Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
|
|
|
1.
|
If
the pressure of a confined gas is tripled while its temperature remains constant, what change will be
observed? a. | The volume of
the gas will triple. | b. | The volume of the gas will decrease to 1/3 its original
value. | c. | The density of the gas will decrease to 1/3 its original
value. | d. | The volume will remain unchanged and the velocity of the
molecules will increase. | e. | The volume will remain unchanged and the velocity of the
molecules will decrease. | | |
|
|
|
2.
|
The
lid is tightly sealed on a rigid flask containing 2.00 L O2 at 15°C and 0.723 atm. If
the flask is heated to 55°C, what is the pressure in the flask? a. | 0.230
atm | b. | 0.465
atm | c. | 0.635
atm | d. | 0.723
atm | e. | 0.823
atm | | |
|
|
|
3.
|
Avogadro's law states that equal volumes of gases under the same conditions of
temperature and pressure have equal ________. a. | masses | b. | numbers of
molecules | c. | molar masses | d. | densities | e. | velocities | | |
|
|
|
4.
|
The
pressure in a 10.0 L flask is 0.912 atm at 78°C. How many moles of gas are in the flask?
(R = 0.08206 L·atm/mol·K) a. | 0.111 mol | b. | 0.317
mol | c. | 1.42
mol | d. | 3.16
mol | e. | 241
mol | | |
|
|
|
5.
|
Which
of the following gases has the lowest density at 25°C and 5.0 atm?
|
|
|
6.
|
Ammonia gas is synthesized according to the balanced equation
below.
N2(g) + 3 H2(g) ® 2
NH3(g)
If 2.50 L N2 react with 7.00 L
H2, what is the theoretical yield (in liters) of NH3? Assume that the volumes
of reactants and products are measured at the same temperature and pressure. a. | 2.50
L | b. | 4.67
L | c. | 5.00
L | d. | 7.00
L | e. | 10.5
L | | |
|
|
|
7.
|
Which
of the following are postulates of kinetic-molecular theory of gases?
1. The distance between gas molecules is large in comparison to their
size.
2. The velocity of a gas molecule is inversely proportional to its
temperature.
3. Gas molecules are in constant, random
motion.
4. At a given temperature, all gases have the same average kinetic
energy.
a. | 1 and
4 | b. | 1, 2, and
4 | c. | 1, 3, and
4 | d. | 2 and
3 | e. | 3 and
4 | | |
|
|
|
8.
|
Non-ideal behavior for a gas is most likely to be observed under conditions
of a. | high temperature
and high pressure. | b. | low temperature and high pressure. | c. | low temperature
and low pressure. | d. | standard temperature and pressure. | e. | high temperature
and low pressure. | | |
|
|
|
9.
|
One
way in which real gases differ from ideal gases is that the molecules of a real gas a. | have no kinetic
energy. | b. | occupy no volume. | c. | are attracted to
each other. | d. | have positive and negative spins. | e. | are always
polar. | | |
|
|
|
10.
|
A
sample of gas occupies 175 mL at 22°C and 218 mm Hg. What is the pressure of the gas if the
volume is decreased to 122 mL and the temperature increased to 75°C? a. | 51.7
mmHg | b. | 97.8 mm
Hg | c. | 103 mm
Hg | d. | 312 mm
Hg | e. | 369 mm
Hg | | |
|
|
|
11.
|
The
average velocity of a gas molecule is a. | inversely proportional to its kinetic
energy. | b. | proportional to the gas constant,
R. | c. | inversely proportional to the square root of its
mass. | d. | directly proportional to the square of its temperature
inºC. | e. | inversely proportional to the square of its temperature in
K. | | |
|