Name
Date
Pd
Chemistry – Unit 7– Chemical Reactions
Balancing Reaction Equations Worksheet 1
Balance the following equations by inserting the proper coefficients. You must keep track of the total
number of elements on each side of the equation by keeping a tally beneath each reaction. BOX YOUR
COEFFICIENTS when finished. For selected reactions, draw Before and After particle diagrams
(molecules or ions) to show the particles involved in the reaction instead of doing the tally.
1.
____C + ____H2O  ____CO + ____H2
2.
____MgO  ____Mg + ____O2
3.
____Al
#3
+
____O2

____Al2O3
Before
After
4.
____Zn + ____H2SO4  ____ZnSO4 + ____H2
5.
____Cl2 + ____KI  ____KCl + ____I2
6.
____CuCl  ____Cu + ____Cl2
7.
____Na + ____Cl2  ____NaCl
8.
____Al
#8
+
____HCl

____AlCl3
Before
Modeling Chemistry
+
____H2
After
1
U7 WS1 2013
9.
____Fe2O3  ____Fe + ____O2
10.
____P + ____O2  ____P2O5
11.
____Mg + ____HCl  ____MgCl2 + ____H2
12.
____H2 + ____N2  ____NH3
13.
____BaCl2 + ____H2SO4  ____BaSO4 + ____HCl
14.
____CH4
#14
+
____O2

____CO2
Before
+
____H2O
After
15. a) ____ZnCl2 + ____(NH4)2S  ____ZnS + ____ NH4Cl
b) What is the molar mass of each reactant?
c) How many moles of zinc chloride would be in 25 g sample? How much mass would a
0.55 mole sample of ammonium sulfide have?
Modeling Chemistry
2
U7 WS1 2013
Unit 7 – Worksheet 1 – KEY
 You must have an atom tally / show work in some way beneath
each reaction to receive full credit.
1.
1 C + 1 H2O  1 CO + 1 H2
2.
2 MgO  2 Mg + 1 O2
3.
4 Al + 3 O2  2 Al2O3
4.
1 Zn + 1 H2SO4 
5.
1 Cl2 + 2 KI  2 KCl + 1 I2
6.
2 CuCl  2 Cu + 1 Cl2
7.
2 Na + 1 Cl2  2 NaCl
8.
2 Al + 6 HCl
9.
2 Fe2O3  4 Fe + 3 O2

1 ZnSO4 + 1 H2
2 AlCl3 + 3 H2
10. 4 P + 5 O2  2 P2O5
11. 1 Mg + 2 HCl  1 MgCl2 + 1 H2
12. 3 H2 + 1 N2  2 NH3
13. 1 BaCl2 + 1 H2SO4  1 BaSO4 + 2 HCl
14. 1 CH4 + 2 O2 
1 CO2 + 2 H2O
15. 1 ZnCl2 + 1 (NH4)2S  1 ZnS + 2 NH4Cl
b) ZnCl2 : 136.32 g ZnCl2 / mol
(NH4)2S : 68.14 g (NH4)2S / mol
c) 0.18 mol ZnCl2
37 g (NH4)2S
Modeling Chemistry
3
U7 WS1 2013