rates of reaction

• mean rate of reaction


  amount of prduct or reactant used/time taken
• gradient of tangent 


  change in y (product or reactant used)/change in x (time)
• factors affecting rates of reaction

  • concentration
  • surface area
  • temperature
  • catalyst
  • pressure
• reversible reaction


  shows that the reaction goes both ways

  • product to reactant
  • reactant to product
• equilibrium


  where the forward reaction is going the same rate as the backward reaction
• at equilibrium:


  • both reactants are still happening, but there is no overall effect
  • equilibrium is only reached if reversible reactions take place in a closed system, so no reactants or products can escape
• le chatelier's principle


  if you change the conditions of a reversible reaction at equilibrium, the system will try to counteract the change
• le chatelier's principle - changing concentration

  • if you increase concentration of the reactants, equiibrium will shift to the side where there is less concentration
• le chatelier's principle- changing temperature


  • if temperature is increased, equilibirum will shift to the endothermic side (to decrease the temp.)
  • if temperature s decreased, equilibrium will shift to the exothermic side (to increase the temp.)
• le chatelier's principle
- changing pressure


  • changing the pressure only affects the equilibirum involving gases
  • he pressure depends on the number of molecules in the reactant or product
  • if pressure is increased, equilibrium will shift to the side where there are smaller number of molecules
  • if pressure is decreased, equilibrium will shift to the side where there are more number of molecules