Chapter 5 Chemical Reactions and Quantities 5.3 Types of Reactions Copyright © 2005 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.

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

Formation of MgO

Decomposition In a decomposition reaction, one substance splits into two or more simpler substances. 2HgO(s) 2Hg(l) + O2(g) 2KClO3(s) 2KCl(s) + 3 O2(g)

Decomposition of HgO

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)

Zn and HCl is a Single Replacement Reaction

Double Replacement In a double replacement, two elements in the reactants exchange places. AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq) ZnS(s) + 2HCl(aq) ZnCl2(aq) + H2S(g)

Example of a Double Replacement

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)

Learning Check Identify each reaction as 1) combination 2) decomposition 3) single replacement 4) 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)

Solution 1 A. 3Ba(s) + N2(g) Ba3N2(s) 3 B. 2Ag(s) + H2S(aq) Ag2S(s) + H2(g) 4 C. SiO2(s) + 4HF(aq) SiF4(s) + 2H2O(l) 4 D. PbCl2(aq) + K2SO4(aq) 2KCl(aq) +PbSO4(s) 2 E. K2CO3(s) K2O(aq) + CO2(g)