South Pasadena • Chemistry
Name
Period
Date
5 · Chemical Reactions
SINGLE
REPLACEMENT
WORKSHEET
1. The balanced equation for the reaction between aluminum and lead nitrate:
2 Al + 3 Pb(NO3)2  3 Pb + 2 Al(NO3)3
The elements and ions involved are:
The charges are:
The half-reaction involving Al is:
Al  Al + 3 e
3+
Al
Pb2+
0
+2
NO3–

Pb
Al3+
0
+3
NO3–
The half-reaction involving Pb is:
–
Pb2+ + 2 e– Pb
The charge on Al is changing from 0 to +3.
The charge on Pb is changing from +2 to 0.
Because it’s getting more [ positive | negative ], so
Because it’s getting more [ positive | negative ], so
Al is [ gaining | losing ] electrons
Pb is [ gaining | losing ] electrons
and is being [ oxidized | reduced ].
and is being [ oxidized | reduced ].
2. Predict the products and write the balanced equation for each reaction. Then identify the element that is
oxidized and reduced, and write the half-reactions.
(a) Magnesium metal is placed in a solution of nickel chloride.
BALANCED EQUATION:
Mg + NiCl2

Ni
+ MgCl2
Ni0
Mg2+
CHARGES
Mg0
Ni2+
OXIDATION HALF-REACTION:
REDUCTION HALF-REACTION
Mg  Mg2+ + 2 e−
Ni2+ + 2 e−  Ni
ELEMENT THAT IS OXIDIZED:
ELEMENT THAT IS REDUCED:
Mg
(b)
Ni
Chlorine gas is bubbled in a solution of potassium bromide.
BALANCED EQUATION:
Cl2 + 2 KBr 
Br2 + 2 KCl
CHARGES
Cl0
OXIDATION HALF-REACTION:
2 Br− Br2 +
ELEMENT THAT IS OXIDIZED:
Br
Br−
Br0
Cl−
REDUCTION HALF-REACTION
2 e−
Cl2 + 2 e−  2 Cl−
ELEMENT THAT IS REDUCED:
Cl
(c)
Zinc metal is placed in a solution of hydrochloric acid.
BALANCED EQUATION:
Zn
+ 2 HCl 
H2
+ ZnCl2
H0
Zn2+
CHARGES
Zn0
H+
OXIDATION HALF-REACTION:
REDUCTION HALF-REACTION
−
2 H+ + 2 e−  H2
Zn  Zn + 2 e
2+
ELEMENT THAT IS OXIDIZED:
ELEMENT THAT IS REDUCED:
Zn
(d)
H
Iron metal is placed in a solution of cupric sulfate to form a ferric sulfate solution.
BALANCED EQUATION:
2 Fe + 3 CuSO4 
3 Cu
+ Fe2(SO4)3
CHARGES
Fe0
Cu2+
Cu0
OXIDATION HALF-REACTION:
REDUCTION HALF-REACTION
Fe  Fe3+ + 3 e−
Cu2+ + 2 e−  Cu
ELEMENT THAT IS OXIDIZED:
ELEMENT THAT IS OXIDIZED:
Fe
(e)
Fe3+
Cu
Copper metal is placed in a solution of silver nitrate to form a cupric nitrate solution.
BALANCED EQUATION:
Cu + 2 AgNO3 
2 Ag + Cu(NO3)2
Cu0
Ag0
CHARGES
Ag+
OXIDATION HALF-REACTION:
REDUCTION HALF-REACTION
Cu  Cu2+ + 2 e−
Ag+ + e−  Ag
ELEMENT THAT IS OXIDIZED:
ELEMENT THAT IS OXIDIZED:
Cu
(f)
Cu2+
Ag
Sodium metal is placed in water. (Hint: write water as HOH.)
BALANCED EQUATION:
2 Na + 2 HOH

H2
+ 2 NaOH
CHARGES
Na0
OXIDATION HALF-REACTION:
Na  Na+ + e−
ELEMENT THAT IS OXIDIZED:
Na
H+
H0
Na+
REDUCTION HALF-REACTION
2 H+ + 2 e−  H2
ELEMENT THAT IS OXIDIZED:
H