The Rate and Extent of Chemical Change - Chemistry Paper 2

• Mean rate of reaction

  Quantity of reactant used / Time taken
• Mean rate of reaction

  Quantity of product formed / Time taken
• Factors which affect rate of reaction

  • Temperature
  • Pressure
  • Concentration
  • Surface area
  • Catalyst
• A catalyst provides an alternate route for the reaction to take, with a lower activation energy
• • Exothermic reactions give out energy to the surroundings
  • Endothermic reactions take in energy from the surroundings
• Reactions are reversible when the products can react to produce the original reactants
• Equilibrium is when the forwards and backwards reactions occur at the same rate in a closed system
• • Increasing the temperature will make the equilibrium shift towards the endothermic direction
  • Decreasing the temperature will make the equilibrium shift to the exothermic direction
• If you increase the pressure, the equilibrium will shift to the side where there are fewer molecules to counteract the change
• If you increase the concentration of the reactants the equilibrium will shift to the products