Gases
Practice Test
1.
How many moles of an ideal gas are contained in 8.21 L at 73°C and 380 torr?
a.
1.5 x 10
23
b.
0.14
c.
7.5 x 10
23
d.
0.25
2.
A 10.0-L vessel contains gas A at a pressure of 300.0 torr. A 3.00-L vessel contains gas B at a pressure of 400.0 torr. Gas A is forced into the second vessel. Calculate the resulting pressure in torr. Assume the temperature remains constant.
a.
1800 torr
b.
1000 torr
c.
2000 torr
d.
1400 torr
3.
If the pressure exerted by a gas at 100°C in a volume of 0.044 L is 3.81 atm, how many moles of gas are present?
a.
1.0 mol
b.
100 mol
c.
1.8 x 10
2
mol
d.
5.5 x 10
-3
mol
4.
Calculate the number of moles of gas contained in a 16.0-L vessel at 373 K with a pressure of 2.50 atm.
a.
2.8 x 10
-3
mol
b.
1.31 x 10
-1
mol
c.
0.766 mol
d.
1.31 mol
5.
What is the molar mass of a gas if 0.104 g of the gas occupies 48.7 mL at STP?
a.
34.5 g/mol
b.
40.0 g/mol
c.
28.2 g/mol
d.
47.9 g/mol
6.
If 1.00 L of a gas is 4.40 times as heavy as 1.00 L of O
2
at the same temperature and pressure, then what is the molar mass of the unknown gas?
a.
67.0 g/mol
b.
70.4 g/mol
c.
141 g/mol
d.
88.0 g/mol
7.
What is the name given to a gas whose particles do not take up space, do not have intermolecular attractive forces, and follow the gas laws under all conditions of temperature and pressure?
a.
diatomic gas
b.
ideal gas
c.
real gas
d.
noble gas
8.
Particles of matter that are in constant, random motion and that have a size that is much smaller than the distance between them are _____________.
a.
liquids
b.
gases
c.
solutions
d.
solids
9.
A gaseous compound is 30.6% nitrogen and 69.4% oxygen by mass. A 5.25-g sample of the gas occupies a volume of 1.00 L and exerts a pressure of 1.26 atm at –4.0°C. What is the molecular formula for the gas?
a.
NO
b.
N
2
O
4
c.
N
3
O
6
d.
NO
2
10.
<.br>
What volume will 0.554 mol of gas occupy at STP?
a.
40.4 L
b.
3.34 L
c.
12.4 L
d.
0.25 L
11.
What is the volume of 2.0 moles of a gas at STP?
a.
22.4 L
b.
0.0223 L
c.
0.0446 L
d.
44.8 L
12.
The pressure of a sample of helium in a 1.0-L container is 0.857 atm. What is the new pressure if the sample is placed in a 0.5-L container? (Assume the temperature is constant.)
a.
0.143 atm
b.
0.429 atm
c.
1.38 atm
d.
1.71 atm
13.
How can the molar volume of a gas be defined?
a.
the volume that one gram occupies at 100°C and 1 atm pressure
b.
the volume that one mole occupies at STP
c.
the volume that one gram occupies at STP
d.
the volume that one mole occupies at 100°C and 1 atm pressure
14.
Which of the following states that equal volumes of gases at the same temperature and pressure contain the same number of particles?
a.
Avogadro’s principle
b.
Charles’s law
c.
Boyle’s law
d.
Gay-Lussac’s law
15.
How many grams of ammonia (NH
3
) are present in a sample that occupies 2.0 L at a pressure at 2.0 atm and 25°C?
a.
2.7 grams
b.
0.36 grams
c.
0.16 grams
d.
6.3 grams
16.
A sample of gas is held in a 10.0-L volume at 175 kPa. The temperature is kept constant while the volume is decreased until the pressure is 350 kPa. What is the new volume of the gas?
a.
175 L
b.
10.0 L
c.
1.0 L
d.
5.0 L
17.
A gas occupies a volume of 1.0 L at 25°C. What volume will the gas occupy at 100°C?
a.
1.3 L
b.
0.80 L
c.
1.0 L
d.
4.0 L
18.
Determine the Celsius temperature of 1.50 moles of ammonia contained in a 10.0-L vessel under a pressure of 2.0 atm.
a.
0.0°C
b.
162°C
c.
-111
d.
-50°C
19.
A 0.5-L container of nitrogen gas is heated under constant pressure to the boiling point of water. What is its new volume?
a.
0.86 L
b.
0.64 L
c.
0.5 L
d.
0.79 L
