Name_________________________________Period_________Date_____________
Ch. 8: Chemical Reactions and Equations
Practice Problems and Review
Balancing Equations
Balance the equations below.
(1)
Fe
+
S8 
FeS
(2)
Ag(NO3)
+
NaBr 
(3)
K(ClO3)

KCl
(5)
KI
+
Pb(NO3)2

(6)
Al
+
O2

Al2O3
(7)
Fe2O3
+
C
(8)
Zn
+
(9)
NO2
+
(10)
Na (NO3)
+
PbI2
+
K(NO3)

Fe
+
CO
Cu2(SO4)

Cu
+
Zn(SO4)
H2O

HNO3 +
K(ClO4)

KCl
+
(11)
Ca
+
H2O

Ca(OH)2
(12)
Cl2O7 +
H2O

HClO4
(13)
C6H14 +
O2

CO2
+
H2O
(14)
HCl
CaCO3 
CO2
+
H2O
+
AgBr
+O2
NO
O2
+
H2
+
CaCl2
Symbols Used in Equations
Fill in the chart of symbols below with the missing information.
Meaning
Symbol
Reversible Reaction- when products can re-form from reactants
(s)
Precipitate has formed
(l)
Dissolved in water
In gaseous form
↑
Reactants are heated
Reactants are heated
Reaction is carried out at 5 atm of pressure
Reaction is done at temperature of 3° C
An unspecified catalyst is used to speed up the reaction
Platinum metal is used as a catalyst in this reaction.
Writing Equations
Write the balanced formula equations for each of the word equations
below.
1. iron + sulfur  iron (II) sulfide
2. silver nitrate + sodium bromide  sodium nitrate + silver bromide
3. potassium chlorate
4. water
electricty


heated

potassium chloride + oxygen
hydrogen + oxygen
5. potassium iodide + lead (II) nitrate  lead (II) iodide + potassium nitrate
6. aluminum + oxygen  aluminum oxide
7. iron (III) oxide + carbon  iron + carbon monoxide
8. Iron (III) chloride + ammonium hydroxide  Iron (III) hydroxide +
ammonium chloride
9. Aluminum chromate + ammonium sulfate  ammonium chromate +
aluminum sulfate
10.Magnesium + Nitrogen  Magnesium nitride
11.Zinc + Ferric sulfate  Zinc sulfate + Ferrous sulfate
Writing Word and Formula Equations
Write a word equation and a balanced formula equation for each of the
reaction descriptions below.
1. Hydrogen peroxide in an aqueous solution decomposes to produce
oxygen and water.
2. Solid copper metal reacts with aqueous silver nitrate to produce solid
silver metal and aqueous copper nitrate.
3. Solid zinc metal reacts with aqueous copper sulfate to produce solid
copper metal and aqueous zinc sulfate.
4. Nitrogen dioxide gas reacts with water to form aqueous nitric acid and
nitrogen monoxide gas.
5. Solid potassium chlorate decomposes to form solid potassium chloride
and oxygen gas.
6. When potassium chlorate is heated, oxygen gas is released and potassium
chloride is left behind.
7. When solid calcium carbonate is heated, it decomposes into solid calcium
oxide and gaseous carbon dioxide.
8. Hydrogen sulfide gas is bubbled into a solution of mercury (II) chloride to
form solid mercuric sulfide and hydrochloric acid.
9. Phosphorus (V) oxide powder is sprinkled over distilled water to create
phosphoric acid.
10.When a bar of zinc metal is immersed in a solution of copper (II) sulfate,
a solution of zinc sulfate forms along with solid copper metal.
11.A small piece of sodium metal is added to water to make hydrogen gas
and a solution of sodium hydroxide.
12.When solutions of manganese (II) sulfate and ammonium sulfide are
mixed, solid manganese (II) sulfide and aqueous ammonium sulfate are
created.
13.Carbon disulfide vapor is burned in oxygen to create 2 gaseous products:
carbon dioxide and sulfur dioxide.
14.When a solution of hydrogen peroxide is heated, it decomposes into
water and oxygen gas.
15.Solid copper (II) sulfide is heated strongly in oxygen gas to make copper
metal and sulfur dioxide.