher in the cylinder). After the heating
process, the gas occupied a volume of 1.957 L. What was the temperature
of the gas after the heating? For full credit, you must express your
final answer in Celcius (^{o}C). (Hints: Note that the process is
isobaric. Also, assume that the cylinder does not leak, and no
chemical reaction takes place in the gas, so that the number of moles
will be constant.)

2. A gas was confined in a closed, rigid steel tank having a volume of
4.953 L. At 15.81 ^{o}C, the gas exerted a pressure of 1.935 atm. If the
gas is heated to a temperature of 99.48 ^{o}C, what pressure will
it exert?
(Hints: Since the gas is in a closed, rigid steel tank, its volume will
be constant. Also assume the tank does not leak, and no chemical reaction
takes place in the gas, so that the number of moles will be constant).

3. A gas was confined in a cylinder fitted with a movable piston.
At 21.52 ^{o}C, the gas occupied a volume of 3.774 L and exerted a pressure
of 1.506 atm. The gas was isothermally compressed (by pushing in the
piston) until the gas pressure was 2.713 atm. What volume did the gas
occupy after the compression? (Hints: Note that the process is
isothermal. Also assume the cylinder does not leak, and no chemical
reaction takes place in the gas, so the number of moles will be
constant).

4. A gas was confined in a cylinder fitted with a movable piston. At 17.31 ^{o}C, the gas occupied a volume of 1.957 L and exerted a pressure of
2.154 atm. The gas was simultaneously heated and compressed. After the
heating and compression, the gas had a temperature of 66.51 ^{o}C and
occupied a volume of 1.218 L. What pressure did the gas exert under
these conditions?

5. A steel tank contains 9.173 g of nitrogen gas
(N_{2}) at 22.84 ^{o}C.
The gas exerts a pressure of 4.183 atm. What is the volume of the tank?
Atomic weights needed to work this problem are as follows:

N = 14.00674

6. A steel tank having a volume of 5.906 L contains 6.817 g of methane
gas (CH_{4}) at 26.19 ^{o}C. What pressure does the methane exert? Atomic
weights needed to work this problem are as follows:

H = 1.00794 and C = 12.011

7. A steel tank having a volume of 3.584 L contains 5.831 g
of ammonia gas (NH_{3}). The gas pressure is 2.431 atm. What is the temperature
of the gas? For full credit, your final answer must be expressed in
Celcius (^{o}C). Atomic weights needed to work this problem are as
follows:

H = 1.00794 and N = 14.00674

8. What is the density of propane gas
(C_{3}H_{8}) at 27.50 ^{o}C
and 1.007 atm? Atomic weights needed to solve this problem are as
follows:

H = 1.00794 and C = 12.011

9. What is the meaning of the term "isochoric"?

10. What two gas parameters must be constant in order to use Charles' Law? You must identify both to receive full credit.

ANSWERS1) 122.38

6) 1.767 atm 7) 36.96

9) Isochoric means the volume is constant

10) Gas pressure and number of moles must be constant to use Charles' Law