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Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
87
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER 9
a. A water solution of zinc bromide (ZnBr 2 ) and a water solution of potassium hydroxide form a water solution of
potassium bromide and a precipitate of zinc hydroxide.
b. A water solution of copper(II) sulfate and a water solution
of barium chloride produce a water solution of copper(II)
chloride and solid barium sulfate.
c. A precipitate of iron(III) carbonate and a water solution of
sodium nitrate are formed when a water solution of iron(III)
nitrate and a water solution of sodium carbonate are mixed.
9.3 Reactions in Aqueous Solutions
When a substance dissolves in water, a solution forms. A solution
is a homogeneous mixture because it has a constant composition
throughout. A solution contains one or more substances called
solutes dissolved in the solvent. The solvent is the most plentiful
substance in a solution. An aqueous solution is a solution in which
the solvent is water. When dissolved to form aqueous solutions, the
ions of ionic compounds separate. Some molecular compounds also
produce dissolved ions in water. If hydrogen ions are produced, the
substance is called an acid. For example, the gaseous molecular
compound hydrogen chloride (HCl) forms H ϩ and Cl Ϫ ions in aqueous solution, which is called hydrochloric acid.
When aqueous solutions that contain ions are mixed, the ions
may react in a double-replacement reaction. The product is typically
a solid precipitate, water, or a gas. An example of a doublereplacement reaction that produces a precipitate occurs when aqueous solutions of sodium chloride and silver nitrate are mixed to form
a precipitate of solid silver chloride.
NaCl(aq) ϩ AgNO 3 (aq) 0 NaNO 3 (aq) ϩ AgCl(s)
To show all of the particles in solution as they really exist, a
complete ionic equation can be written.
Na ϩ (aq) ϩ Cl Ϫ (aq) ϩ Ag ϩ (aq) ϩ NO 3
Ϫ (aq) 0
Na ϩ (aq) ϩ NO 3
Ϫ (aq) ϩ AgCl(s)
The sodium and nitrate ions are on both sides of the equation. Such
ions that do not participate in a reaction are called spectator ions.
An ionic equation that does not show spectator ions but only the
Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
87
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER 9
a. A water solution of zinc bromide (ZnBr 2 ) and a water solution of potassium hydroxide form a water solution of
potassium bromide and a precipitate of zinc hydroxide.
b. A water solution of copper(II) sulfate and a water solution
of barium chloride produce a water solution of copper(II)
chloride and solid barium sulfate.
c. A precipitate of iron(III) carbonate and a water solution of
sodium nitrate are formed when a water solution of iron(III)
nitrate and a water solution of sodium carbonate are mixed.
9.3 Reactions in Aqueous Solutions
When a substance dissolves in water, a solution forms. A solution
is a homogeneous mixture because it has a constant composition
throughout. A solution contains one or more substances called
solutes dissolved in the solvent. The solvent is the most plentiful
substance in a solution. An aqueous solution is a solution in which
the solvent is water. When dissolved to form aqueous solutions, the
ions of ionic compounds separate. Some molecular compounds also
produce dissolved ions in water. If hydrogen ions are produced, the
substance is called an acid. For example, the gaseous molecular
compound hydrogen chloride (HCl) forms H ϩ and Cl Ϫ ions in aqueous solution, which is called hydrochloric acid.
When aqueous solutions that contain ions are mixed, the ions
may react in a double-replacement reaction. The product is typically
a solid precipitate, water, or a gas. An example of a doublereplacement reaction that produces a precipitate occurs when aqueous solutions of sodium chloride and silver nitrate are mixed to form
a precipitate of solid silver chloride.
NaCl(aq) ϩ AgNO 3 (aq) 0 NaNO 3 (aq) ϩ AgCl(s)
To show all of the particles in solution as they really exist, a
complete ionic equation can be written.
Na ϩ (aq) ϩ Cl Ϫ (aq) ϩ Ag ϩ (aq) ϩ NO 3
Ϫ (aq) 0
Na ϩ (aq) ϩ NO 3
Ϫ (aq) ϩ AgCl(s)
The sodium and nitrate ions are on both sides of the equation. Such
ions that do not participate in a reaction are called spectator ions.
An ionic equation that does not show spectator ions but only the