Gases
Practice Test
1.
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
2.
A gas occupies a volume of 1.0 L at 25°C. What volume will the gas occupy at 100°C?
a.
4.0 L
b.
1.0 L
c.
0.80 L
d.
1.3 L
3.
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.
0.79 L
b.
0.64 L
c.
0.5 L
d.
0.86 L
4.
How can the molar volume of a gas be defined?
a.
the volume that one gram occupies at STP
b.
the volume that one mole occupies at STP
c.
the volume that one gram occupies at 100°C and 1 atm pressure
d.
the volume that one mole occupies at 100°C and 1 atm pressure
5.
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What volume will 0.554 mol of gas occupy at STP?
a.
12.4 L
b.
0.25 L
c.
40.4 L
d.
3.34 L
6.
Balance the following equation with the smallest whole-number coefficients. What is the coefficient for H
2
O in this equation?
PBr
3
+ H
2
O → H
3
PO
3
+ HBr
a.
2
b.
1
c.
4
d.
3
7.
What is the maximum amount of product that can be produced from a given amount of reactant?
a.
mole ratio
b.
percent yield
c.
actual yield
d.
theoretical yield
8.
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.
28.2 g/mol
c.
40.0 g/mol
d.
47.9 g/mol
9.
What is the ratio between the coefficients of any two substances in a balanced equation?
a.
chemical formula
b.
quadratic equation
c.
mole ratio
d.
molar mass balanced equation
10.
Determine the number of atoms in 3.54 mol S.
a.
1.70 x 10
24
b.
1.70 x 10
23
c.
2.13 x 10
24
d.
2.13 x 10
23
11.
At the same ______, the particles of different gases have the same average kinetic energy.
a.
density
b.
pressure
c.
volume
d.
temperature
12.
What is the maximum amount of Ca
3
(PO
4
)
2
that can be prepared from 9.8 grams of Ca(OH)
2
and 9.8 grams of H
3
PO
4
?
3Ca(OH)
2
+ 2H
3
PO
4
→ Ca
3
(PO
4
)
2
+ 6H
2
O
a.
13 g
b.
8.6 g
c.
10.3 g
d.
6.8 g
13.
Based on the following equation, how many moles of hydrochloric acid are needed to react with 0.64 moles of potassium permanganate?
2KMnO
4
+ 8 HCl → 3 Cl
2
+ 2 MnO
2
+ 4 H
2
O + 2KCl
a.
2.7 mol HCl
b.
0.21 mol HCl
c.
5.1 mol HCl
d.
0.64 mol HCl
14.
What is the SI base unit used to measure the amount of a substance?
a.
kelvin
b.
kilogram
c.
meter
d.
mole
15.
How many moles of sulfur are present in 5 moles of H
2
SO
4
?
a.
5 mol
b.
2 mol
c.
1 mol
d.
10 mol
16.
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.
N
3
O
6
b.
NO
c.
NO
2
d.
N
2
O
4
17.
How many moles of HCl will just react with 0.424 g Ba(OH)
2
?
2HCl + Ba(OH)
2
→ BaCl
2
+ 2H
2
O
a.
2.48 x 10
-3
mol
b.
4.94 x 10
-3
mol
c.
9.90 x 10
-3
mol
d.
1.24 x10
-3
mol
18.
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.
6.3 grams
b.
2.7 grams
c.
0.36 grams
d.
0.16 grams
19.
What is the percent yield of CO
2
if a reaction using 10.0 g CO with excess O
2
produces 12.8 g CO
2
?
2CO + O
2
→ 2CO
2
a.
81.50%
b.
84.40%
c.
76.40%
d.
78.10%
20.
According to the kinetic-molecular theory, which of these describes a gas?
a.
small particles in constant, random motion
b.
large particles far apart in uniform motion
c.
small particles far apart in uniform motion
d.
large particles in constant, random motion
