Gases
Practice Test
1.
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?
SC.A.1.4.5
a.
NO
b.
NO
2
c.
N
3
O
6
d.
N
2
O
4
2.
A gas occupies a volume of 1.0 L at 25°C. What volume will the gas occupy at 100°C?
SC.B.1.4.3
a.
1.3 L
b.
4.0 L
c.
0.80 L
d.
1.0 L
3.
If sufficient hydrochloric acid is used to react completely with 48.6 g of magnesium, how much hydrogen will be produced?
2HCl+Mg→MgCl
2
+H
2
SC.B.1.4.2
a.
2 mol
b.
6 g
c.
3 g
d.
1 mol
4.
Determine the number of atoms in 3.54 mol S.
SC.A.2.4.2
a.
1.70 x 10
23
b.
2.13 x 10
24
c.
1.70 x 10
24
d.
2.13 x 10
23
5.
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?
SC.A.1.4.3
a.
0.36 grams
b.
6.3 grams
c.
2.7 grams
d.
0.16 grams
6.
Which of the following illustrates effusion of a gas?
a.
Fragrance of cologne is present in a room in which none has been used.
b.
Cooking aromas from the kitchen can be detected by a person on the front porch.
c.
A tire deflates after being punctured by a nail.
d.
A dog follows a scent during a search and rescue mission.
7.
Which of the following states that equal volumes of gases at the same temperature and pressure contain the same number of particles?
SC.H.1.4.5
a.
Avogadro’s principle
b.
Charles’s law
c.
Gay-Lussac’s law
d.
Boyle’s law
8.
How many particles are present in one mole of particles?
SC.A.2.4.2
a.
3.0 x 10
8
b.
6.02 x 10
23
c.
12
d.
1
9.
What mass of SrF
2
can be prepared from the reaction of 10.0 g Sr
OH
2
with excess HF?
Sr
OH
2
+2HF→SrF
2
+2H
2
O
SC.B.1.4.2
a.
9.67 g
b.
10.3 g
c.
9.82 g
d.
10.0 g
10.
What is the first thing you must do to solve a stoichiometric problem?
a.
Find the excess reactant.
b.
Find the limiting reactant.
c.
Find the empirical formula.
d.
Write a balanced chemical equation.
11.
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.
100 mol
b.
1.8 x 10
2
mol
c.
1.0 mol
d.
5.5 x 10
-3
mol
12.
Determine the Celsius temperature of 1.50 moles of ammonia contained in a 10.0-L vessel under a pressure of 2.0 atm.
SC.A.1.4.3
a.
-111
b.
162°C
c.
0.0°C
d.
-50°C
13.
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
SC.B.1.4.2
a.
84.40%
b.
78.10%
c.
76.40%
d.
81.50%
14.
The measure of the average kinetic energy of the particles in a sample of matter is _____.
SC.B.1.4.3
a.
temperature
b.
velocity
c.
speed
d.
heat
15.
What relationship is demonstrated by the expansion of a gas—filled balloon when it is heated?
SC.B.1.4.3
a.
Gay-Lussac’s law
b.
Boyle’s law
c.
Charles’s law
d.
Avogadro’s number
16.
Balance the following equation with the smallest whole—number coefficients. What is the coefficient for O
2
in the balanced equation?
C
5
H
10
+O
2
→ CO
2
+H
2
O
SC.B.1.4.2
a.
10
b.
5
c.
15
d.
20
17.
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.
88.0 g/mol
b.
67.0 g/mol
c.
70.4 g/mol
d.
141 g/mol
18.
What mass of SrF
2
can be prepared from the reaction of 8.05 g of Sr
OH
2
with 3.88 g of HF?
Sr
OH
2
+2HF→SrF
2
+2H
2
O
SC.B.1.4.2
a.
11.7 g
b.
8.32 g
c.
10.5 g
d.
12.2 g
19.
What is the percent yield for the reaction between 9.8 grams of Ca
OH
2
and 9.8 grams of H
3
PO
4
when 2.5 grams of
Ca
3
PO
4
2
are actually obtained?
3Ca
OH
2
+2H
3
PO
4
→Ca
3
PO
4
2
+6H
2O
SC.B.1.4.2
a.
27%
b.
36%
c.
19%
d.
9%
20.
Which reactant in the following reaction is in excess when 9.8 grams of Ca
OH
2
is reacted with 9.8 grams of H
3
PO
4
?
3Ca
OH
2
+2H
3
PO
4
→Ca
3
PO
4
2
+6H
2
O
SC.B.1.4.2
a.
H
2
O
b.
Ca
OH
2
c.
Ca
3
PO
4
2
d.
H
3
PO
4
