Classifying Chemical Reactions Section 10.2

Objectives Classify chemical reactions Identify the characteristics of different classes of chemical reactions

Key Terms Synthesis reaction Combustion reaction Decomposition reaction Single-replacement reaction Double-replacement reaction precipitate

5 Types of Reactions Synthesis Combustion Decomposition Single-Replacement Double-Replacement

Synthesis Reaction Two or more substances combine to form one single product. A + B  AB Ex: 2Na(s) + Cl2(g)  2NaCl(s)

Combustion Reaction Oxygen combined with a substance releasing energy (light and heat) Many combustion reactions are also synthesis reactions Ex: 2H2(g) + O2  2H2O(g)

Decomposition reactions One compound breaks down into 2 or more compounds or elements Often requires energy Setup: AB A + B Ex: NH4NO3(s)  N2O(g) + 2H2O(g) Heat was required

Replacement Reactions Replacement of an element in a a compound 2 kinds of replacement reactions: Single Double

Single Replacement Reactions Atoms of one element replace the atoms of another element in a compound Setup: A+ BX  AX + B

Activity Series of Metals Whether or not a metal will replace another metal or any other substance depends on its reactivity Figure 10-10 on page 288 Metals can replace any metal BELOW it on the series. Not ABOVE it (NR)

Practice Problems Page 289

Double Replacement Reactions Involves the exchange of ions between 2 compounds Setup: AX + BY  AY + BX If a solid is produced during the reaction it is called a precipitate

Practice Problems Page 291

Homework Page 291 #27-32