1. Chemical Reactions and Quantities
Types of Reactions Oxidation-Reduction Reactions

2. Type of Reactions
Chemical reactions are classified into four general types
Combination
Decomposition
Single Replacement
Double Replacement

3. 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

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

5. 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

6. 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

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

8. Learning Check R2 Classify the following reactions as
1) single replacement
2) double replacement
__A. 2Al + 3H2SO Al2(SO4) H2
__B. Na2SO4 + 2AgNO Ag2SO4 + 2NaNO3
__C. 3C + Fe2O Fe CO

9. 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

10. Learning Check R3 Balance the combustion equation
___C5H ___O ___CO2 + ___H2O

11. Oxidation and Reduction
Reactions that involve a loss or gain of electrons
Occurs in many of the 4 types of reactions and combustion
Important in food metabolism, batteries,
rusting of metals

12. Requirements for Oxidization-Reduction
Electrons are transferred
Two processes occur
Oxidation = Loss of electrons (LEO)
Zn Zn2+ + 2e-
Reduction = Gain of electrons (GER)
Cu e Cu

13. Balanced Red-Ox Equations
Combine the oxidation and reduction reactions to make Loss of electrons = Gain of electrons Zn + Cu2+ + 2e- Zn2+ + 2e- + Cu Zn + Cu2+ Zn2+ + Cu

14. Learning Check R3
Identify the following as an 1) oxidation or a reduction process: __A. Sn Sn4+ + 4e- __B. Fe3+ + 1e- Fe2+ __C. Cl2 + 2e- 2Cl-