3.2.2 Reaction Rates

• What does the rate of reaction refer to?

  The change in concentration or amount of a reactant or product per unit time.
• How is the rate of reaction measured?

  By using the formula: amount of reactant used or product made divided by time.
• What must happen for a reaction to occur according to collision theory?

  Particles must collide in the right direction and have the minimum amount of kinetic energy.
• What is activation energy?

  The minimum amount of energy required for a reaction to occur.
• What does an energy profile diagram show?

  Changes in energy during a reaction, including reactants and products.
• How does the shape of the energy profile relate to activation energy?

  The activation energy is represented by the peak of the profile between reactants and products.
• What does the Maxwell-Boltzmann distribution illustrate?

  The energy distribution of gas particles in a sample.
• What does the area under the Maxwell-Boltzmann distribution curve represent?

  The total number of molecules in the sample.
• What is the difference between the most likely energy and the mean energy of particles?

  The most likely energy is the peak of the distribution, while the mean energy is the average energy of all particles.
• How does temperature affect the rate of reaction?

  Higher temperatures increase the average kinetic energy of particles, leading to more frequent and energetic collisions.
• What happens to the Maxwell-Boltzmann distribution curve when temperature is increased?

  The curve shifts to the right, the peak lowers, and the area beyond the activation energy increases.
• Why does increasing pressure affect the rate of reaction?

  Increasing pressure brings particles closer together, leading to more frequent collisions.
• How does increasing concentration affect the rate of reaction?

  Higher concentration increases the likelihood of collisions between particles.
• What is a catalyst?


  A substance that increases the rate of reaction without being consumed in the process.
• How does a catalyst lower activation energy?

  By providing an alternative pathway for the reaction.
• What is a heterogeneous catalyst?


  A catalyst that is in a different phase from the reactants.
• What is the role of zeolite as a catalyst?

  Zeolite increases the surface area for reactions to occur due to its microscopic pores.
• What factors affect the rate of reaction?

  • Temperature
  • Pressure
  • Concentration
  • Presence of catalysts
• What are the types of catalysts and their characteristics?

  • Homogeneous catalysts: Same phase as reactants.
  • Heterogeneous catalysts: Different phase from reactants.
• What are the tiny microscopic pores in catalysts called?

  Micropores
• How do micropores affect the surface area of a catalyst?

  They increase the surface area, allowing reactions to happen more quickly.
• What is a zeolite?

  A type of catalyst with a large surface area due to micropores.
• What are the two types of catalysts?

  • Homogeneous catalysts: same phase as reactants, often in aqueous solutions.
  • Heterogeneous catalysts: different phase from reactants, often solid in gas reactions.
• What does "heterogeneous" mean in the context of catalysts?

  It means the catalyst is in a different phase from the reactants.
• What is the Haber process used for?

  Manufacturing ammonia from nitrogen gas and hydrogen gas.
• What type of catalyst is used in the Haber process?


  An iron catalyst.
• How does increasing the surface area of a solid catalyst affect the rate of reaction?

  It increases the rate of reaction by allowing more particles to react simultaneously.
• What is an example of a homogeneous catalyst?

  Sulfuric acid.
• How do homogeneous catalysts differ from heterogeneous catalysts in terms of their involvement in reactions?

  Homogeneous catalysts are used up and then reformed, while heterogeneous catalysts are not used up.
• What is the effect of a catalyst on the activation energy of a reaction?

  A catalyst lowers the activation energy.
• How does a catalyst affect the Boltzmann distribution of particles?

  • A catalyst lowers the activation energy.
  • More particles have enough energy to react.
  • The area beyond the activation energy increases.
• What does an energy profile diagram show when a catalyst is used?

  • Reactants and products are shown.
  • The activation energy is lower with a catalyst.
  • The energy profile is shorter with a catalyst.
• Why are catalysts used in industry?

  They lower temperature requirements, speed up reactions, and change product properties.
• What is the role of Ziegler catalysts?


  They convert polymers into more dense, rigid, and higher melting point plastics.
• How do catalysts contribute to environmental benefits?

  They reduce energy requirements and waste production, leading to lower CO2 emissions.
• What is the function of catalytic converters in cars?

  They reduce pollution from exhaust gases.
• What metals are commonly used in catalytic converters?

  Rhodium and platinum.
• What harmful gases do catalytic converters help convert into less harmful substances?

  Carbon monoxide and nitrogen monoxide.
• What methods can be used to measure the rate of a reaction?

  1. Timing the formation of a precipitate.
  2. Measuring mass loss of gas produced.
  3. Measuring the volume of gas produced over time.
• What is the "disappearing cross" method used for?

  To time how long it takes for a precipitate to form.