1 Chapter 5 Chemical Reactions and Quantities 5.3 Types of Reactions Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

2 Type of Reactions Chemical reactions can be classified as combination reactions. decomposition reactions. single replacement reactions. double replacement reactions.

3 Combination In a combination reaction, two or more elements form one product. or simple compounds combine to form one product. + 2Mg(s) + O 2 (g) 2MgO(s) 2Na(s) + Cl 2 (g)2NaCl(s) SO 3 (g) + H 2 O(l)H 2 SO 4 (aq) AB AB

4 Formation of MgO

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

6 Decomposition of HgO

7 Learning Check Classify the following reactions as 1) combination or 2) decomposition. ___A. H 2 (g) + Br 2 (g) 2HBr(l) ___B. Al 2 (CO 3 ) 3 (s) Al 2 O 3 (s) + 3CO 2 (g) ___C. 4Al(s) + 3C(s) Al 4 C 3 (s)

8 Solution Classify the following reactions as 1) combination or 2) decomposition: 1 A. H 2 (g) + Br 2 (g) 2HBr(l) 2 B. Al 2 (CO 3 ) 3 (s) Al 2 O 3 (s) + 3CO 2 (g) 1 C. 4Al(s) + 3C(s) Al 4 C 3 (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) ZnCl 2 (aq) + H 2 (g) Fe(s) + CuSO 4 (aq)FeSO 4 (aq) + Cu(s)

10 Zn and HCl is a Single Replacement Reaction

11 Double Replacement In a double replacement, two elements in the reactants exchange places. AgNO 3 (aq) + NaCl(aq)AgCl(s) + NaNO 3 (aq) ZnS(s) + 2HCl(aq)ZnCl 2 (aq) + H 2 S(g)

12 Example of a Double Replacement

13 Learning Check Classify the following reactions as 1) single replacement 2) double replacement. __A. 2Al(s) + 3H 2 SO 4 (aq) Al 2 (SO 4 ) 3 (s) + 3H 2 (g) __B. Na 2 SO 4 (aq) + 2AgNO 3 (aq) Ag 2 SO 4 (s) + 2NaNO 3 (aq) __C. 3C(s) + Fe 2 O 3 (s) 2Fe(s) + 3CO(g)

14 Solution Classify the following reactions as 1) single replacement 2) double replacement 1 A. 2Al(s) + 3H 2 SO 4 (aq) Al 2 (SO 4 ) 3 (s) + 3H 2 (g) 2 B. Na 2 SO 4 (aq) + 2AgNO 3 (aq) Ag 2 SO 4 (s) + 2NaNO 3 (aq) 1 C. 3C(s) + Fe 2 O 3 (s) 2Fe(s) + 3CO(g)

15 Learning Check Identify each reaction as 1) combination 2) decomposition 3) single replacement4) double replacement A. 3Ba(s) + N 2 (g) Ba 3 N 2 (s) B. 2Ag(s) + H 2 S(aq)Ag 2 S(s) + H 2 (g) C. SiO 2 (s) + 4HF(aq) SiF 4 (s) + 2H 2 O(l) D. PbCl 2 (aq) + K 2 SO 4 (aq) 2KCl(aq) + PbSO 4 (s) E. K 2 CO 3 (s) K 2 O(aq) + CO 2 (g)

16 Solution 1 A. 3Ba(s) + N 2 (g) Ba 3 N 2 (s) 3 B. 2Ag(s) + H 2 S(aq) Ag 2 S(s) + H 2 (g) 4 C. SiO 2 (s) + 4HF(aq) SiF 4 (s) + 2H 2 O(l) 4 D. PbCl 2 (aq) + K 2 SO 4 (aq) 2KCl(aq) +PbSO 4 (s) 2 E. K 2 CO 3 (s) K 2 O(aq) + CO 2 (g)