Chapter 7 Chemical Reactions 7.4 Types of Reactions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Type of Reactions Chemical reactions can be classified as Combination reactions. Decomposition reactions. Single Replacement reactions. Double Replacement reactions. Combustion reactions.

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

Formation of MgO Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Decomposition In a decomposition reaction, One substance splits into two or more simpler substances. 2HgO(s) 2Hg(l) + O2(g) 2KClO3(s) 2KCl(s) + 3O2(g) Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Decomposition of HgO Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Learning Check Classify the following reactions as 1) combination or 2) decomposition: ___A. H2(g) + Br2(g) 2HBr(l) ___B. Al2(CO3)3(s) Al2O3(s) + 3CO2(g) ___C. 4Al(s) + 3C(s) Al4C3(s)

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

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) Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Zn and HCl is a Single Replacement Reaction Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Double Replacement In a double replacement reaction, Two elements in the reactants exchange places. AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq) ZnS(s) + 2HCl(aq) ZnCl2(aq) + H2S(g) Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Example of a Double Replacement Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

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) 2Fe(s) + 3CO(g)

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) 2Fe(s) + 3CO(g)

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) 3CO2(g) + 4H2O(g) Fuels burned in oxygen produce CO2, H2O, and energy.

Example of a Combustion Reaction Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Learning Check Balance the combustion equation ___C5H12 + ___O2 ___CO2 + ___H2O

Solution Balance the combustion equation 1 C5H12 + 8 O2 5 CO2 + 6 H2O

Summary of Reaction Types Table 7.4 Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

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) 2KCl(aq) + PbSO4(s) E. K2CO3(s) K2O(aq) + CO2(g) F. C2H4(g) + 3O2(g) 2CO2(g) + 2H2O(g)

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) 2KCl(aq) + PbSO4(s) 2 E. K2CO3(s) K2O(aq) + CO2(g) 3 F. C2H4(g) + 3O2(g) 2CO2(g) + 2H2O(g)