Honors Chemistry - Chemical Reactions Practice
Section 1: Reactions and Equations
1) Define a chemical reaction. Use the terms “reactant and product” and
write at least three sentences in your definition. Don’t give
examples… just a definition.
2) Determine if the following are chemical or physical changes.
a. You crumple this problem set up.
b. You tear this problem set up.
c. You light this problem set on fire and it turns into a pile of ash.
d. You place a piece of calcium in a beaker of water.
e. You place a sponge in a beaker of water.
f. You strike a piece of lead with a hammer and the piece of metal
bends.
g. The addition of a solution of lead (II) nitrate to a solution of
sodium phosphate to produce a solution of sodium nitrate and
solid particles of lead (II) phosphate.
h. You breathe in O2 gas and exhale CO2 gas…
3) Give three types of evidence that indicate a chemical reaction has
taken place.
4) The mass of the reactants must equal the mass of the products in any
chemical change. Why?
5) Why does your car stop running when you run out of gas?
6) Glow sticks are actually two sticks in one… a thin glass tube rests
inside the larger exterior plastic tube. Inside the glass tube is one
reactant. Outside the small thin glass tube and inside the large plastic
stick is the other reactant. When you buy a glow stick at the 4th of
July Parade the first thing you have to do is snap the tube. What does
snapping the tube do and how does this lead to a chemical reaction?
7) When balancing a chemical reaction the subscripts in the formulas can
NEVER be changed. Why?
8) The reaction below is balanced, but there are only ten molecules of
reactants while there are twelve molecules of products. How can this
be balanced?
C6H12 + 9 O2  6 CO2 + 6 H2O
9) What is the difference between a word equation and a chemical
equation?
10) Which numbers in the following balanced reaction of aluminum and
sulfuric acid are coefficients and which are subscripts?
3 H2SO4+ 2 Al  Al2(SO4)3 + 3 H2
11) Write the word equation for the following balanced reactions:
a. 2 Mg (s) + O2 (g)  2 MgO (s)
b. HCl (aq) + NaOH (aq)  H2O (l) + NaCl (aq)
c. 2 NH4NO3 (s) 2 N2 (g) + O2 (g) + 4 H2O(g)
d. NaOH (aq)+ AgNO3 (aq)  AgOH (s) + NaNO3
12) Balance the following reactions – be sure to copy them correctly into
your problem set…
a. C2H6 (g) + O2 (g)  CO2 (g) + H2O (g)
b. NaCl (aq) + Pb(NO3)2 (aq)  NaNO3 (aq) + PbCl2 (s)
c. Ca (s) + H2O (l)  Ca(OH)2 + H2 (g)
d. Ca(HCO3)2 (s)  CaO (s) + CO2 (g) + H2O (g)
e. Cu (s) + S6 (g)  CuS (s)
13) When nitric acid (HNO3) is added to a solid piece of copper, a brown
noxious gas called nitrogen dioxide is produced along with hydrogen
gas and a solution of copper (II) nitrate.
a. Write the word equation for the statement above.
b. Write the unbalanced formula equation.
c. Count the atoms for each element as a reactant
d. Count the atoms for each element as a product
e. Balance the reaction
14) Write a balanced chemical reaction for the following word equations.
a. Potassium chlorate decomposes to form potassium chloride and
oxygen.
b. Aqueous solutions of copper (II) nitrate and sodium hydroxide
react to form solid copper (II) hydroxide and a solution of sodium
nitrate.
c. Diphosphorous tetrabromide reacts with fluorine gas to produce
diphosphorous tetrafluoride and liquid bromine.
d. Octane (C8H12) and oxygen react to produce carbon dioxide and
water.
15) Why is being able to name compounds correctly so important in
chemistry?
16) List the diatomic elements – give their names and molecular formulas.
Multiple Choice Section
17) This law states the mass of reactants has to be equal to the mass of the
products.
a. The Law of Definite Proportions
b. The Law of Multiple Proportions
c. The Law of Conservation of Mass
d. The Law of Chemical Reactions
18) Which of the following is a chemical change?
a. Pouring a glass of milk
b. Adding chocolate syrup to the milk
c. Stirring the chocolate syrup into the milk
d. Letting the milk sit out overnight and waking up to find sour
milk
19) Which of the following is NOT a chemical change?
a. Lighting a match
b. Lighting a Bunsen Burner
c. Ice in a beaker over the Bunsen burner turn into water
d. Adding pieces of calcium to the water in the beaker
20) What are the coefficients that will balance this reaction?
___ HCl (aq) + ___ Mg(OH)2 (aq)  ___ H2O (l) + ___MgCl2 (aq)
a. 1, 2 ,2, 1
b. 2, 1, 2, 1
c. 2, 2, 1, 1
d. 2, 1, 1, 2
21) What is the “x” in the following equation?
C5H12 + _x_ O2  5 CO2 + 6H2O
a. 4
b. 5.5
c. 16
d. 8
e. 10
22) According to the diagram on the right, which equation would
correctly represent the reaction?
a)
b)
c)
d)
e)
8X
8X
8X
X
2X
+ 8Y 8Z
+ 2Y 8Z
+ 16 Y  24 Z
+ 2Y 2Z
+ Y 3Z
Y
Z
X
Section 2: Classifying Chemical Reactions
23) Balance and Identify the Reaction Type for these reactions
a. H2 (g) + N2 (g)  NH3 (g)
b. H2O (g)  H2 (g) + O2 (g)
c. H2 (g) + O2 (g)H2O (aq)
d. Na (s) + 2 HCl (aq)  H2 (g) + NaCl (aq)
e.
24) Identify the Reaction Types of These Balanced Reactions
a.
b.
c.
d.
e.
f.
g.
h.
LiI (aq) + AgNO3(aq)LiNO3(aq)+ AgI (s)
Na (s) + AgNO3 (aq)  NaNO3 (aq) + Ag(s)
H2CO3 (aq)  H2O (l) + CO2 (g)
HCl (aq) + NaOH (aq)  NaCl (aq) + H2O(l)
Na2CO3(aq) + CaSO4(aq) Na2SO4(aq) + CaCO3(s)
4H2O (l) + 3Fe(s)  Fe3O4 (s) + 4H2 (g)
4 Al(s) + 3 O2 (g)  2 Al2O3 (g)
CH4 (g) + 2 O2 (g)  CO2 (g) + 2 H2O (g)
25) What reactant is always needed for a combustion reaction to take
place? What are the two products that are always produced in the
complete combustion of an organic fuel?
26) What three elements are produced in the decomposition of sodium
sulfate?
27) What four elements are needed to run the synthesis reaction that
forms the ionic compound ammonium sulfate?
28) What does the activity series show? What is the rule of thumb that
you should remember when looking at the activity series?
29) What is a precipitate?
30) Use your activity series to determine which reactants will react:
a. Na (s) + HCl (aq)
b. Mg (s) + NaCl (aq)
c. Au (s) + FeCl3 (aq)
or
or
or
H2 (g) + NaCl (aq)
Na (s) + MgCl2 (aq)
Fe (s) + AuCl (aq)
Multiple Choice section
31) Which product is missing from this single replacement reaction?
Cu (s) + H2SO4 (aq)  CuSO4 (aq) + ???
a. H (g)
b. H2 (g)
c. CuO (s) d. O2 (g)
e. CO2 (g)
32) Lead(IV) oxide changes to lead(II) oxide when heated. Which set of
masses
could occur in this experiment? 2 PbO2 (s)  2 PbO (s) + O2 (g)
a) test tube
19.0 g
test tube + PbO2 18.7 g
test tube + PbO 18.0 g
b) test tube
test tube + PbO2
test tube + PbO
19.0 g
19.3g
18.0 g
c) test tube
19.0 g
test tube + PbO2 22.0 g
test tube + PbO 21.8 g
d) test tube
test tube + PbO2
test tube + PbO
19.0 g
22.0 g
22.3 g
Single Replacement Reactions
33) Predict if these single replacement reactions will run based upon the
activity series.
a.
Ag (s) + Fe(NO3)3aq)
b.
Fe (s) + AgNO3 (aq)
c.
Al (s) + Cu(NO3)2 (aq)
34) Given the following data, write an activity series or the elements A, B
and C.
Atoms of A react with ions of B
Atoms of A react with ions of C
Atoms of B do not react with ions of C
Atoms of B do not react with ions of A
Atoms of C react with ions of B
Atoms of C do not react with ions of A