Chemical Equilibrium

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Chemical Equilibrium

• Chapter 14

• Outline
• Reversibility of Reactions
• Homogeneous Equilibrium
• Le Châteliers Principle
• Equilibrium Constants
• Heterogeneous Equilibrium
• Catalyst

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What is dynamic equilibrium?
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What happens to the reactions rates at
equilibrium?
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CO (g) H2O (g) ? H2 (g) CO2 (g)
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N2 (g) 3 H2 (g) ? 2 NH3 (g)
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What effect do concentration changes have on
equilibrium?
When NO2 is added, some of it combines to make
more N2O4
Tro Chemistry A Molecular Approach, 2/e
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What effect do concentration changes have on
equilibrium?
When N2O4 is added, some of it decomposes to make
more NO2
Tro Chemistry A Molecular Approach, 2/e
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How can we tell where a reaction lies?
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Initial and Equilibrium Concentrations forH2 (g)
I2 (g) ? 2HI (g) _at_ 445 C
Con Initial centra tion Eq Con uilibri centr um ation Equilibrium Constant
H2 I2 HI H2 I2 HI
0.50 0.50 0.0 0.11 0.11 0.78
0.0 0.0 0.50 0.055 0.055 0.39
0.50 0.50 0.50 0.165 0.165 1.17
1.0 0.5 0.0 0.53 0.033 0.934
Tro Chemistry A Molecular Approach, 2/e
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How does temperature affect Kc for exothermic
reactions?
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How does a catalyst change the equilibrium
constant?
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Chapter 14 Examples Le Châteliers Principle

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Chapter 14 Examples Le Châteliers Principle

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How are Q and K related?
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Q, K, and the Direction of Reaction
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Chapter 14 Examples Equilibrium

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Chapter 14 Examples Equilibrium

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Chapter 14 Examples Equilibrium

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Chapter 14 Examples Equilibrium

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Chapter 14 Examples Equilibrium

• If S2 has an initial concentration of 2.00 M and
  there is 150. g of carbon, how many grams of
  carbon disulfide will there be in a 5.00 L flask
  at equilibrium? Given
• S2 (g) C (s) ? CS2 (g) Kc 9.40 at 900 C

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Chapter 14 Examples Equilibrium

• Calculate the equilibrium concentrations of
  iodine chloride, iodine, and chlorine gases, when
  0.88 mol I2, and 0.88 mol Cl2 are added to a 1.5
  L reaction flask. The concentration equilibrium
  constant for the reaction is 0.11.
• 2 ICl (g) ? I2 (g) Cl2 (g)

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Chapter 14 Examples Equilibrium

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Chapter 14 Examples Equilibrium

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Chapter 14 Examples Equilibrium

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Chapter 14 Examples Equilibrium

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What are some special types of equilibrium
constants?

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Chapter 14 Examples Successive Approximation

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Chapter 14 Examples Successive Approximation

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Chapter 14 Examples Successive Approximation

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Chapter 14 Examples Successive Approximation

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Chapter 14 Examples Successive Approximation

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