1. Chapter 7 Chemical Reactions
7.4
Types of Reactions
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2. Type of Reactions Chemical reactions can be classified as
Combination reactions.
Decomposition reactions.
Single Replacement reactions.
Double Replacement reactions.
Combustion reactions.

3. Combination In a combination reaction,
Two or more elements form one product.
Or simple compounds combine to form one product. +
2Mg(s) + O2(g) 2MgO(s)
2Na(s) + Cl2(g) 2NaCl(s)
SO3(g) + H2O(l) H2SO4(aq) A B A B

4. Formation of MgO
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5. Decomposition In a decomposition reaction,
One substance splits into two or more simpler substances.
2HgO(s) Hg(l) + O2(g)
2KClO3(s) KCl(s) + 3O2(g)
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6. Decomposition of HgO Copyright © 2008 by Pearson Education, Inc.
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7. Learning Check Classify the following reactions as
1) combination or 2) decomposition:
___A. H2(g) + Br2(g) HBr(l)
___B. Al2(CO3)3(s) Al2O3(s) + 3CO2(g)
___C. 4Al(s) + 3C(s) Al4C3(s)

8. Solution Classify the following reactions as
1) combination or 2) decomposition:
1 A. H2(g) + Br2(g) HBr(l)
2 B. Al2(CO3)3(s) Al2O3(s) + 3CO2(g)
1 C. 4Al(s) + 3C(s) Al4C3(s)

9. Single Replacement In a single replacement reaction,
One element takes the place of a different element in a reacting compound.
Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)
Fe(s) + CuSO4(aq) FeSO4(aq) + Cu(s)
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10. Zn and HCl is a Single Replacement Reaction
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11. Double Replacement In a double replacement reaction,
Two elements in the reactants exchange places.
AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)
ZnS(s) HCl(aq) ZnCl2(aq) + H2S(g)
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12. Example of a Double Replacement
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13. Learning Check Classify the following reactions as
1) single replacement 2) double replacement
__A. 2Al(s) + 3H2SO4(aq) Al2(SO4)3(s) + 3H2(g)
__B. Na2SO4(aq) + 2AgNO3(aq) Ag2SO4(s) + 2NaNO3(aq)
__C. 3C(s) + Fe2O3(s) Fe(s) CO(g)

14. Solution Classify the following reactions as
1) single replacement 2) double replacement
1 A. 2Al(s) + 3H2SO4(aq) Al2(SO4)3(s) + 3H2(g)
2 B. Na2SO4(aq) + 2AgNO3(aq) Ag2SO4(s) + 2NaNO3(aq)
1 C. 3C(s) + Fe2O3(s) Fe(s) CO(g)

15. Combustion In a combustion reaction,
A compound such as carbon reacts with oxygen, O2.
C(s) + O2(g) CO2(g)
CH4(g) + 2O2(g) CO2 (g) + 2H2O(g)
C3H8(g) + 5O2(g) CO2(g) + 4H2O(g)
Fuels burned in oxygen produce CO2, H2O, and energy.

16. Example of a Combustion Reaction
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17. Learning Check Balance the combustion equation
___C5H ___O ___CO2 + ___H2O

18. Solution
Balance the combustion equation
1 C5H O CO H2O

19. Summary of Reaction Types
Table 7.4
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20. Learning Check Identify each reaction as: 1) combination
2) decomposition 3) combustion
4) single replacement 5) double replacement
A. 3Ba(s) + N2(g) Ba3N2(s)
B. 2Ag(s) + H2S(aq) Ag2S(s) + H2(g)
C. SiO2(s) + 4HF(aq) SiF4(s) + 2H2O(l)
D. PbCl2(aq) + K2SO4(aq) KCl(aq) + PbSO4(s)
E. K2CO3(s) K2O(aq) + CO2(g)
F. C2H4(g) + 3O2(g) CO2(g) + 2H2O(g)

21. Solution Identify each reaction as: 1) combination
2) decomposition 3) combustion
4) single replacement 5) double replacement
1 A. 3Ba(s) + N2(g) Ba3N2(s)
4 B. 2Ag(s) + H2S(aq) Ag2S(s) + H2(g)
5 C. SiO2(s) + 4HF(aq) SiF4(s) + 2H2O(l)
5 D. PbCl2(aq) + K2SO4(aq) KCl(aq) + PbSO4(s)
2 E. K2CO3(s) K2O(aq) + CO2(g)
3 F. C2H4(g) + 3O2(g) CO2(g) + 2H2O(g)