rate of reaction

• What is the rate of a reaction?

  Measure of reactant usage or product formation
• What must happen for a chemical reaction to occur according to collision theory?

  Reactant particles must collide with enough energy
• What is a successful collision?

  A collision that produces a reaction
• What is activation energy?

  Minimum energy needed for a successful collision
• What happens during a collision between reactant particles?

  • Particles move towards each other
  • They collide and reform into new pairs
  • New pairs move away from each other
• How can the rate of a reaction be determined?

  By measuring changes in reactants or products
• What is the unit for measuring the rate of reaction when measuring mass?

  g/s or g/min
• When is measuring mass useful in a reaction?

  When carbon dioxide is a product leaving container
• What is the unit for measuring the rate of reaction when measuring volume?

  cm$^3$ s$^{-1}$ or cm$^3$ min$^{-1}$
• How can the rate of reaction be analyzed graphically?

  • Plot mass or volume of product against time
  • Steeper line indicates a greater rate of reaction
  • Faster reactions finish sooner than slower reactions
• What does the gradient of a reaction graph represent?

  The rate of reaction
• How does increasing concentration or pressure affect the rate of reaction?

  Increases frequency of successful collisions
• What happens to reactant particles when concentration or pressure increases?

  They become more crowded
• What is the relationship between surface area to volume ratio and reaction rate?

  • Larger surface area increases reaction rate
  • More reactant particles are exposed
  • More frequent collisions occur
• What happens when a large lump of solid is divided into smaller pieces?

  Surface area to volume ratio increases
• How does temperature affect the rate of reaction?

  Higher temperature increases particle movement and collisions
• What is a catalyst?

  A substance that increases reaction rate
• What is the role of a catalyst in a reaction?

  Provides an alternative pathway with lower activation energy
• What are enzymes?

  Catalysts in biological reactions
• How do catalysts affect activation energy?

  • Lower activation energy compared to uncatalyzed reaction
  • Increase frequency of successful collisions
  • Do not change collision frequency
• What does a reaction profile show?

  • Changes in energy of reactants and products
  • Activation energy of the reaction
  • Pathway of the reaction