DATE:
NAME: KEY /68
CLASS:
BLM 3-6
Balancing Equations
SKILL BUILDER
Goal  Practise balancing and classifying chemical equations.
What to Do
Answer the questions in each section in the space provided.
Balancing Formation Reaction Equations
1. Balance each equation for a formation reaction.
(a) 4K(s)
+
O2(g)

2K2O(s)
(b)
P4(s)
+
10 Cl2(g)

4PCl5(s)
(c)
8Cu(s)
+
S8(s)

8CuS(s)
(d)
2Mg(s)
+
O2(g)

2MgO(s)
(e)
4Fe(s)
+
3O2(g)

2Fe2O3(s)
(f)
4P4(s)
+
5S8(g)

8P2S5(s)
(g)
2C(s)
+
O2(g)

2CO(g)
(h)
N2(g)
+
2O2(g)

2NO2(g)
(i)
6Li(s)
+
N2(g)

2Li3N(s)
(j)
S8(s)
+
8O2(g)

8SO2(g)
2. Write a balanced chemical equation to represent each reaction described below.
(a) Solid aluminum metal reacts with oxygen gas to form solid aluminum oxide.
4 Al (s) + 3 O2 (g)  2 Al2O3 (s)
(b) Metallic zinc combines with elemental sulfur to form zinc sulfide.
8 Zn (s) + S8(s)  8 ZnS (s)
Balancing Decomposition Reaction Equations
3. Balance each equation for a decomposition reaction.
(a) 2NaCl(s)

2Na(s)
+
Cl2(g)
(b)
CaBr2(s)

Ca(s)
+
Br2(l)
(c)
CCl4(l)

C(s)
+
2Cl2(g)
(d)
2NCl3 (g)

N2(g)
+
3Cl2(g)
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be held responsible for content if any revisions, additions, or deletions are made to this page.
DATE:
NAME:
CLASS:
BLM 3-6
Balancing Equations (continued)
SKILL BUILDER
(e)
P4O10(s)

P4(s)
+
5 O2(g)
(f)
2Ag2O(s)

4Ag(s)
+
O2(g)
(g)
2HCl(aq)

H2(g)
+
Cl2(g)
(h)
2KI(s)

2K(s)
+
I2(s)
(i)
2AlCl3(s)

2Al(s)
+
3Cl2(g)
(j)
2CuO(s)

2Cu(s)
+
O2(g)
4. Write a balanced chemical equation to represent each reaction described below.
(a) Rubidium oxide decomposes into its elements.
2Rb2O (s)  4 Rb (s) + O2 (g)
(b) Calcium chloride decomposes into its elements.
CaCl2  Ca(s) + Cl2 (g)
Balancing Single Replacement Reaction Equations
5. Balance each equation for a single replacement reaction.
(a) 6K(s)
+
2H3PO4(aq)

2K3PO4(aq)
+
3H2(g)
(b)
2Fe(s)
+
3H2S(aq)

Fe2S3(s)
+
3H2(g)
(c)
Cl2(g)
+
MgBr2(aq)

MgCl2(aq)
+
Br2(aq)
(d)
Cu(s)
+
Ag2CO3(s)

CuCO3(s)
+
2Ag(s)
(e)
Br2(g)
+
2KI(aq)

I2(aq)
+
2KBr(aq)
(f)
3Mg(s)
+
Zn3(PO4)2(s)

Mg3(PO4)2(s)
+
3 Zn(s)
(g)
3K(s)
+
Al(NO3)3(aq)

Al(s)
+
3KNO3(aq)
(h)
Ca(s)
+
2H2O(l)

Ca(OH)2(s)
+
H2(g)
(i)
2 Na(s)
+
H2SO4(s)

Na2SO4(aq)
+
H2(g)
(j)
2K(s)
+
2 H2O(l)

2 KOH(aq)
+
H2(g)
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.
DATE:
NAME:
CLASS:
BLM 3-6
Balancing Equations (continued)
SKILL BUILDER
6. Write a balanced chemical equation to represent each reaction described below.
(a) Silver reacts with gold(III) nitrate.
3 Ag (s) + Au(NO3)3 (aq)  3 Ag(NO3) + Au (s)
(b) Copper reacts with lead(II) sulfate.
Cu (s) + Pb(SO4) (aq)  Cu(SO4) (aq) + Pb (s)
Balancing Double Replacement Reaction Equations
7. Balance each equation for a double replacement reaction.
(a) Na2SO4(aq)
+
BaCl2(aq)

BaSO4(s)
+
2NaCl(aq)
(b)
2HNO3(aq)
+
Ba(OH)2(aq)

2 H2O(l)
+
Ba(NO3)2(aq)
(c)
3Na2CO3(aq)
+
2 Fe(NO3)3(aq)

Fe2(CO3)3(s)
+
6 NaNO3(aq)
(d)
3 CaCl2(aq)
+
2 K3PO4(aq)

Ca3(PO4)2(s)
+
6 KCl(aq)
(e)
Al2(SO4)3(aq)
+
3Ba(OH)2(aq)

2Al(OH)3(s)
+
3 BaSO4(s)
(f)
2NaOH(aq)
+
H2SO4(aq)

2H2O(l)
+
Na2SO4(aq)
(g)
2Na3PO4(aq)
+
3 Ag2SO4 (s)

3Na2SO4(aq)
+
2 Ag3PO4(s)
(h)
Na2CrO4(aq)
+
Cu(NO3)2(aq)

2NaNO3(aq)
+
CuCrO4(aq)
(i)
H3PO4(aq)
+
3 KOH(aq)

3H2O(l)
+
K3PO4(aq)
(j)
Na2CO3(aq)
+
2 HNO3(aq)

H2CO3(aq)
+
2NaNO3(aq)
8. Write a balanced chemical equation to represent each reaction described below.
(a) Solutions of sodium hydroxide and hydrochloric acid react.
NaOH (aq) + HCl (aq)  NaCl (s) + H2O (l)
(b) A silver nitrate solution reacts with a sodium chloride solution.
Ag(NO3) (aq) + NaCl (s)  AgCl + Na(NO3) (aq)
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.
DATE:
NAME:
CLASS:
BLM 3-6
Balancing Equations (continued)
SKILL BUILDER
Balancing Combustion Reaction Equations
9. Balance each equation for a combustion reaction.
(a) 2C2H6(g)
+
7 O2(g)

4CO2(g)

+
6H2O(g)
3CO2(g)
+
4 H2O(g)
(b) C3H8(g)
+
5 O2(g)
(c) 2C6H14(g)
+
19 O2(g) 
12CO2(g)
+
14 H2O(g)
(d) 2C8H18(g)
+
25 O2(g) 
16 CO2(g)
+
18 H2O(g)
(e) 2C2H2(g)
+
3 O2(g)

2CO2(g)
+
2H2O(g)
(f)
C2H4(g)
+
3 O2(g)

2 CO2(g)
+
2 H2O(g)
(g) 2ZnS(s)
+
3O2(g)

2ZnO(s)
+
2SO2(g)
(h) 4CH3NO2(l) +
11O2(g)

4CO2(g)
+
6H2O(g)
(i)
4NH3(g)
7O2(g)

4NO2(g)
+
6H2O(g)
(j)
2 C2H5SH(g)
+
9 O2(g)
 4 CO2(g) +
+
6 H2O(g)
+
4NO2(g)
+ 2 SO2(g)
10. Write a balanced chemical equation to represent each reaction described below.
(a) Candle wax, C25H52, is burned to produce carbon dioxide and water.
C25H52 (s) + 38 O2 (g)  25 CO2(g) + 26 H2O (g)
(b) Sucrose, C12H22O11, is burned to produce carbon dioxide and water.
C12H22O11 (s) + 12 O2(g)  12 CO2 (g) + 11 H2O (g)
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.
DATE:
NAME:
CLASS:
BLM 3-6
SKILL BUILDER
Balancing Equations (continued)
Classifying and Balancing Equations
11. Classify each reaction as a formation (F), decomposition (D), single replacement (SR), double replacement
(DR), or combustion (C) reaction. Then balance each equation.
Reaction
Classification
3Li(s)
+
AlCl3(aq)

Al (s)
2NH3(g)

N2(g)
+
3H2(g)
D
2K(s)
+
Br2(l)

2KBr(s)
F
C10H22(l)
+
O2(g)

CO2(g)
+
H2O(g)
C
H2CO3(aq)

2H2O(l)
+
(NH4)2CO3(aq)
DR
2NH4OH (aq) +
+
3LiCl(aq)
SR
2H2O(l)

2H2(g)
+
O2(g)
D
2Al(s)
+
3Cl2(g)

2AlCl3(s)
F
2Zn(s)
+
SnF4(aq)

Sn(s)
+
2ZnF2(aq)
SR
Copyright © 2004 McGraw-Hill Ryerson Limited. Permission to edit and reproduce this page is granted to the purchaser for use in her/his classroom. McGraw-Hill Ryerson shall not
be held responsible for content if any revisions, additions, or deletions are made to this page.