LecturePLUS Timberlake 99 Chapter 5 Chemical Reactions and Quantities Types of Reactions Oxidation-Reduction Reactions.

LecturePLUS Timberlake 99

Chapter 5Chemical Reactions and

Quantities

Types of Reactions

Oxidation-Reduction Reactions


Type of Reactions

Chemical reactions are classified into four general types

Combination

Decomposition

Single Replacement

Double Replacement


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


Decomposition

One substance is broken down (split) into two or more simpler substances.

AB A + B

2HgO 2Hg + O2

2KClO3 2KCl + 3 O2


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


Solution R1


1) combination or 2) decomposition:

_1_A. H2 + Br2 2HBr

_2_B. Al2(CO3)3 Al2O3 + 3CO2

_1_C. 4 Al + 3C Al4C3


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


Double Replacement

Two elements in reactants take the place of each other

AB + CD AD + CB

AgNO3 + NaCl AgCl + NaNO3

ZnS + 2HCl ZnCl2 + H2S


Learning Check R2


1) single replacement

2) double replacement

__A. 2Al + 3H2SO4 Al2(SO4)3 + 3H2

__B. Na2SO4 + 2AgNO3 Ag2SO4 + 2NaNO3

__C. 3C + Fe2O3 2Fe + 3CO


Solution R2


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


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


Learning Check R3

Balance the combustion equation

___C5H12 + ___O2 ___CO2 + ___H2O


Solution R3

Balance the combustion equation

1 C5H12 + 8 O2 5 CO2 + 6 H2O


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


Requirements for Oxidization-Reduction

Electrons are transferred

Two processes occur

Oxidation = Loss of electrons (LEO)

Zn Zn2+ + 2e-

Reduction = Gain of electrons (GER)

Cu2+ + 2e- Cu


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


Gain/Loss of Hydrogen

In organic and biological reactions

oxidation = Loss of H

reduction = Gain of H


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-


Solution R3

Identify the following as an 1) oxidation or a reduction process:

1_ A. Sn Sn4+ + 4e-

2_ B. Fe3+ + 1e- Fe2+

2_ C. Cl2 + 2e- 2Cl-


Learning Check R4

In light-sensitive sunglasses, UV light initiates an oxidation-reduction reaction

Ag+ + Cl- Ag + Cl

A. Which reactant is oxidized

1) Ag+ 2) Cl- 3) Ag

B. Which reactant is reduced?

1) Ag+ 2) Cl- 3) Cl


Solution R4

In light-sensitive sunglasses, UV light initiates an oxidation-reduction reaction

Ag+ + Cl- Ag + Cl

A. Which reactant is oxidized

2) Cl- Cl- Cl + e-

B. Which reactant is reduced?

1) Ag+ Ag+ + e- Ag

LecturePLUS Timberlake 99 Chapter 5 Chemical Reactions and Quantities Types of Reactions Oxidation-Reduction Reactions.

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