Chapter 10 REACTION RATES & EQUILIBRIUM

• What is collision theory?

  Particles must collide in the right direction and have the minimum kinetic energy for a reaction to occur
• Why do most collisions not lead to reaction?

  The majority of the particles do not reach the activation energy
• What does the area under the Boltzman distribution show?

  The number of particles
• Why does increased temperature increase the rate of reaction?

  Particles have more kinetic energy so they move around more so more successful collisions
• Why does increased pressure increase the rate of reaction?

  Increased pressure means the particles are closer together so they collide more often with more successful collisions
• Why does increased concentration increase the rate of reaction?

  Increased concentration increases the amount of particles therefore particles are closer together so higher chance of a successful collision
• What is the role of a catalyst?

  Provide an alternative pathway that has a lower activation energy and remains unchanged at the end of the reaction
• What are heterogeneous catalysts?

  Catalysts in a different phase to the reactants
• What are homogeneous catalysts?

  Catalysts that are in the same phase as the reactants
• Why do homogeneous catalysts form an intermediate?

  Because they react with the reactants which then react with each other and the catalyst is reformed at the end of the reaction
• Why are catalytic converters good for the environment?

  They reduce the amount of pollutants produced by cars
• Why does increasing the surface area of a heterogeneous catalyst increase rate of reaction?

  There is more surface for successful collisions to take place on
• Why are catalysts good?

  • speed up reactions
  • make products faster at a lower temperature saving money
  • can change the properties of a product
• What is dynamic equilibrium?

  When the concentration of reactants and products are equal
• What is Le Chatelier's Principle?

  If a reaction at equilibrium is subjected to a change in pressure, temperature or concentration, the position of equilibrium will move to counteract the change
• What affect to catalysts have on equilibrium?

  None, they only help the system reach equilibrium faster
• What happens if temperature of an exothermic reaction is increased?

  The position of equilibrium will shift, favouring the endothermic reaction
• What happens if temperature of an endothermic reaction is increased?

  The position of equilibrium will shift, favouring the exothermic reaction
• What happens to Kc when temperature shifts equilibrium to the right?

  The value of Kc will increase
• What happens to Kc when temperature shifts equilibrium to the left?

  The value of Kc decreases
• What does a Kc value of 1 mean?

  The position of equilibrium is halfway between the products and the reactants
• What does a Kc value greater than 1 mean?

  The position of equilibrium is closer towards the products
• What does a Kc value less than 1 mean?

  The position of equilibrium is closer towards the reactants