Chapter 12:
Stoichiometry
Practice Test
1.
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.
76.40%
b.
84.40%
c.
78.10%
d.
81.50%
Hint
2.
The substance that limits the extent of a chemical reaction has a special name. What is this substance called?
a.
limiting product
b.
excess reactant
c.
limiting reactant
d.
excess product
Hint
3.
What is the ratio between the coefficients of any two substances in a balanced equation?
a.
chemical formula
b.
molar mass balanced equation
c.
mole ratio
d.
quadratic equation
Hint
4.
The reaction of 5.0 grams of fluorine with excess chlorine produced 5.6 grams of ClF3. What percent yield of ClF
3
was obtained?
Cl
2
+ 3F
2
2ClF
3
a.
58%
b.
76%
c.
86%
d.
69%
Hint
5.
Balance the following equation with the smallest whole-number coefficients. What is the coefficient for H
2
O in this equation?
a.
1
b.
2
c.
4
d.
3
Hint
6.
How many grams of O
2
are required to burn 18 g C
5
H
12
?
C
5
H
12
+ 8O
2
5CO
2
+ 6H
2
O
a.
80 g
b.
16 g
c.
32 g
d.
64 g
Hint
7.
How many moles of CO
2
would be produced from 56 moles of O
2
according to the following balanced equation?
2C
2
H
6
+ 7O
2
4CO
2
+ 6H
2
O
a.
48 mol
b.
16 mol
c.
32 mol
d.
224 mol
Hint
8.
In the chemical reaction below, 3.27 grams of Zn are reacted with 3.30 grams of HCl. Which component will limit the reaction?
Zn + 2HCl
ZnCl
2
+ H
2
a.
Zn
b.
H
2
c.
HCl
d.
ZnCl
2
Hint
9.
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
a.
10.5 g
b.
12.2 g
c.
8.32 g
d.
11.7 g
Hint
10.
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
a.
15
b.
10
c.
20
d.
5
Hint
11.
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.
10.3 g
b.
13.4 g
c.
8.6 g
d.
6.8 g
Hint
12.
What is the first thing you must do to solve a stoichiometric problem?
a.
Find the limiting reactant.
b.
Find the empirical formula.
c.
Write a balanced chemical equation.
d.
Find the excess reactant.
Hint
13.
Balance the following equation with the smallest whole-number coefficients. How many moles of Ag
2
S can be prepared from 3 moles of Ag? Ag + H
2
S + O
2
Ag
2
S + H
2
O
a.
4.0 mol
b.
1.5 mol
c.
1.0 mol
d.
2.0 mol
Hint
14.
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
a.
Ca
3
(PO
4
)
2
b.
H
2
O
c.
Ca(OH)
2
d.
H
3
PO
4
Hint
15.
Balance the following equation with the smallest whole-number coefficients. How many grams of O
2
will be produced if 23.2 g of XeF
2
reacts with excess water?
XeF
2
+ H
2
O → Xe + HF + O
2
a.
2.19 g
b.
4.42 g
c.
1.10 g
d.
3.31 g
Hint
16.
What is the scientific law that states that matter is not created or destroyed but only transformed in a chemical reaction.
a.
law of gravity
b.
law of conservation of mass
c.
law of conservation of energy
d.
law of conservation of momentum
Hint
17.
How many grams of Fe
2
O
3
are present in 0.82 mol Fe
2
O
3
?
a.
260 g
b.
65 g
c.
130 g
d.
195 g
Hint
18.
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
+ H2
a.
6 g
b.
1 mol
c.
3 g
d.
2 mol
Hint
19.
How many moles of sulfur are present in 5 moles of H
2
SO
4
?
a.
10 mol
b.
2 mol
c.
1 mol
d.
5 mol
Hint
20.
What do the coefficients in the following balanced chemical equation mean?
2H
+ O
2
2H
2
O
a.
2 moles of hydrogen and 1 mole of oxygen in the products
b.
2 moles of oxygen and 1 mole of hydrogen in the reactants
c.
2 moles of hydrogen and 1 mole of oxygen in the reactants
d.
2 moles of oxygen and 1 mole of hydrogen in the products
Hint
