Chemistry 123

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Chemistry 123

• Week of 14 April 2008

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Rate of reaction

• How will the rate of reaction change under each
  of the following conditions
  Fe (s) 5 CO (g) ? Fe(CO)5 (l)
• The pressure of CO(g) is doubled.
• Pulverized iron is used (rather than one large
  chunk).
• The temperature of the reaction is decreased by
  10C.
• The reaction is carried out in a solvent
  (acetone).
•  

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Rate laws

• A  ?  products
• What is the rate law if the reaction is zero
  order with respect to A?first order with respect
  to A?second order with respect to A?
• Explain how the rate of reaction would be
  affected by doubling the concentration of A for
  each of these caseszero order first order
  second order

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Method of initial rates
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(No Transcript)
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CHCl3 (g) Cl2 (g) ? CCl4 (g) HCl (g)

• Write the rate law for the reaction
• Determine the rate constant, k, for the reaction

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Decomposition of N2O5
0
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Half-lives for 1st order reaction
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Reaction orders and rate laws

• For the reaction A ? products
• Rate decreases as the reaction proceeds. 
• The half-life of the reaction is found to depend
  on the initial concentration of A. 
• What is the order of the reaction?

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Check-in

• True or False
• When the concentration of A doubles, the rate of
  the reaction doubles.
• False       
• Doubling the concentration of A quadruples the
  rate of the reaction

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Reaction orders and rate laws

• True or False
• A plot of 1/A versus time is linear
• True  

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Reaction orders and rate laws

• The half-life of the reaction gets longer as the
  initial concentration of A increases.
• False
• The half-life of the reaction decreases as the
  initial concentration of A increases.
• Or
• The half-life of the reaction increases as the
  initial concentration of A decreases.