Unit 4: Reaction Rates

• How can I make a reaction happen?

1. Whether or not a reaction occurs depends on several factors that we can manipulate to control our environment.

IB Objectives: SL      Option (A.2, A.3)     HL

• Define the term rate of reaction and describe measurement of rate of reaction as the increase or decrease in concentration of reactants or product per unit time
• Describe the steps involved in a chemical reaction: reaction mechanism and define rate determining step
• Define activation energy and activated complex
• State that catalysts are used to lower the activation energy of a reaction
• Use Collision Theory to describe how temperature, concentration, surface area, degree of randomness and catalysts affect the rate of reaction
  • Increasing temperature increases proportion of molecules with E >= Ea
• Define the terms rate constant and order of reactions
• Derive the rate expression for a reaction from data
  • Rate = k[A]^m[B]ⁿ
  • where k = rate constant, [A]= concentration of A in mole dm^-3 etc,
  • m and n are integers m+n = overall order of the reaction
• Draw and analyie grahical representations for zero, first and second-order reactions
• Define the term half-life and calculate half-life for first-order reactions (using graphs and from equation)
• Define the terms rate-determing step, molecularity and activated complex
• Describe the relationship between mechanism, order, rate-determining step and activated comples

• Kinetics Intro & Collision Theory
• Rate laws
• Reaction Mechansim
• Activation Energy

• Kinetics Intro
• Calculating Rate Law
• Reaction Mechanisms (you will not do this for mechanisms that involve intermediates)
• Review Questions w/Answers
• Catalysts Web Research

• Iodine Clock Lab
• Factors that Affect Reaction Rates
• Sulfur clock rate law determination lab
• HL: Activation Energy (Vernier)
• HL: Investigate factors that affect enzyme activity
• HL: Enzyme reaction rate determination