Types of Reactions You need to be able to identify each type. Synthesis reactions Decomposition reactions Single displacement reactions Double displacement reactions Combustion reactions You need to be able to identify each type.

1. Synthesis Example C + O2 O C +  O C General: A + B  AB

Combination (Synthesis) Two or more elements or simple compounds combine to form (synthesize) one product A + B AB 2Mg + O2 2MgO 2Na + Cl2 2NaCl SO3 + H2O H2SO4 LecturePLUS Timberlake 99

Ex. Synthesis Reaction

Practice Predict the products. Na(s) + Cl2(g)  Mg(s) + F2(g)  Al(s) + F2(g)  2 2 NaCl(s) MgF2(s) 2 3 2 AlF3(s) Now, balance them.

2. Decomposition Example: NaCl  Cl Na Cl + Na General: AB  A + B

Ex. Decomposition Reaction

LecturePLUS Timberlake 99 Decomposition One substance is broken down (split) into two or more simpler substances. AB A + B 2HgO 2Hg + O2 2KClO3 2KCl + 3 O2 LecturePLUS Timberlake 99

LecturePLUS Timberlake 99 Learning Check R1 Classify the following reactions as 1) combination or 2) decomposition: ___A. H2 + Br2 2HBr ___B. Al2(CO3)3 Al2O3 + 3CO2 ___C. 4 Al + 3C Al4C3 LecturePLUS Timberlake 99

LecturePLUS Timberlake 99 Solution R1 Classify the following reactions as 1) combination or 2) decomposition: _1_A. H2 + Br2 2HBr _2_B. Al2(CO3)3 Al2O3 + 3CO2 _1_C. 4 Al + 3C Al4C3 LecturePLUS Timberlake 99

Went from neutral (0) to (+2) Went from (+2) to Neutral (0) 3. Single Displacement Example: Zn + CuCl2 Zn was oxidized Went from neutral (0) to (+2)  Zn Cl Cu + Cl Zn Cu + Cu was reduced Went from (+2) to Neutral (0) General: AB + C  AC + B

LecturePLUS Timberlake 99 Single Replacement One element takes the place of an element in a reacting compound. A + BC AB + C Zn + 2HCl ZnCl2 + H2 Fe + CuSO4 FeSO4 + Cu LecturePLUS Timberlake 99

Ex. Single Replacement Reaction

Single Replacement Reactions Write and balance the following single replacement reaction equation: Zn(s) + HCl(aq)  ZnCl2 + H2(g) 2 NaCl(s) + F2(g)  NaF(s) + Cl2(g) Al(s)+ Cu(NO3)2(aq) 2 2 2 3 3 Cu(s)+ Al(NO3)3(aq) 2

4. Double displacement General: AB + CD  AD + CB Example: MgO + CaS 

LecturePLUS Timberlake 99 Double Replacement Two elements in reactants take the place of each other AB + CD AD + CB AgNO3 + NaCl AgCl + NaNO3 ZnS + 2HCl ZnCl2 + H2S LecturePLUS Timberlake 99

Double Replacement Reactions Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together Example: AgNO3(aq) + NaCl(s)  AgCl(s) + NaNO3(aq) Another example: K2SO4(aq) + Ba(NO3)2(aq)  KNO3(aq) + BaSO4(s) 2

LecturePLUS Timberlake 99 Learning Check R2 Classify the following reactions as 1) single replacement 2) double replacement __A. 2Al + 3H2SO4 Al2(SO4)3 + 3H2 __B. Na2SO4 + 2AgNO3 Ag2SO4 + 2NaNO3 __C. 3C + Fe2O3 2Fe + 3CO LecturePLUS Timberlake 99

LecturePLUS Timberlake 99 Solution R2 Classify the following reactions as 1) single replacement 2) double replacement 1_A. 2Al + 3H2SO4 Al2(SO4)3 + 3H2 2_B. Na2SO4 + 2AgNO3 Ag2SO4 + 2NaNO3 1_C. 3C + Fe2O3 2Fe + 3CO LecturePLUS Timberlake 99

Practice Predict the products. HCl(aq) + AgNO3(aq)  CaCl2(aq) + Na3PO4(aq)  Pb(NO3)2(aq) + BaCl2(aq)  FeCl3(aq) + NaOH(aq)  H2SO4(aq) + NaOH(aq)  KOH(aq) + CuSO4(aq) 

5. Combustion Reactions Combustion reactions - a hydrocarbon reacts with oxygen gas. This is also called burning!!! In order to burn something you need the 3 things in the “fire triangle”: 1) Fuel (hydrocarbon) 2) Oxygen 3) Something to ignite the reaction (spark)

Combustion Reactions In general: CxHy + O2  CO2 + H2O Products are ALWAYS carbon dioxide and water. (although incomplete burning does cause some by-products like carbon monoxide) Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C8H18)

LecturePLUS Timberlake 99 Combustion A reaction in which a compound (often carbon) reacts with oxygen C + O2 CO2 CH4 + 2O2 CO2 + 2H2O C3H8 + 5O2 3CO2 + 4H2O C6H12O6 + 6O2 6CO2 + 6H2O LecturePLUS Timberlake 99

Combustion Example C5H12 + O2  CO2 + H2O Write the products and balance the following combustion reaction: C10H22 + O2  8 5 6

LecturePLUS Timberlake 99 Learning Check R3 Balance the combustion equation ___C5H12 + ___O2 ___CO2 + ___H2O LecturePLUS Timberlake 99

LecturePLUS Timberlake 99 Solution R3 Balance the combustion equation 1 C5H12 + 8 O2 5 CO2 + 6 H2O LecturePLUS Timberlake 99