Stoichiometry
Practice Test
1.
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
a.
9.82 g
b.
10.0 g
c.
9.67 g
d.
10.3 g
2.
What do the coefficients in the following balanced chemical equation mean?
2H
2
+ O
2
→ 2H
2
O
a.
2 moles of hydrogen and 1 mole of oxygen in the reactants
b.
2 moles of oxygen and 1 mole of hydrogen in the reactants
c.
2 moles of oxygen and 1 mole of hydrogen in the products
d.
2 moles of hydrogen and 1 mole of oxygen in the products
3.
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.
224 mol
b.
32 mol
c.
16 mol
d.
48 mol
4.
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.
12.2 g
b.
11.7 g
c.
10.5 g
d.
8.32 g
5.
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.
ZnCl
2
d.
HCl
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.
3
b.
4
c.
1
d.
2
7.
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.
1.24 x10
-3
mol
b.
2.48 x 10
-3
mol
c.
9.90 x 10
-3
mol
d.
4.94 x 10
-3
mol
8.
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
3
PO
4
c.
Ca(OH)
2
d.
H
2
O
9.
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
a.
36%
b.
9%
c.
19%
d.
27%
10.
What is the balanced chemical equation for the reaction between hydrochloric acid and calcium carbonate when the products of the reaction are calcium chloride, carbon dioxide, and water?
a.
HCl + CaCO
3
→ CaCl
2
+ CO
2
+ H
2
O
b.
HCl + CaCl
2
→ CaCO
3
+ CO
2
+ H
2
O
c.
2HCl + CaCO
3
→ CaCl
2
+ CO
2
+ H
2
O
d.
2HCl + CaCl
2
→ CaCO
3
+ CO
2
+ 2H
2
O
11.
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
a.
6 g
b.
2 mol
c.
3 g
d.
1 mol
12.
The substance that limits the extent of a chemical reaction has a special name. What is this substance called?
a.
limiting reactant
b.
excess product
c.
limiting product
d.
excess reactant
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
a.
78.10%
b.
76.40%
c.
84.40%
d.
81.50%
14.
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.
0.64 mol HCl
b.
0.21 mol HCl
c.
2.7 mol HCl
d.
5.1 mol HCl
15.
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 momentum
c.
law of conservation of mass
d.
law of conservation of energy
16.
The reaction of 5.0 grams of fluorine with excess chlorine produced 5.6 grams of ClF
3
. What percent yield of ClF
3
was obtained?
Cl
2
+ 3F
2
→ 2ClF
3
a.
86%
b.
69%
c.
58%
d.
76%
17.
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
18.
How many moles of sulfur are present in 5 moles of H
2
SO
4
?
a.
2 mol
b.
10 mol
c.
1 mol
d.
5 mol
19.
What is the maximum amount of product that can be produced from a given amount of reactant?
a.
theoretical yield
b.
mole ratio
c.
percent yield
d.
actual yield
