Unit 3A Basic Chemical Reactions

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Unit 3A Basic Chemical Reactions

• Chapter 6 and 7

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• 6.1 What are the types of evidence that a
  chemical reaction has taken place?

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6.2 Chemical Equations

• Chemical equations are important
• Reactant vs. Product
• Physical States
• Solid
• Liquid
• Gas
• Aqueous
• Practice Writing Equations Problems

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6.3 Balancing Chemical Reactions

• Law of Conservation of Mass
• Identities of compounds must never
  ________________
• .
• Use of Coefficients
• See How to Write and Balance Equations on pg.
  153

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7.1 Predicting Reactions

• Most Common Driving Forces
• .
• .
• .
• .

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7.7 Classification of Reactions

• Synthesis
• Decomposition
• Single Displacement Reactions
• Double Displacement Reactions (A/B, Precip.,
  others)
• Aqueous Reactions
• Precipitation Reactions double displacement
  that produces a solid
• Acid/Base Reactions - double displacement that
  produces water
• REDOX Reactions synthesis and single
  displacement reactions that transfer electrons
• Combustion

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Single Displacement Reactions

• A BC ? AC B
• Predict products using the activity series

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Combustion Reactions

• Hydrocarbon O2 (g) ? CO2(g) H2O (g)

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Synthesis Reactions

• A B ? AB

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Decomposition Reactions

• AB ? A B

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7.2 Reactions in Which a Solid Forms

• Precipitation reactions are ___________.
• Strong electrolytes
• Precipitates
• Predicting Precipitates (see rules on pg. 172)

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Solubility and Conductivity
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Solubility Rules
Soluble Compounds Important Exceptions
Family 1A (Alkali Metals) None
NH4 None
NO3- None
C2H3O2- None
ClO3- None
Cl-, Br-, I- Ag, Hg22, Pb2
SO42- Ca2, Sr2, Ba2, Hg22, Pb2
Insoluble Compounds Important Exceptions
S2-, O2- NH4, Alkali Metals, Ca2, Sr2, Ba2
CO32- NH4, Alkali Metals
PO43- NH4, Alkali Metals
SO32- NH4, Alkali Metals
OH- NH4, Alkali Metals, Ca2, Sr2, Ba2
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Predicting Precipitates

• Write the reactants.
• Determine which ions will form new compounds.
• We call this double displacement.
• Use solubility rules to identify which product
  forms a precipitates.

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7.3 Describing Reactions in Aqueous Solutions

• Molecular Equations
• Ionic Equations
• Spectator Ions
• Net Ionic Equations

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7.4 Reactions that Form Water

• Acid and Base Reactions
• Double Displacement Reaction
• Neutralization
• HA BOH ? HOH AB
• We will discuss these in more at the end of the
  semester.

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Classification Summary
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7.5 Reactions that Transfer Electrons (Honors)

• Oxidation-Reduction Reactions (REDOX)
• Synthesis reactions of Metals with Non-metals.
• Electrons are transferred from the metal to the
  non-metals.
• Na (s) Cl2 (g) ? NaCl (s)
• ?

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18.1 Oxidation Reduction Reactions (Honors)

• Oxidation is
• Reduction is
• You must be able to identify an
  oxidation-reduction reaction.
• Examples
• Practice p. 576 s 3-6

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18.2 Oxidation States (Honors)

• Allows us to keep track of electrons in
  oxidation-reduction reactions.
• Assigns charges to various atoms in a compound.
• In a binary ionic compound (Type I)
• In an uncombined element
• In a covalent compound
• See rules on p. 556

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• Practice p. 557 Self Check 18.2
• p. 577 s 13-22

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18.3 Oxidation-Reduction Reactions between
Nonmetals (Honors)

• Objectives To understand oxidation and reduction
  in terms of oxidation states.
• To learn to identify oxidizing and reducing
  agents.
• Remember LEO the lion says GER

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• Practice Find which species has been oxidized
  and reduced in the following reaction
• N2 (g) 3H2(g) ? 2NH3(g)
• Oxidizing Agent
• Reducing Agent
• Practice p. 577-578 s 29-36

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In the reaction 2Al(s) 3I2(s) ? 2AlI3(s), which
element is the reducing agent, and which one is
the oxidizing agent?
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18.4 Balancing Oxidation-Reduction Reactions by
the Half-Reaction Method (Honors)

• Why cant we use the old way?
• Half-reactions
• Reduction Half-reaction (example)
• Oxidation Half-reaction (example)
• Balancing Half Reactions
• Practice p. 578 s 41-42

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18.5 Electrochemistry An Introduction (Honors)

• Electrochemistry-
• Two Types of
• Processes
• 1.
• 2.

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In the same vessel no work is done, but if we
separate the two half-reactions we can accomplish
work.
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What happens after the reaction proceeds?
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Salt Bridge
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Galvanic Cell (Electrochemical Battery) Parts
(Honors)

• Salt Bridge
• Oxidation Chamber
• Reduction Chamber

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Real Life Examples of REDOX (Honors)

• Fuel Cell
• 2H2(g) O2(g) ? 2H2O(l)
• We can make the reverse reaction occur by
  applying an electrical current to the REDOX
  reaction. This is called ELECTROLYSIS.

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18.6 Batteries (Honors)

• Figure 18.6 In a lead storage battery each cell
  consists of several lead grids that are connected
  by a metal bar. Lead is oxidized and functions as
  the anode. The PbO2 accepts electrons, so it
  functions as the cathode.

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18.8 Electrolysis (Honors)

• Definition
• Electrolysis of Water
• Electrolysis of Aluminum