Rate of Reaction

• What is the rate of a reaction?


  How quickly reactants are used up or products are produced
• What is the equation for calculating the mean rate of reaction?


  mean rate = change in quantity of product or reactant / time taken
• What is the unit for rate of reaction in a reaction involving a change in mass?

  g/s
• What is the unit for rate of reaction in a reaction involving a change in volume?

  cm3/s
• What is the activation energy?


  The minimum amount of energy colliding particles have to have before a reaction will take place
• What effect does increasing concentration have on the rate of reaction?


  It increases the rate of reaction
• Why does increasing concentration have this effect?


  More reactant particles in the same volume lead to more frequent collisions
• What effect does increasing pressure have on the rate of reaction?


  It increases the rate of reaction
• Why does increasing pressure have this effect?


  Less space between particles means more frequent collisions
• What effect does increasing surface area have on the rate of reaction?


  It increases the rate of reaction
• Why does increasing surface area have this effect?


  More reactant particles are exposed and able to collide, leading to more frequent collisions
• What effect does increasing temperature have on the rate of reaction?


  It increases the rate of reaction
• Why does increasing temperature have this effect?


  Particles move faster, leading to more frequent collisions
• What is a catalyst?


  A substance that increases the rate of a reaction but is not used up in the reaction
• How do catalysts increase the rate of a reaction?


  They lower the activation energy of the reaction, so more collisions result in a reaction