Chapter%207%20Chemical%20Reactions%20and%20Quantities

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Chapter 7Chemical Reactions and Quantities

• Types of Reactions
• Oxidation-Reduction Reactions

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Type of Reactions

• Chemical reactions are classified into four
  general types
• Synthesis
• Decomposition
• Single Replacement
• Double Replacement
• Combustion

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Synthesis (Combination)

• 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

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Lab Examples Synthesis

• 1. 2 Cu(s) O2(g) ? 2 CuO (s)

2
2

• 2. __ Mg(s) O2(g) ? __MgO (s)

Before After
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Decomposition

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

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Lab Examples Decomposition
1
1
1

• 3. __CuCO3(s) ? __ CuO(s) ___ (g)

CO2
Before After
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Learning Check R1

• Classify the following reactions as
• 1) syntheses or 2) decomposition
• ___A. H2 Br2 2HBr
• ___B. Al2(CO3)3 Al2O3 3CO2
• ___C. 4 Al 3C Al4C3

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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

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Single Replacement

• One element takes the place of an element in a
  reacting compound.
• A BC AB C
• Mg 2HCl MgCl2 H2
• Fe CuSO4 FeSO4 Cu

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Lab Single Replacement
1
1
ZnCl2
Zn
2
1

• 4. ___(s) __ HCl (aq) ? _______ (aq) __
  H2 (g)

Before During After
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Lab Single Replacement
FeSO4
1
1
Cu

• 5. ____(s) __ CuSO4 (aq) ? _______ (aq)
  ___(s)

Fe
1
1
Before During After
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Double Replacement

• Two elements in reactants take the place of
  each other
• AB CD AD CB
• AgNO3 NaCl AgCl NaNO3
• ZnS 2HCl ZnCl2 H2S

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Lab Double Replacement

• 6. Zn(C2H3O2)2 (aq) ____ (aq) ? NaC2H3O2 (aq)
  Zn3(PO4)2 (s)

2
CO2
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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

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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

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Combustion

• A reaction in which a compound (often carbon)
  reacts with oxygen
• CH4 2O2 CO2 2H2O
• C3H8 5O2 3CO2 4H2O
• C6H12O6 6O2 6CO2 6H2O

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Demo Combustion

• Whoosh in a Bottle
• __ CH3OH (l) __ O2 (g)?

2
4
3
2
__ CO2 (g) __ H2O (l)
2 C 1 4 H 2 3 O 3
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Demo Combustion
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Demo Combustion

• Hexene on Ramp
• __ C6H14(g) __ O2 (g)?

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12
2
14
__ CO2 (g) __ H2O (l)
6 C 1 14 H 2 2 O 3
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Demo Combustion
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Learning Check R3

• Balance the combustion equation
• ___C5H12 ___O2 ___CO2 ___H2O