Types of Chemical Reactions

Combination Reaction (also called Synthesis) Starts with: –Two or more elements or compounds Ends with: –One compound Example: Mg + O 2  MgO 2Mg + O 2  2MgO

Decomposition Reaction Starts with: –One compound Ends with: –Two or more elements or compounds Example: CuCO 3  CuO + CO 2

Single-Replacement Reaction Starts with: –One element and one compound Ends with: –One element and one compound Example: Mg + HCl  MgCl 2 + H 2 Mg + 2HCl  MgCl 2 + H 2

Double-Replacement Reaction Starts with: –Two compounds Ends with: –Two different compounds Example: KI + Pb(NO 3 ) 2  PbI 2 + KNO 3 2KI + Pb(NO 3 ) 2  PbI 2 + 2KNO 3

Combustion Reaction Starts with: –Oxygen and a compound of C, H (and sometimes O). Ends with: –Almost always CO 2 and H 2 O Example: CH 4 + O 2  CO 2 + H 2 O CH 4 + 2O 2  CO 2 + 2H 2 O

Reaction Relationships Combination –Two people form a couple Decomposition –A couple breaks up Single Replacement –Love Triangle: One person breaks up a couple and forms a new couple. Double Replacement –Two couples break up and form two new couples